Table of Content

15 March 2010, Volume 31 Issue 6
Processing Technology
Response Surface Methodology as An Approach to Optimization of Extraction of Volatile Oil from Leaves of Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens Mazel ex H.de leh
QIN Jiao1,YAO Yong-hong1,HOU Zhi-xia2,ZHANG Bo-lin1,LU Zhao-lin3,*
2010, 31(6):  1-5.  doi:10.7506/spkx1002-6300-201006001
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Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens Mazel ex H.de leh. leaves were used as raw material to extract volatile oil using a modified oil extraction apparatus. Based on single factor experiments, the optimal extraction process was determined using central composite design combined with response surface methodology. Results showed that the optimal extraction process was based on heat reflux extraction of powdered raw material below 10 mesh in particle size with distilled water at a liquid/solid ratio of 35:1 (mL/g) for 4.5 h. The observed and predicted values of extraction yield of volatile oil from Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens Mazel ex H.de leh. leaves were 0.32% and 0.35%, respectively. This method has some advantages over conventional method, like simplicity as well as high extraction yield and abundant chemical composition of volatile oil.

Ultrasonic-assisted Extraction of Sulfated Polysaccharides from Eucheuma striatum
WANG Yong-liang,FAN Xian,LI Yu-lan,YE Cai-ping,CEN Ying-zhou*,XU Shao-yu
2010, 31(6):  6-10.  doi:10.7506/spkx1002-6300-201006002
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One-factor-at-a-time and orthogonal array methods were used to investigate the optimal ultrasonic-assisted extraction process of sulfated polysaccharides from Eucheuma striatum (ESSP) in this work. Results indicated that the optimal values of technological parameters, including ultrasonic treatment time and power and material/liquid ratio for achieving a maximum sulfated polysaccharide yield of 48.14% with an increased of 12.08% compared with that given by hot water extraction were 20 min, 150 W and 1:90 (g/mL), respectively. The dried crude product obtained using the optimized ultrasonic-assisted extraction process exhibited polysaccharide and sulfate group contents of 96.94% and 19.66%, respectively. Neither protein nor nucleic acid was found in ESSP obtained using hot water extraction or this method, which contained characteristic peaks of polysaccharides and sulfate groups shown in IR spectrum.

High-throughput Determination of Mannitol and Polysaccharide in Medicinal Cordyceps and Optimization of Extraction Process of Mannitol
XIAO Dai-min,XIAO Jian-hui*,SUN Zhong-hua,ZHANG Zhi-min,LIANG Zong-qi
2010, 31(6):  11-15.  doi:10.7506/spkx1002-6630-201006003
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In an effort to provide experimental evidences for quality control of bio-products from medicinal Cordyceps, a highthroughput method for the quantitative determination of mycelial mannitol and polysaccharide in Cordyceps mycelia using ultraviolet/visible spectrophotometry coupled with universal microplate reader was presented. In addition, the optimal extraction process of mannitol from dried Cordyceps mycelia was determined using orthogonal array design. Results showed that the analytical method developed had a good linearity and reproducibility with relative standard deviations (RSD) of 3.82% and 1.01% for detecting mannitol and polysaccharide, respectively. The spike recovery ratios of mannitol and polysaccharide were 99.03% and 100.99%, respectively. The optimal design for mannitol extraction from Cordyceps mycelia was that this material was extracted with 60-fold weight of ultrapure water at 40 ℃ twice for 1 h each time. A significant increase in detectable level of mannitol in fermented mycelia of Paecilomyces gunnii Liang, Metarhizium taii Liang et Liu and Penicillium jiangxiense Kong et Liang was obtained using the optimal extraction process, in which mannitol contents of 4.73%, 8.72% and 11.81% and polysaccharide contents of 11.29%, 11.61% and 11.52% were determined, respectively. These results demonstrate the advantage of the analytical method as a rapid and effective tool for high-throughput determination of mycelial mannitol and polysaccharide in medicinal Cordyceps and the promising potential of Penicillium jiangxiense Kong et Liang mycelia as a source of fungusderived mannitol.

Preparation and Characterization of Tartary Buckwheat Bran Oil/β-cyclodextrin Inclusion Complex
MA Chun-fang1,YANG Lian-zhi2,WANG Jun1,WANG Min1,*
2010, 31(6):  16-19.  doi:10.7506/spkx1002-6630-201006004
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Tartary buckwheat bran oil (TBBO) was included into β-cyclodextrin to form an inclusion complex for preventing its oxidation. The optimal inclusion process was investigated using Box-Behnken central composite design combined with response surface methodology (RSM), the resulting inclusion compound was structurally characterized by infrared (IR) spectroscopy and scanning electron microscopy (SEM), and its antioxidation stability was evaluated. Results showed that the optimum values of crucial technological parameters affecting TBBO inclusion were obtained as follows: inclusion time 21 min, ratio of β-cyclodextrin to TBBO 5.7:1 (m/m), and ratio of water to β-cyclodextrin 4.2:1(V/m). The content of oil in TBBO/ β-cyclodextrin inclusion complex obtained under optimized preparation process was 8.07%, and the utilization rate of oil was 76.55%. These results demonstrate that TBBO can be included effectively and β-cyclodextrin inclusion results in the significantly improved stability of TBBO. The developed inclusion process has the advantages of low cost, simplicity and excellent antioxidant effect, thereby providing a promising approach for the prolongation of storage period of plant oil.

Phospholipase A1 Modification for Preparation of Egg Yolk Powder with High Emulsifying Properties
HUANG Dan,MA Mei-hu*,CAI Zhao-xia,LI Yong-liang
2010, 31(6):  20-25.  doi:10.7506/spkx1002-6630-201006005
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Phospholipase A1 (PLA1) was used for enzymatic modification of egg yolk to prepare egg yolk powder with high emulsifying properties in the present study. The optimal reaction conditions of PLA1 for maximizing the release of free fatty acids from egg yolk were determined by single factor and orthogonal array methods as follows: reaction temperature 55 ℃, reaction time 4.5 h, enzyme amount 1500 U/g, initial pH 6.0, and substrate concentration 200 g/L. According to the particle size distribution of egg powder measured using laser particle size analyzer, no obviously destructive effect of PLA1 on the structure of egg yolk was observed. The emulsifying capacity, emulsifying stability and thermostability of PLA1-modified egg yolk powder were enhanced by 75%, 389% and 132%, respectively, when compared with common egg yolk powder. Color change of egg yolk powder before and after modification measured using Chroma Meter (Ultra scan XE, Hunter Lab) indicated that PLA1 treatment resulted in increases of L* value from 86.04 to 87.87 and b* value from 38.82 to 54.22 but a decrease of a* value from 5.23 to 0.11.

Application of Response Surface Methodology for Optimization of Production of Thermal Irreversible Gel with High Textual Properties
QU Chao1,ZHANG Gen-sheng1,QIAO Xiao-ling2,*,GUO Ai-ju2,CHEN Wen-hua2,LI Jia-peng2
2010, 31(6):  26-31.  doi:10.7506/spkx1002-6630-201006006
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Response surface methodology based on central composite design was applied to study the optimal values of critical process parameters affecting textural properties of a thermal irreversible gel, including ratio of carrageenan to konjaku powder (m/m), calcium hydroxide solution amount, precooking temperature. Mathematical models were established for the elasticity, tenderness or hardness of the gel as a response value of the above parameters. The determination coefficient R2 and level of significance test for established models were 0.968 and P = 0.005, extreme significance level for elasticity, 0.976 and P = 0.002, extreme significance level for tenderness, and 0.876 and P = 0.141, insignificance level for hardness and, therefore, the models have high fitting degree and reliability. The fact that the deviations between actual values and predicted values of elasticity, tenderness and hardness were only 1.51%, 3.09% and 4.5%, respectively, demonstrates that these models can accurately describe the interactive relationships among ratio of carrageenan to konjaku powder (m/m), calcium hydroxide solution amount, precooking temperature and has high usability in optimizing process parameters. The optimal values of ratio of carrageenan to konjaku powder (m/m), calcium hydroxide solution amount, precooking temperature were determined to be 0.3:1, 0.06% and 90 ℃, respectively.

Processing Technology
Comparative Study of Different Extraction Techniques for Extraction of Magnolol and Honokiol from Branches of Megnolia Hypoleuca
ZHANG Zhao-hui,WANG Qiu-lan,YAO Mao-jun
2010, 31(6):  32-35.  doi:10.7506/spkx1002-6630-201006007
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Heat reflux, ultrasonic-assisted extraction, microwave-assisted extraction and supercritical carbon dioxide extraction were compared for extraction of magnolol and honokiol from branches of Megnolia Hypoleuca. Reverse-phase HPLC was used for quantitative analysis of magnolol and honokiol. Results showed that among four extraction techniques, the least time was consumed for the microwave-assisted extraction of magnolol and honokiol, and the single microwave-assisted extraction for 40 min at 200 W (1-2.8 PV) with 65% ethanol as extraction solvent using a material/liquid ratio of 1:40 (mg/mL) gave the highest yields of magnolol and honokiol, which were valued at 7.893 mg/g and 1.938 mg/g, respectively.

Ultrasonic-assisted Extraction of Polyphenols from Hops and Comparative Analysis of Polyphenol Content in Wild Hops from Different Habitats of Xinjiang Region
WANG Fang,ZHANG Xia*,XIONG Jie,WANG Shao-ming
2010, 31(6):  36-38.  doi:10.7506/spkx1002-6630-201006008
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The optimum ultrasonic-assisted extraction process of polyphenols from hops was investigated using orthogonal array design and based on this, wild hops from 9 habitats of Xinjiang region were compared for difference in polyphenol content. Results indicated that an extremely significant difference in polyphenol content among the wild hops from 9 habitats of Xinjiang region was observed. Wild hops from Aleimalei town, Xinyuan county and Daxigou town, Huocheng county, Yili area exhibited the highest polyphenol content of 40.17 mg/g and the lowest of 26.37 mg/g, respectively.

Macroporous Resin Adsorption for Separation of Polyphenols in Carambola Dregs
LU Qun-jin,YI Jie-rong*,DING Yong
2010, 31(6):  39-42.  doi:10.7506/spkx1002-6630-201006009
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According to adsorption and desorption performance towards polyphenols, an optimal macroporous resin was chosen from D4020, NKA-9, NKA-II and AB-8 resins for purifying crude polyphenols extracted from carambola dregs. AB-8 resin was found to have the best adsorption and desorption performance towards polyphenols and consequently, was chosen. The optimal adsorption conditions of carambola polyphenols onto AB-8 resin were determined as follows: polyphenol concentration of sample solution 0.9 mg/mL, sample pH 4.5, and feeding rate 2 BV/h, and the optimal ethanol concentration and flow rate for the desorption of carambola polyphenols were 60% and 0.5 mL/min. The content of carambola polyphenols in purified products under these conditions was 58.82%.

Response Surface Methodology as An Approach for Optimization of Simultaneous Extraction of Polysaccharides and Total Flavonoids from Radix Puerariae
KONG Juan,LIU Xiao-yu*,WANG Rui-xia,PANG Ling
2010, 31(6):  43-47.  doi:10.7506/spkx1002-6630-201006010
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Radix Puerariae was used as raw material to simultaneously extract polysaccharides and total flavonoids by hot water extraction. Based on single factor experiments, a central composite design (CCD) involving three variables such as material/liquid ratio and extraction time and temperature at three levels was employed for establishing a quadratic regression model describing weighted extraction yield (at 1:1 weight ratio) of polysaccharides and total flavonoids at different levels of the above variables. The optimal values of these variables were determined by response surface analysis. Moreover, the validity of the established model was verified. Results showed that both extraction temperature and time had a significant effect on polysaccharide yield, whereas no significant effect of material/liquid ratio was observed. The predicted and observed values of weighted extraction yield of polysaccharides and total flavonoids were achieved under the following optimal conditions: extraction for 2.2 h at a material/ liquid ratio of 1:25.2 and 98.4 ℃.

Enzymatic Hydrolysis Followed by Ultrasonic-assisted Extraction and Macroporous Resin Adsorption for Purification of Total Flavonoids from Flos Chrysanthemi Indici
YAO Chao1,YU Hai-ning2,RUAN Hui1,HE Guo-qing1,SHEN Sheng-rong1,*
2010, 31(6):  48-51.  doi:10.7506/spkx1002-6630-201006011
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Cellulase hydrolysis followed by ultrasonic-assisted extraction was adopted to extract crude total flavonoids from Flos Chrysanthemi Indici. The optimal cellulase hydrolysis and ultrasonic-assisted extraction processes were both investigated by orthogonal array design. Besides, the purification of the crude total flavonoids with D-101 macroporous resin column was explored. Results showed that the optimal cellulase hydrolysis could be achieved via hydrolysis for 6 h at 40 ℃, pH 6.0, 1:10 material/liquid ratio (g/mL) and 1.5% enzyme dose, and the use of 70% ethanol solution to extract the cellulase hydrolysate of Flos Chrysanthemi Indici for 0.5 h resulted in an optimal extraction of total flavonoids. The purification process consisting of adsorption of total flavonoids onto D-101 macroporous resin column at natural flow rate, washing of the column with water for the removal of impurities and desorption with 60% ethanol gave a recovery and purity of total flavonoids of 7% and more than 50%, respectively.

Extraction and Determination of Arachidonic Acid in Mnium spinosum
WANG Gui-hua,XIE Shu-lian*
2010, 31(6):  52-54.  doi:10.7506/spkx1002-6630-201006012
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Mnium spinosum (Voit) Schwagr was extracted with different organic solvents in Soxhlet extractor. The resulting extracts were then purified by silica column chromatography for analyzing arachidonic acid (AA) content by HPLC. Results showed that ethanol extract of Mnium spinosum (Voit) Schwagr exhibited an AA content of 6.5%, while no AA wad detected in petroleum ether extract and n-hexane extract of Mnium spinosum (Voit) Schwagr. Thus, ethanol is superior to other two solvents for extracting considerable AA from Mnium spinosum (Voit) Schwagr.

Extraction of Isochrysis galbana Extracellular and Intercellular Polysaccharides
SUN Ying-ying1,LEI Qi-yao1,LIU Xiao-xiao1,ZHU Ming1,WANG Chang-hai2,3
2010, 31(6):  55-59.  doi:10.7506/spkx1002-6630-201006013
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After 10 days of cultivation in f/2 medium under appropriate conditions, Isochrysis galbana cells and cultivation supernatant were separated by centrifugation and prepared into powders by freeze drying method for extracting intercellular and extracellular polysaccharides by hot water extraction, respectively. A series of single factor experiments was conducted to examine the effects of technological parameters such as extraction time, pH, extraction temperature and material/liquid on extraction of intercellular and extracellular polysaccharides. Subsequently, the optimal values of the parameters were determined using orthogonal array design. Finally, extracted intercellular and extracellular polysaccharides were analyzed for protein and polysaccharide contents. Single factor analysis showed that extraction time, pH and extraction temperature all had an obvious effect on extraction of intercellular and extracellular polysaccharides. For intercellular polysaccharide extraction, the optimal values of the three parameters were 180 min, 9 and 70 ℃, respectively; in contrast, an optimal extracellular polysaccharide extraction was obtained under the following parameters: pH 10 and 80 ℃ for 300 min extraction. Material/liquid ratio had little effect on extraction of intercellular and extracellular polysaccharides, and an appropriate value of 20:1 (mL/g) was found. Orthogonal array design analysis demonstrated that the optimal values of extraction time, pH and extraction temperature were 180 min, pH 8, 70 ℃ and 15:1 for intercellular polysaccharide extraction and 240 min, pH 9, 70 ℃ and 15:1 for extracellular polysaccharide extraction. The protein and polysaccharide contents in target products obtained under optimized technological parameters were 1.18% and 22.1% for crude intercellular polysaccharide and 0.82% and 18.6% for crude extracellular polysaccharide, respectively. So low protein content and so high polysaccharide content indicate high purity of target polysaccharides resulting from the orthogonal array optimization, which is favorable to further purification.

Acid-catalyzed Hydrolysis of Hesperidin
ZHENG Mei-yu,XIA Qi-le,XING Jian-rong,YANG Ying,LU Sheng-min*
2010, 31(6):  60-64.  doi:10.7506/spkx1002-6630-201006014
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To provide a method for preparing two hesperidin hydrolysates, namely hesperetin-7-glucoside and hesperetin, acidcatalyzed hydrolysis of hesperidin in an alkaline organic solvent system was explored and the resulting hesperidin hydrolysates were preliminarily separated. Crucial factors affecting acid-catalyzed hydrolysis, such as acid kind, hydrolysis mode, acid concentration, composition of alkaline organic solvent system and hydrolysis time were investigated. Results showed that full dissolution of hesperidin in a mixed system of sodium hydroxide solution and isopropyl alcohol under preheating condition followed by hydrolysis for 15-45 min catalyzed with 1.5 mol/L hydrochloric acid resulted in an optimal hesperidin hydrolysis. Moreover, a satisfying separation of 3 hydrolysis products obtained was achieved using their difference of dissolubility in acetone and water. Thus, some concentration of hydrochloric acid in an appropriate alkaline organic solvent medium can give a good catalysis for hesperidin hydrolysis.

Extraction of Total Flavonoids from Star Anise and Its Residue Left after Volatile Oil Extraction
SHU Xin,LIU Xiong-min,WANG Qiao
2010, 31(6):  65-69.  doi:10.7506/spkx1002-6630-201006015
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In the present study, hot ethanol reflux extraction was adopted for extracting total flavonoids from star anise or its residue left after volatile oil extraction. The optimal processes for extracting total flavonoids from two materials were investigated by single factor and orthogonal array methods. Results showed that three-time extraction for 120 min each time gave an optimal extraction of total flavonoids from star anise at a material/liquid ratio of 1:30 with 80% ethanol as extraction solvent and from star anise residue at a material/liquid ratio of 1:10 with 50% ethanol, respectively. Under the above conditions, the yields of total flavonoids from star anise and its residue were 23.61% and 16.81%, respectively.

Ultrasonic-assisted Extraction and Radical Scavenging Activity of Total Flavanoids from Different Parts of Mikania micrantha
ZHU Hui1,MA Rui-jun1,WU Shuang-tao2,FANG Xu1,DING Xuan1
2010, 31(6):  70-73.  doi:10.7506/spkx1002-6630-201006016
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The optimal procedures for extracting total flavonoids from roots, stems, leaves and flowers of Mikania micrantha L. under the assistance of ultrasonic were studied using orthogonal array design. Besides, total flavonoids extracted were tested for hydroxyl free radical scavenging activity. Results showed that the optimal values of crucial technological parameters including ethanol concentration, solid/liquid ratio and ultrasonic working power were 50%, 1:25 and 200 W for extraction of total flavonoids from roots, 50%, 1:20 and 500 W for extraction of total flavonoids from stems, 90%, 1:20 and 500 W for extraction of total flavonoids from leaves, and 70%, 1:25 and 200 W for extraction of total flavonoids from Mikania micrantha L. flowers. There was a positive correlation between hydroxyl radical scavenging activity and concentration of total flavonoids from roots, stems, leaves and flowers of Mikania micrantha L. observed at four experimental levels, and the hydroxyl radical scavenging rates at the concentration level of 1.32 mg/mL were 33.86%, 32.58%, 38.79% and 21.84%, respectively, lower than that of BHT, a common antioxidant. Thus, Mikania micrantha L., an invasive weed, has a certain potential for exploitation and utilization due to its short growth period and abundance.

Macroporous Resin Adsorption for Purification of Total Flavonoids from Bergenia emeiensis CY Wu Leaves
CHEN Jiao1,LI Yun-xiang1,*,CHEN Guang-deng1,CAI Ling-yun1,2
2010, 31(6):  74-79.  doi:10.7506/spkx1002-6630-201006017
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An optimal macroporous resin and its optimal technological parameters for purification of crude total flavonoids separated from Bergenia emeiensis CY Wu leaves were investigated in the present study. HPD-600 resin was chosen due to its excellent adsorption and desorption performance. Static and dynamic adsorption and desorption behaviors of HPD-600 resin were evaluated for achieving an optimal purification of total flavonoids. Results showed that the optimal purification process was that sample solution at pH 3-4 and the concentration level of 0.5-0.6 mg/mL was made to flow through HPD-600 resin column with a maximum injection volume of 3 BV and subsequently, the column was washed with 3 BV of water for the removal of impurities and eluted with 4 BV of 90% ethanol at a flow rate of 2 mL/min. More than 80% total flavonoids with a purity of more than 29% were recovered using the above process. These data demonstrate the excellence of HPD-600 resin in purifying total flavonoids from Bergenia emeiensis CY Wu leaves and the advantages of the developed method for industrial application, like simple operation, safety, and low cost.

Optimization of Two Extraction Techniques of Total Flavonoids from Tartary Buckwheat and HPLC Determination Based on the Two Extraction Techniques of Total Flavonoids in Tartary Buckwheat
LI Xin,WANG Bu-jun*
2010, 31(6):  80-85.  doi:10.7506/spkx1002-6630-201006018
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Ultrasonic or constant temperature shaking water bath was used for extraction of total flavonoids from tartary buckwheat in the present study. The optimal ultrasonic-assisted and constant temperature shaking water bath extraction procedures were investigated by single factor and orthogonal array methods. Meanwhile, HPLC determination based on the two optimized extraction techniques of total flavonoids in tartary buckwheat was carried out. Results showed that the optimal values of crucial parameters affecting extraction of total flavonoids, including ethanol concentration, liquid/solid ratio and extraction time were 80%, 40:1 and 30 min for ultrasonic-assisted extraction and 80%, 30:1 and 3 h for constant temperature shaking water bath extraction. Very close yields of total flavonoids were obtained in extraction from tartary buckwheat by both techniques. However, much less time consumption was needed for ultrasonic-assisted extraction. Moreover, analytical figures of merit including spike recovery, reproducibility and precision for HPLC determination of total flavonoids in tartary buckwheat, in which both techniques were used for sample preparation, were satisfying.

Optimization of Enzymatic Hydrolysis of Chicken Meat for Production of Anti-oxidant Peptides Using Response Surface Methodology
TANG Dao-bang1,PEI Xiao-ping1,2,XU Yu-juan1,WU Ji-jun1
2010, 31(6):  86-90.  doi:10.7506/spkx1002-6630-201006019
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Central composite design combined with response surface methodology was employed to develop an optimal papain hydrolysis procedure of chicken meat for production of anti-oxidant peptides with high superoxygen anion free radical scavenging activity of hydrolyzed chicken meat. Along with this, correlation between degree of hydrolysis (DH) of chicken meat and superoxygen anion free radical scavenging activity was analyzed. Results showed that the optimal values of crucial technological parameters affecting chicken meat hydrolysis were determined as follows: hydrolysis of substrate at a concentration level of 6.9% for 6.5 h at 62 ℃ and pH 6.7 with 5988 U/g of enzyme amount. DH of chicken meat was positively or negatively correlated with superoxygen anion free radical scavenging activity of hydrolyzed chicken meat within some range. Within 0 - 6.5 h of hydrolysis, DH of chicken meat and free radical scavenging activity of hydrolyzed chicken meat both tended to obviously increase. With prolonged hydrolysis time, DH of chicken meat continued to increase, whereas free radical scavenging activity of hydrolyzed chicken meat exhibited an obvious decrease. Six-hour hydrolysis gave a DH of chicken meat of 18.66%, and the superoxygen anion free radical scavenging rate of corresponding hydrolysis products was 32.91%.

Processing Technology
Optimization of Extraction of Radix Asparagi Polysaccharides Using Response Surface Methodology
WANG Ming-yan,LU Jia-feng,WANG Xiao-shun,XU Xing-you
2010, 31(6):  91-95.  doi:10.7506/spkx1002-6630-201006020
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Optimal hot water extraction of polysaccharides from Radix Asparagi was explored using central composite design (CCD) combined with response surface methodology (RSM). CCD experimental data were fitted to create two mathematical models describing yield (Y1) and purity (Y2) of Radix Asparagi polysaccharides (RAP) obtained at different levels of critical parameters, such as extraction temperature and time and material/liquid ratio. Results showed that the above parameters all had a remarkable effect on Y1 and Y2, and extraction for 4.2 h at 78 ℃ with a material/liquid ratio of 22:1 (mL/g) resulted in an optimal compromise between Y1 and Y2. The observed values of Y1 and Y2 were 5.24 % and 26.42%, respectively, exhibiting a good agreement with their predicted values. This reveals the good applicability and feasibility of RSM for optimizing extraction process of polysaccharides from Radix Asparagi.

Optimization of Formulation of Compound Lyophilization Protectant for Production of Synbiotics from Supernatant of Bacillus natto Fermented Rice Bran
QI Hong-bing1,CHEN Yu-dong1,CHEN Jun2
2010, 31(6):  96-100.  doi:10.7506/spkx1002-6630-201006021
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Rice bran was fermented with Bacillus natto and the 64-hour fermentation broth was separated by centrifugation to harvest supernatant. In the presence of protectant, the supernatant was vacuum lyophilized to produce a synbiotics. To maximize the survival rate of Bacillus natto, several protectants with good performance were chosen and formulated and subsequently, their optimal formulation was investigated using orthogonal arrays design. Moreover, the tolerance of synbiotics developed to simulated gastroenteric environment was explored. Results showed that the optimal compound lyophilization protectant formula consisted of skimmed milk powder 15%, sucrose 5% and β-cyclodextrin 5%. This formula resulted in an obvious increase of survival rate of Bacillus natto, reaching up to 82.1%. The synbiotics developed exhibited good tolerance to gastric fluid, intestinal fluid and digestive enzymes and could be stored for a long period of time under cold environment. Its hydroxyl free radical scavenging rate presented a dramatic decrease during storage at 25 or 37 ℃, whereas only a slight decrease was observed at 4 ℃.

Water Extraction and Antioxidant Activity of Fucoidan from Laminaria japonica
CHENG Shi-wei,CHEN Chao-nan,FENG Zhi-bin,ZHANG Yu-xiang
2010, 31(6):  101-104.  doi:10.7506/spkx1002-6630-201006022
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Hot water extraction followed by ethanol precipitation was used for production of fucoidan from Laminaria japonica in this study. To maximize fucoidan yield, the optimal values of crucial parameters of hot water extraction, including extraction temperature and time and material/liquid ratio were determined by single factor and orthogonal array methods to be 70 ℃, 6 h and 1:40, respectively. Under the above conditions, the maximum yield of fucoidan with 96.9% purity was up to 4.99%. Laminaria japonica fucoidan had strong antioxidant performance in vitro, which was reflected by hydroxyl and superoxide anion free radical scavenging activities, reducing power and nitrite scavenging activity under simulated gastric environment, and its antioxidant performance in vitro exhibited a gradual increase with its increasing concentration.

Processing Technology
Application of Textured Soybean Protein in Vegetarian Sterilized Ham Sausage Processing
LI Xin-hua,ZHANG Zhen*
2010, 31(6):  105-108.  doi:10.7506/spkx1002-6630-201006023
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In the present study, textured soybean protein (TSP), which is rich in nutrition and tastes similar to meat, but gives a soybean odor, was pretreated with hot water to remove the odor and used as an alternative to meat to process vegetarian sterilized ham sausages. Orthogonal array design was adopted for investigating optimal thermal pretreatment of TSP and formulation of TSP-based on ham sausages. Results showed that the optimal thermal pretreatment for obtaining an optimal sensory score of TSP was achieved via 4-time soaking in 65 ℃ hot water for 30 min each time. The optimal TSP-based on ham sausage formula leading to the best sensory evaluation consisted of soybean protein 100% (moisture content 65%), water 150%, corn starch 12%, carrageenan-konjac compound gum (at a mass ratio of 4:1) 6%, and soybean oil 12%.

Ultrasonic-assisted Acidic Acetone Extraction of Hemin from Porcine Blood
WANG Chang-guo1,2,DAI Ya1,LIU Shao-min2,YANG Wen-min1
2010, 31(6):  109-113.  doi:10.7506/spkx1002-6630-201006024
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To modify the acidified acetone-sodium acetate extraction technique of hemin from porcine blood, ultrasonic was used to disrupt porcine red blood cells for accelerating the release of intracellular hemoglobin. Meanwhile, extracted hemin was structurally characterized by infrared spectroscopy and UV-Visible absorption spectroscopy, and quantitative analysis was carried out by UV-Visible absorption spectroscopy. Results showed that crucial parameters affecting ultrasonic disruption of porcine red blood cells such as ultrasonic power, water/ethanol volume ratio and ultrasonic treatment time were optimized to be 800 kW, 15:1 and 6 min, respectively. Under optimized parameters, 86.62% hemin with 92.67% purity was extracted. This method demonstrates the merits of simplicity, low cost and high purity of final products.

Development of A Functional Beverage from Supernatant of Ganoderma lucidum Fermented Brown Rice Wort Containing Barley Wort and Soybean Sprout Slurry Blended with Fruit Juices
CHEN Zhi-jie1,2,YANG Zhen-dong1,GU Zhen-xin2,*
2010, 31(6):  114-117.  doi:10.7506/spkx1002-6630-201006025
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Supernatant of submerged fermented brown rice wort containing barley wort and soybean sprout slurry by Ganoderma lucidum was blended with various fruit juices for developing a healthcare beverage. To maximize sensory score of the beverage, D-optimal mixture design was used for investigating optimal formulation of the supernatant and apple, white grape and orange juices. Moreover, an optimal stabilizer for the beverage was determined according to the value of stability factor. Results showed that the optimal beverage formula resulting in the highest sensory score consisted of the supernatant 27.0%, apple juice 24.9%, white grape juice 20.2% and orange juice 27.9%. Xanthan gum at the concentration of 0.2% could well stabilize the beverage, which gave a stability factor of 99.3%.

Preparation of Cross-linked Corn Starch under Microwave Irradiation
ZHAO Ye1,ZHANG Huan-rong2,PENG He-hua1,LIU Xiong1,*
2010, 31(6):  118-121.  doi:10.7506/spkx1002-6630-201006026
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Sodium tripolyphosphate was used as cross-linking reagent to prepare cross-linked corn starch under microwave irradiation. The effects of preparation process parameters such as pH, sodium tripolyphosphate amount and microwave power and irradiation time on sedimentation volume of cross-linked corn starch were investigated by single factor and orthogonal array methods. Results showed that the optimal values of these parameters for reaching the highest sedimentation volume of rosslinked corn starch were pH 10.5, sodium tripolyphosphate amount accounting for corn starch 2.5%, and microwave power 350 W for an irradiation duration of 5 min. Our investigation demonstrates that time consumption for cross-linking reaction of corn starch is largely shortened by using microwave irradiation technique. Therefore, this technique has a promising potential for industrial dry preparation of cross-linked corn starch

Processing Technology
Response Surface Methodology for Optimization of Alcohol Extraction Technique of Red Pigment from Sunflower Hulls
WEI Li,SHAN Chun-hui*
2010, 31(6):  122-126.  doi:10.7506/spkx1002-6630-201006027
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Based on single factor experiments, central composite design (CCD) combined with response surface methodology (RSM) was employed to optimize alcohol extraction of red pigment from sunflower hulls. Results showed that the optimal values of crucial process conditions such as extraction temperature and time and material/liquid ratio were 54 ℃, 112 min and 1: 22, respectively. Under these conditions, the maximum red pigment yield was predicted to be 661.74 mg/100 g, very close to the observed value.

Orthogonal Array Design for Optimization of Extraction of Biochanin A from Chickpea Seed
TIAN Chun-yuan
2010, 31(6):  127-130.  doi:10.7506/spkx1002-6630-201006028
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Orthogonal array design was used to optimize hot ethanol reflux extraction of biochanin A from chickpea (Cicer arietinium L.) seed in this study. Results showed that an optimal compromise between biochanin A yield and purity was achieved by two-time extraction at a material/liquid ratio of 1:10 for 1.5 h each time. This extraction method, thanks to its convenience, safety, low cost and high efficiency, can be popularized for the large-scale production. Moreover, based on optimized hot ethanol reflux extraction, a RP-HPLC method was developed for rapid and accurate determination of biochanin A from chickpea seed.

Processing Technology
Extraction, Purification and Anticoagulant Activity of Polysaccharides from Opuntia milpa alta
CAI Wei-rong1,GU Xiao-hong2,3,TANG Jian2,3,*
2010, 31(6):  131-136.  doi:10.7506/spkx1002-6630-201006029
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Opuntia milpa alta was used as raw material to extract active polysaccharaides by hot water extraction. Extracted Opuntia milpa alta polysaccharaides were purified/fractionated by DEAE-Sepharose CL-6B and Sepharose CL-6B chromatography to obtain fractions WSP1 and WSP3 and subfraction from fraction WSP2 WSP2a. Response surface analysis based on central composite design was employed to examine effects of extraction temperature and time and liquid/material ratio on Opuntia milpa alta polysaccharaide extraction. Besides, WSP1, WSP3 and WSP2a were analyzed for monosaccharide composition and anticoagulant activity. Results showed that two-time extraction for 3.63 h each time at 75 ℃ and a liquid/material ratio of 3.42 mL/g gave an optimal crude Opuntia milpa alta polysaccharaide yield, reaching up to 0.655% (calculated on the basis of wet weight). WSP1, WSP3 and WSP2a exhibited weight average molecular weights of 2.32×106, 1.24 ×106 and 7.92×106, respectively. The predominant monosaccharide in WSP1 was galactose. WSP2a consisted of 6.3% of rhamnose, 32.3% of arabinose, 12.9% of xylose, 1.5% of mannose, 4.8% of glucose, 37.1% of galactose, 0.7% of glucuronic acid and 4.4% of galacturonic acid. The monosaccharide composition of WSP3 mainly consisted of arabinose, xylose, rhamnose and trace of glucose, mannose and uronic acid. WSP2a and WSP3 showed obvious anticoagulant activity.

Supercritical Carbon Dioxide Fluid Extraction of Functional Components from Momordica charantia L. Fruits
ZHANG Zhong-wei1,XIE Ming-yong2,*,WANG Yuan-xing2,LI Feng2
2010, 31(6):  137-140.  doi:10.7506/spkx1002-6630-201006030
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The supercritical carbon dioxide fluid extraction (SFE-CO2) was adopted to extract total momordicosides and total flavones from Momordica charantia L. fruits. Two sets of parameters for extracting total momordicosides and total flavones were optimized to maximize their yields using a U11(1110) uniform design and two regression models decribing the effects of extraction pressure and temperature and amount of added modifier (absolute ethanol) on the extraction of total momordicosides and total flavones were built up. The optimal conditions for the improved extraction of total momordicosides were determined as follows: extraction pressure 25.5 MPa, extraction temperature 42.5 ℃ and amount of added ethanol 180 mL, while those for extracting total flavones were 27.5 MPa, 39.5 ℃ and 226 mL, respectively. The maximum extraction yields of both total momordicosides and total flavones could be achieved by extraction for 3 h followed by one-step separationa at 35 ℃.

TCT-GC/MS Analysis of Volatile Composition of Jackfruit (Artocarpus heterophyllus)
ZHENG Hua,ZHANG Hong*,GAN Jin,YU Lian-song,ZHANG Ru-guo,
2010, 31(6):  141-144.  doi:10.7506/spkx1002-6630-201006031
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Thermal-desorption cryo-trapping gas chromatography/mass spectrometry (TCT-GC/MS) based on dynamic head-space sampling was adopted to analyze volatile composition of jackfruit peel and flesh. Results showed that jackfruit peel and flesh were both rich in esters. Higher n-propyl acetate and n-hexyl acetate contents were observed in jackfruit peel than in flesh, whereas methyl isoamyl, butyl valerate and ethyl butyrate exhibited a higher content in jackfruit flesh than in peel. The content of ethyl n-valerate in jackfruit peel was close to that in flesh. No other esters as well as alcohols, carboxylic acids (anhydrides), nitrogen - containing and sulfate-containing compounds were simultaneously detected in jackfruit peel and flesh. No aldehydes, ethers and terpenes were detected in jackfruit peel, whereas jackfruit flesh contained them.

Analysis & Detection
Application of Luminescent Vibrio fischeri to Rapid Determination of Melamine in Liquid Milk
ZHANG Guo-hui1,2,ZHAO Ji1,*,SHAO Yu-qin1,YU Jing-li1,LIU Fang1
2010, 31(6):  145-147.  doi:10.7506/spkx1002-6630-201006032
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A method based on the toxicity effect of melamine on luminescent bacterium Vibrio fisheri measured using Skalar ToxTracer system was developed for determining melamine in liquid milk. Results showed that there was a positive correlation between inhibitory rate of melamine against luminescent intensity of Vibrio fisheri and melamine concentration in aqueous solution with a correlation coefficient ranging within 0.83-0.99, whereas inhibitory rate of melamine against luminescent intensity of Vibrio fisheri was negatively correlated with melamine concentration in liquid milk, and the correlation coefficient was between 0.79 and 0.94. This method, thanks to the characteristics of rapidity, simplicity, sensitivity and low cost, is expected to gain an extensive application to food safety detection.

Estimation of Total Bacterial Count in Pork Using Electronic Nose
WANG Dan-feng,WANG Xi-chang,LIU Yuan*,ZHAO Yong,GU Sai-qi,XIE Jing,PAN Ying-jie
2010, 31(6 ):  148-150.  doi:10.7506/spkx1002-6630-201006033
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To provide experimental basis for estimation of total bacterial count in pork using electronic nose, mathematical models describing the relationship between output signal of electronic nose indicating change in volatile composition of chilled pork stored at 4 or 20 ℃ and total bacterial count in pork were investigated by partial least squares regression (PLS-regression). Results showed that pork samples stored for different days could be discriminated by principal component analysis (PCA). The correlation coefficients of developed mathematical models for estimating total bacterial count in pork stored at 4 or 20 ℃ were 0.9003 and 0.9940, respectively, which revealed good linearity. Electronic nose can accurately detect the changes in volatile composition and total bacterial count in pork during storage, thereby providing a useful tool for detecting harmful microorganisms in pork.

Bicinchoninic Acid Method for Determination of Protein Content in Milk
LU Yuan1,MA Yu1,FENG Zhi-ming1,YU Feng-jiang1,LIU Cai-yun2,YI Yin-sha1,*
2010, 31(6):  151-154.  doi:10.7506/spkx1002-6630-201006034
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Bicinchoninic acid (BCA) method was used for determining protein content in milk and compared with Kjeldahl method. Meanwhile, the resistance of BCA method to interference of urea, a nitrogen-containing interferer, was analyzed. Results showed that an average absorbance at 562 nm wavelength was obtained in precision test of BCA method, and the standard deviation was 0.004. Spike recoveries at two levels of protein determined by BCA method were within the range of 98.00%- 103.00%. In 6 replicated experiments, average values of protein content in 50- and 100-fold diluted milk were determined to be 791.2 and 803.4 μg/mL by BCA method and 370.2 and 384.0 μg/mL by Kjeldahl method, respectively. Experiments on urea interference revealed RSDs below and over 5% for protein determinations by BCA and Kjeldahl methods, respectively. As a conclusion, BCA method has the advantages of simplicity and good reliability, stability and resistance to urea interference, thereby providing an attractive alternative to Kjeldahl method for protein determination.

Comparative Analysis of Nutrients in Fruit Body, Mycelia and Fermentation Broth of Lyophyllum decastes
XI Ya-li1,WANG Zhi-jiang1,WANG Xiao-qin2,WEI Sheng-long1,*
2010, 31(6):  155-157.  doi:10.7506/spkx1002-6630-201006035
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Vitamin, amino acid, mineral substance, crude protein, crude fat and crude fiber contents in fruit body, mycelia and fermentation broth of Lyophyllum decastes were determined using relevant Chinese national standard methods, and the method stipulated in Technical Standards Testing & Assessment of Health Food (2003 Version) of the Chinese ministry of health was used for determining crude polysaccharides in these materials. Results showed that fruit body, mycelia and fermentation broth of Lyophyllum decastes revealed crude protein contents of 21.4%, 28.3% and 0.084%, crude fat contents of 1.44%, 2.78% and 0.11%, carbohydrate contents of 53.04%, 54.7% and 2.82%, crude polysaccharide contents of 3.55%, 1.77% and 0.12% , total amino acid contents of 16.82, 19.8 and 0.088 g/100 g, amino acid kinds of 17, 18 and 6, lysine contents of 1.13, 1.18 and 0 g/100 g, vitamin kinds of 5, 5 and 4, niacin contents of 21.2, 25 and 0.084 mg/100 g, mineral substance kinds of 7,5 and 1, and selenium contents of 0.013, 0.080 and 0 mg/kg, respectively. The contents of crude fiber in fruit body and mycelia of Lyophyllum decastes were 9.52% and 5.32%, whereas no crude fiber was detected in fermentation broth of Lyophyllum decastes. These results indicate that fruit body, mycelia and fermentation broth all have a high utilization value due to their abundant nutrition.

Comparative Analysis of Odor and Volatile Composition of Different Parts of Grass Carp (Ctenopharyngodon idella) Carcass
WANG Lu,WANG Xi-chang*, LIU Yuan
2010, 31(6):  158-164.  doi:10.7506/spkx1002-6630-201006036
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Different parts of grass carp carcass were compared for differences in odor and volatile composition measured using electronic nose and headspace solid-phase microextraction (HS-SPME) coupled to GC-MS, respectively. In HS-SPME, PDMS/ DVB fiber was used. Results showed that a good discrimination of odor difference between red and dorsal or ventral meat of grass carp was achieved using electronic nose, while odor difference between dorsal and ventral meat of grass carp could not be discriminated. Totally, 44, 42 and 55 kinds of volatile compounds were identified in dorsal, ventral and red meat of grass carp, respectively, of all which, volatile carbonyl compounds and alcohols were predominant, with total relative contents of 88.38%, 74.88% and 82.54%, respectively.

Accelerated Solvent Extraction Followed by Gas Chromatography-Mass Spectrometric Determination of Bisphenol A in Candy Packaging Materials
CHEN Qi-rong,WEI Yan,LANG Shuang,XIA Min
2010, 31(6):  165-167.  doi:10.7506/spkx1002-6630-201006037
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An accelerated solvent extraction followed by gas chromatography-mass spectrometric method was presented for determining bisphenol A in candy packaging materials. Samples were extracted with a mixture (7:3, V/V) of dichloromethane and acetone in an accelerated solvent extractor, derivatized with a commercial BSTFA-TMCS mixture prior to GC-MS analysis. Mean spike recoveries of bisphenol A at three levels were between 75.2% and 90.7%, and the limit of detection (LOD) of bisphenol A was 5 μg/kg. This method has the characteristics of simplicity, high accuracy and precision and good reproducibility.

Surface Plasmon Resonance for Rapid Determination of Sulfamethoxazole in Milk
ZHOU Hong-min1,OU Hui-chao1,JIANG Hao1,JIANG Hai-feng1,WANG Xiao-ping2,LUO Zhao-feng1,*
2010, 31(6):  168-171.  doi:10.7506/spkx1002-6630-201006038
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A method based on surface plasmon resonance technique was developed for rapid determination of sulfamethoxazole (SMX) in milk. SMX was covalently coupled to laboratory prepared CM5 chip to obtain SMX chip. The optimal antibody working concentration and chip regeneration conditions were investigated. Meanwhile, the stability of SMX chip was measured. A series of different concentrations of SMX was added to blank milk samples to construct a standard curve for SMX quantification according to the principle of competitive immune inhibition assay. Eighteen commercial milk samples were determined by the developed method. SMX chip displayed good stability, and the relative standard deviation (RSD) for 90 cycles was 1.23%. The limit of detection (LOD) of SMX was 3.2 ng/mL. SMX contents below the required threshold level were observed in 16 of 18 milk samples. Less than 15 min was consumed for the determination of SMX by the developed method. Thus, this method may offer a simple and efficient approach for SMX quantification.

Analysis & Detection
Electronic Nose for Measurement of Freshness Change of Chilled Pork during Storage at Different Temperatures
GU Sai-qi1,WANG Xi-chang1,LIU Yuan1,*,ZHAO Yong1,ZHANG Jing-jing1,XIE Jing1,ZHENG Jing-zhou2
2010, 31(6):  172-176.  doi:10.7506/spkx1002-6630-201006039
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Electronic nose was used to measure the freshness change of chilled pork during storage at -18, 0, 4, 10 or 20 ℃. Injection volume of minced samples was optimized to be 1500 μL. Principal component analysis (PCA) of volatile odor of chilled pork was conducted. Electronic nose output signal was plotted as a function of storage time to estimate shelf-life of chilled pork stored at different temperatures. Partial least squares regression (PLS-regression) was employed to analyze correlation between electronic nose output signal and sensory evaluation score of volatile odor of chilled pork stored at 4 or 20 ℃. Results showed that there was a significant difference in volatile odor of chilled pork stored for different time at -18, 0, 4, 10 or 20 ℃. Higher storage temperature resulted in earlier occurrence of significant decrease of freshness. The shelf-life of chilled pork stored at the above temperatures was 336, 180, 72, 48 h and 18 h, respectively. The correlation coefficients between electronic nose output signal and sensory evaluation score of volatile odor of chilled pork stored at 4 and 20 ℃ were as high as 0.9982 and 0.9998, respectively, demonstrating that electronic nose is a reliable alternative to sensory evaluation for analysis of volatile odor of chilled pork. Electronic nose sensors TA/2, T40/1, T40/2, P30/2, P40/1, P10/2 and P10/1 were all found to give excellent specific responses to various characteristic odors of pork.

Bioactive Substances in Horse Fat Tissue
LI Hua1,ZHANG Xiao-ping2,RONG Qun2
2010, 31(6):  177-179.  doi:10.7506/spkx1002-6630-201006040
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Bioactive substances in horse fat tissue such as unsaturated fatty acids and vitamins were analyzed by gas chromatography (GC) and high-performance liquid chromatography (HPLC), respectively. Results showed that horse fat tissue contained over 60% of unsaturated fatty acids and over 20% polyunsaturated fatty acids. The contents of fat soluble vitamins, namely vitamins A and E, were 7.2 and 88.6 mg/kg, respectively. These results demonstrate that horse fat tissue is a good source of natural antioxidants.

Gas Chromatography Tandem Triple Quadrupole Mass Spectrometric Determination of Cyanuric Acid and Melamine in Milk Powder
LI Dong-gang,JU Fu-long,LI Chun-juan
2010, 31(6):  180-184.  doi:10.7506/spkx1002-6630-201006041
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A gas chromatography tandem triple quadrupole mass spectrometric (GC-QqQ-MS/MS) method was presented for the determination of cyanuric acid and melamine in milk powder. Samples were extracted with methanol and derivatized with a mixed system composed of BSTFA and TMCS (99:1, V/V) prior to GC-QqQ-MS/MS analysis in multiple reaction monitoring (MRM) mode. The optimal values of crucial instrument parameters and matrix effects were investigated. Cyanuric acid was qualified using the ion pairs of m/z 345 > 215 and m/z 345 > 330 and quantified using the ion pair of m/z 345 > 215. Melamine was qualified using the ion pairs of m/z 345 > 171 and m/z 342 > 327 and quantified using the ion pair of m/z 342 > 327. The developed method exhibited good linearity within the range of 0.010 to 0.500 mg/L. Limit of detection was 0.016 for cyanuric acid and 0.003 mg/kg for melamine (RSN =3). Precision RSDs for determining cyanuric acid and melamine were within the ranges of 4.5%-8.6% and 3.9%-6.2%, respectively. Recoveries of cyanuric acid and melamine in an infant formula milk power sample spiked at two levels were ranged from 84.0% to 102.0% and from 88.5% to 104.0%, respectively.

High Performance Liquid Chromatographic Method for Simultaneous Determination of Six Quinolone Residues in Aquatic Products
QIAN Zhuo-zhen1,2,SU Xiu-hua3,WEI Bo-juan4,WU Cheng-ye1,*
2010, 31(6):  185-189.  doi:10.7506/spkx1002-6630-201006042
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A solid-phase extraction followed by reversed-phase high performance liquid chromatographic (SPE-RP-HPLC) method was presented for the simultaneous determination of 6 quinolone residues (enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin, oxolinic acid and flumequine) in aquatic products. Sample extraction, cleanup on a C18 cartilage column and chromatographic separation were investigated. A RP-HPLC system equipped with fluorescence detector (λex = 280 nm, λem = 480 nm) was used for analyzing 6 quinolones, and their quantification was achieved by external standard method. Six quinolones exhibited good linearity within the range of 0.02-2.0 μg/mL and the regression coefficients were all over 0.99. The developed method showed limits of detection of 2 μg/kg for ciprofloxacin, enrofloxacin, norfloxacin, ofloxacin and 5 μg/kg for oxolinic acid and flumequine (RSN = 3), and limits of quantification of 5 μg/kg for ciprofloxacin, enrofloxacin, norfloxacin, ofloxacin and 10μg/kg for oxolinic acid and flumequine (RSN = 10). Satisfying results were obtained in spike recovery experiments and average spike recoveries of 5 replicates at three levels were within the range of 78.8%-92.9%, with RSD range of 2.97%-7.10%. This method, thanks to its simplicity, sensitivity and reliability, has good suitability for the simultaneous determination of 6 quinolone residues in aquatic products.

Analysis & Detection
Simultaneous Determination of Fifteen Trace Elements in Cuttlebone Using Flame Atomic Absorption Spectrometry (FAAS)
YANG Zhen-ping1,BIAN Qing-quan2,*
2010, 31(6):  190-192.  doi:10.7506/spkx1002-6630-201006043
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A flame atomic absorption spectrometric (FAAS) method was developed for the simultaneous determination of 15 trace elements in cuttlebone. This method exhibited spike recoveries for 15 trace elements ranging from 96.5% to 108.7%, with RSDs of less than 2.8% and good accuracy and precision. A higher content of trace elements essential to the human body including Zn, Fe, Mn and Cu was detected in cuttlebone. Additionally, Pb, As and Cd were also detected.

Evaluation of Heavy Metal Contamination of High-quality Apples in Shaanxi
LI Na,DONG Wen-bin,HU Xian-li,YANG Jin,WANG Jin-zi
2010, 31(6):  193-195.  doi:10.7506/spkx1002-6630-201006044
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To establish a database of heavy metal content of high-quality apples in Shaanxi so as to provide evidence for making macroscopic decisions by relevant authorities, microwave digestion followed by inductively coupled plasma atomic emission spectroscopic technique was used to determine lead, arsenic, copper, cadmium, chromium contents in 47 apple samples harvested from 5 high-quality apple-producing counties in Shaanxi Province. Results showed that the apple samples tested exhibited a Pb content range of 0-0.113 mg/kg, which was 38.3% higher than the required threshold level in the industry standard NY/T268-95 of China s Ministry of Agriculture. The contents of Cd and Cr were both less than 0.025 mg/kg, the content of Cu between 0.089 and 1.709 mg/kg, and the content of As less than 0.1 mg/kg. The above data demonstrate all the apple samples tested can be classified into green food class.

Analysis & Detection
HPLC-MS Determination of Catechins in Tender Areca Nut
WANG Ming-yue1,2,LUO Jin-hui2,ZHAO Zhen-dong3
2010, 31(6):  196-198.  doi:10.7506/spkx1002-6630-201006045
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An Agilent HPLC-MS system was used to determine catechins in tender areca nut. Sample preparation was achieved through methanol extraction with the assistance of ultrasonic, petroleum ether extraction for the removal of impurities, ethyl acetate extraction and vacuum concentration. Results showed that catechins in tender areca nut mainly comprised (+) - catechin and epigallocatechin gallate.

Comparative Analysis of Bioactive Components in Fruit Bodies of Phellinus linteus Growing on Six Species of Trees
QI Xin1,2,ZHANG Jun2,CHEN Ying2,WANG Chang-lu1,*
2010, 31(6):  199-201.  doi:10.7506/spkx1002-6630-201006046
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Fruit bodies of Phellinus linteus growing on 6 species of trees were compared for differences in contents of bioactive components including polysaccharides, total flavonoids and total triterpenoids. Results showed that there were significant differences in bioactive components in fruit bodies of Phellinus linteus growing on 6 species of trees. Fruit body of Phellinus linteus growing on mulberry tree exhibited contents of polysaccharides, total flavonoids and total triterpenoids of 3.84%, 5.12% and 2.2%, respectively, higher than those of fruit bodies of Phellinus linteus growing on other 5 tree species. The lowest polysaccharide content of 1.35% was observed in fruit body of Phellinus linteus growing on Syringa reticulata var.mandshurica Fruit body of Phellinus linteus growing on silver birch exhibited the lowest contents of total flavonoids and total triterpenoids, which were 0.68% and 0.32%, respectively.

Comparative Analysis of Contents of Flavonoid Compounds in Various Species of Citrus Peel and Their Dynamic Changes in Quzhou Ponkan Peel during Postharvest Storage
ZHANG Yu1,WU Hui-ming2,WANG Wei1,WANG Jian-qing1,BAI Li-ping1
2010, 31(6):  202-204.  doi:10.7506/spkx1002-6630-201006047
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‘Miyagawa Wase’ satsuma mandarin (Citrus unshiu Marc.), Quzhou ponkan (Citrus reticulata Blanco cv. Ponkan)‘, Hamlin’ orange (Citrus sinensis (L.) Osbeck), Changshanhuyou tangelo (Citrus paradisi cv.Changshanhuyou) and tonkan (Citrus tankan Hayata) peels were compared for differences in respective and total contents of 6 main flavonoid compounds such as naringin, hesperidin, neohesperidin, nobiletin, tangeretin and sinensetin determined by rapid resolution liquid chromatography. Meanwhile, content changes of chlorophyll, carotenoids and 6 main flavonoid compounds in Quzhou ponkan peel were measured during postharvest storage. Results showed that among 5 species of citrus, Changshanhuyou tangelo peel revealed the highest total content of 6 main flavonoid compounds and naringin and neohesperidin were predominant flavonoid compounds in it. The predominant flavonoid compound in both ‘Miyagawa Wase’ satsuma mandarin and ‘Hamlin’ orange peels was hesperidin. Quzhou ponkan and tonkan peels both mainly contained hesperidin and nobiletin. There were a decrease of chlorophyll content and an increase of carotenoid content in Quzhou ponkan peel during postharvest storage. The respective contents of 6 flavonoid compounds all exhibited an obvious increase followed by a slight decrease after 15 days of storage.

Near-infrared Spectroscopic Analysis of Peroxide Value of Soybean Oil
WANG Li-qi1,ZHANG Li-yong1,*,ZHU Xiu-chao2
2010, 31(6):  205-207.  doi:10.7506/spkx1002-6630-201006048
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In this study, peroxide values of 255 soybean oil samples measured by iodimetric assay were used for calibration and near-infrared spectral data of these samples were collected. In the quantitative analysis of peroxide value, three models were established using partial least squares regression (PLS-regression), multiple linear regression (MLR) and principal component regression (PCR). Comparative analysis indicated that among the established models, PLS-regression model exhibited the best reliability in predicting peroxide value of soybean oil, with correlation coefficients of calibration and validation sets of 0.916 and 0.922, respectively.

Simultaneous Determination of Exogenous Anabolic Steroid Residues in Milk by Ultra Performance Liquid Chromatography -Electrospray Tandem Mass Spectrometry (UPLC-MS/MS)
ZHANG Ai-zhi,WANG Quan-lin*
2010, 31(6):  208-212.  doi:10.7506/spkx1002-6630-201006049
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A rapid, specific and highly sensitive method was developed for the determination of 7 exogenous anabolic steroid residues in milk based on ultra performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS) in the positive ion mode using multiple reaction monitoring (MRM). Samples were extracted with methanol with the assistance of ultrasonic and cleaned up using LC-C18 solid phase extraction cartridge. Qualitative and quantitative analysis was carried out in the MRM mode after chromatographic separation using Waters ACQUITY UPLCTM BEH C18 (1.7 μm, 2.1mm × 100 mm) column. The limits of detection (LOD) of 7 exogenous anabolic steroids by the method ranged from 0.01 to 0.25μg/kg and the limits of quantification (LOQ) were in the range of 0.06-0.5 μg/kg. Average spike recoveries for 7 exogenous anabolic steroids at the level of 10 μg/kg ranged from 83% to 124%, with relative standard deviations (RSDs) between 4.3% and 24%.

Ion Chromatographic Determination of Nitrite and Nitrate in Chinese Preserved Sausages
FENG Shun-qing1,LI Ming-zhu2,LAO Jin-hua3
2010, 31(6):  213-215.  doi:10.7506/spkx1002-6630-201006050
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A method using ion chromatography with electrochemical detection was developed for the determination of nitrite and nitrate in Chinese preserved sausages. Sample preparation was achieved by ultrapure water extraction with the assistance of ultrasonic, elimination of interference of fat, protein and a large number of chlorine ions and filtration through a 0.45μm pore size nylon membrane. In the ion chronographic analysis, an IonPac AS9-HC analytical column (4 mm × 250 mm) protected with an IonPac AG9-HC guard column (4 mm × 50 mm) was used, and the eluant was 9.0 mmol/L Na2CO3 aqueous solution. Nitrite and nitrate both presented a good linear relationship between peak area and concentration. The limits of detection of the method for nitrite and nitrate were 0.5 and 1.0 mg/kg, respectively.

Determination of Total Sulfonamide Residue in Pork Using Surface Plasmon Resonance
XIA Min1,LUO Jin2,ZHANG Jing-hua1,GU Xue-xin2
2010, 31(6):  216-219.  doi:10.7506/spkx1002-6630-201006051
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A new method based on surface plasmon resonance (SPR) was established to determine total sulfonamide residue in pork. A commercial sensor chip CM5 was activated and derivatized with HBS-EP buffer at a flow rate of 80 μL/min, blocked with 1 mol/L cholamine aqueous solution at a flow rate of 10 μL/min, and regenerated with 0.1 mol/L sodium hydroxide aqueous solution to obtain a resonance chip. Relative resonance intensity generated from resonance chip surface presented a good response to sulfonamide concentration ranging from 0.5 to 50 ng/mL. The method exhibited an average spike recovery range of 75.7% to 99.2% at three levels and a limit of detection of 2.5 μg/kg. Reproducibility experiments gave a RSD of 1.3% (n = 6). This method presents the benefits of simplicity and high sensitivity, thereby providing a rapid analytical approach for the control of quality and safety of meat products.

Analysis & Detection
Determination of Total Polyphenols in Different Parts of Elaeagnus angustifolia Fruit Growing in Xinjiang
HU Jun-ping1,YANG Jian-hua1,2,WANG Xin-ling1,MUAITAER Nuermaimaiti1,RENA Kasimu1
2010, 31(6):  220-222.  doi:10.7506/spkx1002-6630-201006052
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Gallic acid was used as a standard substance to determine total polyphenol contents in different parts of Elaeagnus angustifolia fruit growing in Xinjiang Autonomous Region by Folin-Ciocalteu method. The calibration curve of gallic acid presented good linearity within the concentration range of 2-12 μg/mL (r = 0.9991). The average of three replicates of spike recovery for total polyphenols at three levels was 98.80%, with a relative standard deviation of 1.81%. Elaeagnus angustifolia seeds exhibited significantly higher total polyphenol content than Elaeagnus angustifolia flesh, with a 3- to 5-fold increase. The method demonstrates the advantages of convenience, rapidity and accuracy, thereby providing an effective approach for the quality control of Elaeagnus angustifolia fruit.

HPLC Determination of 17α-Methyltestosterone Residue in Aquatic Products
CHEN Pei-ji1,LI Liu-dong1,ZOU Qin1,2,LI Zhi-guang1,YANG Jin-lan1,ZHAO Dong-hao1
2010, 31(6):  223-226.  doi:10.7506/spkx1002-6630-201006053
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A simple high-performance liquid homographic (HPLC) method was presented for the determination of 17α- methyltestosterone (17α-MeT) residue in aquatic products. Samples were extracted using ether with the assistance of ultrasounic and cleaned up using petroleum ether. The chromatographic separation was achieved on ODS-C18 column using 77% aqueous methanol solution as an eluant. 17α-MeT was detected using a UV detector and quantified by external standard method. The method revealed spike recoveries for 17α-methyltestosterone in the muscles of T. niloticus, L. vannamei and A. anguilla of not less than 83%, with relative standard deviations of not more than 6.48% and a limit of quantification of 8 μg/kg. The method, thanks to its simplicity and accuracy, is most suitable for the determination of 17α-MeT residue in large quantities of samples.

High Performance Ion Chromatographic Determination of Thiocyanate in Fresh Milk
2010, 31(6):  227-229.  doi:10.7506/spkx1002-6630-201006054
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A high performance ion chromatographic (HPIC) method was developed for determining thiocyanate in fresh milk. Samples were added with 3.0% acetic acid aqueous solution to precipitate protein and filtrated. The filtrate obtained was cleaned up using Dionex OnGuard RP cartridge for the removal of lipids prior to chromatographic separation. The elutant was adjusted to contain 60 mmol/L hydroxyl ions. The external standard method was used for thiocyanate quantification. Stability experiments gave an average retention time and an average peak area of 5 injection replicates of thiocyanate of 15.445 min and 0.1839 μS·min, with RSDs of 0.12% and 0.26%, respectively. Spike recoveries of thiocyanate in milk power and fresh milk at two levels ranged from 96.0% to 98.0%, with RSDs of less than 1.06%. The method exhibited a limit of detection of 0.2 mg/kg and a linear range of 0.5 to 6 mg/L.

Essential Oil of Cuminum cyminum L.: Extraction by Super Critical Fluid Extraction, Purification by Molecular Distillation and GC-MS Analysis of Volatile Composition
HU Xue-fang,DAI Yun-qing,LI Shu-yan,CHEN Qin-qin,JIANG Sha,CAO Yang,NI Yuan-ying*
2010, 31(6):  230-234.  doi:10.7506/spkx1002-6630-201006055
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Purified essential oil of Cuminum cyminum L. was obtained using supercritical carbon dioxide followed by molecular distillation and was analyzed for volatile composition by GC-MS and double column identification. Totally 44 and 39 components were identified in essential oil of Cuminum cyminum L.using DB-5 and INNO-WAX columns, respectively, and 20 components were simultaneously identified using both columns. A quantification method for four major aromatic components including β-pinene, p-cymene, γ-terpinene and cuminal was established using dodecane as an internal standard substance. The above aromatic components all exhibited a good linear relationship between peak area and concentration, with determination coefficients (R2) of more than 0.9996. Purification by molecular distillation resulted in an obvious increase from 11.48% to 30.30% of the content of cuminal, which is responsible for the characteristic aroma of Cuminum cyminum L.

Determination of Melamine Residue in Edible Fungi by Solid Phase Extraction and High Performance Liquid Chromatography
WANG Deng-fei,HUANG Zhi-hui,ZHENG Jun-chao,CHEN Lian-hong,WANG Rui-long
2010, 31(6):  235-238.  doi:10.7506/spkx1002-6630-201006056
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A novel method based on solid phase extraction followed by high performance liquid chromatography (HPLC) was developed for the analysis of melamine residue in edible fungi. Samples were extracted with a mixed system composed of trichloroacetic acid and acetonitrile (3:1, V/V), cleaned up on mixed-mode SPE column and filtrated through 0.45 μm pore size membrane prior to analysis using a HPLC system equipped with PAD. Melamine was quantified by external standard method. The method exhibited a limit of detection of 2.0 mg/kg and a spike recovery range of 81.3% to 91.7% at three levels, with relative standard deviations (RSDs) of not more than 5.6%. The method proves to be most suitable for the determination of melamine residue in edible fungi.

Comparative Study of Different Methods for Determination of Entrapment Efficiency of Mint Flavour Microcapsules
YANG Jun1,ZHAO Sheng1,CHEN Ke-bing1,ZHU Li-yun2,*,JIANG Jia-xin2
2010, 31(6):  239-242.  doi:10.7506/spkx1002-6630-201006057
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Standard curves for determination of menthol responsible for the characteristic aroma of mint flavour, by different methods such as UV absorption spectroscopy, refractive index, near-infrared diffuse reflectance spectroscopy and gas chromatography were established and their linearity was analyzed to select reliable methods for determination of entrapment efficiency of mint flavour microcapsules. Results showed that UV absorption spectroscopy gave a determination coefficient of 0.9317, whereas determination coefficients of other three methods were all over 0.99, indicating a good linear correlation. Therefore, refractive index, near-infrared diffuse reflectance spectroscopy and gas chromatography can provide a relatively accurate determination for entrapment efficiency of mint flavour microcapsules.

HPLC Analysis of Vitamin E Content in Seeds of Different Species of Genus Perilla L.
CAI Qian-rong,WU Wei*,ZHENG You-liang,YANG Wen-ting,XU Ying-wen
2010, 31(6):  243-247.  doi:10.7506/spkx1002-6630-201006058
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HPLC method was used to analyze vitamin E content in 29 seed samples of different original species or variants of genus Perilla L. from Sichuan and Guangdong Provinces, China, Japan, Korea, Thailand or U.S.. Results showed that 29 Perilla L. seed samples were all rich in VE. There were extremely significant differences of total and respective contents of δ-VE, γ- VE and α-VE among 29 Perilla L. seed samples. Total VE contents varied in the range of 79.90 to 383.30 μg/g, with an average value of 199.76 μg/g. The average contents of δ-VE, γ-VE and α-VE were 5.81, 190.47 μg/g and 3.48 μg/g, respectively. Among 29 Perilla L. seed samples, P06-37 from Japan exhibited the highest total VE content, reaching up to 383.30 μg/g. No significant differences in total and respective contents of δ-VE, γ-VE and α-VE among seeds of different original species and variants of genus Perilla L. tested were observed and P. frutescens (L.) Britton var. frutescens (baisu) exhibited the highest average values of total and respective contents of δ-VE, γ - VE and α -VE.

HPLC Determination of Trimethoprim Residue in Aquatic Products
MEI Guang-ming,CHEN Xue-chang,ZHANG Xiao-jun,ZHU Jing-rui,LI Tie-jun,ZHENG Bin*
2010, 31(6):  248-251.  doi:10.7506/spkx1002-6630-201006059
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A reversed-phase high performance liquid chromatographic (RP-HPLC) method was developed for the determination of trimethoprim residue in aquatic products. Samples were extracted with a mixture of chloroform, sulfuric acid and methanol (15:14:6, V/V). The resulting extraction solution was alkalized, reextracted with dichloromethane and cleaned up on MCX column. The eluate was pooled, concentrated nearly to dryness, rediluted with the HPLC mobile phase and filtrated through a 0.45 μm pore size membrane. Trimethoprim was detected with an ultraviolet (UV) detector and quantified by external standard method. Good linearity between chromatographic peak area and trimethoprim concentration ranging from 0.05 to 5.0 μg/mL was found (R2 = 0.999967). Average recoveries of trimethoprim in different blank aquatic products spiked at the levels of 20, 40, 200 μg/kg were all more than 80%, with relative standard deviations of less than 7%. The method exhibited a detection limit of 20 μg/kg. Due to the advantages of simplicity, rapidity, little matrix interference and high accuracy and precision, this method is most suitable for the determination of trimethoprim residue in aquatic products.

Immuunochemiluminpmetric Assay for A Survey of Estradiol and Progesterone Contents in Different Commercial Brands of Whole Milk
XU Zhuang-jian,MA Ya-ping,LI Li-hua,WANG Feng,FAN Li,PANG Xing-fu,XIE Shu-yan
2010, 31(6):  252-254.  doi:10.7506/spkx1002-6630-201006060
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Six commercial brands (A, B, C, D, E and F) of whole milk produced in Wuxi city or other regions from February to April were sampled two batches every month to obtain 36 samples. A survey of estradiol (E2) and progesterone (P4) contents in the whole milk samples measured by immuunochemiluminpmetric assay was carried out in this study. The content of progesterone present in whey obtained from whole milk by centrifugation was directly measured. Before estradiol measurement, whole milk was required to be hydrolyzed with sulfatase. Results showed that no statistic difference in TE2 content (a quarter of E2 content) was observed among 6 commercial brands of whole milk surveyed in this study. Brand F exhibited a higher P4 content than brand C (P<0.05), while other brands do not differ statistically in P4 content. Among 36 whole milk samples, the maximum value of TE2 content was 2.32 higher than the minimum value and the ratio of maximum to minimum P4 contents was 6.67. For brands A, B, C, D, E and F, the ratio of maximum to minimum TE2 contents were 1.38, 1.60, 1.82, 1.79, 2.17 and 1.68, and the ratio of maximum to minimum P4 contents 3.19, 5.98, 2.89, 1.38, 1.86 and 1.67, respectively. The ratios of maximum average to minimum average values of TE2 and P4 contents among 6 brands were 1.25 and 3.05, respectively. The above results indicate that 6 commercial brands of whole milk significantly differ in P4 content, and there is a wide fluctuation range of P4 content in different bitches of the same brand. Moreover, some difference in TE2 content is also found in different bitches of the same brand.

Determination of Trace Elements in Potentilla anserina L. by Microwave Digestion-ICP-AES
WANG Jian-gang1,SONG Shu-ying2
2010, 31(6):  255-257.  doi:10.7506/spkx1002-6630-201006061
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Samples of Potentilla anserina L. root from different growing areas were analyzed by microwave digestion-inductively coupled plasma-atomic emission spectrometry (ICP-AES) for contents of many trace elements including Ni, Mn, Ti, Cu, B, Ba, Fe, Zn, Na, Ca, Mg and K. A mixture of nitric acid and hydrogen peroxide was used for microwave digestion of samples. Results showed that the method exhibited a spike recovery range of 96.6% to 113%, with RSDs of less than 5%. Under optimized experimental conditions, a simultaneous determination of various trace elements was achieved without any interference among them. The sample from Qinghai province contained higher contents of trace elements than that from Gansu province. This indicates that trace element content in Potentilla anserina L. root is closely linked to chemotype. Our findings will provide useful evidences for the better exploration and utilization of Potentilla anserina L..

Analysis & Detection
Dilution-PCR and PCR-DGGE for Evolution of Effect of Pre-treatment Methods on Extraction of Bacterial DNA from Chilled Pork
JIANG Yun1,2,GAO Feng1,XU Xing-lian1,YE Ke-ping1,ZHOU Guang-hong1,*
2010, 31(6):  258-262.  doi:10.7506/spkx1002-6630-201006062
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Dilution-PCR and PCR-DGGE were used to evaluate effect of four pre-treatment methods such as freeze-thaw, ultrasonification, shake and homogenization on extraction of bacterial DNA from chilled pork in this study. After 4 days of storage at 4 ℃, chilled pork was subjected to pre-treatment by the above methods for bacterial DNA extraction followed by dilution- PCR and PCR-DGGE analyses. Results showed that four pretreatment methods results in a slight difference in bacterial DAN yield but had no notable effect on PCR-DGGE analysis. Therefore, these pretreatment methods could be chosen according to actual requirement. Sequence analysis of DGGE bands of 16S rRNA gene V3 region showed that the predominant spoilage bacterium in chilled pork was Pseudomonas and others including Acinetobacter, Brochothrix, and Serratia were also detected.

HRCA-based Strip Test for Detection of Transgenic Components in Food
HAO Zhen-ming1,ZHAO Xin1,WU Xiao-huai2
2010, 31(6 ):  263-266.  doi:10.7506/spkx1002-6630-201006063
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This study aimed to develop a strip test method based on HRCA technique for simultaneous qualitative detection of various transgenic components in food. A mixture of transgenic and nontransgenic soy bean and transgenic maize and potato in some proportion was prepared to evaluate the effectiveness of nitrocellulose membrane strips developed to immobilize specific probes in detecting transgenic components in reaction products obtained through linkage and rolling-cycle amplification. Results showed that nitrocellulose membrane strips carrying specific probes achieved 100% accuracy in detection of pairwise mixtures or full mixture of the above transgenic components or each of them and gave a detection level of 100 pg/μL, which meets the requirements of routine detection. The developed nitrocellulose membrane strips carrying specific probes may provide an effective tool for detection of transgenic components in food.

Analysis of Quality and Safety of Xinjiang Organic Mutton
WU Yun1,WAN Qin2,DENG Jun-ping2,LI Le1,ZHANG Bo-ying2,LI Huan-rong1,*
2010, 31(6 ):  267-269.  doi:10.7506/spkx1002-6630-201006064
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Two brands of commercial organic mutton produced in Xinjiang were compared for differences in sensory quality, heavy metal, antibiotic, and volatile basic nitrogen contents, pesticide residues and microbiological indexes. Results showed that both brands of Xinjiang organic mutton exhibited high quality and good safety and therefore had tremendous development potential. Meanwhile, some measures were proposed to ensure quality and safety of Xinjiang organic mutton.

Packaging & Storage
Changes in Quality Properties of Herring Fillets during Ice Storage
LIANG Qiong,WAN Jin-qing*,WANG Guo-qiang
2010, 31(6):  270-273.  doi:10.7506/spkx1002-6630-201006065
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Sensory, microbiological and physicochemical parameters of herring fillets stored at (-0.8 ± 0.2), -(2.0 ± 1.0) ℃ and (4.0 ± 1.5) ℃were measured at regular intervals. At the end of storage at these temperature conditions, herring fillets exhibited total bacterial counts of 1.17 × 106, 1.12 × 106 CFU/g and 1.2 × 106 CFU/g, pH 6.96, 6.59 and 6.73, and total volatile basic nitrogen (TVB-N) of 24.95, 20.03 mg/100 g and 20.39 mg/100 g, respectively. Herring fillets became close to spoilage on the 5th and 8th day of partial frozen and cold storage, respectively. For ice storage, herring fillets did not become close to spoilage until the 11th day.

Physiological, Biochemical and Microstructural Changes and Their Relationships with Peel Pitting of "Beibei 447 Jincheng" Orange during Postharvest Storage
LI Cong-min1,YANG Xiao-hong1,*,HAO Chun-mei1,WANG Ri-kui2,ZHOU Lian2,HAN Ai-hua2
2010, 31(6):  274-278.  doi:10.7506/spkx1002-6630-201006066
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To reveal the occurrence mechanism of peel pitting of"Beibei 447 Jincheng"orange, physiological, biochemical and microstructural changes of "Beibei 447 Jincheng"orange stored under normal temperature and ventilation condition were measured before and after pitting, and their relationships with pitting were investigated. After the formation of pitting, "Beibei 447 Jincheng" orange peel became crimpled and shriveled. Besides, disruption and atrophy of oil vacuole and deformation of cells around oil vacuole were both observed, and safranine dyed samples exhibited a deep color. A significant correlation was observed among peroxidase (POD), superoxide (SOD), polyphenoloxidase (PPO) activities and relative electrical conductivity (REC) or between these parameters and peel pitting rate. The occurrence of peel pitting was due to the interactions among these parameters. Moreover, there was no linear relationship between PPO activity and total phenol content. Thus, POD, SOD and PPO activities and REC can be considered crucial physiological features indicating peel pitting occurrence.

Modeling of Remaining Shelf-life Prediction of Frozen Lamb
SONG Chen,LIU Bao-lin,WANG Xin,GU Xue-lian,ZHOU Guo-yan,DONG Qing-li,QIN Rui-sheng
2010, 31(6):  279-282.  doi:10.7506/spkx1002-6630-201006067
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Remaining shelf-life prediction of frozen foods stored and transported at a certain temperature is extremely important for ensuring food quality and safety. In this study, change in total bacterial count of sliced frozen lamb stored at -25, -20, -15, 5, 15 or 25 ℃ were measured at regular intervals. Results showed total bacterial count of sliced frozen lamb was increased with prolonged storage time, and there was an increase in bacterial growth rate as storage temperature rose. A mathematical model describing the dynamic relationship between storage temperature and bacterial growth rate was developed, and the relationship between storage temperature and shelf-life of frozen lamb was deduced. Based on this, a model for remaining shelf-life prediction of frozen lamb was developed, which exhibited high reliability in validation experiments.

Effect of Modified Atmosphere Storage on Sensory Quality and Physiological Characteristics of Postharvest Flammulina velutipes
BIAN Xiao-lin,ZHANG Yan-fen,FENG Li,XIAO Hong-mei*
2010, 31(6):  283-287.  doi:10.7506/spkx1002-6630-201006068
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Respiratory intensity, browning degree (BD), peroxidase (POD) and superoxide dismutase (SOD) activities, and malondialdehyde (MDA) content of postharvest Flammulina velutipes modified atmosphere stored under the conditions of 2 ℃, 95% relative humidity and different oxygen concentrations (1%, 2%, 3% or 5%) were examined at regular intervals. Results showed that low concentration (3%) oxygen treatment effectively inhibited respiratory intensity and the increase of MDA content, maintain high levels of POD and SOD activities, reduced nutrient loss, and helped delay senescence and prolong storage period of Flammulina velutipes.

Optimization of Quick Freezing Process of Citrus Petals
DENG Yong-yan1,SHAN Yang2,3,LI Gao-yang2,3,ZHANG Ju-hua2,3,YANG Li4,ZHANG Ji-guang4
2010, 31(6):  288-291.  doi:10.7506/spkx1002-6630-201006069
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Effect of central temperature depending on freezing time and temperature on physicochemical parameters of quick frozen citrus petals was studied. Physicochemical parameters of quick frozen citrus petals were compared with those of fresh citrus petals and changes in physicochemical parameters of quick frozen citrus petals were measured during -18 ℃ storage. Besides, quick frozen citrus petal cans were compared with common citrus petal cans for the differences in physicochemical parameters and consumer preference. Considering feedstock quantity, citrus petal size and degree of maturity, freezing time and temperature should be controlled in the ranges of 10-20 min and -31- -35 ℃, respectively and as a result, central temperature was -18 ℃. Freezing and storage time both had little effect on frozen citrus petal quality. There was no significant difference in consumer preference between quick frozen and common citrus petal cans.

Effect of Storage Conditions on Lipid Peroxidation of Sunflower Seeds
GE Lin-mei,GAO Hai-yan*,MAO Jin-lin,CHEN Hang-jun,FANG Xiang-jun,MU Hong-lei
2010, 31(6):  292-296.  doi:10.7506/spkx1002-6630-201006070
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Changes in acid, peroxide, iodine, p-anisidine and TBA values of sunflower seeds were investigated during storage under different conditions. Results showed that oxidative lipid peroxidation occurred during storage, and an increase of peroxide, acid, p-anisidine TBA values was observed, along with a decrease of iodine value. Low temperature storage and vacuum or light avoiding packaging obviously inhibited oxidative lipid peroxidation, postponed quality deterioration of sunflower seeds, resulted in prolonging storage.

Technology Application
Orthogonal Array Design for Optimization of Production of Ginger Flavored Soymilk
YU Xin1,LI Xiao-hua2,ZHOU Xiao-mei1,HUANG Xiao-hong1
2010, 31(6):  297-301.  doi:10.7506/spkx1002-6630-201006071
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Soybean and ginger were used as main materials to develop ginger flavored soymilk. The production process of ginger flavored soymilk was investigated by single factor and orthogonal array methods. Results showed that the optimal formula of ginger flavored soymilk made from soybean slurry with a material/water ratio of 1:7 (m/m) consisted of ginger juice 8.0%, cane sugar 9.0%, milk powder 5.0%, carrageenan 0.01% (mass fraction), and xanthan gum 0.02 g/100 g. The optimal values of pH, temperature and temperature-holding time for obtaining an optimal coagulation were determined to be 6.2, 60 ℃ and 5 min, respectively. Processed soymilk under the above conditions showed good gel strength and refreshing taste and no soybean odor was smelled.

Preparation of Flammulina velutipes Beef Meatballs
GAO Ya-wen1,LI Zhuang2,LIU Xue-jun1,*
2010, 31(6):  302-305.  doi:10.7506/spkx1002-6630-201006072
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Based on conventional beef meatball formula, Flammulina velutipes, water, starch and salt were added as adjunct materials to develop Flammulina velutipe beef meatballs. To maximize sensory evaluation score, the optimal amounts of these adjunct materials were investigated using orthogonal array design. Results showed that the optimal formula consisted of Flammulina velutipes 20%, water 30%, starch 12% and salt 3%.

Development of Apple-Petasites palmate A. Gray Compound Dietary Fiber Beverage
LI Hong-gao,WANG Yan,SUN Hong-min
2010, 31(6 ):  306-309.  doi:10.7506/spkx1002-6630-201006073
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Apples and Petasites palmate A. Gray were used as main materials to develop compound dietary fiber beverage. Orthogonal array design was employed to investigate optimal tannin removal from Petasites palmate A. Gray and optimal formulation of compound dietary fiber beverage, was apple dietary fiber beberage 40 g/100 mL, Petasites palmate A. Gray dietary fiber beberage 30 g/100 mL, sugar 10 g/100 mL, citric acid 0.25 g/100 mL, honey 2.8 g/100 mL; cmplex stabilizer: CMC 0.1 g/100 mL, glycerin monostearte (GMS) 0.13 g/100 mL, gelatin 0.2 g/100 mL. The produced beverage using optimized process exhibited abundant nutrition and unique flavor.