Table of Content

25 August 2010, Volume 31 Issue 16
Processing Technology
Optimization of Microwave-assisted Extraction of Asparagus officinalis Leaves to Provide a Flavonoids-enriched Infusion for Instant Tea Production
CAI Guang-xia1,CHEN Ji-wang1,*,WANG Yuan-feng2,WEI Xin-lin2
2010, 31(16):  1-5.  doi:10.7506/spkx1002-6630-201016001
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In order to provide an Asparagus officinalis leaf infusion with higher content of flavonoids for asparagus instant tea production, key process conditions (i.e., microwave power, extraction duration and number, and ratio of liquid to material) for the microwave-assisted extraction of Asparagus officinalis leaves were optimized by response surface methodology. Under the following optimized extraction conditions: microwave power 560 W, ratio of liquid to material 17:1 (mL/g), extraction duration 32 s and extraction number 1, the extraction yield of flavonoids was 90.28%. The content of flavonoids in the asparagus instant tea produced was 58.41 mg/g (dry basis).

Prediction Models for the Amounts of Three Food Additives as Protective Agents for Amino Acids in Japanese Scallop Hydrolysate Subjected to Spray Drying
SUN Ping-ping,WANG Jie*,LI Wei-qing,SUN Jian-feng,MU Jian-lou
2010, 31(16):  6-10.  doi:10.7506/spkx1002-6630-201016002
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In order to protect the thermalsensitive substances in Japanese scallop hydrolysate like amino acids from spray drying caused damage, three food additives, namely β-cyclodextrin, modified starch and CMC were used to embed these substances. Japanese scallop meat was homogenized and added with neutral protease and papain for hydrolysis. The hydrolysate was then added with different amounts of the three food additives and subjected to spray drying in order to deal with the effects of their amounts on the retention ratio of amino acids in dried Japanese scallop powder. The results showed that when inlet temperature of 125 ℃, outlet temperature of 80 ℃ and ventilation flow rate of 0.9 m3/ min were used for the spray drying of Japanese scallop hydrolysate, the presence of 25.61% β-cyclodextrin, 25.52% modified starch and 2.96% CMC gave a retention ratio of amino acids of 56.43%, 18.81% higher than that in their absence. Box-Benhnken central composite experimental design was used to provide experimental data for setting up a regression model describing the relationship between the retention ratio of amino acids and the amounts of these three food additives, and response surface analysis was carried out to measure the interactive effects of the three independent variables on the dependent variable. The regression model proved reliable in predicting the retention ratio of amino acids.

Response Surface Methodology as an Approach to Optimize Process Parameters for Pectinase Treatment of Black Berry Slurry for Anthocyanin Extraction
LU Feng-bo1,LIU Gui-ling2,WANG Shuo1,HAN Yong-bin1,*,LI Wei3
2010, 31(16):  11-15.  doi:10.7506/spkx1002-6630-201016003
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To optimize the extraction of anthocyanins from black berry slurry based on pectinase treatment, a Box-Behnken experimental design for three pectinase hydrolysis conditions (namely, pectinase loading and reaction time and temperature) was used to provide experimental data for creating a quadratic regression model reflecting the relationship between the extraction yield of anthocyanins and the hydrolysis conditions and based on this, response surface methodology was used to optimize these hydrolysis conditions. The Design Expert software was employed to inversely resolve the created quadratic regression model, the results indicated that pectinase loading of 0.21%, reaction time of 1.46 h and reaction temperature of 42.7 ℃ were found optimum and that under the optimized conditions, the predicted value of the maximum extraction yield of anthocyanins was 0.645 mg/g, in close agreement with the experimental value. Analysis of pairwise linear correlation among the content of anthocyanins and Hunter colour L*, C* and h values was carried out, and it was found that C* value could represent the content of anthocyanins to a certain extent.

Macroporous Adsorption Resin for the Purification of Flavonoids from Seabuckthorn Pomace
JIAO Yan1,2,WANG Zhen-yu1,3,*
2010, 31(16):  16-20.  doi:10.7506/spkx1002-6630-201016004
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Considering overall adsorption and desorption capacity, X-5 resin was selected out of 7 types of macroporous resins to purify the crude flavonoids extract from seabuckthorn pomace. The optimum process conditions for purifying the crude flavonoids extract using X-5 resin were determined as follows: sample concentration 2 mg/mL, adsorption duration 2 h, amount of distilled water used for washing the resin 4 BV, and amount of 70% ethanol as desorption solvent 4 BV. Optimized purification gave a maximum recovery of flavonoids of 86.78% and an increase in the purity from 11.6% to 34.1%. X-5 resin was used repeatedly 6 times for flavonoids purification, and both the recovery and purity of flavonoids remained higher.

Microwave-assisted Acid Hydrolysis of Wheat B-starch and Preparation of Caramel Pigment from the Hydrolysate
CHEN Hong-xing1,2,GU Zheng-biao1,FANG Jian2,YU Xiao-hong2,LIU Han-wen2
2010, 31(16):  21-23.  doi:10.7506/spkx1002-6630-201016005
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Under the assistance of microwave irradiation, wheat B-starch was hydrolyzed with HCl solution, and the hydrolysate was used to prepare caramel pigment. Wheat B-starch exhibited more nearly complete hydrolysis under the assistance of microwave irradiation in comparison with routine heat treatment, with a much faster reaction rate. Some metal ions such as NaCl, KCl, FeCl3 and MgCl2 had promotional effect on the acid hydrolysis of wheat B-starch. In the presence of each of these salts in 0.05% HCl, wheat B-starch could be completely hydrolyzed in 6 to 8 minutes when microwave power of 580 W was used. A caramel pigment with a color intensity of 28947 EBC units was obtained by adding 4.0% aqueous ammonia (expressed as mass ratio of amino groups to reducing sugar content in the hydrolysate) to the wheat B-starch hydrolysate.

Effects of Different Extraction Processes on the Physico-chemical Properties of Tomato Skin Dietary Fiber
ZHENG Gang1,GUO Xiao-pei1,ZHAO Guo-hua1,2,*,WU Hong3
2010, 31(16):  24-28.  doi:10.7506/spkx1002-6630-201016006
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Four different extraction processes, namely sulfuric acid treatment, sodium hydroxide treatment, sequential treatment with sulfuric acid followed by sodium hydroxide and sequential treatment with trypsin followed by sulfuric acid were used to obtain total dietary fiber (TDF) from tomato skin, a byproduct of the tomato paste industry. The physicochemical properties (waterholding capacity, oil-holding capacity, swelling capacity, cation-exchange capacity and bile salt adsorption capacity) of the obtained TDF products were determined. Among the four extraction processes, sequential treatment with trypsin followed by sulfuric acid gave the best removal of impurities and the resultant product presented the highest soluble dietary fiber content and the best color. The proximate chemical composition and physico-chemical properties of the TDF products obtained using the four extraction processes were obviously different from those of the raw material. Both the TDF products obtained by sodium hydroxide treatment alone and in combination with sulfuric acid treatment had higher water-holding capacity (7.85 g/g and 8.7 4 g/g, respectively) and swelling capacity (4.9 mL/g and 5.5 mL/g, respectively), and the oil-holding and bile salt adsorption capacities of those obtained by sulfuric acid treatment alone and in combination with trypsin treatment were both high, reaching up to 5.49 g/g and 5.91 g/g, and 297.3 mg/g and 329.4 mg/g, respectively. Except sequential treatment with trypsin followed by sulfuric acid, all the three other extraction processes yielded TDF products with a cation exchange capacity higher than that of the raw material.

Optimization of Technological Conditions for Soybean Germination and Change in Chemical Composition during Germination
LI Xiao-mei
2010, 31(16):  29-32.  doi:10.7506/spkx1002-6630-201016007
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To optimize the germination technology of soybean, the effects of three technological conditions, namely temperature, humidity and germination time on isoflavone content, soybean odor evaluation and sprout morphology evaluation were addressed by single-factor and orthogonal array design methods. Also, exploration of the change in chemical composition of soybean during germination was carried out. The optimum values of the above three conditions were found to be: temperature 24 ℃, humidity 85% and germination time 96 h. Under the optimized conditions, soybean sprouts having an isoflavone content of 3.616 mg/g and no soybean odor were obtained. During 120-hour germination, the contents of fat, protein, sugars and ash declined, but those of amino nitrogen and isoflavone markedly ascended, and those of free iron, calcium and magnesium slightly increased. Moreover, soybean odor always tended to decrease over the whole germination period.

Application of RSM to Microwave-assisted Extraction Optimization of Flavanoids from Blueberry Leaves
ZHANG Yu-xiang,QU Hui-ge*,YANG Run-ya,YU Bo,SUN Huan,SHENG Hua-kai
2010, 31(16):  33-37.  doi:10.7506/spkx1002-6630-201016008
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In order to obtain optimum conditions for extracting flavonoids from blueberry leaves under the assistance of ultrasonic, on the basis of single factor investigations, Box-Behnken experimental design was used to provide experimental data for establishing a regression model describing the extraction of flavonoids, and response surface and contour diagrams with the extraction yield of flavonoids as response were plotted for analyzing the pairwise interactive effects of ethanol concentration, material-to-liquid ratio, extraction temperature, microwave power and extraction duration on the response. The analysis of variances revealed that ethanol concentration, extraction temperature and microwave power had significant effect on the extraction yield of flavonoids. Extraction temperature of 72 ℃, ethanol concentration of 64% and microwave power of 456 W were found optimum. Under the optimized conditions, the maximum extraction yield of flavonoids was 4.232%.

Ultrasonic Extraction Optimization of Total Saponins from Opuntia Milpa Alta
LIU Jian-jian,HE Ji-guo*
2010, 31(16):  38-41.  doi:10.7506/spkx1002-6630-201016009
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Objective: To develop a colorimetric method for determining the content of total saponins in Opuntia Milpa Alta and optimize the ultrasonic-assisted ethanol extraction of total saponins from the plant. Methods: For determining the content of total saponins in Opuntia Milpa Alta, a standard curve of oleanolic acid was plotted. Optimization of the ultrasonic-assisted ethanol extraction of total saponins was performed using single factor and orthogonal array design methods. Results: The relative standard deviations of precision and stability of the method were 1.13% and 0.52% respectively, and the average spike recovery was 99.17%, with a RSD of 1.86%. The optimum ultrasonic extraction conditions were found to be: ethanol concentration 80%, solid-to-liquid ratio 1:15, extraction temperature 70 ℃, ultrasonic power 100 W and extraction duration 70 minutes. Conclusion: The developed method for total saponin determination is simple, feasible and accurate. The optimized extraction process is efficient, economical and quick, thereby being easy to popularize.

Change and Prediction Models for Sodium Nitrite Residue in Minced Pork during Processing
SHAO Li-jun,HUAN Yan-jun*,GAN Chun-sheng,LI Pei-hong,LI Yan
2010, 31(16):  42-46.  doi:10.7506/spkx1002-6630-201016010
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Mince pork was cured and then cooked. The effects of curing time, sodium nitrite amount, cooking temperature and mode (atmospheric and high-pressure cooking) on sodium nitrite residue in minced pork were examined. Meanwhile, prediction models for sodium nitrite residue in minced pork as a function of sodium nitrite amount and cooking time were set up, and validation of the prediction models was carried out. At curing stage, sodium nitrite residue determined was positively correlated with the amount of the substance added, but negatively correlated with curing time. At cooking stage, the correlation between sodium nitrite residue and its amount was also positive, but sodium nitrite residue had a negative correlation with cooking temperature and time. The developed prediction models with coefficients of determination of 0.939 for cooking at 80 ℃ and 0.888 for cooking at 121 ℃ showed that high-press cooking had larger effect on the decent rate of sodium nitrite residue than atmospheric cooking, and that cooking temperature had extremely significant effect on sodium nitrite residue (P<0.01). The experimental and predicted values of sodium nitrite residue at the above two cooking temperatures were closely similar, and the relative error was less than 10%.

Air-drying Ripening Process of Cured Japanese Sea Bass and Its Effect on Proteolysis and Sensory Quality
ZHANG Hui-li1,YU Xiang1,ZHANG Hong2,JIN Guo-feng1,ZHANG Jian-hao1,*,
2010, 31(16):  47-51.  doi:10.7506/spkx1002-6630-201016011
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Fresh Japanese sea bass was used as raw material for dry-cured fish production. The orthogonal array design method was used to study the effects of drying temperature, relative humidity, drying time and salt amount on the quality and proteolysis of dry-cured fish products. Proteolysis index (PI, %) gradually increased with rising temperature, while total free amino acid (ΣFAA) showed a tendency to initially increase and then decrease. Drying temperature had significant effect (P <0.01) on both PI and Σ FAA. The optimum process conditions obtained by regression optimization for maximizing Σ FAA were as follows: drying temperature 15-29 ℃, relative humidity 70%-82%, drying time 72 h and salt amount 4.5% (on the basis of fish weight). The dry-cured product obtained under these conditions contained 2.84% of salt and 64.33% of moisture and scored the highest sensory score.

Ultrasonic-microwave Synergistic Extraction of Polysaccharides from Cultivated Ganoderma lucidum
HUANG Sheng-quan1,2,LI Jin-wei3,NING Zheng-xiang1,*
2010, 31(16):  52-55.  doi:10.7506/spkx1002-6630-201016012
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Different cultivated species of Ganoderma from different geographic origins were analyzed for their chemical components, and Ganoderma lucidum from Zhejiang province was found to contain higher content of non-reducing sugars and lower contents of protein and ash and therefore, it was the selected raw material for extracting polysaccharides. The extraction process with water as extraction solvent on an ultrasonic-microwave synergistic extractor was optimized using response surface methodology based on Box-Behnken experimental design. Meanwhile, the structural change of Ganoderma lucidum before and after extraction was observed under scan electron microscope (SEM) and the extraction method developed in this study and the conventional water bath extraction method were compared for differences in the extraction yield of polysaccharides and the infrared spectral characteristics of the extraction products. The optimum conditions for the ultrasonic-microwave synergistic extraction of polysaccharides were found to be: raw material amount 100 g, microwave power 284 W, extraction duration 12 min, and material-to-liquid ratio 1:11.6 (g/mL). Ultrasonic-microwave synergistic extraction was time saving and gave a higher extraction yield of polysaccharides, 3.27%, when compared with the conventional water bath extraction method (115.6% extraction yield of polysaccharides).

Vinegar Production from Pineapple Waste by Semi-Solid State Fermentation
GU Cai-qin,CHEN Wan-ling,ZHENG Zhi-mao,ZHU Dong-xue,LAI Jian-ping,LIN Jin-ying, LAI Ya-ping,ZENG Qing-zhu,ZHOU Yong-qiang
2010, 31(16):  56-60.  doi:10.7506/spkx1002-6630-201016013
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Using pineapple waste that is a by-product of the pineapple processing industry and consists of residual pulp, peels and skin as fermentation substrate, semi-solid state fermentation in a twice sugar supplement mode was carried out for vinegar production. Wine yeast and acetobacter powder AS 1.01 were inoculated for alcoholic and acetic acid fermentation, respectively. Process conditions for pineapple waste fermentation were optimized in order to achieve higher acid production in a shorter time. Amount of inoculated wine yeast of 0.3%, fermentation temperature of 22 ℃, sugar content of 16 °Brix, pH value of 3.5 and fermentation time of 6 days were found optimum for alcoholic fermentation, and the optimum conditions for acetic acid fermentation were found to be: amount of added glucose 2%, initial alcohol concentration 8%, fermentation temperature 29 ℃, amount of inoculated acetobacter powder AS 1.01 of 0.09% and fermentation time ranging from 3 to 4 days. Under these optimum conditions, the acid production (calculated as acetic acid) was up to 6.78 g/100 g of fermented pineapple waste, and the conversion ratio of acetic acid was 82.5%. After soaking, filtration and aging for 1-2 months, the total acid content in the final vinegar product was 3.672 g/100 mL, which had golden yellow color, both vinegar and pineapple flavor and a soft and refreshing taste, and was clear and transparent. Semi-solid state fermentation gave a higher total acid production in a shorter time in comparison with liquid-state fermentation.

Optimization of Ultrasonic-assisted Salt Extraction of Glycosaminoglycan from Antler
ZHENG Lei,JIN Xiu-ming,ZHAO Yu-hong*
2010, 31(16):  61-66.  doi:10.7506/spkx1002-6630-201016014
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Antler was used as raw material to extract glycosaminoglycan (GAG) with alkaline NaCl solution under the assistance of ultrasonic. On the basis of one-factor-at-a-time investigations, Box-Behnken experimental design was employed to provide experimental data for establishing a quadratic regression model describing GAG yield as a response to ultrasonic power, length of ultrasonic treatment and liquid-to-material ratio and these parameters were optimized by response surface methodology. Length of ultrasonic treatment of 19.57 min, ultrasonic power of 401.2 W and liquid-to-material ratio of 43.8:1 were found optimum. Under these optimum conditions, the GAG yield was 3.29% and higher than that of protease hydrolysis based extraction. This method is easy to operate, simple and cost-saving.

Optimization of Ultrasound-assisted Extraction of Polysaccharides from Radix Glycyrrhiza Using
ZHANG Lin,FAN Jin-ling,ZHU Wen-xue,MA Hai-le,FAN Cui-ying
2010, 31(16):  67-71.  doi:10.7506/spkx1002-6630-201016015
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A three-level Box-Behnken design, combined with canonical and ridge analyses, was employed to optimize some process parameters for the ultrasound-assisted extraction of polysaccharides from Radix Glycyrrhiza, one of the most valued traditional Chinese medicines. The most critical factors affecting the extraction of polysaccharides from Radix Glycyrrhiza, were determined to be ultrasound power, length of extraction and extraction temperature. Using multiple regression analysis, the Box-Behnken experimental results were fitted into two quadratic polynomial models describing Radix Glycyrrhiza ploysacchride yield or purity as a function of the 3 above-mentioned factors, with determination coefficients of 98.98% and 91.67%, respectively. The canonical analysis of the established models revealed that three eigenvalues had different signs, indicating a saddle stationary surface. The optimal conditions for the extraction of polysaccharides from Radix Glycyrrhiza were determined using the ridge analysis to be: extraction time, 64.5 min; extraction temperature, 64.6 ℃; and ultrasound power 580 W. Under these conditions, the predicted and experimental values of Radix Glycyrrhiza ploysacchride yield were 9.62% and 9.56%, and those of Radix Glycyrrhiza ploysacchride purity were 71.36% and 65.65%, respectively. The Radix Glycyrrhiza ploysacchride yield given by conventional waterbath extraction for 1 h at 65 ℃ was only the first three of that given by optimized ultrasoundassisted extraction for 1 h at the same extraction temperature. According to infrared spectrometric analysis, the structure of Radix Glycyrrhiza polysaccharides obtained by the two methods were basically identical.

Extraction and Purification of Xanthophyll from Corn Gluten Meal
LI Xiu-xia1,SUN Xie-jun1,HAN Lu-jia2
2010, 31(16):  72-77.  doi:10.7506/spkx1002-6630-201016016
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In order to improve the utilization of corn gluten meal (CGM), the alcalase hydrolysis process of the material for the extraction of xanthophylls and zeaxanthin and the high speed counter current chromatographic (HSCCC) separation of xanthophylls and zeaxanthin from the residue left after alcalase hydrolysis were explored. The effects of pH, temperature, enzyme loading, substrate concentration and hydrolysis duration on the extraction efficiency of xanthophylls were examined. The results showed that the extraction efficiency of xanthophylls was increased significantly by enzyme treatment when compared with the traditional solvent extraction method (P < 0.05). Considering extraction efficiency, production cost and experimental feasibility, the optimum conditions for CGM hydrolysis were determined to be: pH 7.0, reaction temperature 40 ℃, enzyme loading 4000 U/g, substrate concentration 110 g/L and hydrolysis duration 2 h. Under these optimum conditions, the extraction efficiency of xanthophylls was 59.57μg/g. The binary phase system employed for the preparative HSCCC purification of the crude extract was composed of n-hexane, ethyl acetate, ethanol and water (4:1:4:1, V/V). HPLC determination revealed that the purities of the trans-xanthophylls and the trans-zeaxanthin were 90.85% and 91.21%, respectively. Preparative HSCCC could not thoroughly separate the trans and cis isomers of xanthophylls and zeaxanthin, although the technique succeeded in separating the two compounds.

Extraction and Free Radical Scavenging Activity of Total Flavonoids from the Leaves of Ficus carica Linn.
YANG Run-ya,MING Yong-fei,WANG Hui
2010, 31(16):  78-82.  doi:10.7506/spkx1002-6630-201016017
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The orthogonal experimental design method was employed to study the ultrasonic-assisted extraction process of total flavonoids from the leaves of Ficus carica Linn. and their scavenging activities against hydroxyl and superoxide anion free radicals were evaluated. The optimum conditions for extracting total flavonoids from the leaves of Ficus carica Linn. were found to be: ethanol concentration 40%, material-to-liquid ratio 1:60 (g/mL), extraction temperature 60 ℃ and length of ultrasonic treatment of 50 min. Under these optimum conditions, the extraction efficiency of total flavonoids reached as high as 25.04 mg/g. Extraction temperature had the most important effect on the extraction of total flavnoids from the leaves of Ficus carica Linn., followed by length of ultrasonic treatment, material-to-liquid ratio and ethanol concentration. The total flavonoids extract from the leaves of Ficus carica Linn. had marked scavenging effects on both hydroxyl and superoxide anion free radicals in a concentration-dependent fashion.

Optimization of Flavonoids Extraction from Artemisia rupestris L. by Response Surface Methodology
FANG Mei-zhu,CHAO Qun-fang*,LAN Yan,LIU Xiao-ning,XU Xin,FAN Yong-hong,ZHANG Fu-chun
2010, 31(16):  83-86.  doi:10.7506/spkx1002-6630-201016018
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In order to develop an optimal process for the ultrasonic-assisted extraction of flavonoids from Artemisia rupestris L., some crucial process conditions, namely ethanol concentration, material/liquid ratio and length of ultrasonic treatment were optimized using response surface methodology. Ethanol concentration of 76%, material/liquid ratio of 1:1 and length of ultrasonic treatment of 32 min were found optimum. Under the optimized conditions, the yield of flavonoids was 4.50%, with a 34% increase than before optimization.

Identification and Extraction Technology of Melanin from Auricularia auricula
LI Qi,HOU Li-hua,LIU Xin,LI Wei-lin,MA Ai-min*
2010, 31(16):  87-92.  doi:10.7506/spkx1002-6630-201016019
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Auricularia auricula melanin was measured for its solubility and UV and infrared spectral characteristics. Meanwhile, optimization of its extraction technology was conducted. The melanin was soluble in alkaline solution, but insoluble in water, acid solution and organic solvents. The UV and infrared spectral characterization indicated that the melanin had a structure identical to that of synthetic tyrosine melanin, and belonged to the group of 3,4-dihydroxy phenylalanine (DOPA) melanins. The one-factor-at-a-time and orthogonal array design methods were used to optimize the ultrasonic-assisted extraction technology of Auricularia auricula melanin, and extraction duration of 80 min, ultrasonic power of 80 W, NaOH concentration of 1.25 mol/L, material-to-liquid ratio of 1:30 were found optimum, and the crude extract yield reached up to 9.107% under these optimum conditions. Ultrasonic-assisted extraction has some advantages over conventional methods, such as simplicity, rapidity, better effectiveness, and so on.

Effect of Ultra-high Pressure Homogenization on the Microflora of Watermelon Juice
PAN Jian,LIN Chun-ming*,WANG Li,YANG Yi,BIAN Hui-xi,GAO Xiang-lan
2010, 31(16):  93-96.  doi:10.7506/spkx1002-6630-201016020
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To figure out the relationship between ultra-high pressure homogenization (UHPH) treatment and survival of microorganisms, watermelon juice was homogenized under pressures ranging from 0 to 150 MPa and its microbiological indexes were examined. After homogenization at 150 MPa , the total bacterial count (TBC) of watermelon juice decreased by 2.0 to 2.3 logarithm unites, and the total yeast and mold count decreased by 3.1 to 3.5 logarithm unites, but the Bacillaceae count changed little. After once homogenization at 150 MPa , watermelon juice with an initial TBC of 1.0×104 CFU/mL could meet the requirements of the national food hygienic standards, and the overall sensory evaluation was similar to that of freshly squeezed watermelon juice. Although watermelon juice with a higher initial TBC after repeated UHPH treatment could also meet the requirements of the national food hygienic standards, its overall sensory evaluation exhibited a decrease.

Preparation and Functional Properties of Protein Isolates from Pumpkin Seeds
FAN San-hong,LIU Yan-rong,YUAN Chao
2010, 31(16 ):  97-100.  doi:10.7506/spkx1002-6630-201016021
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Protein isolates from pumpkin seeds were obtained by alkaline extraction and acid precipitation. The extraction process was optimized by orthogonal array design method, and some functional properties of the protein isolates were determined. The results showed that the optimum process conditions for the extraction of protein isolates from pumpkin seeds were as follows: pH 11.0; extraction temperature 50 ℃; solid-to-liquid ratio 1:30; and extraction duration 1.5 h. Under these conditions, the extraction yield and the protein purity were up to 85.52% and 91.07%, respectively. The isoelectric point of the protein isolates was around 5.5, and both the water-binding and oil-binding capacities approximately ranged from 1.2 to 1.6 g/g, and the emulsifying capacity was over 80% under a suitable pH, but the foaming capacity was relatively weak.

Ultrasonic-microwave Synergistic Extraction and Antioxidant Activity of Total Flavonoids from Wikstroemia indica (Linn.) C.A. Mey.
LI Jiao-jiao,LI Chao*
2010, 31(16):  101-105.  doi:10.7506/spkx1002-6630-201016022
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We report the response surface optimization of the process of extracting total flavonoids from Wikstroemia indica (Linn.) C.A.Mey with an ultrasonic-microwave synergistic extractor and the subsequent evaluation of antioxidant activity of the extract. Based on a series of one-factor-at-a-time investigates, Box-Behnken experimental design was employed to provide experimental data for developing a regression model with the extraction yield of total flavonoids as dependent variable and three process conditions, namely ethanol concentration, length of extraction and microwave power as independent variables, and the interactive effects of the three independent variables on the dependent variable were analyzed. The optimum process conditions for extracting total flavonoids from Wikstroemia indica (Linn.) C.A.Mey were determined as follows: ethanol concentration, 70%; length of extraction, 123 s; and microwave power, 419 W. Under such conditions, the experimental value of extraction yield of total flavonoids was 1.172%, in substantial agreement with the predicted value of 1.162%. This demonstrates that the developed regression model could give an accurate prediction of extraction yield of total flavonoids. The total flavonoid extract in concentration ranges from 13.16 to 78.96μg/mL and from 0.43 to 52.64μg/mL could scavenge both DPPH and hydroxyl free radicals in a significant concentrationdependent way, with scavenging ratios ranging from 20.87% to 71.11% and from 9.04% to 52.21%, respectively.

Optimization of Extraction of Triterpenoids from Schisandra chinensis (Turcz.) Baill by Response Surface Methodology
LI Bin,LI Yuan-su,MENG Xian-jun*,XUE Xue,WANG Yan-qun
2010, 31(16):  106-110.  doi:10.7506/spkx1002-6630-201016022
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On the basis of one-factor-at-a-time investigations, a 20-run central composite design (CCD) involving in 3 factors at 5 levels was used to provide experimental data for optimizing the utrasonic-assisted extraction of triterpenoids from Schisandra chinensis (Turcz.) Baill by response surface methodology (RSM). The optimum conditions for the utrasonic-assisted extraction of triterpenoids from Schisandra chinensis (Turcz.) Baill were determined to be: ultrasonic frequency 68 Hz, length of extraction 48 min and ethanol concentration 64%. Under the optimized conditions, the experimental yield of triterpenoids was (2.534 ± 0.244)%, which was in good agreement with its predicted counterpart.

Microwave-vacuum Drying Characteristics and Drying Quality of Strawberry Slices
ZHU De-quan1,QIAN Liang-cun2,SUN Lei1,DING Zheng-yao1
2010, 31(16):  111-116.  doi:10.7506/spkx1002-6630-201016024
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To improve the drying productivity and the quality of dried fruits, and to decrease the drying energy consumption, experiments were conducted to study the microwave-vacuum drying characteristics of strawberry slices and the quality of their dried products. The quadratic regression orthogonal design method was employed to establish regression mathematical models describing the relationships between the rehydration ratio of dried strawberry slices, vitamin C retention ratio or the energy consumption durinzg drying and drying power, sample thickness and drying chamber pressure. The effects of these variables on these functions were dealt with. Decreasing sample thickness and drying chamber pressure and increasing drying power could individually result in a higher dehydraation rate. The rehydration ratio of dried strawberry slices and vitamin C retention ratio became both higher, with increasing sample thickness or decreasing drying chamber pressure. The energy consumption during drying tended downward, as sample thickness and drying power increased or drying chamber pressure increased. The optimum process parameters for drying strawberry slices were determined by multivariable nonlinear optimization method as follows: drying power, 6.18 W/g; sample thickness, 5.05 mm; and drying chamber pressure, 55.19 Pa.

Optimization of Ultrasonic-assisted Extraction of Polysaccharides from Enteromorpha prolifera by Response Surface Methodology
GUO Lei1,2,CHEN Yu1
2010, 31(16):  117-121.  doi:10.7506/spkx1002-6630-201016025
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We report the use of response surface methodology for the optimization of process conditions for the ultrasonicassisted hot water extraction of polysaccharides from Enteromorpha prolifera. The effects of three independent variables (namely, extraction temperature, length of extraction and ratio of water to material) on the yield of polysaccharides from E. prolifera (PEP) were evaluated. Extraction temperature of 80 ℃, length of extraction of 28 min and ratio of water to material of 63:1 (mL/g) were found optimum. Under these optimized conditions, the experimental value of PEP yield was 25.84 mg/g, in good agreement with the predicted value. Therefore, the optimized process is very reliable.

Effect of Refining on the Physico-chemical Properties and Nutritional Composition of Solvent Extraction-derived Flaxseed Oil
REN Hai-wei
2010, 31(16):  122-127.  doi:10.7506/spkx1002-6630-201016026
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The changes in physico-chemical properties, fatty acid composition and vitamin E content of solvent extractionderived flaxseed oil during the refining process consisting of degumming, alkaline treatment and bleaching, deodorization were measured in order to address the effect of refining on the physico-chemical properties and nutritional composition of solvent extraction-derived flaxseed oil. Over the whole refining process, the content of phospholipids and acid value markedly decreased, from 1.541 to 0.163 g/100 g and from 2.826 to 0.635 mg KOH/g, respectively. However, no obvious change in iodine value, saponification value and refraction index was observed. The capillary column gas chromatographic analysis revealed that solvent extraction-derived flaxseed oil contained 4 saturated fatty acids (mainly hexadecanoic acid and stearic acid) and 6 unsaturated fatty acids (mainly linolenic acid, linoleic acid and oleic acid). Refining had little effect on the fatty acid composition and total fatty acid content in solvent extraction-derived flaxseed oil, but the relative content of linolenic acid presented an obvious decrease, especially at the stages of bleaching and deodorization. The refining process gave a vitamin E loss of up to 49.19%, indicating that the nutritional composition of solvent extraction-derived flaxseed oil was greatly affected by the refining process.

High Pressure Microwave-assisted Extraction of Arctiin from Fructus Arctii
LI Chao,WANG Wei-dong*,TANG Shi-rong,QIN Wei-dong,CHEN Hua
2010, 31(16):  128-134.  doi:10.7506/spkx1002-6630-201016027
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In this study, we investigated the high pressure microwave-assisted extraction (HPME) optimization of arctiin from Fructus Arctii, analyzed the effect of HPME on the cell wall structure of Fructus Arctii and made a comparison between HPME and three other methods, including atmospheric microwave-assisted extraction, Soxhlet extraction and heat reflux extraction. The optimum process parameters for arctiin extraction by HPME were determined as follows: microwave power 700 W, length of extraction 197 s and extraction pressure 0.4 MPa. Under such conditions, the arctiin yield was 9.010%. HPME had the advantages of efficiency and rapidity over the three other methods. This is likely to be due to tissue structure collapse and cell wall disruption caused by microwave irradiation in high pressure environment. In conclusion, HPME is a feasible method for arctiin extraction from f Fructus Arctii.

Effect of Steeping in Natrium Bisulfurosum Suspension of Saccharomyces cerevisiae on Corn Starch Production
LIU Jun-mei1,WU Jie2,WANG Jin-zhi2,LI Zhuo-wei3,ZHAO Ya-nan1,HU Yao-hui1,*
2010, 31(16):  135-138.  doi:10.7506/spkx1002-6630-201016028
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A two-step steeping method was used to produce corn starch. In the second step, a natrium sisulfurosum suspension of Saccharomyces cerevisiae was used to steep corn. Through single factor investigations, the optimum conditions for the first step were determined to be: natrium sisulfurosum concentration 0.15 g/mL, lactic acid concentration 0.3 g/mL, steeping temperature 50 ℃ and steeping time 10 h, and those for the second step were as follows: steeping temperature 40 ℃, steeping time 24 h, natrium sisulfurosum concentration 0.1 g/mL and inoculum size 5% (V/V). This steeping method could largely shorten production cycle and lower the cost of starch production.

Optimization of Enzymatic Hydrolysis of Swimming Crab Waste for Preparing Protein Hydrolysate
TAO Xue-ming,WANG Ze-nan*,YU Shun-huo, ZHANG Jian-fen
2010, 31(16):  139-144.  doi:10.7506/spkx1002-6630-201016029
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This study investigated the optimization of the preparation of protein hydrolysate from swimming crab waste (SCW) via enzymatic hydrolysis using single-factor and orthogonal array design methods. Among 6 proteases tested, alkaline protease was found optimum for SCW hydrolysis. The optimum hydrolysis conditions for achieving a maximum degree of hydrolysis were determined as follows: reaction temperature 55 ℃, pH 8.5 and enzyme dosage 1000 U/g for a hydrolysis duration of 3.0 h. Under these conditions, the maximum degree of hydrolysis was up to 26.68%. Hydrolysis temperature had the most important effect on the degree of hydrolysis of SCW, followed by enzyme dosage. The hydrolysis product of SCW was smaller than 10 kD in molecular weight. The total amino acid content in the hydrolysate was 1046.7 mg/L, and the total essential amino acid content was 382.5 mg/L, accounting for 36.54% of the total amino acids, and the total content of 4 major taste amino acids was 412.6 mg/L, accounting for 39.42% of the total amino acids. The protein hydrolysate of SCW has high nutritional value and broad application prospect.

Optimization of Key Process Conditions for the Making of Yangzhou-style Large Meatballs
ZHOU Xiao-yan,TANG Jian-hua,CHEN Jian,WANG Xiao
2010, 31(16 ):  145-150.  doi:10.7506/spkx1002-6630-201016030
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Four key process conditions affecting the overall sensory quality of Yangzhou-style large meatballs, i.e., salt and starch amounts, ratio of fat meat to lean meat and cooking time at 7 different levels were investigated by one-factor-at-a-time method. The optimum levels of the process conditions for achieving a maximum overall sensory score of Yangzhou-style large meatballs were determined by orthogonal array design method as follows: ratio of fat meat to lean meat 5:5, salt amount 3 g, starch amount 10 g and cooking time 120 min. Meanwhile, the changes of tenderness, hardness and moisture content of Yangzhou-style large meatballs during cooking were measured and correlation analysis among the overall sensory score, tenderness, hardness and moisture content of Yangzhou-style large meatballs was made.

Analysis & Detection
Electric Nose Analysis of the Effect of Cooking Time on the Flavor of Three Species of Edible Mushroom Soups
LI Qin,ZHU Ke-xue,ZHOU Hui-ming*
2010, 31(16):  151-155.  doi:10.7506/spkx1002-6630-201016031
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In order to find a robust method to evaluate mushroom soup flavor, three species (shiitake, Agaricus bisporus and Boletus edulis) of edible mushroom soups at different cooking times were analyzed by electric nose. The data obtained were analyzed by the methods of principle component analysis (PCA) and linear discrimination analysis (LDA). PCA failed to distinguish mushroom soups from the same species at different cooking times, but could succeed in distinguishing mushroom soups from different species. However, LDA could effectively distinguish both cooking time and mushroom species.

Determination of Volatile Compounds in ‘Chuliang’ Longan Using Headspace Solid-phase Microextraction and GC-MS
ZHANG Yi1,2,GAO Bei1,2,XU Yu-juan1,WEN Jing1,PAN Si-yi2,ZHANG Ming-wei2,3,*
2010, 31(16):  156-160.  doi:10.7506/spkx1002-6630-201016032
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This paper describes a rapid headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometric (GC-MS) method for determining the volatile compounds in ‘Chuliang’ longan. Qualification was performed by both mass spectral and retention index library searching. For semi-quantification, an internal standard solution (IS) of cyclohexanone was used. Operating conditions for headspace solid-phase micro-extraction and GC-MS were optimized. The precision RSDs for the predominant compounds in ‘Chuliang’ longan ranged from 2.12% to 9.08%. Forty-one volatile compounds were detected in ‘Chuliang’ longan and trans-ocimene (81.2%), ethanol (1.92%), allo-ocimene (1.39%), γ-terpinene (0.30%), β-myrcene (0.30%) and linalool (0.26%) were the predominant compounds. The presented method is of simple operation and most suitable for the determination of volatile compounds in ‘Chuliang’ longan.

Determination of Total Flavonoids in Flos Ionicera Using Ion Liquid Modified Glassy Carbon Electrode
LI Hong-bo1,2,JIN Gen-di2,DU Shi2,REN Yan-yan2,HU Xiao-ya2
2010, 31(16):  161-164.  doi:10.7506/spkx1002-6630-201016033
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A glassy carbon electrode modified with hydrophobicity 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6/GCE) was fabricated. Differential pulse stripping voltammetry was used to investigate the electrochemical behavior of luteolin at the modified electrode in 0.2 mol/L phosphate buffer solution, pH 7.0 and a new method for determining total flavonoids in Flos Ionicera was established. It was found that the peak potentials for oxidation and reduction both shifted negatively by 15 mV at the modified electrode as compared with the corresponding bare electrode in 0.2 mol/L phosphate buffer solution (pH 7.0) containing 3 × 10-9 mol/L luteolin and higher oxidation and reduction peak currents of luteolin at the modified electrode were observed. Further experiments demonstrated that oxidation peak current increased linearly with increasing luteolin concentration within the range from 1.0 × 10-10 to 1.6 × 10-8 mol/L with a detection limit of 3.2 × 10-11 mol/L and the range of spike recovery at four levels was between 98.7% and 103.6%. The method is simple, fast, sensitive and accurate, thereby providing an available approach for the determination of total flavonoids in Flos Ionicera.

A Comparative Study of Volatile Components of Sichuan Pepper Oil Resins Derived from Supercritical Fluid (CO2) Extraction and Ultrasonic-assisted Extraction
CAO Yan-ping1,ZHANG Dong2,*
2010, 31(16):  165-167.  doi:10.7506/spkx1002-6630-201016034
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Sichuan peppers from Qingxi town, Hanyuan county were subjected to supercritical carbon dioxide extraction (SCDE) or ultrasonic-assisted extraction (UAE) in order to obtain Sichuan pepper oil resin. SCDE-derived and UAE-derived Sichuan pepper oil resins were analyzed by GC-MS for their volatile composition and their aroma characteristics were evaluated by triangle test in terms of aroma similarity and intensity. The results revealed that SCDE-derived and UAE-derived Sichuan pepper oil resins had different volatile compositions but similar aroma characteristics. A total of 33 volatile compounds were found in SCDE-derived Sichuan pepper oil resin, of which, the predominant ones were 6-octadien-3-ol (47.18%), 3,7-dimethyl- 1,6-octadien-3-ol (12.11%) and D-Limonene (10.59%). The number of the volatile compounds found in UAE-derived Sichuan pepper oil resin was 18 and among these 18 volatile compounds, 1-ethyl-6-ethylidene cyclooctene had the highest relative content, reaching up to 32.04%, followed by D-Limonene (20.92%), linalyl acetate (12.11%) and 3,7-dimethyl-1,6-octadien-3-ol (10.92%).

Rapid Nondestructive Determination of Moisture and Protein Contents in Alaska Pollock Surimi by Near Infrared Reflectance Spectroscopy (NIRS)
WANG Xi-chang,LU Ye,LIU Yuan
2010, 31(16):  168-171.  doi:10.7506/spkx1002-6630-201016035
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In order to achieve rapid nondestructive determination of moisture and protein contents in Alaska pollock surimi, near-infrared quantitative models were established by fitting the near-infrared diffuse reflectance spectral data of Alaska pollock surimi with its chemical values. The models were further developed by partial least square (PLS) regression and the correlation coefficients of the calibration models obtained were above 0.96 and 0.98, respectively, which gave more reliable prediction than its near-infrared transmission counterpart. The RSD values for 10 replicate predictions of moisture and protein contents in Alaska pollock surimi were both less than10% and the relative percentage difference (RPD) values were above 3, showing excellent effectiveness of the models developed in this study in predicting moisture and protein contents in Alaska pollock surimi.

Analysis of Adenosine and Cordycepin in Cordyceps militaris (L.) Link by Reversed Phase-High Performance Liquid Chromatography
LIU Xiao-fang,XUE Chang-hu*,CHANG Yao-guang
2010, 31(16):  172-175.  doi:10.7506/spkx1002-6630-201016036
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In this paper, a RP-HPLC method for determining the contents of adenosine and cordycepin in Cordyceps militaris ( L.) Link is described. The separation column was Capcellpak C18 (150 mm × 4.6 mm, 5μm), which was held at 40 ℃. The mobile phase was composed of a mixed solution containing 20 mmol/L citric acid, 40 mmol/L acetic acid and 20 mmol/L triethylamine and acetonitrile (V/V, 98:2) at a flow rate of 1.0 mL/min. The sample loading volume was 10μL. UV detection was performed at 260 nm. The method showed a good linear relationship between peak area and concentration over the range from 1 to 1000μg/mL (R2 = 0.9999) for adenosine and from 2 to 1000μg/mL (R2 = 1.0000) for cordycepin. The spike recoveries of adenosine in 3 replicates determinations ranged from 93.75% to 96.90% and those of cordycepin from 92.03% to 97.35%.The limit of detection was 0.2 μg/mL for both adenosine and cordycepin. The RSD of precision was 0.116% for adenosine and 0.104% for cordycepin. This method is characterized by simplicity and high sensitivity and accuracy.

Identification of Radiated Pork by GC-MS Determination of Hydrocarbons
MA Tao1,2,LIN Qiong1,3,WANG Zhi-dong3,GAO Mei-xu3,LI Shu-rong3,*, ZHU Jie3,ZHOU Hong-jie3
2010, 31(16):  176-179.  doi:10.7506/spkx1002-6630-201016037
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In order to establish a method for identifying radiated pork based on differences in the contents of hydrocarbons, pork was radiated by 60Coγ ray at different dosages (1, 3, 5 kGy and 7 kGy) and radiated pork was analyzed for kinds and contents of volatile hydrocarbons in it by GC-MS based on a sample preparation procedure consisting of Soxhlet extraction, cleanup by solid-phase extraction for the removal of pigments and fat, nitrogen blowing evaporation to dryness and dilution in n-hexane to 1 mL. It was found that 60Coγ ray radiation resulted in the generation of two new compounds in pork, namely C16:2 and C17:1. and that their contents both increased with increasing radiation dosage. Moreover, after 60Coγ ray radiation at higher dosages, more hydrocarbons were found in pork with higher fatty acid contents.

High-performance Liquid Chromatography with Evaporative Light Scattering Detection for the Determination of Enzymatically Synthesized Lactosucrose
Zheng RUAN
2010, 31(16):  180-183.  doi:10.7506/spkx1002-6630-201016038
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Objective: To develop a simple, accurate and sensitive high-performance liquid chromatographic (HPLC) method with evaporative light scattering detection (ELSD) for the determination of enzymatically prepared lactosucrose (LS) in our laboratory. Methods: The reaction product containing LS was centrifugated and the supernatant was diluted and separated on a Kromasil NH2 column using acetonitrile/water (75:25, V/V) mixture as mobile phase. The ELSD drift tube temperature was set at 70 ℃ and the air pressure at 0.35 MPa. Results: The linear range of LS was between 0.1281 mg/mL and 4.1000 mg/mL (R2 = 0.9994). The method detection limit was 0.01 mg/mL. The average spike recovery at 5 levels was 100.28%, with a relative standard deviation (RSD) of 3.07%. Conclusion: This method is simple, fast and accurate, and can be applied to the determination of LS.

Comparison of Methods for Determining the Hydrolysis Degree of Rape Bee Pollen Protein
LI Tian-jiao,XU Xiang,SUN Li-ping*,DONG Jie,ZHANG Hong-cheng
2010, 31(16):  184-187.  doi:10.7506/spkx1002-6630-201016039
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Rape bee pollen protein was hydrolyzed with Alcalase 2.4L, and the change in degree of hydrolysis (DH) during hydrolysis was determined by pH stat method, OPA method or TNBS method, and differences in determination results were analyzed. DH derived from 118 min hydrolysis was measured by pH stat, OPA and TNBS methods to be 4.7%, 13.4% and 6.6%, respectively. Due to lower absorbance at 340 nm of the products of reaction among OPA reagent, lycine, cysteine and lysine, the determination by OPA method gave a lower DH. Unstable reaction between TNBS reagent and ε-NH2 was likely to due to the presence of certain luminescent substances generated from TNBS reagent. In the case of lower DH, the change in average degree of dissociation of α-NH2 groups could be neglected. In conclusion, pH stat method is a more accurate method than the two other ones.

Determination of Sucrose, Glucose and Fructose in Honey and Wine by Ion Chromatography
YU Na,ZHOU Guang-ming*,ZHU Juan
2010, 31(16):  188-191.  doi:10.7506/spkx1002-6630-201016040
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An ion chromatographic method has been developed for the determination of sucrose, glucose and fructose in honey and wine. The optimal chromatographic conditions were investigated for the separation on METROSEP CARB 1 (150 mm × 4.0 mm) anion exchange column. Pulsed amperometric detector was used for detection. Elutions were performed using 10.0 mmol/L NaOH at a flow rate of 1.0 mL/min. The total analysis time was 25 min. The detection limits for sucrose, glucose, fructose were 0.085, 0.126 mg/L and 1.072 mg/L (20 μL injection), respectively. The RSDs of peak height for 8 consecutive determinations were between 3.12% and 10.56%, and the RSDs of retention time were between 2.36% and 3.25%. The spike recoveries ranged from 90.0% to 99.5%. This method is characteristic of simple sample pretreatment, high sensitivity and shorter analysis time, and can provide a simple and efficient method for the determination of honey and wine.

Determination of Mineral Elements in Different Varieties of Chinese Olives and Quality Comparison
ZHONG Ming-hua1,HUANG Jun-sheng1,REN Nai-lin1,LI Yun2
2010, 31(16):  192-196.  doi:10.7506/spkx1002-6630-201016041
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The contents of 10 mineral elements in 21 different varieties of Chinese olive fruits growing in east Guangdong were measured by the method of microwave digestion followed by flame atomic absorption spectrometry. The results showed the varieties of Chinese olive fruits tested in this study displayed basically identical rank order for 10 mineral elements by content, but there was a great difference in each of these mineral elements among these varieties of Chinese olive fruits. Besides environmental factors, the difference was also ascribed to genetic factors and element absorption. The content ranges of 10 mineral elements in these varieties of Chinese olive fruits were as follows: Ca 2040.20-4348.89 mg/kg, Mg 926.38-1175.12 mg/kg, Na 78.77-143.55 mg/kg, Fe 80.17-88.27 mg/kg, Mn 39.47-62.30 mg/kg, Zn 23.13-28.71 mg/kg, Cu 9.59- 16.39 mg/kg, Cr 3.17-12.95 mg/kg, Co 2.30-4.04 mg/kg, and Ni 1.23-1.27 mg/kg. The excellent Chinese olive varieties were ‘Tulan’, ‘Qingpi’,‘Xiayuan’and‘Xiaodingxiang’, all of which were abundant in mineral elements.

Effects of Temperature for Solid-phase Microextraction on the GC-MS Analysis of Aroma Components of Nanguo Pear Wine
XIN Guang1,2,XIE Ting-ting2,ZHANG Bo2,LI Shu-qian1,2,WANG Yue-nan2
2010, 31(16):  197-199.  doi:10.7506/spkx1002-6630-201016042
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Headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was employed for analyzing the aroma components in Nanguo pear wine. HS-SPME was carried out at 4 different temperatures (20, 30, 40 and 50 ℃) in order to examine the effect of extraction temperature on the GC-MS analysis of the aroma components in Nanguo pear wine. The major aroma compounds identified in Nanguo pear wine extracted at 4 different temperatures were all esters and alcohols. Ethanol, ethyl acetate, 1-propanol, 2-methyl-, 1-butanol, 3-methyl-, 1-butanol, 2-methyl-, butanoic acid, ethyl ester, isoamyl acetate, 3-(methylthio)propanoic acid ethyl ester, phenylethyl alcohol, decanoic acid ethyl ester were all identified in Nanguo pear wine regardless of the HS-SPME temperature setting. The number of the kinds of aroma compounds identified in Nanguo pear wine extracted at 40 ℃ was the largest.

Combination of Thin-layer Chromatography with Phenol-sulfuric Acid Method for Analyzing the Content of Raffinose in Soybean Oligosaccharide
Zheng RUAN
2010, 31(16):  200-203.  doi:10.7506/spkx1002-6630-201016043
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Objective: To establish a method for the fast determination of raffinose in food and oligosaccharide by the combined use of thin layer chromatography (TLC) and phenol-sulfuric acid method. Methods: For the separation of raffinose, the developing solvent used was a mixture of methyl cyanides, acetic acid and water (6:3:2, V/V), and the chromogenic agent was composed of aminobenzene, diphenylamine and phosphoric acid, and the sample loading volume was 5 μL. The separated raffinose brand was harvested and analyzed by phenol-sulfuric acid method. Results: Different components of soybean oligosaccharide (sucrose, raffinose and stachyose) could be well separated by using TLC. The standard curve developed for raffinose determination by phenol-sulfuric acid method presented a linear range from 20 to 80 mg/mL (R2 = 0.9932). The precision RSD for raffinose determination was 1.56%. The method spike recovery was 98.14%, with a RSD of 3.99%. The relative error between the results of determination by this method and HPLC was 3.22%. This method is applicable to the determination of raffinose in food and oligosaccharide.

A Synchronous Spectrofluorimetric Method for the Determination of Three Aromatic Amino Acids in Food and Drug Injection
ZHANG Yue,MA Rui,ZHAO Guan-chao,FAN Shi-hua*
2010, 31(16):  204-207.  doi:10.7506/spkx1002-6630-201016044
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A synchronous spectrofluorimetric method is described for the determination of tryptophane, tyrosine and phenylalanine in food and drug injections in this paper. When Δλ was 70 nm for synchronous scanning, the characteristic peaks of tryptophane, tyrosine and phenylalanine appeared at 280, 228 nm and 206 nm, respectively. Tyrosine and phenylalanine could be directly quantified from their synchronous signals. The synchronous signal of tryptophane was slightly interfered by that of tyrosine, the interference from tyrosine could be effectively removed by the first order derivation synchronous fluorimetry. The detection limit was 6.9 ×10-9 mol/L for tryptophane, 3.8 ×10-8 mol/L for tyrosine and 4.2 × 10-7 mol/L for phenylalanine. No preliminary separation was needed for the determination by this method. It has been successfully applied to the analysis of beer samples and compound amino acids injection.

Changes in Volatile Flavor Components and Lipids of Cantonese Style Sausage during Oven Roasting
LONG Zhuo-shan1,2,XU Yu-juan1,YANG Wan-gen1,*,PAN Si-yi2,TANG Dao-bang1
2010, 31(16):  208-212.  doi:10.7506/spkx1002-6630-201016045
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In order to disclose the development mechanism of volatile flavor in Cantonese style sausage, the changes in its volatile flavor compounds, free fatty acids, triobarbituric acid value (TBA) and carbonyl value were investigated during oven roasting. The results showed that ester compounds were the most dominant ones responsible for Chinese Cantonese sausage s volatile flavor, followed by alcohol compounds. The total content of free fatty acids increased, and the percentage of unsaturated free fatty acids decreased with increasing roasting time (over 32 h), but a opposite change trend was observed for that of saturated free fatty acids. The changes in TBA and carbonyl values were both significant while a small generation of aldehyde and ketone compounds was found during oven roasting, which was probably the result of generating the esters by the reaction of alcohol compounds with fatty acids. Hence, it can be concluded that oxidation and hydrolysis in Cantonese styles sausage is gradually performed during oven roasting and that as a result, esters are continuously produced.

Determination of Amino Acids in the Pupal Exuviae of of Antheraea pernyi by Precolumn Derivatization Coupled with Reversed-Phase High Performance Liquid Chromatography
YANG Bin,RUAN Chang-chun,LIU Zhi,SUN Guang-zhi*
2010, 31(16):  213-216.  doi:10.7506/spkx1002-6630-201016046
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A reversed-phase high performance liquid chromatographic (RP-HPLC) method has been presented for the simultaneous determination of 17 amino acids in the pupal exuviae of Antheraea pernyi. Norleucine was used as internal standard for quantification using the internal standard method. For amino acid analysis, a Venusil-AA amino acid column was used, and phenylisothiocyanate (PITC) was the precolumn derivatization agent. Elutions were carried out in a binary gradient mode. The detection wavelength was set at 254 nm. The calibration curves of 17 amino acids all exhibited good linearity over the range from 0.5 to 0.0125μmol. Mean recoveries for 17 amino acids were between 96.2% and 101.9%. The total amino acid content of the pupal exuviae of Antheraea pernyi was determined to be approximately 21.9%, and the total essential amino acid content represented 33.62% of the total amino acids, and the content of arginine was the highest. This method is simple and efficient and provides a good method for the determination of amino acids in he pupal exuviae of Antheraea pernyi.

Determination of Five Herbicide Residues in Cereals by Gas Chromatography-Mass Spectrometry
TU Hai-yun,JIANG He,LI Wei *
2010, 31(16 ):  217-219.  doi:10.7506/spkx1002-6630-201016047
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A method was established for the determination of 5 herbicide residues (metolachlor, clomazone, acetochlor, metalaxyl and pyrazosulfuron) in cereals using gas chromatography-mass spectrometry (GC-MS). Samples were extracted with acetonitrile and cleaned up with primary secondary amine (PSA) and amino group packing materials. The analysis was carried out using GC-MS with electron impact (EI) source in a simultaneous full scan-selected ion monitoring mode. Quantification was performed using the internal standard method. This method exhibited good linearity within the range from 0.05 to 0.5 mg/L with a correlation coefficient of 0.999. Average recoveries for metolachlor in 6 cereal species spiked at 0.05, 0.1 mg/kg and 0.2 mg/kg ranged from 85% to 99%, with a RSD of smaller than 5%. For this method, matrix solid phase dispersion extraction used gives a rapid sample preparation approach. This method is free of interference from matrices and highly sensitive, and is exactly suitable for the daily large-scale determination of metolachlor, clomazone, acetochlor, metalaxyl and pyrazosulfuron residues in cereals.

Determination of Seven Heavy Metals and Pollution Assessment in Edible Fungi from Sichuan Province
2010, 31(16):  220-224.  doi:10.7506/spkx1002-6630-201016048
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The contents of As, Hg and Pb in 5 edible fungal species from different parts of Sichuan province were determined by atomic fluorescence spectroscopy (AFS) and those of Cu, Cr and Cd by atomic absorption spectroscopy (AAS). Based on the results of determination, an assessment of heavy metal pollution was made by single factor pollution index and Nemerow pollution index methods. The results showed that the total eligibility rate of 52 tested samples was only 7.96%. The contents of Cr, Hg and Cd were above the regulated criteria in some of these samples, and the content of Cr exceeded the national standard more seriously than those of the other two heavy metals. The average content of Mn in all these samples reached 15.93 mg/kg, the highest among the 7 elements. The pollution evaluations also showed that the pollution situation of Cr was the most serious. As a conclusion, heavy metal pollution in edible fungi from Sichuan province is very serious and meanwhile, the relevant standards for Mn content should be improved as soon as possible.

Speciation Analysis of Trace Selenium in Flour and Selenium Rich Salt by Slurry Sampling and Hydride Generation Atomic Fluorescence Spectrometry
SUN Han-wen,FENG Bo
2010, 31(16):  225-228.  doi:10.7506/spkx1002-6630-201016049
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A new method was developed for directly determining total Se, inorganic Se and Se(Ⅵ) using slurry sampling-hydride generation atomic fluorescence spectrometry (SS-HGAFS). For total Se determination, samples were extracted with 5 mL of concentrated HCl, followed by SS-HGAFS analysis. Cyclohexane extraction was used for the separation between inorganic Se and organic Se, and total inorganic Se and Se(Ⅵ) dragged into the water phase were determined by SS-HGAFS in concentrated HCl medium in the absence and presence of 5 g/L Na2SO3, respectively. Organic Se could be calculated by the difference between total Se and inorganic Se, and Se(Ⅳ) by difference of the inorganic Se and the Se(Ⅵ). The method detection limit (RSN = 3) was 0.10 μg/L for Se. Mean spike recoveries for total Se, total inorganic Se and Se(Ⅵ) in real samples of wheat flour, rice flour and Se rich salt were between 90.7% and 107%, with a relative standard deviation (RSD) ranging from 0.7% to 1.9%. The proposed method has the characteristics of accuracy, easy operation, rapidity and high sensitivity, and is most suitable for the speciation analysis of selenium in real samples.

Spectrophotometric Determination of Chitosan Based on Ion Association Reaction with Reactive Red 4
BAI Yan,CHEN Chun,CHEN Zhi-yi,SU Zheng-quan*
2010, 31(16):  229-232.  doi:10.7506/spkx1002-6630-201016050
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A sensitive and rapid analytical method was developed for the determination of chitosan based on the fact that the absorbance of reactive red 4/chitosan complex at 574 nm has linear relationship with the added concentration of chitosan in both B-R buffer solution (pH 4.5) and HAc-NaAc buffer solution (pH 4.5). The linear equation of the method was A = 0.3434c-0.0355 (the unit of c: μg/mL, hereinafter the same) (R2 = 0.9996) in B-R buffer solution and A = 0.3229c-0.03 (R2 = 0.9992) in HAc-NaAc buffer solution with a linear range from 0 to 4.0 μg/mL. The determination results obtained using the above two kinds of buffer solutions had no significant difference and were not affected by the molecular weight of chitosan. This method was utilized to determine the content of chitosan in a commercial brand of chitosan capsules, and the result was consistent with the indicated one. The relative standard deviation (RSD, n = 6) of precision of this method was 1.43% and the mean recovery rate was 101.1%. This method possesses good selectivity and therefore can be applied to the determination of chitosan in complex samples.

Fast Determination of Sudan Dyes Using Poly(3-Thiophenemalonic Acid) Modified Glassy Carbon Electrode
GAO Yuan-jun1,ZHANG Yong-feng1,XU Guang-ri2
2010, 31(16):  233-236.  doi:10.7506/spkx1002-6630-201016051
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Poly(3-thiophenemalonic acid)(3-TPA) modified glassy carbon electrode was prepared by electrochemical polymerization, and the electrochemical behavior of Sudan dyes was studied on the modified electrode using cyclic voltammetric method. The effects of preconcentration time, pH value of buffer solution and scan rate and range were also studied using differential pulse voltammetry in order to determine their optimal values. Under the optimize conditions, the modified electrode showed a linear response over the SudanⅠconcentration range from 2.0 × 10-5 to 1.3 × 10-3 mol/L, with a correlation coefficient of 0.996. The method detection limit was 4.8 × 10-6 mol/L. The average recoveries (3 replicates) of SudanⅠin spiked pepper powder and sauce samples were 99.9% and 99.4%, and the relative standard deviations were 0.25% and 0.21%, respectively. Moreover, the oxidation-reduction mechanism of SudanⅠwas preliminarily discussed.

Analysis of Fatty Acid Composition of the Seed Kernel of Mango from Yunnan
DU Ping1,2,YANG Fang3,*,ZHANG Xian-jun1,2
2010, 31(16):  237-238.  doi:10.7506/spkx1002-6630-201016052
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The seed kernel of mango from Yunnan was subjected to Soxhlet extraction, and the crude fat extraction efficiency was 14.23%. Then the extract was extracted with petroleum ether, saponified, and methyl esterfied and the esterfication products were applied to GC-MS for the analysis of fatty acid composition. Totally 13 fatty acid compounds were separated and their mass fractions were determined by the area normalization method. Most of the compounds were straight-chain fatty acids and the major components were stearic acid, palmitate acid, eicosanoic acid, heptadecanoic acid and docosanoic acid.

Analysis of Volatile Components of Yellow Tea by HS-SPME/GC-MS
LIU Xiao-hui1,2,ZHANG Li-xia1,2,WANG Ri-wei2,3,*,WANG Chao1,2
2010, 31(16):  239-243.  doi:10.7506/spkx1002-6630-201016053
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In order to establish a method for determining the aroma components of yellow tea, headspace solid phase microextraction (HS-SPME) was coupled to GC-MS. The effects of SPME fiber type, temperature and adsorption and desorption times on the kinds and amounts of aroma compounds of yellow tea were evaluated. Optimum adsorption was achieved using DVB-CAR-PDMS fiber for adsorption at 80 ℃ for 1 h. The thermal desorption of adsorbed aroma compounds from the fiber using a GC-MS injection port temperature of 230 ℃ lasted 1 min. A total of 108 aroma compounds were found in yellow tea, including 32 hydrocarbons, 20 esters, 17 alcohols, 17 aldehydes, 8 ketones, 4 oxygen containing compounds, 4 nitrogen containing compounds, 3 acids, 2 sulfur containing compounds and 1 phenol, and the contents of aliphatic hydrocarbons and aldehydes were both higher, but those of terpenes and aromatic compounds were both lower.

Rapid Determination of Micro Fluorine in Wolfberry Fruits at Different Growth Stages
GAO Xiang-yang,HAO Mei
2010, 31(16):  244-246.  doi:10.7506/spkx1002-6630-201016054
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In order to probe into the distribution characteristics of fluorine content in wolfberry fruits at different growth stages, green, yellow and red wolfberry fruits from the same cluster wildly growing in the east suburb of Zhengzhou were extracted with 1.0 mol/L HCl under ultrasonic assistance and the concentrations of micro fluorine in the extracts were directly given by fluorine ion selective electrode. It was showed that wolfberry fruits exhibited a gradual increase in moisture content during ripening, whereas fluorine content had an opposite change. The content of fluorine was 0.68μg/g in green wolfberry fruits, 0.57 μg/g in yellow wolfberry fruits and 0.53 μg/g in red wolfberry fruits. All the relative standard deviations (RSDs) of precision for 5 replicate determinations of green, yellow and red wolfberry fruits were smaller than 3%. The method spike recovery range was between 97.0% and 105.0%. Thanks to the merits of simplicity, rapidity and good practicality, this method deserves to be popularized.

Effect of Degree of Maturity on the Volatile Composition of Mango Fruits
TANG Hui-zhou1,MING Jian1,2,CHENG Yue-jiao1,ZENG Kai-fang1,2,*
2010, 31(16):  247-252.  doi:10.7506/spkx1002-6630-201016055
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Mango fruits with different degrees of maturity from Hainan Island were determined for their volatile composition by headspace solid-phase microextraction and gas chromatography with flame ionization detection coupled with mass spectrometry in order to examine the effect of degree of maturity on the volatile composition of mango fruits. The results demonstrated that mango fruits were rich in a wide variety of volatile compounds. A total of 56 volatile compounds were found in mango fruits, including terpenes, hydrocarbons, aldehydes, ketones, alcohols and esters, and the major ones were terpenes, and their contents in mango flesh and skin decreased as degree of maturity increased and reached their minimum values at the half ripe stage, and the relative content of monoterpenes was bigger than that of sesquiterpenes. The formation of esters in mango skin and flesh was found at the green ripe stage, and the highest relative content was found at the half ripe stage. With increasing degree of maturity, the relative content of alcohols in mango skin presented an increase, while mango flesh at the half ripe stage exhibited the highest accumulation of alcohols. The accumulation patterns of aldehydes in mango skin and flesh were different, and the highest accumulations of aldehydes in them were found at the full ripe and the half ripe stages, respectively. The relative content of hydrocarbons in mango flesh kept gradually decreasing during ripening, whereas mango skin exhibited the highest relative content of hydrocarbons at the half ripe stage. Most volatile compounds were formed at the half ripe stage. Therefore, regulation of mango fruits at this stage is of great significance for the improvement of their aroma quality.

Supercritical Carbon Dioxide Extraction of Oat Bran Oil and Its Fatty Acid Composition
HAN Shun-yu1,2,SONG Xue-mei2,ZHU Xia2,SHANG Xun-wu1
2010, 31(16):  253-257.  doi:10.7506/spkx1002-6630-201016056
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The optimal parameters for the supercritical carbon dioxide (SC-CO2 ) extraction of oat bran oil were determined by orthogonal array design to be: extraction pressure 15 MPa, extraction temperature 35 ℃ and length of extraction 3 hours. The oat bran oil obtained was clear and of golden color and had the characteristic smell of oat. Its fatty acid composition and that of petroleum ether extraction-derived oat bran oil were analyzed by gas chromatography-mass spectrometry (GC-MS), and the results revealed that the major fatty acids found in SC-CO2 extraction-derived oat bran oil were palmitic acid (17.60%), stearic acid (1.32%), oleic acid (40.15%), linoleic acid (37.55%), linolenic acid (1.89%) and elaidic acid (1.52%) and that these compounds in its petroleum ether extraction-derived counterpart were 15.90%, 1.67%, 38.38%, 41.67%, 1.63%, and 1.32%, respectively. The total contents of unsaturated fatty acids in SC-CO2 extraction-derived oat bran oil and its petroleum ether extraction-derived counterpart were 81.11% and 83.00%, respectively.

A Colony PCR Assay for Detecting Shiga toxin-producing Escherichia coli
LI Rui1,XU Fang1,ZHANG Zhong-mei1,MIYAMOTO Takahisa2,ZHU Ting-heng3,*
2010, 31(16):  258-260.  doi:10.7506/spkx1002-6630-201016057
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Specific primers targeting for the stx gene of Shiga toxin-producing Escherichia coli (STEC) were designed, and a colony PCR assay method was then developed based on first screening and selective culture in this study. The assay method could specifically identify E. coli O157 carrying stx1 and stx2 genes, while normal E. coli, Bacillus cereus and Staphylococcus aureus could not produce any PCR products. A STEC strain carrying stx1 gene was detected using the assay method in commercial pork and beef products. The method developed in this study is applicable to food samples for the detection of STEC.

Central Properties of the Metabolites of Houttuynia cordata Thunb. Populations from Different Altitudes in Guizhou
YANG Zhan-nan1,PENG Quan-cai1,2,LUO Shi-qiong2,YU Zheng-wen2,ZHAO Chao1,ZHU Guo-sheng3,GUI Yang3,XIA Pin-hua1
2010, 31(16):  261-269.  doi:10.7506/spkx1002-6630-201016058
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The chemical composition and volatile compound content of Houttuynia cordata in Guizhou province, China, were investigated at different altitudes. Altitudes were characterized by the evolution of chlorogenic acid, rutin, quercetin, quercitrin, hyperoside, kaempferol, isorhamnetin and quercetin-3-O-β-D-glucoside as well as volatile components. Chlorogenic acid and all flavonoids were analyzed by HPLC. The volatile extracts obtained by steam distillation were analyzed using HS-SPME-GC/MS. The chlorogenic acid and flavonoid content of H. cordata remained high at 1400-1500 m and 500-600 m, respectively. The essential oil content remained high at 600 - 700 m. Pharmacological 2-undecanone varied with increasing altitude, and remained high at 700-800 m. The contents of monoterpene (pinene), sesquiterpene (caryophyllene-(Ⅱ)), fatty ketone (2-undecanone), fatty acid (caprinic acid) and fatty acid ester (pentadecanoic acid,2,6,10,14-tetramethyl-,methyl ester) changed significantly at different altitudes.

Loop-mediated Isothermal Amplification Assay for the Detection of Salmonella in Meat and Meat Products
WANG Yu,WANG Zhen-qiang,ZHANG Wei*
2010, 31(16):  270-273.  doi:10.7506/spkx1002-6630-201016059
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A novel nucleic acid amplification method, termed loop-mediated isothermal amplification (LAMP), which amplifies DNA with high specificity, efficiency, and rapidity under isothermal conditions, may be a valuable tool for the rapid detection of infectious diseases. In this study, two pairs of gene-specific primers for the conservative invA gene were designed to establish a LAMP assay for detecting Salmonella. The assay method was applied to detect meat of different animal species, and proved highly sensitive and specific and time saving.

Using Western Blotting to Identify Major Allergens of Four Species of Shrimp
WU Hai-ming,HU Zhi-he*,WANG Chao
2010, 31(16):  274-277.  doi:10.7506/spkx1002-6630-201016060
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Litopenaeus vannamei, Fenneropenaeus chinensis, Metapenaeus ensis and mantis shrimp were evaluated for their major allergens. Composition analysis of protein extracts from these four species of shrimp was carried out using SDS-PAGE, and western blotting was then used to identify their major allergens. The major allergens of Litopenaeus vannamei were protein fractions of 99, 33, 19 kD and 14 kD in molecular weight, and those of Fenneropenaeus chinensis protein fractions of 39, 33 kD and 28 kD, and those of Metapenaeus ensis protein fractions of 33 kD and 24 kD, and those of mantis shrimp protein fractions of 56 kD and 48 kD.

Packaging & Storage
Influences of Commercial Handling and Cold Chain Transportation on Postharvest Peach Quality and Precautions
ZHAO Xiao-fang1,2,WANG Gui-xi1,*,LIANG Li-song1,ZHU Mei-yun2
2010, 31(16):  278-281.  doi:10.7506/spkx1002-6630-201016061
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According to HACCP principle, hazard analysis was performed for the quality changes of postharvest peach fruits during commercial handling and cold chain transportation. As a result, 6 key control points were confirmed, including material acceptance, sterilization, packaging, precooling, cold chain transportation and distribution. In order to provide technical support for the effective control of commercial quality of postharvest peach fruits, precautions were proposed and key technical parameters were also listed.

Effects of Storage Temperature and Exogenous Ethylene on Postharvest Ripening of Jingbai Pear
JIA Xiao-hui,WANG Wen-hui*,TONG Wei,ZHANG Zhi-yun,XIA Yu-jing,WANG Zhi-hua,DING Dan-dan
2010, 31(16):  282-285.  doi:10.7506/spkx1002-6630-201016062
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Freshly harvested Jingbai pears (Pyrus ussuriensis Maxim.) were subjected to precooling for 12 h, followed by either direct storage at 6 different temperatures or storage at (20 ± 1) ℃ after 24 h fumigation at 20 ℃ in the presence of commercial ethylene gas or that released from four bananas with medium degree of maturity. For investigating the effects of temperature and exogenous ethylene on the ripening process and quality of Jingbai pears, ethylene production, respiration rate, fruit firmness, SSC (soluble solid content), pH, ΔE and h values of fruit skin color, weight loss weight loss and percentage of diseased fruits were periodically measured during storage and sensory evaluation was also carried out. Temperature and exogenous ethylene treatment both markedly influenced the ripening process and quality of Jingbai pears. Fruit firmness exhibited an extreme significant linear negative correlation with ripening time (P<0.01). Higher and lower temperatures caused inconformity between fruit skin color and softening rate, and an appropriate temperature (14 ℃) delayed the start time of ethylene peak, but higher temperatures (28 ℃) restrained the synthesis of ethylene and the softening of fruit flesh and resulted in a higher respiration rate, weight loss and percentage of diseased fruits and lower ethylene production. Exogenous ethylene treatment improved fruit respiration and ethylene production, and the application of a proper concentration promoted fruit ripening and gave a uniform degree of maturity and optimum fruit quality. Considering our findings collectively, suitable temperatures for Jingbai pear ripening should be between 17 ℃ and 23 ℃ (20 ℃ found optimum) and the optimum concentration of ethylene is 100 μL/L.

Effect of Heat Shock Treatment on Lignification and Related Enzymes Activities in Jiefangzhong Loquat during Cold Storage
LI Lei,CHEN Fa-he*,WU Guang-bin
2010, 31(16):  286-290.  doi:10.7506/spkx1002-6630-201016063
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In this study, after 30 minutes of thermal treatment at 50 ℃, freshly harvested Jiefangzhong loquats from Putian, Fujian province were divided into cold storage (2-5 ℃) and normal temperature storage (18 -25 ℃). The changes in lignin content, fruit hardness and the activities of polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD) were tracked at 7-day storage intervals for providing experimental evidence for dealing with the effect of prestorage treatment on lignification and the activities of these enzymes related to lignification in refrigerated loquats. During cold storage, the firmness and PAL activity in loquats were both obviously elevated and a positive correlation between the two parameters was observed, with a correlation coefficient of 0.914. Prestorage thermal treatment could delay increases in lignin content and hardness and reduce the activities of PPO, PAL, CAD and POD. Combination of Prestorage thermal treatment with low temperature storage appears to provide an effective approach for delaying lignification of loquat fruits and prolonging their storage life.

Technology Application
Optimization of Technological Conditions for One-step Fermentation for Mulberry Vinegar Production
WANG Zhen-tao1,WAN Yong-ji1,ZHONG Geng2
2010, 31(16):  291-295.  doi:10.7506/spkx1002-6630-201016064
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Mulberry juice containing a certain amount of alcohol was directly inoculated with activated acetic acid bacterial culture for the production of mulberry vinegar by acetic acid fermentation. Based on a series of one-factor-at-a-time experiments, orthogonal array designs were applied to optimize some key technological conditions for the acetic acid fermentation of mulberry juice. Alcohol concentration of 6%, shake flask agitation speed of 130 r/min, innoculum size of 15% were found optimum. Chitosan solution of 1% was selected as an optimum clarifier out of 3 single ones and its optimum amount was 1.6 mL/100 mL. As a result, a clear, transparent, light rose colored and both vinegar-flavored and mulberry-flavored fruit vinegar product was obtained.

Optimization of Carrot Yoghurt Production by Fermentation of Immobilized Lactobacillus delbrueckii subsp bulgaricus and Streptococcus salivarius subsp thermophilus
WU Ding,SUN Jia-wen,YAO Ming-lan,LU Gui-hong
2010, 31(16):  296-299.  doi:10.7506/spkx1002-6630-201016065
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For better development of the carrot industry, carrot rich in various nutriments was used as fermentation substrate to product yoghurt by the fermentation of a mixed starter composed of immobilized Streptococcus salivarius subsp thermophilus and Lactobacillus delbrueckii subsp bulgaricus. The present study focused on developing a novel optimal process for carrot yoghurt production. Based on one-factor-at-a-time investigations, orthogonal array designs were employed to optimize fermentation medium composition and fermentation conditions. The optimal fermentation medium composition was found to be consist of milk powder 9 g, carrot 13 g, white sugar 8 g and distilled water 100 mL, and the optimal mixing ratio for immobilized Streptococcus salivarius subsp thermophilus and Lactobacillus delbrueckii subsp bulgaricus was 2:1 for the fermentation at 37 ℃ for 7 h using an inoculum size of 6% followed by cold storage at 4 ℃ for 12 h. The product obtained under the above optimal conditions was rich in various nutrients and had a pleasant mouth feel.

Optimization of Technological Parameters for Fermented Tea Wine Production
QIU Xin-ping1,LI Li-xiang1,*,JIANG Qi-zhong1,XU Rui-rui1,XIAO Shi-qing1,XIAO Xiu-dan2
2010, 31(16):  300-304.  doi:10.7506/spkx1002-6630-201016066
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Tea infusion derived from microwave-assisted extraction was used as main raw material for fermented tea wine production and for the fermentation, apple juice was added to tea infusion as adjunct. Single factor and orthogonal array design methods were employed to optimize some technological parameters for tea infusion fermentation. Fermentation temperature of 20 ℃, mixing ratio for tea infusion and apple juice of 1:3 (V/V), initial pH of 3.5 and inoculum (Angel branded special yeast for fruit wine fermentation) size of 3% were found optimal and the optimal tea type was black tea. The alcohol content in the fermentation broth obtained under the optimized fermentation conditions was approximately 11%, and the sensory quality was good, and the physiochemical and microbiological indexes met the requirements of relevant national standards. Moreover, the optimized fermentation conditions were validated to reliable. Additions of compound sweet 0.05%, rice wine flavor 0.25%, black tea flavor 0.50%, vanillin 0.2% and ethylmaltol 0.2% to the fermentation broth gave a tea-flavored, elegant and aromatic product.

Development of Defatted Peanut Nutritive Noodles and Their Related Properties
LI Ying1,2,GUO Xiao-dong1
2010, 31(16):  305-311.  doi:10.7506/spkx1002-6630-201016067
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Blends of wheat and defatted peanut flours containing 100%, 95%, 90%, 85% and 80% of wheat flour and 0, 5%, 10%, 15% and 20% of defatted peanut flour (DPF) were prepared, and gluten content and pasting properties were determined. Then the flour blends were processed into frozen noodles. The optimum mixing ratio for wheat and defatted peanut flours, water amount and salt amount for improved sensory evaluation of processed noodles were determined by orthogonal array design to be 10:90, 40% and 2.5%, respectively. The analysis of the quality of DPF frozen noodles showed the gluten content, pasting viscosities and texture properties decreased, while the boiling loss rate increased with increasing DPF amount. The changes in quality attributes of DPF frozen noodles were tracked during 28 days of frozen storage, and the hardness, tensile strength and tensile distance initially displayed a downward trend with prolonged storage period up to 16 days and then tended to be stable and the springiness, cohesiveness and resilience exhibited a slight but not significant increase. These results collectively reveal better storage resistance. According to the Chinese recommended nutrient intake and daily required amount of 200 g of noodles per person, the protein amount provided by the DPF noodles was calculated to represent 60% and 44% of total protein amounts essential for children and the elderly, respectively. Therefore, added DPF may soften the texture of noodles. Defatted peanut nutritive noodles could be acceptable to children and the elderly due to their good eating quality and high nutritional value.