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25 October 2010, Volume 31 Issue 20
Processing Technology
Methods of Removing Heavy Metals for Extracting and Purifying Fucoidans from Brown Seaseeds
LIU Yi-xiang1,LIU Zong-lin2,JI Bao-ping1,WU Yong-pei3,*
2010, 31(20):  1-5.  doi:10.7506/spkx1002-6630-201020001
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In order to remove heavy metals, different concentrations of ethylene diamine tetraacetic acid disodium (EDTA-Na2) and fytic acid were separately added during the extraction of fucoidans from brown seaseeds, and the prepared products were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and hydride generation atomic fluorescence spectroscopy (HGAFS) for the contents of metal elements (such as Mg, Ca, Fe, Mn, Cu, Zn, Ag, Cd, Ba, Pb, As and Hg). Adding 1.0 ×10-2 mol/L EDTA-Na2 could efficiently reduce the contents of Mg, Ca, Mn, Zn, As, Ag, Cd and Pb in the prepared fucoidans, but had no effect on Hg, Fe, Cu and Ba. However, only Ag, Cd and Zn exhibited lower contents due to the addition of 0.10 mol/L fytic acid. The simultaneous binding of As and Hg to fucoidans was conducted in order to evaluate the efficiency of removing heave metal element by acidic treatment followed by ultrafiltration. As a result, no As was detected in the ultrafiltration retenate, while Hg was kept bound with fucoidans after acidic treatment and could not be removed. Thus, adding an appreciate concentration of EDTA-Na2 during extraction and acidic treatment followed by ultrafiltration during purification can obviously reduce the contents of heavy metal elements in the prepared fucoidans. This study provides a good strategy for preparing high-quality fucoidans.

Using Response Surface Methodology to Optimize the Ultrasonic-aided Extraction of Total Triterpenoids from Fruit Bodies of Fomitopsis pinicola (Swartz.: Fr.) Karst.
CHEN Xian-hui,YUAN Bo,JU Xiu-yun,JIANG Ji-hong*
2010, 31(20):  6-10.  doi:10.7506/spkx1002-6630-201020002
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For the optimization of the ultrasonic-aided extraction of total triterpenoids from the fruit bodies of Fomitopsis pinicola (Swartz.: Fr.) Karst., a series of single factor experiments were carried out to explore the effects of temperature, material/liquid ratio, ultrasonic treatment time and ultrasonic power on the yield of total triterpenoids and four-variable, three-level response surface methodology based on the principle of central composite design was employed to analyze the significance and interactions of the above four factors affecting the yield of total triterpenoids by mathematical modeling. The optimal extraction conditions were determined as follows: extraction solvent, 95% ethanol; extraction temperature, 70 ℃; material/liquid ratio, 26:1; ultrasonic treatment time, 39 min; and ultrasonic power, 450 W. The actual yield of otal triterpenoids was 9.79% under such conditions.

Enzymatic Preparation of Oligo-peptides from Whey Protein Concentrate 80
REN Guo-pu,YU Bing
2010, 31(20):  11-14.  doi:10.7506/spkx1002-6630-201020003
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Whey protein concentrate (WPC) 80 was hydrolyzed with an enzyme complex consisting of alacase and papain (1:2 mass ratio) to prepare oligo-peptides in the present study. The hydrolysis conditions for the preparation of oligo-peptides were as follows: substrate concentration, 12 g/100 mL; reaction temperature, 50 ℃; and pH 9.0. The hydrolysate was ultrafiltrated through a sulfonated polysulfone membrane having a molecular weight cut-off (MWCO) of 10 kD under the conditions of normal temperature and 0.25 MPa working pressure difference and debittered by HZ00x resin adsorption. The resultant product had a little bitter taste and a light egg odor. The peptide yield was 36.54% under the above process conditions. The molecular weight distribution of peptides in the final product was mainly dipeptides, tripeptides and tetrapeptides, representing 27.45%, 34.88% and 26.65% of the total peak area, respectively.

Optimizing Holoenzymatic Preparation of Extremely High Maltose Syrup
YE Hong-ling,DU Xian-feng*
2010, 31(20):  15-19.  doi:10.7506/spkx1002-6630-201020004
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Extremely high maltose syrup was enzymatically produced from broken rice. In the production of extremely high maltose syrup, thermal-stable α-amylase, barley-derived β-amylase and pullulanase were used. Orthogonal array design was employed to study the process conditions including amounts of these three enzymes and post-saccharification DE value, and the results showed that the optimal levels of amounts of thermal-stable α-amylase, barley-derivedβ-amylase and pullulanase and post-saccharification DE value were 0.20, 0.50 kg/t and 1.05 kg/t material and around 48%, respectively. Meanwhile, the sugar composition of the prepared product was analyzed by high performance anion-exchange chromatography (HPAC).

Optimization of Conditions for Ultrasonic-assisted Extraction of γ-Glutamyltranspeptidase from Shiitake Mushroom by Response Surface Methodology
LI Jian-rong,YIN Jie,ZHU Jun-li,ZHANG Qing
2010, 31(20):  20-23.  doi:10.7506/spkx1002-6630-201020005
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In order to optimize the ultrasonic-assisted extraction of γ-glutamyltranspeptidase (GGT) from shiitake mushroom, single factor investigations were initially carried out, followed by construction of a three-factor, three-level Box-Benhnken experimental design, quadratic regression fitting for GGT activity as a function of three extraction conditions and response surface analysis. The optimal conditions for the ultrasonic-assisted extraction of GGT were found to be: ultrasonic power, 204.84 W; extraction duration, 28.19 min; and material/water ratio, 1:52.29. Under the above conditions, the experimental value of GGT activity was 11.19 U/g, which was in basic agreement with the model predicted value.

Response Surface Methodology for Optimizing the Ultrasonic-assisted Extraction of Rice Bran Extract with Both High Total Phenolic Content and Total Antioxidant Capacity
ZHU Xiu-ling1,DAI Qing-yuan1,2,CAI Wei-rong1,MA Jing1,GU Rong1
2010, 31(20):  24-30.  doi:10.7506/spkx1002-6630-201020006
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Response surface methodology was employed to optimize the process conditions for the ultrasonic-assisted extraction of rice bran extract with ethanol as the extraction solvent for achieving both high total phenolic content (TPC) and total antioxidant capacity (TAC). The determinations of TPC and TAC were performed using Folin-Ciocalteu method and trolox equivalent antioxidant capacity (TEAC) assay, respectively. The rice bran extract with higher showed higher TPC showed higher TAC. However, there was no absolutely dependent relationship between the two parameters. The optimal conditions for extracting rice bran extract with both high TPC and TAC were determined as follows: ethanol concentration, 90%; extraction temperature 55 ℃; and extraction duration 97 min. Under these conditions, a TPC of (2.76 ± 0.17) mg GAE/g bran (n = 3) and a TAC of (2.99 ± 0.24)μmol TEAC/g bran (n = 3) were observed.

Optimizing the Extraction Processes of Polysaccharides from Fermented Mycelia of Fermentation Supernatant of Fomes officinalis Ames as a Traditional Uyghur Medicine
ZHANG Tao,SUN Jian,HUANG Ling,LOU Kai*
2010, 31(20):  31-36.  doi:10.7506/spkx1002-6630-201020007
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The conditions for extracting intracellular polysaccharides from the fermented mycelia of Fomes officinalis Ames that is a traditional Uyghur medicine in Xinjiang autonomous region and extracting extracellular polysaccharides from the fermentation supernatant of the strain were optimized using single factor and orthogonal array design methods. The optimal conditions for the extraction of intracellular polysaccharides under the assistance of ultrasonic were determined to be: ultrasonic power 90 W; ultrasonic treatment time, 15 min; hot water temperature, 90 ℃; dried mycelia/distilled water ratio, 1:20; and length of extraction time, 3 hours, and an intracellular polysaccharide yield of 66.4 mg/g dried mycelia was obtained under such conditions. The optimal extraction process of extracellular polysaccharides consisted of adjusting the pH of the fermentation supernatant to 7 and adding 60% ethanol for polysaccharide precipitation for 24 hour at 4 ℃, and the resultant polysaccharide yield was 92.1%.

Enzymatic Hydrolysis of Small Yellow Croaker Scraps for Preparing Flavor Precursors
WANG Jing1,HU Meng-xin1,YING Miao-miao2,LI Jian-rong1,*
2010, 31(20):  37-42.  doi:10.7506/spkx1002-6630-201020008
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Small yellow croaker scraps were enzymatically hydrolyzed to obtain flavor precursors. The simultaneous use of alcalase and flavourzyme was found to be the best choice for the production of flavor precursors with higher degree of hydrolysis (DH), and the hydrolysis conditions including material/liquid ratio, hydrolysis duration, enzyme dosage, initial pH and hydrolysis temperature were optimized by single factor method and response surface methodology based on Box-Benhnken experimental design. The optimized values of the four hydrolysis conditions were determined as follows: material/liquid ratio, 1:7; hydrolysis temperature, 55 ℃; initial pH, 8.0; alcalase dosage, 2.5%; and ourzyme dosage, 3.0%. Under these conditions, the DH was 40.11%, and the contents of total amino acids, essential amino acids and four delicious amino acids in the obtained hydrolysate were 86.383, 32.785 g/100 g and 38.384 g/100 g, increasing by 67.56 %, 82.02 % and 79.52% in comparison with those of the start material, respectively. Moreover, the obtained hydrolysate had a strong flavor of small yellow croaker.

Application of Membrane Separation for the Purification of Chlorogenic Acid-rich Extract from Lonicera japonica Thunb.
FAN Yuan-jing1,MA Ling-yun1,XU Xiao-wei1, ZHANG Ping2,FANG Tong-hui2,HU Xiao-wei2
2010, 31(20):  43-46.  doi:10.7506/spkx1002-6630-201020009
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In terms of average membrane permeation flux, membrane retention rate and permeation rate of chlorogenic acid, the applications of three microfiltration membranes (MF1, MF2 and MF3), four ultrafiltration membranes (UF1, UF2, UF3 and UF4) and two reverse osmosis membranes (RO1 and RO2) for the purification of the chlorogenic acid-rich extract from Lonicera japonica Thunb were evaluated. MF1, UF1 and RO2 were found to be even better than other similar membranes. Optimal purification was achieved by the sequential combined use of MF1, UF1 and RO2, and the maximum chlorogenic acid recovery was up to 67.75%, and a product with a purity exceeding 13.21% was obtained. Additionally, diafiltration could improve the treatment effect, and the retention rate of chlorogenic acid was decreased from 9.54% to 1.17% in MF1 separation and from 32.36% to 20.11% in UF2 separation after intermittent diafiltration.

Optimizing the Extraction of Red Pigments from Dry Roselle Calyx by Response Surface Methodology
ZENG Zhe-ling,HAO Chun-qing,LU Wei,PENG Chao
2010, 31(20):  47-51.  doi:10.7506/spkx1002-6630-201020010
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In order to develop an optimal procedure for the extraction of red pigments from dry roselle calyx, single factor method and responses surface methodology (RSM) were applied to study the effects of material/liquid ratio and extraction duration and temperature and their interactions on the total anthocyanin content of the extract. Material/liquid ratio was found to be the most important affecting factor, followed by extraction duration and temperature. The optimal values of the three conditions were determined as follows: material/liquid ratio, 1:24.8; extraction duration, 1.52 h; extraction temperature, 48.74 ℃, and the total anthocyanin content of the extract obtained was 487.6 mg/100 g.

Effect of Proteolytic Pre-treatment on the Extraction of Xanthophylls from Corn Gluten Meal
ZHOU Hai-sheng,JIANG Ling-zhi,HUANG Mei*
2010, 31(20):  52-57.  doi:10.7506/spkx1002-6630-201020011
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After being pre-treated with protease, corn gluten meal received organic solvent extraction to obtain xanthophylls. Neutral protease was selected out of three commercially available proteases to pretreat corn gluten meal due to the highest extraction efficiency of xanthophylls, and methanol was found to be the best solvent for the extraction of xanthophylls among the ten solvents tested. The optimal conditions for neutral protease hydrolysis were determined to be: enzyme load, 14000 U/g substrate, liquid/solid ratio, 20:1; reaction temperature 40 ℃; and reaction duration, 5 h. Compared with direct extraction without proteolytic pre-treatment, the optimized neutral protease hydrolysis resulted in an increase of extraction efficiency of xanthophylls from 165.3 to 340.5 μg/g and a reduction of extraction duration from 5 hour to 20 min.

Development of a Complex Stabilizer for Peanut Protein Beverage
XU Bin,LI Hui-xing
2010, 31(20):  58-60.  doi:10.7506/spkx1002-6630-201020012
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The development of a complex stabilizer for the peanut protein beverage processed in our laboratory is presented. The composition of the stabilizer was optimized by uniform design combined with regression analysis based on sensory evaluation, which was achieved using fuzzy comprehensive evaluation method. The 100 mL of peanut protein beverage added with 0.06 g of xanthan gum, 0.08 g of carrageenin and 0.38 g of SE displayed good stability. SE amount had the largest effect on beverage stability, and the effect of xanthan gum amount was the smallest. The peanut protein beverage with added optimized complex stabilizer was medium preference grade.

Optimization of Enzymatic Polysaccharide Extraction from Acaudina molpadioides Semper by Response Surface Methodology
XU Lu,YE Li-bin,YU Ping,LI Jian-rong*
2010, 31(20):  61-66.  doi:10.7506/spkx1002-6630-201020013
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Papain, pepsin and trypsin were chosen to conduct the single enzyme hydrolysis of Acaudina molpadioides Semper for polysaccharide extraction, and pepsin was the selected enzyme due to the highest polysaccharide yield. The hydrolysis of Acaudina molpadioides Semper with pepsin was optimized by response surface methodology in order to improve polysaccharide yield. The optimal conditions for pepsin hydrolysis were found to be: enzyme load, 0.95%; hydrolysis temperature, 56 ℃; initial pH, 1; and hydrolysis duration, 6 h. An experimental polysaccharide yield of 1.65% was obtained under these conditions, which basically accorded with the model predicted value of 1.59%.

Optimizing Conditions for the Purification of Ginger Essential Oil by Molecular Distillation Using Response Surface Methodology
LIANG Zheng,HU Xue-fang,ZHAO Hang,LI Shu-yan,NI Yuan-ying*
2010, 31(20):  67-71.  doi:10.7506/spkx1002-6630-201020014
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Molecular distillation was used to purify the essential oil from ginger oleoresin extracted with supercritical CO2. Based on single factor investigations, the optimization of distillation temperature and pressure by central composition design coupled with response surface methodology was performed for achieving both higher oil yield and α-zingiberene content. The two factors and the interaction between them all significantly affected oil yield andα-zingiberene content. Distillation temperature of 76 ℃ and distillation pressure of 147 Pa were found optimal, and the resultant oil yield andα-zingiberene content were (42.33 ± 1.65)% and (445.48 ± 6.95) mg/g, respectively.

Purification and Antioxidant Activity of Polyphenols from Apple Tree Leaves
XU Huai-de,WANG Lin-bin,ZHANG Li-jia
2010, 31(20):  72-78.  doi:10.7506/spkx1002-6630-201020015
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The preliminary purification of a polyphenols-rich extract from apple tree leaves prepared in our laboratory was carried out using macroporous resin adsorption, followed by further purification and HPLC analysis. Along with this, the preliminarily purified extract was tested for its ability to scavenge DPPH free radicals and nitrite. X-5 resin was the best resin found for adsorbing and desorbing apple tree leaf polyphenols among eight types of resins tested. The optimum adsorption/ desorption conditions of X-5 resin were determined to be: sample concentration, 3.658 mg/mL; sample pH, 3; sample flow rate, 2.0 mL/min; ethanol concentration for desorption, 40%; desoprtion flow rate, 1.0 mL/min; and desorption solvent volume, 4 BV. After the purification under the above conditions, the purity of polyphenols was increased from 10.07% to 38.55%. The adsorption of X-5 resin towards apple tree leaf polyphenols was an exothermic course and accorded with the Langmuir isothermal model and the Freundlich isothermal model. The purified extract presented stronger DPPH free radical and nitrite scavenging capacities than the native extract. The HPLC analysis showed that the content of phlorizin was 2.45% in apple tree leaves and 47.61% in the further purified extract, which accounted for 91.51% of the total polyphenols.

Microwave-assisted Extraction of Polyphenols from Coffee Bean Residue
SHEN Wang-yang1,JIN Zheng-yu2
2010, 31(20):  79-82.  doi:10.7506/spkx1002-6630-201020016
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In order to improve the utilization rate of coffee bean residue, polyphenols were extracted from coffee bean residue by organic solvent extraction with the aid of microwave. The optimal extraction conditions were explored by response surface methodology and the content of polyphenols was determined by Folin-Ciocalteus colorimetric method. The optimal parameters for the extraction of polyphenols were as follows: extraction solvent, 50% (V/V) acetone; microwave power, 296 W; material/liquid ratio, 1:20; and extraction duration, 17 s. The extraction rate of polyphenols was 5.12% under these optimal extraction conditions, 1.6-fold higher than that obtained without the aid of microwave.

Optimization of Technological Parameters for Pectinase Hydrolysis for Improved Pepino Juice Yield Using Response Surface Analysis
SU Feng-xian1,2,WANG Xiao-qin1,2,GOU Ya-feng1,FAN Zi-hao1,DU Shuang-hu1,ZHANG Fen-qin1,2,*
2010, 31(20):  83-88.  doi:10.7506/spkx1002-6630-201020017
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The optimization of four technological parameters for the pectinase hydrolysis was carried out using response surface and grey correlation analyses in order to improve juice yield. A regression model with juice yield (Y) as a function of initial pH (x1), hydrolysis temperature (x2), hydrolysis time (x3) and enzyme load (x4) was set up as follows: Y = 89.78333+0.86250x3+0.67917x4 + 0.80937x32 - 0.83125x1x2. The analysis of variance for the model showed that hydrolysis time and enzyme load significantly affected juice yield (P<0.05) and that the others had no significant effect on juice yield (P>0.05). The multiple regression analysis indicated that the established model had an excellent goodness of fit, suggesting good reliability in predicting the function.

Optimization of the Preparation Process for Starch Phosphate Monoesters
ZHAO Wei,LI Zhen-hua,FENG Fang
2010, 31(20):  89-92.  doi:10.7506/spkx1002-6630-201020018
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The semi-dry preparation of starch phosphate monoesters from corn starch was optimized using orthogonal array design. The optimal reaction system was found to consist of 9% sodium polyphosphate and 2% urea at pH 5.0 and the reaction was allowed to proceed for 2 h at 150 ℃, and the degree of substitute was up to 0.0516 under these conditions. The established process was stable and repeatable. A higher degree of substitute was obtained at a higher reaction temperature of 180 ℃, but the color of the obtained product needed to be improved. Starch containing 15% moisture was beneficial for the reaction, producing better product color.

Lipase-catalyzed Synthesis of Gallic Acid Lutein Ester
YANG Yun-shang,XU Jian-guo,ZHANG Ying-peng*,LI Chun-lei
2010, 31(20):  93-96.  doi:10.7506/spkx1002-6630-201020019
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Lutein and gallic acid were used as the raw materials to synthesize gallic acid lutein ester through the catalysis of Lipozyme Novo 435. The structure of the synthesized product was determined by IR. The effects of enzyme load, solvent, and water content, reaction temperature and reaction time on the esterification were investigated. The optimal reaction conditions were determined as follows: enzyme load, 10 mg/mL; water content, 60 mg/g; reaction medium, chloroform; reaction temperature, 40 ℃; and reaction time, 30 h. The conversion rate of gallic acid was up to 81.8% under these conditions.

Optimization of Germination Conditions for Soybean
YANG Ming-duo1,2,3,CHEN Jian2,ZHANG Xiao-yu1,3,ZHANG Wei3
2010, 31(20 ):  97-101.  doi:10.7506/spkx1002-6630-201020020
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In this work, the effects of temperature, pH, soaking time and cultivation time on the change of vitamin C content during the germination of soybean were explored through single-factor and orthogonal array experiments on the basis of vitamin C content, sensory evaluation and water content. The optimal germination conditions for soybean were optimized to be germination for 3 d at 25 ℃ following soaking for 8 h in water with a pH adjusted to 6.0.

Extraction, Antioxidant Activity and Antibacterial Effect of Total Flavonoids from Rose Flowers
ZHOU Xiao-qi1,2,FANG Min1,GONG Zhi-yong1,*
2010, 31(20):  102-105.  doi:10.7506/spkx1002-6630-201020021
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On the basis of single factor and orthogonal array experiments, the optimal process for the extraction of total flavonoids from rose was explored. The optimal extraction conditions were found to be: extraction solvent, 75% ethanol; extraction temperature, 80 ℃; extraction duration, 3 h; and material/solvent ratio of 1:25. The scavenging capacity of ethanol extract from rose on DPPH free radicals was up to 90.23%. Meanwhile, strong antibacterial effect of ethanol extract from rose against Staphylococcus aureus and Bacillus subtilis were also observed through Oxford Cup experiments.

Optimizing the Ethanol Reflux Extraction of Arecoline from Betel Nut Husk
LUO Shi-shu,ZHANG Hai-de*,ZHU Li,LIU Xiao-ling
2010, 31(20):  106-110.  doi:10.7506/spkx1002-6630-201020022
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The extraction of arecoline from betel nut husk was performed using ethanol refluxing. Arecoline content in the extract was determined by HPLC as the evaluation indicator. The optimal extraction conditions were determined as follows: ethanol concentration, 85%; material/liquid ratio, 1:14 (g/mL); extraction temperature, 85 ℃; and pH 8. The extraction rate of arecoline was (0.251 ± 0.03)% under these conditions.

Optimization of the Preparation of CMC Active Calcium from Degreased Ictalurus punctatus Bone
SHAO Ming-shuan,TAO Min,XIANG Wei,MENG Chang-wei,LIN Lin,
2010, 31(20):  111-115.  doi:10.7506/spkx1002-6630-201020023
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The degreasing of Ictalurus punctatus bone and the preparation of CMC active calcium from degreased fish bone through thermal soaking in a mixed acid made up of citric acid and malic acid were studied in this work. The effects of soaking temperature and time, mixing ratio for malic acid and citric acid, total acid amount and fish bone granular size on calcium yield were examined. The optimal procedure for degreasing Ictalurus punctatus bone was soaking in 5% aqueous NaOH solution for 6 h, and the total calcium content after the degreasing was 30.38%. The optimal conditions for the preparation of CMC active calcium were determined to be: mixing ratio for malic acid and citric acid, 1:2; total acid amount, 15 g/100 mL; material granular size, 120 mesh; soaking temperature, 100 ℃; and soaking duration, 60 min. A calcium yield of 87.13% was obtained under such conditions.

Ultrasonic-assisted Extraction of Lac Dye
ZHANG Hong1,2,FANG Gui-gan1,ZHENG Hua2
2010, 31(20):  116-120.  doi:10.7506/spkx1002-6630-201020024
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In order to effectively extract lac dye under the assistance of ultrasonic, single factor and orthogonal array design methods were used to optimize process parameters including ultrasonic power, extraction time, pulse time and material/liquid ratio. The optimal extraction conditions were determined as follows: material/liquid ratio, 1:6; ultrasonic power, 1200 W; extraction duration, 18 min; frequency, 20 kHz; pulse-on time, 9 s, pulse-off time, 12 s; and extraction number, 3. The extraction efficiency was up to 85.15% and the yield of lac dye was 0.55% under the optimal extraction conditions.

Optimization of the Preparation Process for Silkworm Chrysalis-derived Highly Deacetylated Chitosan
ZHAO Wei,LI Jian-ke*
2010, 31(20):  121-126.  doi:10.7506/spkx1002-6630-201020025
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The chitin obtained as light yellow powder from the residue of silkworm chrysalis left after oil and protein extraction was utilized as the start material to prepare highly deacetylated chitosan in the present study. On the basis of single-factor investigations, quadratic orthogonal rotation combination design was employed to investigate the effects of soaking time in absolute ethanol, NaOH concentration, thermal treatment temperature and duration and material/liquid ratio on deacetylation degree of chitosan. An orthogonal regression model for deacetylation degree of chitosan against the above five factors was constructed. Using frequency analysis method, the optimal conditions for the preparation of highly deacetylated chitosan were determined as follows: soaking time in absolute ethanol, 1.7 h; NaOH concentration, 44%; thermal treatment temperature, 94 ℃; treatment time, 9 h; material/liquid ratio (g/mL), 1:28; and replacement frequency of NaOH, once every two hours. Under these conditions, a product with 95.96% deacetylation degree, 7.45×105 relative molecular mass, 56.98% yield, 3.20% moisture content, 0.35% ash content was obtained as natural white chitosan and each of its major quality indexes met the relevant industrial standards.

Isolation and Preparation of Teasaponin Monomers from Tea Seed Cake by High-Speed Counter-current Chromatography
CHEN Li,DENG Ze-yuan,HU Jiang-ning*,LI Jing,FAN Ya-wei,LIU Rong
2010, 31(20):  127-131.  doi:10.7506/spkx1002-6630-201020026
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Objective: To develop a rapid and efficient method for preparing teasaponin monomers from tea seed cake using preparative high-speed counter-current chromatography (HSCCC). Methods: A crude extract rich in teasaponin monomers was obtained from tea seed cake by microwave-assisted extraction, and preliminarily purified by D-101 macroporous resin chromatography, followed by further HSCCC purification/fractionation with a binary phase system made up of ethyl acetate, n-butanol and 3% acetate (1:4:4, V/V) at a flow rate of 1.5 mL/min with rotation at 800 r/min under the conditions of 267 nm detection wavelength and 100 mg sample load. The final purification product was analyzed by HPLC. Results: Two teasaponin monomers with 99.1% and 94.5% purities were obtained after the HSCCC separation, and their dry weights were 11 mg and 15 mg, respectively. Conclusion: The proposed HSCCC method has the characteristics of simplicity, rapidity and high product purity, thereby providing a novel strategy for the separation of teasaponin monomers.

Optimization of Supercritical Fluid Carbon Dioxide Extraction of Oil from Caculis of Schisandra chinensis (Turcz.) Baill by Response Surface Methodology
LI Bin, MENG Xian-jun*,LI Yuan-su,WANG Yan-qun,FU Jun-fan,XUE Xue,WANG Dong
2010, 31(20):  132-136.  doi:10.7506/spkx1002-6630-201020027
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Based on the single factor experimental results, response surface methodology (RSM) was employed to optimize the process conditions for extracting essential oil form the caculis of Schisandra chinensis (Turcz.) Baill with supercritical fluid carbon dioxide (SF-CO2). A three-factor, five-level central composite design (CCD) was used to provide experimental data for establishing a regression model describing the SF-CO2 extraction. Extraction pressure, extraction temperature, CO2 flow rate and cross-interaction between extraction pressure or temperature and CO2 flow rate exhibited a significant effect on oil extraction yield. The optimal extraction conditions were found to be: extraction pressure, 36.32 MPa; extraction temperature, 42.27 ℃; and CO2 flow rate,17.01 L/h. The extraction yield of oil was 0.432% under these optimal extraction conditions, which was in good agreement with the value predicted by the regression model. This method is characterized by low energy consumption and pollution as well as high efficiency.

Preparation and Sustained-release Performance of Chitosan-Sodium Alginate Sodium-Sodium Ferrous Chlorophyllin Microcapsules
MENG Qing-ting,CHEN Wan-dong
2010, 31(20):  137-140.  doi:10.7506/spkx1002-6630-201020028
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Sodium ferrous chlorophyllin was microencapsulated into chitosan-sodium alginate micropheres for the purpose of sustained release. The microencapsulation process for sodium ferrous chlorophyllin was optimized using orthogonal array design for achieving both higher entrapment efficiency and drug loading. Meanwhile, the sustained release of the prepared microcapsules in mimic gastric and intestinal environments was observed. The optimal microcapsule formula was found to be composed of 15 mg/mL sodium alginate, 4 mg/mL chitosan and 20 mg/L CaCl2 with a core material/wall material ratio of 1:4. The microcapsules obtained using this formula displayed good sustained-release performance in both mimic environments.

Preparation and Antioxidant Activity Evaluation of Amino Acid Chelated Calcium from Tilapia Scraps
HU Zhen-zhu1,2,YANG Xian-qing1,*,MA Hai-xia1,LI Lai-hao1,WU Yan-yan1,SHI Hong1
2010, 31(20):  141-145.  doi:10.7506/spkx1002-6630-201020029
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Through double-enzyme hydrolysis, tilapia scraps were separated into two fractions, namely a compound amino acid solution and an insoluble residue left after the hydrolysis. The residue was processed into power and further hydrolyzed acidically to offer a calcium-containing solution for the reaction with the above prepared compound amino acid solution, producing amino acid chelated calcium. The optimal chelation reaction conditions for achieving maximum chelation rate were investigated, and the reaction product was tested for its for its antioxidant activity by reducing power and free radical scavenging assays. pH of 7.0, reaction time of 90 min, reaction temperature of 60 ℃ and amino nitrogen content of 1.6 g/L were found optimal, and the resultant chelation rate was 57.22 %. The antioxidant evaluation indicated that the condensed amino acid chelated calcium solution obtained had reducing power in a positive volume-dependent fashion in a proper range. The maximum scavenging rates against hydroxyl and superoxide anion free radicals were 6.60% and 51.67%, respectively.

Optimization of Extrusion Technology of Rice Bran by Response Surface Methodology and Measurement of Its Physical Properties
ZHANG Yan-rong,FENG Yan,SUN Li-qin,WANG Da-wei*
2010, 31(20):  146-151.  doi:10.7506/spkx1002-6630-201020030
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In order to optimize the extrusion technology of rice bran, the effects of rice bran granule size, water content and extrusion temperature on the yield of soluble dietary fiber from rice bran were explored by response surface methodology on the basis of single factor experiments. The optimal extrusion conditions were determined to be: rice bran granular size, 0.175 mm; water content, 33%; and extrusion temperature 164 ℃. The yield of soluble dietary fiber from rice bran was 19.23% under these extrusion conditions, which was close to the theoretical value. The importance of the above three process conditions affecting the extraction rate of soluble dietary fiber from strong to weak was in an order of water content, extrusion temperature and rice bran size. The extruded rice bran exhibited a significant improvement in expansion power, water-holding capacity, water-binding capability and oil-absorbing capacity. Comprehensive material property value of extruded rice bran exhibited a 2.12-fold improvement. Therefore, the extrusion technology can greatly improve the content of soluble dietary fiber in rice bran and comprehensive material properties, which will provide theoretical references for the utilization of rice bran in food industry.

Application of Ultrasonic Technology to the Enzymatic Hydrolysis of Paphia undulata Muscle
CHEN Chun-xin1,SUN Hui-li2,WU Jia-hui1,CHEN Xin1,CHEN Zhi-gang3,CHEN Xiao-gang1
2010, 31(20):  152-158.  doi:10.7506/spkx1002-6630-201020031
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The present study was aimed at optimizing the ultrasonic-assisted enzymatic hydrolysis of Paphia undulata muscle for producing short-chain peptides using response surface analysis based on a series of single-factor investigations. By means of the principles of Box-Benheken central composite experimental design, a four-variable, five-level response surface analysis was designed to discuss the effects of ultrasonic treatment time and power, hydrolysis temperature and solid/liquid ratio on shortchain peptide production. The optimal levels of these four process conditions were determined as follows: ultrasonic treatment time, 4 h; hydrolysis temperature, 55 ℃; ultrasonic power, 140 W; and solid/liquid ratio, 1:2 (g/mL). The experimental value of peptide yield was 5.15%, 1.1-fold higher than that obtained without ultrasonic assistance.

Optimization of Formulation of a Non-phosphate Water-holding Agent for Penaeus vannmei by Response Surface Methodology
ZOU Ming-hui1,2,LI Lai-hao1,*,HAO Shu-xian1,YANG Xian-qing1,SHI Hong1,WEI Ya1,CEN Jian-wei1
2010, 31(20):  159-165.  doi:10.7506/spkx1002-6630-201020032
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In this work, we developed a compound non-phosphate solution consisting of sodium chloride, trehalose and sodium alginate lysate for improving the water-holding capacity of Penaeus vannmei. The formulation of the compound solution was optimized via response surface methodology (RSM). On the basis of single-factor investigations, Box-Benhnken central composite experiments were made to offer data for the establishment of quadratic regression models for post-cooking sensory evaluation (Y1) and thawing loss rate (Y2) as a function of final concentrations of the above three solutes in mixed solution, and the optimal values of the three variables were determined through response surface analysis. The sensory quality of Penaeus vannmei was found to be negatively related to its thawing loss rate. The optimal compound non-phosphate solution contained 2.5 g/L sodium chloride, 5.0 g/L trehalose and 10.0 g/L sodium alginate lysate, and a sensory score of 8.2 and a thawing loss rate of 2.29% were obtained when the solution was used to treat Penaeus vannmei.

Effect of Food Additive on Sensory Quality of Microwave-cooked Instant Frozen Stuffed Dumplings
CHANG Jun-xiao,XIE Xin-hua,PAN Zhi-li,LI Zhen,CHEN Jun,AI Zhi-lu*
2010, 31(20):  166-169.  doi:10.7506/spkx1002-6630-201020033
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In order to improve the quality of microwave-cooked instant frozen stuffed dumplings, the effects of food additives and their addition amounts on sensory quality of microwave-cooked instant frozen stuffed dumplings was explored. The optimal addition parameters for food additives in microwave-cooked instant frozen stuffed dumpling was investigated by central composite rotation design to be 0.05% monoglyceride, 0.2% compound phosphate, 0.5% sodium carboxymethyl cellulose (CMC) and 0.1% xanthan gum. The instant frozen stuffed dumplings prepared under these optimal conditions were characteristics of plumpness, delicious taste and moderate viscoelasticity. The sensory evaluation score of microwave-cooked instant frozen dumplings was 82, which was consistent with the predicted value.

Effects of Water Content and Temperature on Browning of Ginseng Products Prepared by Twin-screw Extrusion
LI Fan-zhu1,JIN Tie1,ZHANG Xian1,RYU Gi-hyung2,*
2010, 31(20):  170-172.  doi:10.7506/spkx1002-6630-201020034
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In order to develop a new method for preparing red ginseng products, the effects of water content in raw materials and barrel temperature on browning of ginseng products prepared by twin-screw extrusion were investigated. The results indicated that the L value of extrusion powder decreased with increasing barrel temperature (100, 120 ℃ and 140 ℃). At the same barrel temperatures, the L value of extrusion power increased, but the a value decreased with increasing water content in raw materials. The b value reached its maximum at 120 ℃. Ginseng with higher browning during extrusion displayed higher reducing sugar content but lower starch content. Under the same extrusion conditions, lower water content resulted in an increase in amino nitrogen consumption. Extruded finseng products were better than traditional red ginseng form the viewpoint of color.

Optimization of Acid Hydrolysis of Agar by Response Surface Methodology
YANG Xian-qing1,LIU Gang1,2,QI Bo1,LI Lai-hao1,HAO Shu-xian1,DIAO Shi-qiang1
2010, 31(20):  173-177.  doi:10.7506/spkx1002-6630-201020035
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Agar was subjected to acid hydrolysis and the content of agar oligosaccharides was determined by hydrochloric acid and phenol-sulfuric acid method. On the basis of single factor experiments, the hydrolysis procedure was optimized using response surface methodology, and a mathematical regression model (Y= 81.5933+0.7175X1+1.8938X2+2.7313X3-3.1567X12-3.3042X22-3.3092X32-0.6625X1X2+0.0475X1X3-0.8000X2X3) was established for predicting the yield of agar oligosaccharides (Y) at different levels of hydrochloric acid concentration (X1), hydrolysis time (X2), and solid/liquid ratio (X3). The optimal hydrolysis conditions were determined to be hydrochloric acid concentration of 0.105 mol/L, solid/liquid ratio of 4.5:100 (g/mL) and hydrolysis time of 96 min. The yield of agar oligosaccharides was up to 81.43% under the optimal hydrolysis conditions, which was in good agreement with the predicted value.

Preparation and Stability of Folic Acid Liposomes
TONG Gui-hong,LIU Cheng-mei*,LIU Wei,YANG Shui-bing,LIU Wei-lin,YIN Ting-ting,ZHENG Hui-juan
2010, 31(20):  178-182.  doi:10.7506/spkx1002-6630-201020036
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The combination of thin film hydration and ultrasonic treatment was used to prepare folic acid liposomes with lecithin and cholesterol as the membrane material and folic acid as the core material. Dialysis-spectrophotometry method was applied to determine the encapsulation efficiency of folic acid liposomes. Based on a series of single-factor experiments, the optimal conditions for preparing folic acid liposomes were explored by orthogonal array design to be preparation temperature of 60 ℃, pH 8.0, the mass ratio between lecithin and cholesterol of 5:1, and folic acid concentration of 1.4 mg/mL. The prepared liposomes under these optimal conditions had an entrapment efficiency of 30.36% with an average particle size of 335.4 nm. The liposomal suspension was sealed in a bottle and stored at 4 ℃ for 15 days for stability evaluation based on measurement of average particle size, and the results indicated that the average particle size had no significant change, which was in the range of 300 to 400 nm, and that the suspension had a good stability.

Membrane Separation Technique for Purifying Proanthocyanidins from Peanut Skin
LIU Zhi-qiang1,2,ZHANG Chu-shu1,SUN Jie1,YU Li-na1,ZHANG Yan2,WANG Shi-qing2,YANG Qing-li1,*
2010, 31(20):  183-186.  doi:10.7506/spkx1002-6630-201020037
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The proanthocyanidin-rich extract from peanut skin was purified and condensed by membrane separation technique. The purification effects of membrane modules with different pore sizes (NF-500, HPS-1, PS-5 and PS-10) on the extract were assessed. Collectively considering product yield and purity, the optimal purification conditions were using HPS-1 module at a trans-membrane pressure of 0.54 MPa and an operating temperature of 25 ℃. Under such purification conditions, the yield and purity of purified proanthocyanidin were up to 13.3% and 85.8%, respectively.

Optimization of Supercritical Carbon Dioxide Extraction of Volatile Components from Sauced Duck Using Response Surface Methodology
WANG Qiang1,DENG Ze-yuan1,*,FAN Ya-wei1,HU Jiang-ning1,LIU Rong1,LI Jing1,
2010, 31(20):  187-191.  doi:10.7506/spkx1002-6630-201020038
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Response surface methodology (RSM) was employed to optimize the supercritical CO2 extraction conditions for volatile components from sauced duck. The effects of extraction pressure, temperature and duration on the ratio between volatile components and total extract were investigated. Results indicated that the ratio between volatile components and total extract was decreased with the increase of extraction temperature and pressure, while the ratio exhibited an initial increase and a final decrease with the increase of extraction time. The optimal extraction pressure, extraction temperature and extraction time were determined to be 11 MPa, 41 ℃ and 60 min, respectively. The ratio between volatile components and total extract was up to 83.45% under these optimal extraction conditions. A total of 60 volatile compounds were identified in extract by GC-MS. Most of these volatile compounds were lipid oxidation and Maillard-reaction products, such as aldehydes, ketones, aliphatic hydrocarbons, aromatic hydrocarbons, esters and heterocyclic compounds.

Separation and Purification of Monascus Pigments by High-speed Counter-current Chromatography
ZHENG Yun-quan1,LI Yong-ning1,WANG A-wan2,CHEN Fen-ling2,SHI Xian-ai2,GUO Yang-hao1,2,*
2010, 31(20):  192-195.  doi:10.7506/spkx1002-6630-201020039
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Six azaphilone-type pigments were separated from Monascus-fermented solid medium and purified/fractionated by by high-speed counter-current chromatography (HSCCC). A solvent system with weak polarity involving four components nhexane, ethyl acetate, methanol and water was selected and used for HSCCC. Based on a comparative analysis of partition coefficients of target compounds in different solvent systems, a two-step HSCCC routine was developed. After separation by HSCCC and crystallization with acetone, six azaphilone-type pigments with high purity were obtained. The purity of each pigment was above 98.5% and their yields were between 81.40% and 84.78%. Their molar absorption coefficients were 13313, 13877, 9380, 9360, 25621 L/(mol·cm) and 25849 L/(mol·cm), separately.

Optimization of the Extraction of Peanut Protein Isolate
JIAO Li-yuan1,2,LU Jing-jun3,LU Feng-sheng4,YU Li-na2,YANG Qing-li2,*,SUN Jie2,BI Jie2,ZHANG Chu-shu2
2010, 31(20):  196-201.  doi:10.7506/spkx1002-6630-201020040
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Alkali extraction followed by acid precipitation was used to extract peanut protein isolate from defatted peanut powder. The extraction procedure was optimized by response surface methodology (RMS) on the basis of single factor experiments. Extraction time and pH exhibited a significant nonlinear effect on the purity of peanut protein isolate. The optimal extraction conditions were determined to be: extraction time, 131 min; extraction temperature, 50 ℃; alkali extraction pH, 10; and material/liquid ratio, 1:12. The purity and yield of peanut protein isolate were 95.05% and 71%, respectively, under the optimized extraction conditions.

Preparation and Antioxidant Activity Evaluation of Flammulina velutipes Polysaccharide/Fe(Ⅱ) Chelate
MA Li-hua,QIN Wei-dong,CHEN Xue-hong,YI Jian-wen
2010, 31(20):  202-207.  doi:10.7506/spkx1002-6630-201020041
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In this study, the optimal conditions for the chelating reaction between Flammulina velutipes polysaccharide and Fe(Ⅱ) for achieving maximum chelating degree were investigated using single-factor method and response surface analysis, and evaluation of antioxidant activity of the obtained Flammulina velutipes polysaccharide/Fe(Ⅱ) chelate was performed. A maximum chelating degree of 86.21% was achieved when the reaction between Fe(Ⅱ) with an initial concentration of 6 mg/mL and Flammulina velutipes polysaccharide (3.54:1, mg/mg) was allowed to proceed for 6 h. Moreover, the antioxidant activity evaluation indicated that the abilities of Flammulina velutipes polysaccharide to scavenge hydroxyl and DPPH free radicals and the inhibitory effect against lecithin peroxidation were all improved after the chelation with Fe(Ⅱ).

Optimization of Compound Protease Hydrolysis for Chicken Protein through Response Surface Methodology
LIU Gai-ying1,PAN Dao-dong1,2,*,GUO Yu-xing1
2010, 31(20):  208-214.  doi:10.7506/spkx1002-6630-201020042
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In order to obtain better precursor of meat flavors, chicken protein was hydrolyzed by compound proteases to produce active peptides. The effect of hydrolysis temperature, pH, liquid-solid ratio and hydrolysis time on hydrolysis degree was explored to optimize the hydrolysis conditions of chicken protein through Box-Benhnken response surface analysis on the basis of single-factor experiments.The optimal hydrolysis temperature, pH, liquid/solid ratio and hydrolysis time were found to be 51.13 ℃, 6.99, 2.85:1 and 5.22 h, respectively. Under these optimal hydrolysis conditions, the predicted hydrolysis degree was 35.22%, which was consistent with the average of three replicates of (35.09 ± 0.51)% obtained in the validation experiments.

Optimization of the Supercritical Fluid Degreasing of Rice Bran by Response Surface Methodology
WANG Da-wei,ZHOU Qing-tao,FENG Yan,DU Cai-xia
2010, 31(20):  215-219.  doi:10.7506/spkx1002-6630-201020043
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Supercritical carbon dioxide extraction was applied to degrease rice bran in the present study. The process conditions for the degreasing of rice bran was optimized by response surface methodology. The effects of extraction temperature, extraction time and extraction pressure on lipid removal rate were explored with Box-Benhnken experimental design coupled with response surface analysis on the basis of single factor experiments. The optimal extraction parameters were determined as follows: extraction temperature, 46 ℃; extraction time, 94 min; and extraction pressure, 27 MPa. A lipid removal rate of 18.34% (g/100g rice bran, or 92.19% degreasing efficiency) under these optimal extraction conditions, which was close to the theoretical value. Therefore, the developed mathematical model was reliable in predicting lipid removal rate. The analysis of variance exhibited that the importance of the above three factors affecting lipid removal rate from strong to the weak were extraction pressure, extraction temperature and extraction time.

Optimization of Stepwise Dual-enzymatic Preparation of Peanut Polypeptides
YU Li-na,GONG Qing-xuan,YANG Qing-li*,SUN Jie,BI Jie,ZHANG Chu-shu,YU Yang
2010, 31(20):  220-225.  doi:10.7506/spkx1002-6630-201020044
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In order to exploit and utilize peanut protein resource and obtain high value-added protein products, defatted peanut protein powder was subjected to stepwise hydrolysis initially with alcalase followed by flavourzyme. The conditions for flavourzyme hydrolysis was optimized by response surface methodology in the present study. The effects of enzyme amount, substrate concentration, hydrolysis temperature, hydrolysis time and pH on soluble nitrogen content in peanut protein hydrolysate were explored by single-factor method, and a mathematical regression model describing soluble nitrogen content in peanut protein hydrolysate at different levels of four other factors except pH was established. The optimal process parameters for flavourzyme hydrolysis were found to be: pH, 7.0; enzyme amount, 1714 U/g substrate; hydrolysis temperature, 55 ℃; and hydrolysis duration, 90 min. Te soluble nitrogen content in the peanut protein hydrolysate obtained under the above conditions was 9.44 mg/mL.

Papain Hydrolysis for the Extraction of Polysaccharides from Apostichopus japonicus Alimental
CHEN Tao1,2,ZHANG Jian2,WANG Mao-jian2,*
2010, 31(20):  226-229.  doi:10.7506/spkx1002-6630-201020045
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The enzymatic hydrolysis of Apostichopus japonicus alimental tract with papain was carried out for polysaccharide extraction, and the obtained polysaccharides were preliminarily characterized. Three hydrolysis parameters including hydrolysis time and temperature as well as enzyme amount were optimized. The relative molecular mass and sulfate group content of the purified product of the crude extract obtained after deproteinization by Sevag method and subsequent Sephacryl S-400 gel filtration chromatography were measured. Enzyme amount of 10400 U/g, hydrolysis temperature of 55 ℃and hydrolysis time of 6 h were found optimal, and the polysaccharide yield was 8.1‰ under these hydrolysis conditions. After Sephacryl S-400 column purification, an acidic polysaccharide with single composition was obtained, and its relative molecular mass might be 25 kD and its sulfate group content was approximately 9.29%.

Preparation and Stability of Vitamin C Liposomes
YANG Shui-bing,LIU Cheng-mei*,LIU Wei,LIU Wei-lin,TONG Gui-hong,ZHANG Yu,ZHENG Hui-juan
2010, 31(20):  230-234.  doi:10.7506/spkx1002-6630-201020046
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Lecithin and cholesterol were used the membrane-forming materials to prepare vitamin C liposomes by thin film hydration-ultrasonic method. Based on single-factor experiments, the optimal preparation conditions for vitamin C liposomes were determined by orthogonal array design to be preparation temperature, 65 ℃; lecithin/cholesterolthe mass ratio, 5:1; total lipid/vitamin C mass ratio, 25:1; and total lipid/ surfactant mass ratio 10: 2. An encapsulation efficiency of vitamin C liposomes as high as 42.1% was achieved under these optimal preparation conditions, and the average particle size of the prepared vitamin C liposomes was 373.9 nm. The stability of vitamin C liposomes was investigated by evaluating the change of its average particle size during storage at 4 ℃ for 15 days. The average particle size of vitamin C liposomes had no significant change, suggesting excellent stability.

Compound Flavourzyme Hyrolysis for Flavor Improvement of Goose Liver Sauce
XIE Zhang-bin1,LUO Ting1,FAN Ya-wei 1,*,DENG Ze-yuan1,LIU Rong1,LI Jing1,HU Jiang-ning1,DU Jin-ping2
2010, 31(20):  235-239.  doi:10.7506/spkx1002-6630-201020047
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A commercially available compound flavourzyme was used to hydrolyze goose liver sauce in order to improve its flavor. Four key hydrolysis parameters including initial pH, hydrolysis temperature, hydrolysis time and enzyme/substrate ratio were optimized by single-factor method and response surface methodology for achieving maximum degree of hydrolysis, and the results showed that the optimal levels of these parameters were as follows: initial pH, 6.42; hydrolysis temperature, 57.60 ℃, hydrolysis time, 3.59 h; and enzyme/substrate ratio, 3.42:100 (3-fold volume of water added to goose liver sauce). This study reveals that compound flavourzyme hydrolysis can substantially liver odor and improve the flavor of goose liver sauce.

Extraction and Antioxidant Activity of Polyphenols from Cashew Apple Pomace
TANG Yan-ping,ZHANG Wei-min,CHEN Wen-xue,LI Cong-fa,MIAO Zi-jian,LIU Si-xin*
2010, 31(20):  240-245.  doi:10.7506/spkx1002-6630-201020048
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In order to improve the added value of cashew apple processing, the extraction process of polyphenols from cashew apple pomace was optimized by response surface methodology. Along with this, the antioxidant activity of the extract was evaluated by DPPH and ABTS free radical scavenging assays. The optimal extraction parameters were determined as follows: extraction solvent, 40% ethanol; liquid/material ratio, 35:1; reflux temperature, 95 ℃; and extraction time, 150 min. The extraction rate of polyphenols from cashew apple residue was 1.54% under these optimal extraction conditions. The ethanol extract of cashew apple pomace exhibited strong antioxidant activity. However, red cashew apple pomace exhibited stronger DPPH free radical scavenging capacity than yellow cashew apple pomace. In reverse, yellow cashew apple pomace exhibited stronger ABTS free radical scavenging capacity than red cashew apple pomace. The EC50 values of red cashew apple pomace for DPPH free radicals and of yellow cashew apple pomace for ABTS free radicals were 1.35 mg/mL and 0.057 mg/mL, respectively.

Enzymatic Preparation of Polypeptides from Potato Protein
CAO Yan-ping1,YANG Xiu-li2,XUE Cheng-hu1,DAI Hong-zhe1,JIA Huai-liang1
2010, 31(20):  246-250.  doi:10.7506/spkx1002-6630-201020049
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In this work, potato protein was used as the raw material to prepare polypeptides by enzymatic hydrolysis. The effects of four process conditions on the degree of hydrolysis of potato protein were explored. Neutral protease was the best choice for the hydrolysis of potato protein. Hydrolysis duration was found to be the most critical process condition, followed by hydrolysis temperature, enzyme dose and substrate concentration. The optimal values of the four process conditions were determined as follows: substrate concentration, 8%; hydrolysis temperature, 45 ℃; enzyme dose, 5.0 mg; and hydrolysis duration, 3 h. The degree of hydrolysis of potato protein was as high as 23.4% under such hydrolysis conditions.

Ultrasonic-aided Extraction and Stability Assessment of Blueberry Pigments
YANG Xue-fei,PAN Li-hua,LUO Jian-ping*
2010, 31(20):  251-255.  doi:10.7506/spkx1002-6630-201020050
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The ultrasonic-aided extraction of blueberry pigments was optimized by single-factor and central composite design methods. Besides, the stability of blueberry pigments under different environmental conditions was also measured. The optimal conditions for the extraction of blueberry pigments were found to be: extraction solvent, 45% alcohol; ultrasonic power, 450 W; material/liquid ratio, 1:13, extraction temperature, 55 ℃, extraction duration, 50 min; and pH 4.5. The extraction rate of blueberry pigments was 3.26% under these optimal conditions. Blueberry pigments were thermostable. The stability of blueberry pigments was good in the respective presence of K+, Na+ and Mg2+ and potassium sorbate, while Zn2+, Fe2+, Fe3+, Ca2+ and alkaline condition could damage their stability.

Characterization and Microencapsulation of Alcohol Extract from Propolis Residue Left after SFE-CO2 Extraction
JI Ting,LI Wen-yan,CEN Ning,WU Hong-an
2010, 31(20):  256-259.  doi:10.7506/spkx1002-6630-201020051
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In order to elevate the utilization value of propolis residue from supercritical carbon dioxide fluid (SFE-CO2) extraction, the residue was reextracted with absolute alcohol, and the extract obtained was subjected to comparisons with alcohol and SFE-CO2 extracts from propolis for differences in flavonoid compound composition and antioxidant effect and to microencapsulation by lyophilization. Total flavonoid content in the alcohol extract from propolis residues left after SFE-CO2 extraction was 118.798 mg/kg, which was close to the alcohol extract from propolis. The protective effects of different propolis products on the peroxidation of lard were different and deceased in the following order: the alcohol extract from propolis> the alcohol extract from propolis residue left after SFE-CO2 extraction > the SFE-CO2 extract from propolis. Thus, the alcohol extract from propolis residue left after SFE-CO2 extraction is a superior antioxidant. Its microcapsules were exquisite powder with a loose texture and the embedding rate was 69.87%.

Optimal Conditions and Kinetics of Enzymatic Hydrolysis of Banana Corm Powder
CHEN Wei,HUANG Guang-min*
2010, 31(20):  260-265.  doi:10.7506/spkx1002-6630-201020052
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The optimal conditions for the hydrolysis of banana corm powder with thermostable alpha-amylase were investigated by single-factor and orthogonal array design methods, and a kinetic analysis of the hydrolysis of banana corm powder was performed. Liquefaction temperature of 85 ℃, pH of 6.4, substrate concentration of 30 mg/mL and enzyme loading of 0.064 mL/g were found optimal, and a DE value of 37.61% was obtained under these conditions. The Vm and Km were determined to be 0.708mg/ (mL·min) and 27.410 mg / mL, respectively.

Ultrasonic Treatment Followed by Microwave Treatment for Extraction of Flavonoids from Orange Peel
MA Ming-you1,LIU Jian-ben1,WU Xian-ming2,3,CHEN Shang2,3,WEN Xiao4
2010, 31(20 ):  266-269.  doi:10.7506/spkx1002-6630-201020053
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In order to improve the extraction yield of total flavonoids from orange peel, sequential treatments with ultrasonic followed by microwave were used for the extraction of total flavonoids. The effects of concentration of ethanol as the extraction solvent, solid/liquid ratio and microwave power and treatment time on the extraction yield of total flavonoids were explored by single-factor and orthogonal array design methods. The combination of ultrasonic with microwave gave higher extraction efficiency than the use of ultrasonic and microwave alone, and a maximum extraction yield of total flavonoids was achieved after soaking in 20-fold volume of 70% ethanol for 30 min, followed by ultrasonic treatment for 30 min and subsequent 400 W microwave treatment for 3 min.

Analysis & Detection
Direct Competitive Enzyme-linked Immunosorbent Assay for the Rapid Determination of Salbutamol
WANG Bao-ling1,2,YUAN Li-peng2,LEI Hong-tao2,*,XU Zhen-lin2,YANG Jin-yi2,
2010, 31(20):  270-274.  doi:10.7506/spkx1002-6630-201020054
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A direct competitive enzyme-linked immunosorbent assay (dcELISA) was developed for rapidly determining salbutamol. Horseradish peroxidase-labeled salbutamol monoclonal antibodies were synthesized by sodium periodate method. The optimal coating concentration and antibody dilution were determined by chequerboard titration. The effects of surfactants, ion concentration, methanol content and pH on the sensitivity of dcELISA were investigated by single-factor experiments. The results showed that the optimal molar ratio of enzyme-labeled antibody was 2.1. The optimized assay conditions for both the highest sensitivity and the best stability were as follows: coating antigen concentration, 1μg/mL; and dilution fold of antibodyenzyme conjugate in 0.01 mol/L pH 7.4 PBS dilution containing 0.05 % Tween-20, 0.5 mol/mL NaCl, and 5% methanol, 2560. The developed method presented an IC50 of 10.3 ng/mL, a detection limit of 0.049 ng/mL, a linear range of 0.3 to 76.30 ng/mL, with an intra-batch CV of 13.8 % and an inter-batch CV of 22.38%, and 321.18% and 29.09% cross-reactivity rates with clenbuterol and brombuterol, respectively, without notable cross-reactivity with other structural analogues of salbutamol. This study provides valuable experimental data for developing a commercial immunoassay kit for the rapid determination of multiresidues of salbutamol and clenbuterol.

Application of High Performance Capillary Electrophoresis to the Determination of Flavonoid Compounds
ZHOU Yi-ming1,ZHOU Xiao-li1,*,CUI Lin-lin2
2010, 31(20):  275-277.  doi:10.7506/spkx1002-6630-201020055
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A method was developed for the determination of flavonoid compounds using high performance capillary electrophoresis (HPCE). The electrolyte buffer used was 20 mmol/L borax/boracic acid solution (pH 8.4). Electrophoresis was performed at 25 ℃ and 20 kV voltage. The detection wavelength was set as 245 nm. The developed method displayed good linearity. A thorough chromatographic separation of flavonoid compounds was achieved within 10 min, which meets the requirements for qualification and quantification. This method giving good separation and having high precision is applicable for the determination of flavonoid compounds in practice.

Analysis of Nutritional and Flavor Compounds in Fresh Muraenesox cinereus Muscle
ZHAO Hui1,XU Da-lun1,*,ZHOU Xing-yu1,WANG Yan-hui2,YANG Wen-ge1
2010, 31(20):  278-281.  doi:10.7506/spkx1002-6630-201020056
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To study the nutritional and flavor characteristics of Muraenesox cinereus, the general nutrients, fatty acids, free amino acids, ATP, ATP-related compounds and volatile components in the muscle of fresh M.cinereus were determined by GCMS. The results showed as follows: 1) In the total fatty acids, the unsaturated fatty acids (UFA) and polyunsaturated fatty acids (PUFA) accounted for 65.41% and 23.63%, respectively. The muscle of M.cinereus was abundant in DHA and EPA; 2) The free amino acids in fresh M.cinereus included mainly Gly, Lys and Ala, and their contents were 2.41, 1.50 g/kg and 0.89 g/kg, respectively; 3) IMP played an important role in the delicious taste of M.cinereus, and its content was up to 7.15μmol/g; and 4) Hydrocarbon compounds took the largest percentage in the volatile compounds of M.cinereus, but aldehydes, ketones and sulfur compounds contributed the smell characteristics of M.cinereus.

Determination of Hydrolyzed Animal Protein in Dairy Products by High-performance Liquid Chromatography with Evaporative Light Scattering Detection
ZHAO Yan-yan1,2,LIU Li-yan2,DU Guang-ling1,HAN Yuan-yuan1,BAI Jie1,GENG Cheng-guang2,GAO Qian2
2010, 31(20):  282-285.  doi:10.7506/spkx1002-6630-201020057
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Objective: To develop a high-performance chromatographic method with an evaporative light scattering detector (ELSD) for the quantified determination of hydrolyzed animal protein in dairy products. Methods: Acidic hydrolysis was employed for sample pretreatment. The chromatographic column used for analyte separation was Shim-pack C18 (4.6 mm × 250 mm, 5μm) with 3.8 mmol/L heptafluorobutyric acid/methanol (8:2, V/V) as the mobile phase at a flow rate of 1.0 mL/min. The ELSD drift temperature was set at 50 ℃, and the carrier gas pressure at 350 kPa. The sample load of 10μL was adopted. The content of hydroxyproline determined under these conditions was used to characterize the level of hydrolyzed animal protein in samples. Results: The developed method displayed good linearity over the concentration range of 10 to1000μg/mL, with a determination coefficient of 0.99993 (n = 5) and its detection limit was 5μg/mL. The average spike recovery for hydroxyproline was 99.83%, with 2.77% RSD. Conclusion: This method without sample derivatization has the benefits of simplicity of operation as well as high sensitivity and accuracy, and is applicable for the determination of hydroxyproline.

Determination of Tetracycline Residues in Aquatic Products by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry
LIN Jing,ZHANG Jin-hu,ZHENG Yu,YANG Yong,YU Chai,WU Wen-fan
2010, 31(20):  286-289.  doi:10.7506/spkx1002-6630-201020058
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An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of six tetracylines in aquatic products. Samples were extracted with 0.01 mol/L Na2EDTA/ Mcllvaine buffer solution. After filtrated and degreased by n-hexane, the extract was passed through Oasis HLB solid phase extraction column and eluted with methanol, and the eluate was then pooled together and evaporated until dryness under nitrogen and redissolved in 1.0 mL of dissolving solution. The solution was separated on a RP-UPLC column and detected by triplequadrupole MS. The electrospraying was operated in the positive ionization mode and the identification of analytes was achieved using multiple reaction monitoring (MRM) mode. Quantitation was carried out using the external standard method. The standard curves for all the compounds were linear over the concentration range of 5.0 to 50.0μg/kg with correlation coefficients between 0.9969 and 0.9999. The spike recoveries at four levels of 5.0, 10.0, 25.0, 50.0μg/kg ranged form 61% to 97%, and the relatives standard deviations (RSD) were in the range of 1.3% to 5.7%. The limits of detection of the method for the analytes were all 2.5μg/kg. Owing to the merits of simplicity, selectivity and sensitivity, the proposed method has been successfully applied to the determination of tetracyclines in aquatic products.

Determination of Heavy Metals in Vegetables by Microwave Digestion/Inductively Coupled Plasma Atomic Emission Spectroscopy
CONG Qiao,CAI Yan-Rong
2010, 31(20):  290-292.  doi:10.7506/spkx1002-6630-201020059
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A microwave digestion/inductively coupled plasma atomic emission spectroscopy (ICP-AES) method was presented for the determinations of Zn, Pb, Cu and Cd in vegetables. The detection limits of the method for the elements varied from 0.006 to 0.018 mg/L, with relative standard deviations between 0.17% and1.76%, and the spike recovery ratios for them were in the range from 99.00% to 102.95%. The actual applications demonstrate that this method is sensitive, and that the leaf vegetables can adsorb more heavy metals than fruit vegetables such as eggplant.

Development and Application of a Multiplex PCR/DHPLC Method for Detecting Four Common Diarrheogenic Escherichia coli Strains
XU Yi-gang1,CUI Li-chun2,*,LI Su-long1,CAO Ji-juan3,JIANG Yan-chun1,ZHANG Zi-qun1,LIU Xin-liang1
2010, 31(20):  293-297.  doi:10.7506/spkx1002-6630-201020060
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Four pairs of specific primers were designed according to the sequences of the LT gene from enterotoxigenic E.coli (ETEC), the bfpA gene from enteropathogenic E.coli (EPEC), the O antigen gene from enterohemorrhagic E.coli (EHEC) and the invasive plasmid gene from enteroinvasive E.coli (EIEC) for the development of a multiplex polymerase chain reaction/denaturing high performance liquid chromatography (PCR/DHPLC) method for the simultaneous detection of the four common diarrheogenic E.coli strains. The PCR/DHPLC method had high sensitivity and its detection limit was 6×101 copies/μL for EHEC, 1.3×102 copies/μL for ETEC, 9×101 copies/μL for EPEC and 7×101 copies/μL for EIEC. The specificity evaluation showed that 6 of 41 stains from 22 species were determined to be positive. This method proves to be applicable and suitable for the detection of infection with one or more of the four E.coli strains.

Determination and Evaluation of Volatile Components of Soymilk Yoghurts Fermented by Lactic Acid Bacteria
ZHANG Jia1,MA Yong-kun1,2,*,CUI Feng-jie1,CHEN Fan1,SUN Le-liu2,XIA Rong2
2010, 31(20):  298-302.  doi:10.7506/spkx1002-6630-201020061
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The volatile components of the soymilk yoghurts fermented by Streptococcus thermophilus plus Lactobacillus bulgaricus (1:1 or 1:2 mixing ratio) or Lactobacillus helveticus (1:1 mixing ratio) were analyzed using headspace solid phase microextraction (SPME) combined with gas chromatograph/mass spectrometer (GC-MS) and sensory evaluation was conducted for these yoghurt samples. The effects of different species of Lactobacillu and mixing ratio for Lactobacillu and Streptococcus thermophilus on the volatile components of soymilk yoghurts were explored. In comparison with pre-fermented soymilk, all the three soymilk yoghurts showed significantly higher contents of ketones and acids but significantly lower contents of aldehydes and alcohols. The contents of the key flavor compounds found in all of them were different. The results of evaluation were consistent with those of aroma composition analysis. The soymilk yoghurt produced with Streptococcus thermophilus plus Lactobacillus bulgaricus at 1:1 mixing ratio had strong aroma and high acidity. Therefore, an excellent fermentation starter has been found for the production of soymilk yoghurt through this study.

Electrochemical Determination of Bisphenol A in Food Packaging Materials
WANG Yu-chun,LIU Zhao-rong,GONG Qiao-juan
2010, 31(20):  303-306.  doi:10.7506/spkx1002-6630-201020062
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Using large effective area and more catalytic active centers of the functionalized SWCNT modified electrode, we discussed the electrocatalytic activity of bisphenol A (BPA) on the modified electrode. Based on this investigation, an optimized electrochemical method was presented for the determination of this molecule in food packaging materials. The cyclic voltammetry was carried out at 0.10 V/s scanning speed after 100 s of accumulation in pH 6.5 PBS solution at 0.2 V voltage. The anodic peak current (Ipa) had good linear correlation with BPA concentration over the range from 2.0×10-8 to 3.5×10-5 mol/L. The detection limit of BPA was 8.0×10-9 mol/L (RSN = 3). Moreover, the stability, repeatability and interference resistance of the modified electrode were investigated. This was followed by application evaluation of the developed method to the determination of BPA in four food packaging materials. Recoveries of BPA varying from 97.5% to 105% were obtained, indicating the excellence of this method.

Time-resolved Fluoroimmunoassay of Clenbuterol Hydrochloride using Europium Labeled Antigen
FAN Xiao-bo1,2,YANG Jin-yi2,GAO Xiu-jie2,WU Ying-song2,SUN Yuan-ming2,LEI Hong-tao2,*
2010, 31(20):  307-310.  doi:10.7506/spkx1002-6630-201020063
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A convenient, rapid and sensitive method has been presented for the determination of clenbuterol hydrochloride (CBL) using the direct competitive time-resolved fluoroimmunoassay (TRFIA). In the direct competitive assay, the anti-CBL monoclonal antibody was bound on the surface of a 96-cell microplate, and samples containing CBL or the standards competed for the antibody binding sites with Eu3+ labeled antigen in the wells of microplate. The determinations of CBL in porcine urine and tissue samples showed that the limit of detection was 0.02μg/L, with spike recoveries ranging from 91% to 101%. The cross-reaction rates with other six drugs were less than 1%. The proposed TRFIA method is sensitive and specific, and can be used for the determination of CBL residue in food samples.

Determination of the Content of Vitamin C in Siraitia grosvenorii Fruits by HPLC
NING De-sheng,LIANG Xiao-yan,FANG Hong
2010, 31(20):  311-313.  doi:10.7506/spkx1002-6630-201020064
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Objective: To set up a HPLC method for the determination of the content of vitamin C in the fruits of Siraitia grosvenorii. Methods: The chromatographic separation was achieved on SinoChrom ODS-BP (250 mm×4.6 mm, 5μm) held at 25 ℃ using a mixture composed of 0.05% H3PO4 and CH3OH (98:2, V/V) as the mobile phase at a flow rate of 1.0 mL/min. The diode array detector wavelength was set at 242 nm. The injection volume used was 10μL. Results: The developed calibration curve of vitamin C displayed good linearity over the concentration range from 0.08 to 5.0 mg/mL, with a correlation coefficient equaling 1. The average recovery of five replicates for vitamin C was 99.3% with 1.93% relative standard deviation (RSD). Conclusion: This method is simple, quick, precise and stable, and can used for determining the content of vitamin C in the fruits of Siraitia grosvenorii.

Gas Chromatography Couple to Tandem Mass Spectrometric Determination of Dimethyl Fumarate in Foods
ZHANG Qing-zhi,SUN Zhong-song*,WANG Jing-tang,CAI Fa
2010, 31(20):  314-317.  doi:10.7506/spkx1002-6630-201020065
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To solve the problems of complexity of sample matrix and interference, gas chromatography couple with tandem mass spectrometry (GC-MS/MS) was utilized to set up a method for the determination of dimethyl fumarate in foods. Sample pretreatment prior to the injection into the instrument was achieved through extraction with acetonitrile extraction and subsequent cleanup on C18 column. The collision induced dissociation (CID) voltage selected was 15 V. The method showed good linearity over the range of 0.05 to 10.00 mg/L (R 2= 0.9998), with a limit of detection (LOQ) of 0.045 mg/L. The external standard method was used for quantification. The spike recoveries of dimethyl fumarate at spike levels of 0.05, 0.50 and 1.00 mg/kg was between 87% and 108%, with a relative standard deviation ranging from 2.77% to 8.70%. Compared with GC and GC-MS methods, the proposed GC-MS/MS method has the benefits of less time consumption and interference and higher sensitivity, and is more suitable for the analysis of foods samples in batches.

Detection of Adulteration in Sesame Oil Using Electronic Nose
PAN Lei-qing,TANG Lin,ZHAN Ge,LIANG Chen-xi,XIE Yi-ping,TU Kang*
2010, 31(20):  318-321.  doi:10.7506/spkx1002-6630-201020066
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In this study, the detection of adulteration in sesame oil was performed using a PEN3 electronic nose system. Sesame oils adulterated with different concentrations of cheaper seed oils such as soybean oil, corn oil and sunflower oil were distinguished. Principal component analysis (PCA) and linear discriminant analysis (LDA) were used. The results showed that the adulteration of sesame oil could be detected effectively and LDA was more competent than PCA. Sesame oils adulterated with soybean oil or corn oil at levels of adulteration exceeding 50% were distinguished easily by PCA and the distinguishable adulteration level for sunflower oil was beyond 70% (V/V). However, LDA could easily distinguish different levels of adulteration with each of the three cheaper seed oils.

Ultrasonic-aided Extraction and GC-MS Analysis of Fatty Acids from Akebia trifoliata Seed
OUYANG Yu-zhu1,2,LI Yong2,WU Dao-hong2,TIAN Xiang-rong1
2010, 31(20):  322-324.  doi:10.7506/spkx1002-6630-201020067
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The ultrasonic-aided extraction of Akebia trifoliata seed oil was achieved using alcohol, ethyl acetate, n-butanol or acetone as the extraction solvent. Along with this, the oils extracted with the four solvents were comparatively analyzed for their fatty acid composition by gas chromatography-mass spectrometry (GC-MS). Alcohol was found to be available for better sensory quality of oil, and ethyl acetate for higher oil yield, and the resultant oil yields were 19.23% and 35.69%, respectively. There were 11 fatty acids detected in Akebia trifoliata seed oil, and the major unsaturated fatty acids were oleic acid and linoleic acid, occupying 71.97% and 83.79%, respectively.

Effect of Methyl Position on Aroma Intensity of Methylvaleric Acids
LIU Yu-ping1,YIN De-cai1,LI Ning1,2,SUN Bao-guo1,CHEN Hai-tao1,*
2010, 31(20):  325-328.  doi:10.7506/spkx1002-6630-201020068
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2-Methylvaleric acid, 3-methylvaleric acid and 4-methylvaleric acid are three isomers of methylvaleric acids and all of them can be used in food. Their aroma intensities are different. In this work, the aroma thresholds of the three methylvaleric acids were evaluated by 3-AFC test to be 63.49, 0.886 mg/kg and 0.713 mg/kg, respectively. Meanwhile, their aroma intensities were also compared with the determined values by electronic nose. Results showed that the aroma intensities of the three flavor compounds from strong to weak were 4-methylvaleric acid, 3-methylvaleric acid and 2-methylvaleric acid at identical concentrations of 10, 100 mg/kg and 1000 mg/kg. The determined results by both methods were consistent. Therefore, the position of the methyl group exhibited an obvious effect on aroma intensity of methylvaleric acids and the aroma intensity was increased with the increase of distance between the methyl group and the carboxyl group.

Optimization of SPME-GC-MS Conditions for Flvour Compounds Determinationin in Duck Meat by Response Surface Analysis
WANG Wu,ZHA Fu-ben,ZHANG Jing,SHEN Jun-chen,REN Zhi-wei
2010, 31(20):  329-334.  doi:10.7506/spkx1002-6630-201020069
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To lay a foundation for the accurate determination of the flour compounds in duck leg meat by solid-phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS), the optimization of the SPME conditions affecting the total ion current chromatographic peak area of duck meat extract was investigated using single factor and response surface methodology based on Box-Behnken central design. The optimal extraction conditions were obtained as follows: sample load 2.4 g and extraction temperature 49 ℃ for an extraction duration of 42 min. Totally 27 volatile flavor compounds were identified in duck meat. They were aldehydes, ketones and N-, S-, O containing and heterocyclic compounds.

GC Method for the Determination of Forty Pesticide Residues in Shiitake Mushroom
WANG Hui-feng,FENG Shu-hui,JIA Bin
2010, 31(20):  335-341.  doi:10.7506/spkx1002-6630-201020070
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Objective: To develop a capillary GC method for the determination of the residues of 24 organochlorines or synthetic pyrethroid and 16 organophosphorus pesticides in shiitake mushroom. Methods: Samples were weighed into Teflon centrifuge tubes and high-speed homogenized with acetonitrile, and the supernatant was then condensed until almost dry and applied to a carbon/NH2 SPE column for cleanup. After recondensation until almost dry, the eluate was rediluted with n-hexane before being injected into the analytical instrument. Electron capture detector was used to detect organochlorines and pyrethroids and flame photometric detector to detect organophosphorus. Using the external standard method, quantitation was carried out. Results: The linear range of the proposed method was between 0.016μg/mL and 0.80 μg/mL, with a correlation coefficient of larger than 0.999, and its recovery, repeatability RSD and detection limit varied from 73.0% to 113%, from 3.2% to 5.9% and from 0.0005 to 0.05 mg/kg. Conclusion: A simple, sensitive and reproducible method applicable to the determination of pesticide multiresidues in shiitake mushroom and other species of mushroom has been developed.

Comparison on Volatile Compounds in Cultured Grass Carp at Different Growth Stages
SHI Wen-zheng,WANG Xi-chang*,LIU Yuan,TAO Ning-ping,WU Jing-ye
2010, 31(20):  342-347.  doi:10.7506/spkx1002-6630-201020071
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In this work, the volatile compounds in the meat of grass carp were analyzed by headspace solid phase micro-extraction (HS-SPME) followed by gas chromatography coupled with mass spectrometry (GC-MS) and electronic nose. The results indicated that electronic nose could discriminate dorsal meat, belly meat, red meat from grass carp with different body weights, except dorsal meat and belly meat from big grass carp. A total of 42, 41 and 43 volatile compounds were identified in the dorsal meat, belly meat and red meat of big grass carp, and the numbers of volatile compounds identified in the dorsal meat, belly meat and red meat of small grass carp were 30, 39 and 52, respectively. The volatile compounds found were mainly volatile carbonyl compounds and alcohols, accounting for higher than 90%. The contents of volatile compounds exhibited a significant difference between big and small grass carp.

Analysis and Simulation of Aroma Composition of Tianfuhao Pork Shoulder
LI Jian-hua1,SUN Bao-guo1,HUANG Ming-quan1,LIU Yu-ping1,QI Yong-qiu2,MIAO Zhi-wei2,CHEN Hai-tao1,*
2010, 31(20):  348-350.  doi:10.7506/spkx1002-6630-201020072
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The volatile components in Tianfuhao pork shoulder were analyzed by solid phase micro-extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Totally 30 kinds of aroma components were identified in Tianfuhao pork shoulder, including acetylpyrazine, 2-cyclopenten-1-one, 2-hydroxy-3-methyl-1-propanol, 3-(methylthio)-4Hpyran-4-one, 2-ethyl-3-hydroxy-acetic acid, benzaldehyde, and 4-methoxy-tetrahydrothiophen-3-one. On the basis of analysis, the components of meaty aroma, spiced aroma, spicy aroma, fatty and oily aroma and acid aroma were the major contributors to the flavor of Tianfuhao pork shoulder, which will be helpful for designing and simulating the flavor of Tianfuhao pork shoulder.

Determination of Calcium Concentration in Milk by Microwave Digestion and Micro-titration
DU Jian-zhong1,YANG Mei-bo1,ZHU Yong-bin1,DING Ding2,3
2010, 31(20):  351-354.  doi:10.7506/spkx1002-6630-201020073
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The determination of calcium concentration in milk was achieved using microwave digestion and micro-titration. Satisfying results of determining Ca2+ concentration in milk were obtained when a 10.00 mL sample of milk was digested with a mixture consisting of 5 mL of 98% HNO3 and 3 mL of H2O2 fortified with 0.4 mL of triethanolamine for eliminating the interference from Al3+ and Fe3+. The average consumptions of EDTA standard solution for Yili branded pure milk and high calcium milk were 1.616 mL and 1.450 mL with RSDs of 0.16% and 0.32%, respectively. The average spike recovery rate of seven replicate determinations was in the range of 98% to 101.5%. The accuracy and precision of the micro-titration method were both comparable to those of the traditional digestion and titration methods. This method is a simple, rapid, reagent-saving and environmentally friendly.

Comparative Evaluation of Two Methods for Determining Spoilage Ability of Fish Spoilage Bacterium Shewanella putrefaciens
XU Zhen-wei1,2,XU Zhong1,YANG Xian-shi1,*,GUO Quan-you1,LI Xue-ying1
2010, 31(20):  355-359.  doi:10.7506/spkx1002-6630-201020074
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After inoculation with Shewanella putrefaciens, a common fish spoilage bacterium, the sterile block and juice of large yellow croaker were stored at (5 ± 1) ℃, and the changes in sensory quality, total volatile base nitrogen (TVBN), trimethylamine (TMA) and bacterial count, the growth kinetic parameters of this species of bacteria and the yield factors of microbial metabolites (YTVBN/CFU and YTMA/CFU) in sterile fish block and juice during the storage were comparatively measured in order to evaluate the two methods of determining the spoilage ability of Shewanella putrefaciens. The post-inoculation shelf-lives of sterile fish block and juice were 162 h and 132 h, respectively, the TVBNs 32.16 mg/100 mL and 29.64 mg/100 mL, the TMAs 9.31 mg/100 mL and 0.99 mg/100 mL, the bacterial counts 8.67 lg(CFU/mL) and 8.56 lg(CFU/mL), the YTVBN/CFU values 2.58×10-10 mg TVBN/CFU and 1.98 × 10-10 mL TVBN/CFU, and the YTMA/CFU values 2.12 × 10-10 mg TMA/CFU and 1.27 × 10-11 mL TMA/CFU at the end of shelf-life. The reliable parameter indicating the spoilage of fish juice was TVBN rather than TMA. The relative error between the YTVBN/CF values of fish block and juice was 23.64%. Thus, sterile fish juice is a promising matrix for the reliable determination of bacterial spoilage ability.

Simultaneous Determination of 9 Kinds of Mycotoxins in Maize, Peanut and Wheat by Ultra-high Performance Liquid Chromatography-Tandem Mass Spectrometry
LIAN Hui-feng1,ZHAO Xiao-tian2,WANG Rong-zhen3,SONG Huan1,LIN Qin-bao2,*
2010, 31(20):  360-366.  doi:10.7506/spkx1002-6630-201020075
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A simultaneous determination method for nine kinds of mycotoxins in maize, peanut and wheat was developed using ultra-high performance liquid chromatography-tendem mass spectrometry (UPLC-MS/MS). Samples were sequentially extracted with PBS solution followed by 70% methanol, and then the extracts were pooled and cleaned up with immunoaffinity column, followed by blowing to dryness under nitrogen gas stream, reconstitution with acetonitrile/water mixture before the analysis on UPLC-MS/MS. The MS conditions used were negative (ESI+) and positive (ESI-) electrospray ionization and MRM models. The results indicated as follows: 1) all the nine kinds of mycotoxins had good linear relationship with peak area over the range from 0.1 to 400μg/kg, and the detection limits for them ranged from 0.1 to 20μg/kg; and 2) The average recovery rates in the above three matrices spike at three levels were between 59.5% and 118.8%, with a relative standard deviation (RSD) varying from 2.4% to 12.8%. This analytical method meets the requirements for trace assays. In addition, it is simple, rapid, accurate and suitable for the simultaneous determination of nine kinds of mycotoxins in maize, peanut and wheat.

Rapid Determination of Total Organic Matter in Food Plastic Bag by Flow Injection Coupled with Chemiluminescence
WANG Chang-qing,GAO Xiang-yang*,SHI Han-yu
2010, 31(20):  367-370.  doi:10.7506/spkx1002-6630-201020076
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The aim of the present study was to develop a novel analytical method for rapidly determining total organic matter in food plastic bag using flow injection coupled with chemiluminescence. Samples received ultrasonic-assisted extraction and subsequent microwave pressure digestion prior to the analysis with luminol-H2O2-Cr3+ flow injection chemiluminescence system. Chromium (Ⅲ) (considered equivalent to total organic matter) displayed a linear range of 1.154×10-10 to 1.154×10-5 mol/L (1/3Cr3+) and a detection limit of 4.476×10-11 mol/L (1/3Cr3+), with a relative standard deviation (RSD) of 3.1% (n = 3). The proposed method is characterized by high sensitivity, ease of operation, rapid determination and low cost. All these figures of merits benefit its promotion and popularization.

Determination of Astaxanthin in Shrimp Shells by High Performance Liquid Chromatography
JIANG Miao1,2,YANG Xian-qing1,*,LI Lai-hao1,CEN Jian-wei1,HAO Shu-xian1,
2010, 31(20):  371-375.  doi:10.7506/spkx1002-6630-201020077
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A method for determining astaxanthin in shrimp shells was established using high performance liquid chromatography (HPLC). The optimal conditions for sample preparation were explored by orthogonal array design to be extraction with ethyl acetate under the assistance of ultrasound treatment for 30 min followed by oscillation for 15 min and the procedure was repeated twice for full extraction of astaxanthin. A good linear relationship determined by HPLC method was observed when astaxanthin concentration was in the range of 0.2 to 10μg/mL (R2 = 0.9999). The recovery rates for astaxanthin in a spiked sample ranged between 80.41% and 109.21% with relative standard deviations (RSD) between 4.65% and 7.45%. The limit of detection was 0.075 mg/kg. This method is characteristic of rapidity, accuracy, high sensitivity and recovery rate and good reproducibility.

Primer Screening and Optimization of PCR System for the Detection of Puffer Fish
CHEN Wen-bing1,ZHAO Chen1,2,SHAO Bi-ying1,JIANG Shu-xun1,YAN Cheng1,LI Shou-song1,LIN He-tong2
2010, 31(20):  376-381.  doi:10.7506/spkx1002-6630-201020078
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According to the sequence of cytochrome b gene of puffer fish published in GenBank, seven pairs of puffer fishspecific primers were designed with Primer Premier 5.00 version. After PCR screening, the primer HT-1, which could detect the target DNA fragment in eight samples of puffer fish from different aquatic breeding farm in Fujian province, was selected to establish a PCR method for the detection of puffer fish in this work. Furthermore, six key factors affecting PCR including Taq enzyme and template DNA amounts as well as final magnesiumion (Mg2+), dNTPs and primer concentrations were optimized in order to establish optimal PCR system. And the optimal composition of a 20μL PCR system in water consisted of 2μL of 10 × PCR buffer, 1.5 mmol/L MgCl2, 1.0 U Taq DNA polymerase, 300μmol/L dNTPs, 0.2μmol/L primer and 400 ng of template DNA. The thermal program for PCR was as follows: predenaturation at 94 ℃ for 5 min, denaturation at 94 ℃ for 30 sec, annealing at 62 ℃ for 30 s, polymerization at 72 ℃ for 30 s, and after 40 cycles, final polymerization at 72 ℃ for 5 min. The proposed PCR method was found to be specific through the comparison of PCR results amplified from puffer fish DNA and non-puffer fish DNA. The detection limit was 0.1%, and PCR detection rate for 0.1% content of puffer fish samples was 97.5% or more.

Determination of Glucocorticoid Residues in Animal Muscle by Rapid Resolution Liquid Chromatography-Tandem Mass Spectrometry
GAO Wen-hui1,LI Hui2,ZHANG Jing-xuan2
2010, 31(20):  382-385.  doi:10.7506/spkx1002-6630-201020079
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A method was developed for the determination of seven glucocorticoid residues in animal muscle using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample extraction was performed using ethyl acetate, followed by cleanup based on solid phase extraction (SPE). The chromatographic separation was achieved on a C18 column (150 mm×2.1mm, 3.5μm) with water/acetonitrile/formic acid system as the mobile phase in gradient elution mode. The MS condition used was negative electrospray ionization mode. Under these conditions, the linear range of the developed method was between 0.5 ng/mL and 5 ng/mL, with a linear correlation coefficient of no less than 0.9963, the detection limit was 1.0μg/kg for beclomethasone, 2.0 μg/kg for hydrocortisone, 0.5μg/kg for the others, and the average spike recoveries for the seven molecules were between 82.75% and 91.87%, with a relative standard deviation (RSD) of 4.43% or lower (n = 5).

Thermo-luminescence for Qualifying Irradiated Tea
ZHOU Hong-jie1,2,WANG Feng1,2,HA Yi-ming1,2,LI Shu-rong1,2,PAN Jia-rong1,WANG Zhi-dong1,*
2010, 31(20):  386-388.  doi:10.7506/spkx1002-6630-201020080
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Objective: To explore the qualitative identification of irradiated tea through thermo-luminescence (TL) analysis. Methods: Silicate minerals from tea were isolated, collected and measured with TL dosimeter. A TL glow curve was established. The comparisons of integrated intensity, peak value and peak temperature of TL glow curve between unirradiated tea and irradiated tea samples at different irradiation dosages were made. Results: The integrated intensity of TL glow curves of unirradiated tea samples was less than 50; the peak value did not exceed 0.4, and the peak temperature was more than 260 ℃. However, the integrated intensity of TL glow curves of irradiated tea samples was larger than 50000; the peak value was higher than 600, and the peak temperature was in the range of 160 to 190 ℃. Conclusion: TL analysis method can discriminate irradiated tea and unirradiated tea well. This method is very useful, especially for samples that can not be irradiated at the reference dosage.

Determination of Multi-residues of Phenoxy Acid Herbicides in Cereals by Liquid Chromatography-Tandem Mass Spectrometry
CHENG Jing1,2,DING Lei2,JIANG Jun-shu1,2,*,LU Ye-ju1,2
2010, 31(20):  389-393.  doi:10.7506/spkx1002-6630-201020081
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A new method using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the analysis of six phenoxy acid herbicide residues in cereals has been developed. The optimized sample pretreatment procedure consisted of extraction with acetonitrile, acidification with acetic acid and cleanup before the analysis on a LC-ESIMS/MS instrument. Separated analytes were determined using multiple reaction monitoring (MRM). Quantitation was performed using external standard method. The proposed method displayed a detection limit between 0.005 and 0.01 mg/kg and good linearity over the range from 0.01 to 0.5 mg/L, with a r2 > 0.99. At a spike level of 0.2 mg/kg, mean recoveries from rice ranged between 86.1% and 96.8% for different analytes. The method is simple, efficient and sensitive, and its each performance characteristic meets the requirements for the determination of phenoxy acid herbicide residues in cereasl at home and abroad.

Screening for Colour Developer and Optimization of Reaction Conditions for Fast Determination of Basic Orange Ⅱ in Foods
JI Shu-juan,ZHANG Qing-huan,SHEN Yi-xiao
2010, 31(20):  394-398.  doi:10.7506/spkx1002-6630-201020082
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Using the ability of basic orange Ⅱ to develop color, a fast method was presented for the determination of this dye. The optimal conditions for color development were investigated. A reagent system composed of potassium ferricyanide and Iron (Ⅲ) was found to the best color developer through comparative analysis of color developing effects of different color developers and observation of absorbance change, and the optimal ratio of potassium ferricyanide solution (3 g/L) to ferric chloride solution (4.5 g/L) was 1:1. The optimal reaction conditions were determined based on absorbance at 755 nm wavelength as follows: color developer amount, 0.7 mL; and reaction temperature, 50 ℃ for a reaction duration of 20 min.

Extraction and Composition Analysis of Volatile Components in Leaves of Cinnamomun burmannii B1.
SU Jian-yu,CHEN Ling*,LI Bing,LI Lin
2010, 31(20):  399-401.  doi:10.7506/spkx1002-6630-201020083
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Steam distillation was used to extract essential oil from the leaves of Cinnamomun burmannii B1. The compositions and their relative contents in essential oil were quantitatively determined by GC-MS with peak area normalization method. Results indicated that a total of 40 volatile compounds were identified, which was accounted for 99.4% of total volatile compounds. The predominant volatile components were D-borneol (78.6%), bornyl acetate (3.26%), (-)-spathulenol (2.60%) and eucalyptol (1.92%), respectively. Therefore, D-borneol was one of the major components in Cinnamomun burmannii B1, which exhibited a promising prospect for developing medical products and perfume.

Determination of Monobutyrin by GC-MS
YI Lu-yao1,2,ZHENG Wei-wan1,*,LIAO He-jing1
2010, 31(20):  402-405.  doi:10.7506/spkx1002-6630-201020084
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A GC-MS method for quantitative analysis of monobutyrin was established. The determination parameters were the capillary column DB-5MS (30 × 0.25 mmm, 0.25μm), injection temperature of 280 ℃ programmed temperature increase from 100 to 150 ℃ with an increase rate of 10 ℃/min, then programmed temperature increase from 150 ℃ to final temperature of 250 ℃ at an increase rate of 30 ℃/min, helium flow rate of 1.0 mL/min and split ratio of 10:1, respectively. Results indicated that a good linear relationship between integral value (Y) of peak area and the content of monobutyrin (X) in the range of 0.5-10μg/mL was observed and the linear equation was Y=146961X-30250 (r=0.9997). Recovery rate of monobutyrin were 99.9% with the RSD of 1.7%. The limit of determination was 0.2 ng. This method is simple, accurate and reproducible so that it can be used for the determination of monobutyrin.

Determination of Volatile Components of Chilled Pork Based on SPME-GC-MS
XIAO Hong,XIE Jing*
2010, 31(20):  406-409.  doi:10.7506/spkx1002-6630-201020085
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In order to optimize the extraction conditions of chilled pork, the volatile components in chilled pork were extracted by solid phase micro-extraction (SPME) and determined by gas chromatography-mass spectrometry (GC-MS). The volatile components in chilled pork were analyzed during the various storage temperatures and time. Results indicated that the optimal SPME conditions was extraction using a 65 μm PDMS/DVB fiber at 35 ℃ for 40 min. Totally 25 volatile compounds were identified and the relative contents of trimethylamine and alcohols were increased with the extension of storage time.

Analysis of Fatty Acids in Different Parts from Nanguoli Pear Fruits by GC-MS
ZHANG Bo1,FENG Fan2,XIN Guang1,2,*,LI Tie-chun1
2010, 31(20):  410-412.  doi:10.7506/spkx1002-6630-201020086
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Fatty acids in different parts of Nanguoli pear fruits including seed, peel and flesh were extracted by using Soxhlet extraction method, and then analyzed by gas chromatography-mass spectrometry (GC-MS). Results indicated that there were 14 fatty acids in seeds of Nanguoli pear. The major components were decanoic acid (0.05%), palm oil (0.29%), isopalmitic acid (0.38%), palmitic acid (9.08%), 14-methyheptadecanoic acid (0.12%), linoleic acid (55.64%), oleic acid (27.18%), stearic acid (2.23%), arachidonic acid (0.77%), arachic acid (1.85%), heneicosamoic acid (0.19%), n-docosanoic acid (0.38%), tricosanoic acid (0.06%) and wood tar oil (0.15%). These 14 compounds were account for 98.37%. There were 4 fatty acids in peel of Nanguoli pear, which were palmitic acid (6.79%), linoleic acid (9.65%), oleic acid (33.73%) and stearic acid (1.51%). These 4 compounds were account for 51.68%. There were 3 fatty acids in flesh of Nanguoli pear, which were palmitic acid (4.59%), linoleic acid (22.81%) and oleic acid (15.87%). These 3 compounds were account for 43.27%. Linoleic acid and oleic acid were the major components of unsaturated fatty acids.

Detection of Pathogenic Vibrio parahaemolyticus by Western Blotting
YANG Jing-ya,ZHANG Jian,ZHAO Yong,TAO Yan,LU Xiao-fan,CHAO Ruo-yu
2010, 31(20):  413-416.  doi:10.7506/spkx1002-6630-201020087
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Objective: To purify thermostable direct hemolysin (TDH) from the culture of Vibrio Parahaemolyticus and to establish western blotting method for determining pathogenic Vibrio parahaemolyticus. Methods: The specific anti-serum was obtained from immune mice using TDH. The working concentration of serum samples was determined by chessboard assay. The specificities of pathogenic Vibrio parahaemolyticus and non-pathogenic Vibrio parahaemolyticus were also determined. Results: The working concentration of serum samples was 1:3200. The samples with clear dots were judged as the positive reaction. V. parahaemolyticus was positive in pathogenic Vibrio parahaemolyticus, while non-pathogenic Vibrio parahaemolyticus was negative. Conclusion: Western blotting can be used to detect pathogenic Vibrio parahaemolyticus with the characteristics of high sensitivity, simple operation and eye-observable results.

Determination of Benzoic Acid and Sorbic Acid in Honey and Honey Products by Ultra-performance Liquid Chromatography
HUANG Jing-ping1,2,LI Yi1,2,ZHOU Jin-hui1,2,WU Li-ming1,2,CHEN Lan-zhen1,2,ZHAO Jing1,2,XUE Xiao-feng1,2,*
2010, 31(20):  417-420.  doi:10.7506/spkx1002-6630-201020088
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In this article, extraction, clean-up and ultra-performance liquid chromatographic analysis of benzoic acid and sorbic acid in honey and honey products were investigated. The samples were dissolved in water first. Benzoic acid and sorbic acid were extracted by an ultrasonic method. After clean up processing with high-speed centrifugation and filtration, the extract was determined by an ultra-performance liquid chromatography with PDA detector. A gradient separation was achieved within 4 min using BEH Shield RP18 column (2.1 mm ×100 mm, 1.7 μm) with ammonium acetate and ethanol as a mobile phase. The developed method was a simple, fast and sensitive. The limit of detection for benzoic acid and sorbic acid were 2.5 mg/kg and 2.0 mg/kg, respectively. The recovery rates of spiked benzoic acid and sorbic acid were 94.1%-102.3% and 96.2%-99.8%, respectively. The relative standard deviations were less than 5%. This method has been successfully applied to analyze some real samples from beekeeper and market for investigating the distribution of benzoic acid and sorbic acid in honey and honey products.

Packaging & Storage
Effect of Post Harvest Heat Treatment on Quality of Muskmelon during Storage
YUAN Li,BI Yang*,GE Yong-hong,WANG Yi,LI Ying-chao,YIN Yan,ZHAO A-mei
2010, 31(20):  421-424.  doi:10.7506/spkx1002-6630-201020089
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‘Yujinxiang’ muskmelon was immersed in 53 ℃ hot water for 3 min, and stored at room temperature after drying. Quality of muskmelon was investigated every 2 days during storage. Results showed that hot water treatment alleviated the weigh loss, and the decline of firmness, total soluble solid, titratable acidity, and the deterioration of flavor and taste. However, hot water treatment had no effect on the color of muskmelon.

Changes of Quality and Antioxidant Capacity of Different Parts of Plum Fruit at Two Storage Temperatures
GUO Xiao-min1,2,AN Lin1,2,WANG You-sheng1,2,*,WANG Gui-xi3,WANG Zhi-yuan1,2,LI Li-ping1,2
2010, 31(20):  425-429.  doi:10.7506/spkx1002-6630-201020090
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The quality changes of plum fruit (Prunus salicina cv. Black amber) during storage at 20 ℃ and 2 ℃ were evaluated and the antioxidant capacity of different parts of plum pulp were determined. Plum fruits stored at 20 ℃ showed a significant decline in firmness, along with the scavenging activity of superoxide, DPPH radical and hydroxyl radical, whereas fruit pH value, along with total antioxidant activity, total phenol and total flavonoid concentration increased with time. In contrast, the low temperature alleviated these trends of fruit quality and antioxidant activity parameters simultaneously, Correlation analysis revealed that both total phenolic and flavonoid content were highly correlated (P < 0.01) with total antioxidant capacity of plum fruit. In addition, the significant difference between outer and inner part of plum fruit was observed in terms of total antioxidant activity, hydroxyl radical scavenging activity, total phenol and total flavonoid contents, as well as the correlation between their antioxidant capacity and fruit quality attributes, expressed as the antioxidant activity of outer part of plum showed stronger correlation with SSC, whereas the inner part correlated more highly with pH value. The results indicated that postharvest quality deterioration of plum fruit may be attributed to the decrease of superoxide, DPPH radical, and hydroxyl radical scavenging activity.

Effect of Precooling on Quality and Physiology of Pisum sativum L. during Controlled Atmosphere (CA) Storage
DAI Yun-yun,LUO Hai-bo,JIANG Li,JIANG Juan,YU Zhi-fang*
2010, 31(20):  430-433.  doi:10.7506/spkx1002-6630-201020091
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Pisum sativum L. was cooled to 2 ℃ (central temperature) 0, 6 or 12 h after harvest, and then stored in the controlled atmosphere of 3% O2, 5% CO2 and 92% N2 at 1 ℃. On the 10th, 20th and 30th day of storage, Pisum sativum L was moved to room temperature for 2 days, and the respiration intensity, color, content of malondialdehyde (MDA) and superoxide anion radical, and the activity of superoxide dismutase (SOD), peroxidase (POD) were determined. The results showed that immediately precooled Pisum sativum L had lower level of respiration intensity, cellulose O2 - ·, MDA, and higher level of POD and SOD activity than the 2 other groups. Therefore, immediate precooling improves the quality of Pisumt sativum L. during shelf life.

Effect of Electric Fields on Quality of Mature-green Tomato Fruits during Storage
WANG Yu1,WANG Bao-gang2,LI Li-te3
2010, 31(20):  434-438.  doi:10.7506/spkx1002-6630-201020092
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The effect of high voltage electric fields on the after-ripening process and quality during storage of ZhaoYan219 tomatoes (Lycopersicom esculentum) was investigated. The firmness, color and decay index of electric field-treated tomatoes were determined during storage. The optimum conditions of electric field treatment were optimized. The results showed that -200kV/m of intermittent static electric field treatment (2 h/d) and -200~200 kV/m 40 kHz alternating electric field pre-treatment (2 h) delayed significantly the decline of firmness, the change in color from green to red of tomato fruit during storage, and decreased the decay index (P < 0.05), and thus prolonged the storage time of tomatoes. However, continuous treatment of intermittent static field and alternating electric field accelerated the ripening process.

Effect of Chitosan Treatment on Postharvest Quality and Disease Resistance of Navel Orange
LIU Feng,CHEN Ming,CHEN Jin-yin*
2010, 31(20):  439-443.  doi:10.7506/spkx1002-6630-201020093
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The effects of different concentration chitosan treatments on postharvest quality and disease resistance of Newhall navel orange were studied. The results showed that chitosan treatments inhibited respiration rate, delayed the ascent of total sugar and the descent of titratable acid and resulted in less VC content loss during cold storage (8 ℃), indicating that the quality of chitosan treated fruit is maintained well. Meanwhile, chitosan treatments also maintained the activities of SOD, PAL, chitinase and β-1,3-glucanase of fruits at a higher level during the later storage period and enhances the disease resistance of fruits. Different concentration chitosan treatments had different effects on the postharvest quality and disease resistance of navel orange, and 1.5% chitosan treatment displayed the best effect, followed by 2.0% and 1.0% chitosan treatments.

Quality Change of Tilapia Fillets during Chilling Storage
LI Sha1,2,LI Lai-hao1,*,YANG Xian-qing1,HUANG Hui1,CEN Jian-wei1,SHI Hong1,LI Shan1
2010, 31(20):  444-447.  doi:10.7506/spkx1002-6630-201020094
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In this study, the quality change of tilapia fillets during chilling storage was investigated, which was focused on sensory evaluation, pH, TVB-N, K value, Ca2+-ATPase activity and TBA value. Results indicated that sensory evaluation value was well correlated with TVB-N, K value and Ca2+-ATPase activity. After the chilling storage for 5 days, the quality of tilapia fillets exhibited a decrease trend. The sensory evaluation value and Ca2+-ATPase activity were decreased to 16 and 27.24%, respectively. However, the K value and TVB-N was increased to 29.5% and 15.775 mg/100 g, respectively. The quality of tilapia fillets began to deteriorate after the storage for 12 days. At that time point, the sensory evaluation value, K value, TVB-N, Ca2+-ATPase activity were 8, 54%, 29.96 mg/100g and 53.36%, respectively. Therefore, these indices can be used to evaluate the quality change of tilapia fillets during chilling storage.

Quality Change in ICF-treated Grass Carp Blocks during Frozen Storage
NI Ming-long,ZHU Zhi-wei,ZENG Qing-xiao
2010, 31(20):  448-452.  doi:10.7506/spkx1002-6630-201020095
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In order to explore the effect of immersion chilling and freezing (ICF) on the quality of frozen food, the quality change of ICF-treated grass carp in multi-element aqueous solution composed of salt sodium, ethanol and glycol propylene at -40 ℃ were investigated and also compared with traditional air-blast freezing (-40 ℃, 6 m/s). Results indicated that the frozen rate of ICF exhibited 1.5-fold faster than that of air-blast freezing. The uptake amounts of sodium chloride, ethanol, and propylene glycol in grass carp were 0.14%, 0.17%, 0.63% and 0.94%, respectively. Compared with traditional air-blast freezing, ICF-treated samples had higher salt-soluble protein, less lipid oxidation, reduced drip loss and low moisture loss. Therefore, ICF exhibited more beneficial for maintaining texture properties and provided a better quality for grass carp during frozen storage.

Disease-resistant Effect of Paclobutrazol Induction on Wounded Fruits of Postharvest Shatian Pomelo
ZHANG Jing,DIAO Jun-ming,HUANG Si-mei,DIAO Shu-ping
2010, 31(20):  453-458.  doi:10.7506/spkx1002-6630-201020096
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In order to improve disease-resistant capability of postharvest Shatian pomelo during storage at room temperature, the paclobutrazol was used to treat wounded fruits for evaluating the disease-resistant response due to the induction of paclobutrazol. Postharvest Shatian pomelo was cut 10 wounds with a size of 1 cm2, and then immersed in paclobutrazol solution for 1 min. The treated fruits was wrapped with PVC film and stored at room temperature after 7-day pre-storage. During storage, the color of normal peel adjacent to the wounds was changed from orange to light green at the early stage of the storage, and gradually recovered to orange. However, the wounded surface was changed from white to light green at the beginning of storage, and then to brown as the extension of storage time. The hardness of the wounds exhibited a gradual increase and the white cortex below the wounds was changed to brown. Cell wall of the wound surface layer was become thinker and grains in the white cortex of cells near to the wounds were observed. The infection rate of wounded fruits treated with paclobutrazol solution at the concentration of 1.0 mmol/L paclobutrazol was 13.33% after 90-day storage. Therefore, paclobutrazol has obvious diseaseresistance effect on postharvest Shatian pomelo fruits through the induction of paclobutrazol.

Respective and Combined Effects of 1-Methylcyclopropene and Nano-packaging on Postharvest Quality of Jiro Persimmon Fruits
WANG Min1,TU Kang1,*,PAN Lei-qing1,MEI Wei-yun2
2010, 31(20):  459-463.  doi:10.7506/spkx1002-6630-201020097
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The postharvest Jiro persimmon fruits from Yunnan were used as the materials to explore the effects of 1-methylcyclopropene, nano-packaging and combinatorial treatments on the quality of postharvest Jiro persimmon fruits during storage at 20 ℃ through the determination of respiration intensity, ethylene release amount, firmness, weight loss, total soluble solids, titratable acids and ascorbic acid. Results indicated that 1.0 μL/L 1-MCP treatment exhibited better efficiency in decreasing respiration intensity, inhibiting ethylene release and attenuating the reduction of firmness for persimmon fruits than nanopackaging. However, compared with 1.0 μL/L 1-MCP treatment, nano-packaging exhibited a better effect on the inhibition of weight loss, attenuation of the increase of titratable acids, and the maintaining of ascorbic acid. Moreover, a synergistic effect was observed in the combinatorial treatment between 1.0 μL/L 1-MCP and nano-packaging, which could extend the storage period of postharvest persimmon fruits from 10 days to 15 days. However, three treatments did not exhibit an obvious influence on total soluble solids.

Quality Change of Antarctic Krill during Chilling Storage
LI Xue-ying1,CHI Hai1,2,YANG Xian-shi1,*,XU Zhong1,GUO Quan-you1
2010, 31(20):  464-468.  doi:10.7506/spkx1002-6630-201020098
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The quality change of Antarctic krill during the storage at 0 ℃ and 3 ℃ was evaluated by pH, meat productivity, soluble protein content and sensory evaluation. Meanwhile, the change in relative molecular mass of proteins from Antarctic krill was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Results indicated that pH in Antarctic krill exhibited a gradual increase during the period of storage for 24 h at 0 ℃ and 3 ℃, which were 8.21 ± 0.01 and 8.28 ±0.02, respectively. The meat productivity was decreased from (61.92 ± 2.50)% to (22.65 ± 6.81)% and (13.64 ± 2.72)%, respectively. Soluble protein content also exhibited a decrease and reduced to (19.0 ± 0.50) mg/(10 g wet weight) and (25.5 ±2.00) mg/(10 g wet weight), respectively. Totally 5 protein bands after 1-h storage at 0 ℃ and 3 ℃ was shown in the SDS-PAGE, which had molecular weights of 49.5, 32, 29, 26 kD and 13.2 kD, respectively. However, the protein with molecular weights of 29 kD exhibited the fastest degradation. The highest and lowest values of sensory evaluation were 9.5 ± 0.05, 9.4 ± 0.12, 1.3 ±0.10 and 1.0 ± 0.08, respectively. All of these investigations suggested that the quality of Antarctic krill could be quickly decreased due to its autolysis during storage at 0 ℃ and 3 ℃. Therefore, in order to achieve the best quality and edible properties of Antarctic krill, the optimal processing should be completed within 10 hours at 0 ℃ and 3 ℃ during storage.

Effect of BTH Treatment on Defense Enzymes in Postharvest Mango Fruits from Different Varieties
PAN Yong-gui,LIU Xin-hua,LI Shou-ying
2010, 31(20):  469-472.  doi:10.7506/spkx1002-6630-201020099
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Nang klangwan and Tainong mango fruits were used as the experimental subjects to conduct BTH treatments. The effect of BTH treatment on the activities of major defense enzymes such as phenylalanine ammonia-lyase (PAL), polyphenoloxiase (PPO) and peroxidase (POD) in postharvest fruits was evaluated to explore the disease-resistance mechanisms of mango fruits from different varieties. Results indicated that the activities of PAL, PPO and POD in Tainong mango fruits were obvious higher than those in Nang klangwan mango fruits during storage. However, after treated with BTH, the Mango fruits from both varieties exhibited an obvious increase in the activities of three enzymes. Meanwhile, more increase in the activities of three enzymes was observed in Tainong mango fruits. In addition, there was an obvious correlation between BTH-induced enhancement of disease resistance and the activities of PAL, PPO and POD in fruits.

Growth and Development Patterns of Hongyang Kiwi Fruits
DING-Jie1,LIU Shu-xiang1,SONG Hui-hui1,WANG Rui-ling1,QIN Wen1,2,*
2010, 31(20):  473-476.  doi:10.7506/spkx1002-6630-201020100
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The dynamic changes in size and weight of fruits, and the contents of total acid, carbohydrates including starch and soluble sugar, soluble solids, ascorbic acid and soluble proteins in Hongyang kiwi fruits during the growth period of 30-135 days after pollination were determined. Results showed that the growth curve of vertical and horizontal diameters for fruits exhibited a fast-slow-fast-slow growth pattern, which was S-shaped curve during the growth period of 30 - 135 days after pollination; the growth curve of fruit weight exhibited a triple S-shaped curve; the content of total acid reached up to the maximal value of 19.34 mmol/100 g on the 100th day, then exhibited a linear decline; the content of starch reached up to the highest level on the 105th day after pollination, then started to drop; the contents of soluble sugar and soluble solids exhibited an increase trend till the maturation of fruits, and a rapid increase trend at the late stage of fruit maturation was observed; the content of total soluble solids was up to 8.7% on 135th day; the contents of ascorbic acid and soluble proteins exhibited a gradual increase trend during fruit maturation, which climbed up to the maximal value of 181.17 mg/100 g and 132.04μg/g, respectively, on the 120th day, then exhibited a decrease till the maturation of fruits. Based on these analyses, the best quality of fruits can be achieved at the 120th day after pollination.

Non-enzymatic Browning of Pickled Jerusalem Artichoke during Storage
WANG Wei-dong1,2,SUN Yue-e1,LI Chao1,YANG Dong-mei1,ZHUANG Ping3
2010, 31(20):  477-480.  doi:10.7506/spkx1002-6630-201020101
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The effects of package materials and water used in preparation processing on the browning of pickled Jerusalem artichoke during storage were explored and physiochemical properties of pickled Jerusalem artichoke during storage were determined to explore the browning mechanisms. Results indicated that the browning of pickled Jerusalem artichoke during storage was non-enzymatic browning, which was mainly due to oxidative polymerization of polyphenols and Maillard reaction. The metal ions at the low concentration level did not result in browning. The browning of pickled Jerusalem artichoke exhibited a declined trend at the condition of adding anti-browning agents such as sodium erythorbate, disodium stannous citrate and EDTA. Moreover, disodium stannous citrate was the best anti-browning agent for pickled Jerusalem artichoke during storage with accelerated browning experiments.

Effect of Storage Temperature on Quality of Loquat Fruits from Different Cultivars
YANG Zhen-feng,WANG Zhen-zhe,JIN Xin
2010, 31(20):  481-484.  doi:10.7506/spkx1002-6630-201020102
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The effects of different storage temperatures (0 ℃ and 25 ℃) on the contents of total soluble solids, total titratable acids, juice productivity, relative conductivity, total phenols and lignin in Dahongpao and Ninghaibai loquat fruits were investigated. Results indicated that the quality of loquat fruits was deteriorated due to the decrease in the contents of total soluble solids, total titratable acids and juice productivity during storage. Low temperature storage (0 ℃) could maintain relatively higher levels of total soluble solids and total titratable acids, but accelerate the reduction of total phenols and result in flesh lignification. The content of lignin exhibited an obvious increase in the fruits during storage at 25 ℃. These results suggested that flesh lignification was a senescence phenomenon in postharvest loquat fruits, and inappropriate chilling storage will promote the incidence of flesh lignification.

Effect of Bleached Shellac Coating on Volatile Components of Apple during Storage at Room Temperature
ZHENG Hua,GAN Jin,ZHANG Hong*,MA Li-yi,ZHANG Wen-wen,ZHAO Hong
2010, 31(20):  485-489.  doi:10.7506/spkx1002-6630-201020103
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In order to investigate the effects of bleached shellac coating treatment on aromatic components in fruits during storage at room temperature, the volatile components in Shuijing Red Fuji apple during 15 to 60 days of storage were isolated by dynamic head-space adsorption method and analyzed by thermal cryo-trapping-gas chromatography/mass spectroscopy (TCTGC/MS). Results indicated that esters were the predominant compounds among all volatile components and the relative content of esters was account for 64%-80% of the total volatile components. Meanwhile, approximately 5%-10% α-farnesene was observed in intact fruits, which did not result in oxidation, senescence or damage of fruits. During the storage period at room temperature, 1-butanol, 2-methyl-1-butanol, 1,2-pentadiol and other alcohols were easily detected, which are helpful to maintain ester and other major substances as the aromatic components of fruits.

Kinetic Model of Quality Change for Trachinotus ovatus during Storage
HUANG Hui,LI Lai-hao*,YANG Xian-qing,HAO Shu-xian,MA Hai-xia,CEN Jian-wei,LI Sha
2010, 31(20):  490-493.  doi:10.7506/spkx1002-6630-201020104
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Total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and aerobic bacterial count of Trachinotus ovatus at different storage temperatures were investigated. The kinetic models of TVB-N, TBA and aerobic bacterial count were established to predict shelf life and control the quality change of Trachinotus ovatus during storage. Results indicated that TVB-N, TBA and aerobic bacterial count were increased during storage with the increase of storage time and temperature. The reaction model was first order and Arrhenius equation could be used to describe the change of TVB-N, TBA and aerobic bacterial count. The kinetic models of Trachinotus ovatus were t = (lnAt-lnA0)/(1.68×109×e-56600/RT) for TVB-N, t = (lnAt-lnA0)/(3.10×108× e-52090/RT) for TBA, t = (lnAt - lnA0)/(1.87 × 108 × e-47550/RT) for aerobic bacterial count. Therefore, the storage period of Trachinotus ovatus could be calculated using these models.

Technology Application
Development of Milk-vinegar Beverage
LI Min1,PAN Dao-dong1,2,*
2010, 31(20):  494-498.  doi:10.7506/spkx1002-6630-201020105
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Defatted milk powder and Zhenjiang white vinegar were used as the major materials to prepare the milk-vinegar beverage. The effects of other ingredients and their addition amounts on the stability, taste and flavor of milk-vinegar beverage were explored through single factor and orthogonal experiments. The optimal formula of milk-vinegar beverage were composed of 4% defatted milk powder, 7% sugar, 0.4% CMC-NaFH9, 0.1% xanthan gum, 0.02% acesulfame-K, 0.15% citric acid and 4 mL/100g white vinegar, respectively. The developed milk-vinegar beverage was characteristics of delicious taste, sweet and sour, rich nutrients, unique flavor and special aroma of milk and vinegar.

Antioxidant Activity of Soluble Polysaccharides from Brewer s Spent Grains and Development of a Compound Orange Juice Beverage with Them
FU Quan-yi,LI Lin,YU Xu-cong,YUAN Hui-juan,LIU Guo-qin,LI Bing*
2010, 31(20):  499-503.  doi:10.7506/spkx1002-6630-201020106
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Soluble polysaccharides were extracted from brewer s spent grains by ultra-fine grinding and ultrasound-assisted extraction method. Result showed that soluble polysaccharides had strong antioxidant activity. These soluble polysaccharides were used as the supplementary materials to develop a novel polysaccharide beverage. The optimal formula of this beverage (100mL) was composed of 2 g of soluble polysaccharides, 0.5430 g of total acid, 12.15 g of total sugar, 18.97 mg of vitamin C and 0.2029 g of protein. Therefore, this beverage is a high quality drink containing vitamin C and polysaccharides.

Application of Ultrasonic Technology in the Production of Corn Syrup Beverage
GE Ying-liang1,WANG Ji-wei1,JI Ya-li2,WANG Yu-wei1
2010, 31(20):  504-508.  doi:10.7506/spkx1002-6630-201020107
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The high-quality sweet corn from Northeast China was used as the raw material to prepare corn syrup beverage through ultrasonic technology. The optimal preparation processing parameters were crushing power of 600 W, crushing time of 7 s, crushing repeat time of 30, material-liquid ratio of 1:3, gelatinization temperature of 90 ℃, gelatinization time of 4 min and stabilizer amount of 0.05%. Compared with traditional processing, ultrasonic technology exhibited a better effect on tasteful, fragrant, and slightly yellowish and nutritious corn syrup beverage.

Preparation of Fiber-rich Corn Vermicelli
YANG Yu-min1,WANG Da-wei2,*
2010, 31(20):  509-512.  doi:10.7506/spkx1002-6630-201020108
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The processing technology for preparing fiber-rich corn vermicelli was optimized by single factor and orthogonal experiments. Results indicated that special corn flour with adding 6% high-quality dietary fiber, 4% bitter gourd powder, 6% Artemis sphaerocephala Krasch powder and 2.5% salt could prepare nutrient-rich corn vermicelli with excellent color and delicious taste, which was suitable for diabetes.

Development of a Purple Sweet Potato Beverage
MU Li-ping,LEI Ji*,LI Bo,LI Xiao-jiang
2010, 31(20):  513-517.  doi:10.7506/spkx1002-6630-201020109
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Purple sweet potato was used as the raw material to investigate the preparation processing of purple sweet potato beverage. The effects of sweet potato starch liquefaction by α-amylase and high temperature were compared, and then the starch was glycosylated by glucoamylase. The effect of treatment processing on anthocyanin was also explored on the basis of soluble solids, absorbance and color difference. Results indicated that the favorable hydrolysis of starch and the minimal loss of anthocyanin in purple sweet potato beverage could be achieved through following process: pulping of steamed sweet potato with water in double mass, then treating with 0.020 g/100mL α -amylase hydrolysis at 70 ℃ for 40 min, and followed by glycosylating with 0.04 g/100mL glucoamylase for hydrolysis at pH 5.0 for 40 min. An excellent beverage with attractive color, flavor and taste was developed by 30% purple sweet potato juice, 8% sucrose and 0.05% citric acid in soft water.

Processing Technology Optimization of Fermented Rice Cake with Sweet Potato
LI Xue,YU Chen,LI Xiu-juan,PAN Si-yi,XU Xiao-yun*
2010, 31(20):  518-521.  doi:10.7506/spkx1002-6630-201020110
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In this work, the processing parameters for fermented rice cake (FRC) were optimized through adding a certain amount of mashed sweet potato. The effects of steaming time and the addition amounts of sweet potato, water, baking soda and sugar on the quality of FRC with sweet potato were explored by single factor and orthogonal experiments on the basis of sensory evaluation and textural property analysis (TPA). The optimal processing parameters were achieved to be rice-sweet potatowater ratio of 10: 9: 7, fermentation time of 3 hours, the addition amounts of sugar and baking soda of 7% and 0.6‰, and steaming time of 13 minutes under normal pressure. The best quality of FRC with sweet potato was achieved at the optimal processing conditions.

Optimization of Processing of Salt-baked Chicken Wings
YANG Wan-gen,SUN Hui-gang,WANG Wei-dong,QIN Jie,SHEN Hai-peng
2010, 31(20):  522-526.  doi:10.7506/spkx1002-6630-201020111
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In order to reduce the amount of pigments and phosphate salts used in salt-baked chicken wings (SBCW), the technological processing and the formula of phosphate salts were optimized by single-factor and orthogonal experiments through evaluating the effects of baking time, baking temperature, soaking time in phosphate solution on color difference and sensory quality. Meanwhile, the effect of phosphate ratio on water-holding capacity of chicken was also explored through orthogonal experiments. Results indicated that the optimal parameters for producing SBCW were baking time of 110 min, baking temperature of 170 ℃ and soaking time of 3 h. The optimal ratio for sodium pyrophosphate, sodium tripolyphosphate and sodium hexametaphosphate was 2:1:1. The excellent sensory quality and higher water-holding capacity of salt-baked chicken wings were achieved under the optimal processing conditions.