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Table of Content

01 June 2010, Volume 31 Issue 11
Basic Research
Change of Major Enzymes during Pile-fermentation Process of Pu'er Tea
ZHANG Ling-zhi CHENG Chu-zhen LI Ye
2010, 31(11):  1-4.  doi:10.7506/spkx1002-6630-201011001
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In order to explore the mechanism for quality improvement of Pu'er tea, the change of enzymes including cellulase, pectinase, amylase, polyphenol oxidase (PPO), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) was investigated during different stages of pile-fermentation process of Pu'er tea. During pile-fermentation process, cellulase and amylase exhibited a similar change trend that was a gradual increase from sun-dried green tea (S0) to 2nd-turned sample (S2), reaching a maximum value, and a subsequent decrease in 3rd-turned sample (S3), which maintained a higher enzyme activity than S0, although the decrease; pectinase exhibited a rapid increase trend from S0 to S1, and a following decline from S1 to S3. In addition, an increase from S0 to S2 and a subsequent reduction from S2 to S3 for the change trend of PPO, GSH-PX and SOD were observed. These investigations also suggested that pile-fermentation degree could provide a significant effect on activities of hydrolases and oxidases. Therefore, proper pile-fermentation process will be of benefit to the improvement of quality and functions of Pu'er tea.

Rheological Properties of Yinmi Starch Paste
YANG Chao1 ZHAO Na1 TIAN Bin-qiang1 DENG Qian-chun2 XIE Bi-jun1 SUN Zhi-da1,*
2010, 31(11):  5-10.  doi:10.7506/spkx1002-6630-201011002
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The rheological properties of Liangyoupeijiu and Jingnuo NO.6 rice starch pastes as well as Yinmi starch pastes processed from each of them were studied at varying concentrations and temperatures. Both native rice starch pastes and Yinmi starch pastes were both typical non-Newtonian and shear-thinning fluids, the viscosity decreased with the increasing shear rate; the rheological behaviors of Jingnuo NO.6 rice Yinmi starch paste were fitted well by power law equation. The dynamic rheological measurement showed that the storage modulus (G′) and loss modulus (G″) of the starch pastes decreased sharply at the initial temperature of heating, then gently decreased, followed by different increases at about 90 ℃, and finally decreased again. While going through the entire temperature rise program, the loss factor (tanδ) showed an upward trend after an initial drop. Both native starch pastes exhibited higher viscosity but lower elasticity than their corresponding Yinmi starch pastes.

Sterilization Mechanism of High-pressure Carbon Dioxide-caused Acidification
ZHOU Xian-han1 SONG Jun-hua2 ZENG Qing-mei1 ZHANG An1 CHENG Li-mei1 HU Xing-jun1 ZOU Xu-peng1
2010, 31(11):  11-14.  doi:10.7506/spkx1002-6630-201011003
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The sterilization mechanism of high-pressure carbon dioxide-caused acidification was studied using a wild-type strain of Escherichia coli and two mutant strains derived from it with low activity of P-ATPase or F-ATPase. The results showed that high-pressure carbon dioxide under the identical condition exhibited better lethal effect on both the mutant strains than on the wild-type strain. Meanwhile, a remarkable effect of H+-ATPase activity on sterilization was observed. Therefore, these investigations indicated that high-pressure carbon dioxide could result in intercellular acidification to cause bacterial death during sterilization.

Effect of Dynamic High Pressure Microfluidization on Molecular Weight Distribution and Functional Groups of Hemicellulose B Fractions Purified from Soybean Dregs Dietary Fibers
KAN Miao1 ZHANG Yu1,2 LIU Cheng-mei2,* LIU Wei2 WAN Jie2
2010, 31(11 ):  15-19.  doi:10.7506/spkx1002-6630-201011004
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Two hemicellulose B fractions HCLB-1 and HCLB-2 were purified by DEAE-Sepharose Fast Flow column chromatography from soybean dregs dietary fibers prepared in our lab and their respective aqueous solutions at 10 mg/mL were treated with the technique of dynamic high pressure microfluidization (DHPM) at varying pressures. Untreated and treated HCLB-1 and HCLB-2 were tested for their molecular weight distribution and functional groups. The results showed that DHPM treatment had an obvious effect on the molecular weight distribution of HCLB-1and HCLB-2. The molecular weight distribution of treated HCLB-1 exhibited 910, 177 kD and 62 kD molecular weight peaks. An 813 kD molecular weight peak was found in the molecular weight distribution of treated HCLB-2. DHPM treatment resulted in red shift/blue shift of characteristic absorption peaks of functional groups in HCLB-1or HCLB-2 observed from their FT-IR spectra. The O-H stretching vibration appearing at 3416 cm-1 in HCLB-1 and the stretching vibration at 1058 cm-1 representing ether linkage presented blue shift to 3405  cm-1 and 1048 cm-1, respectively, while the C-H stretching vibration a red shift from 2923 to 2928 cm-1 after DHPM treatment. Also, there were red shit from 1413 to 1417 cm-1 and blue shift from 1377 to 1369 cm-1. However, the respective characteristic absorption peaks of water andβ-glycosidic linkage kept unchanged basically. The changes in the FT-IR spectral characteristics of HCLB-2 were similar to those in the FT-IR spectral characteristics of HCLB-2.

Basic Research
Changes and Correlations of Main Chemical Components during Pu'er Tea Processing
TIAN Yang1 XIAO Rong1,* XU Kun-long2 JIANG Bo2 SHI Chong-ying1
2010, 31(11):  20-24.  doi:10.7506/spkx1002-6630-201011005
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Special grade sun dried green tea of Yunnan large leaf was used as the experimental subject to examine the changes and correlations of main chemical components during Pu'er tea processing. The results demonstrated that the main chemical components changed greatly during Pu'er tea processing. Tea polyphenol decreased by 59.74%, while theaflavin, thearubigin and theabrownin increased. Among them, the increment of theabrownin was the highest. Its content reached 7.19% in made tea. The content of water extract and free amino acid decreased by 23.36% and 57.98%, respectively, after the end of processing. The content of caffeine and tea polysaccharides increased to some degree, and total ash content changed little. According to the correlation analysis and regression analysis using SPSS software, it was demonstrated that a significant negative correlation was found between tea polyphenol and theabrownin, with correlation coefficient -0.993. In addition, significant positive correlations were also found between water extract and tea polyphenol or free amino acid, with correlation coefficients 0.996 and 0.994, respectively and the regression equation was Y1 = 28.845 + 0.283X1 + 1.429X2. Tea polyphenol had a significant correlation with thearubigin or theabrownin, and the regression equation was Y2 = 45.695-1.180x2-3.641x3.

Effect of Whey Protein Concentration on Suwari and Modori Phenomena of Horse-mackerel Surimi
CHEN Hai-hua1,2 XUE Chang-hu2
2010, 31(11):  25-30.  doi:10.7506/spkx1002-6630-201011006
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The effect of whey protein concentration (WPC) on the suwari and modori phenomena of horse-mackerel surimi prepared under the heating condition of 30 ℃/90 ℃ or 50 ℃/90 ℃ was studied. Regardless of heating conditions, added WPC resulted in a higher breaking force, a higher gel strength and the deformation of surimi gels. Optimal gel properties were observed with 5% WPC, setting at 30 ℃ for 5 h and then heating at 90 ℃ for 20 min. Addition of 5% WPC had significant inhibition effect on the modori phenomena when setting at 50 ℃, which increased breaking force, deformation and gel strength of surimi gels. Addition of 10% WPC showed an optimal inhibition effect. No changes in whiteness were observed for gels with less than 0.5% addition of WPC, while more than 1% addition of WPC resulted in a lower whiteness. The microstructure of surimi gels generally became denser due to the addition of WPC, leading to the increased gel strength.

Purification with Macroporous Adsorbent Resins and in vitro Antioxidant Evaluation of Pomegranate Peel Polyphenols
ZHAO Yan-hong LI Jian-ke* LI Guo-rong
2010, 31(11):  31-37.  doi:10.7506/spkx1002-6630-201011007
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Objective: To purify pomegranate peel polyphenols with macroporous adsorbent resins and evaluate their antioxidant activity in vitro. Methods: The crude polyphenol extract obtained from pomegranate peel through ultrasound-assisted extraction was separated and purified with 10 kinds of domestic macroporous adsorbent resins, and the adsorption kinetics was investigated. In addition, four classical antioxidant assessment methods were used to evaluate the antioxidant activity of the purified pomegranate peel polyphenols. Results: The content of pomegranate peel polyphenols in the crude extract was increased from 35.05% to 87.81% using macroporous adsorbent resins D160 and XRD-6 and the content of punicalagin was increased from 21.25% to 73.96%. in vitro antioxidant activity of the extract exhibited a dose-effect relationship relevant to the content of polyphenols, especially punicalagin. Conclusion: The application of macroporous adsorbent resins appears to be feasible for the separation and purification of pomegranate peel extract, and punicalagin is a key antioxidant component in pomegranate peel polyphenol mixtures.

Comparative Analysis of Body Wall of Stichopus japonicus Selenka and Acaudina leucoprocta H.L.Clark
HOU Fu-jing LI Yan-yan JIN Chun-hua XU Cai-yun XU Jia-jie DONG Ming-min DING Jin-feng SU Xiu-rong*
2010, 31(11):  38-41.  doi:10.7506/spkx1002-6630-201011008
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Objective: With the aim of providing a theoretical basis for the high value utilization of Acaudina molpadioides, this paper reports a comparative analysis of nutritional value and structural characteristics between Acaudina molpadioides and  Stichopu sjaponicus. Methods: Acaudina molpadioides and Stichopu sjaponicus were tested for their basic nutrient composition. Meanwhile, their ultrastructure, denaturation transition temperature and infrared spectral characteristics were measured using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy, respectively. Results and Conclusion: Acaudina molpadioides and Stichopu sjaponicus contained 54.80% and 52.08% of proteins, 0.42% and 3.27% of crude fat, and 1.12% and 1.05% of total sugars, respectively. SEM observations indicated that the muscle fibers of A. molpadioides were thicker and packed in a messy and close arrangement, while those of Stichopu sjaponicus were thinner and neatly arranged with larger gaps among the bundles. The denaturation temperatures of proteins in Stichopu sjaponicus and A. molpadioides were determined by DSC studies to be 51.8 ℃ and 53.4 ℃ respectively. A characteristic absorption peak at 873 cm-1 was seen from the FTIR spectrum of Acaudina molpadioides, which is useful to allow effective identification of the sea cucumber species.

Effects of Thermal Treatment Mode and Temperature on Meat Quality of Beef Semitendinosus Muscle
CHANG Hai-jun1,2 CAO Ying-ying1 WANG Qiang3 XU Xing-lian1 HUANG Ming1 ZHOU Guang-hong1,*
2010, 31(11):  42-46.  doi:10.7506/spkx1002-6630-201011009
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The main objective of this study was to investigate the effects of thermal treatment mode and internal core temperature on the meat quality of beef Semitendinosus muscle. Muscle samples were heated to an internal core temperature of 40, 50, 60, 70, 80 ℃ or 90 ℃ in a water bath and in a microwave oven respectively. The changes of meat quality properties with internal core temperature were examined. The results indicated that water bath heated muscle samples always exhibited a substantial increase in Warner-Bratzler shear force (WBSF) with increasing internal core temperature, but microwave heated muscle samples presented an irregular change in WBSF. WBSF manifested a significant difference (P<0.05) at a core temperature of 50 ℃ or 90 ℃ between water bath and microwave treated samples. As heating temperature increased, the muscle microstructure was changed significantly as exhibited by the denaturation and shrinkage of connective tissue and collagen and the reduction of fiber diameter caused by the shrinkage of muscle fibers. Therefore, thermal treatment mode and temperature had significant effects on the meat quality of beef Semitendinosus muscle.

Microwave Drying Characteristics of Onion
LI Sheng-sheng1 XU Huai-de1,* LI Yu-jin2 WANG Jing1
2010, 31(11):  47-50.  doi:10.7506/spkx1002-6630-201011010
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The aim of the present study was to investigate the drying characteristics of onion under varying microwave powers. The results showed that much shorter length of time was required for microwave drying when compared to hot air drying. The lengths of time required for microwave drying at 119 W and 231 W powers were 0.35 times and 0.125 times shorter than those required for hot air drying at 80 ℃. Under the condition of microwave power 383 W, onion began to become brown. Under the condition of microwave power above 385 W, increasing microwave power could result in more serious brown of onion. However, under the conditions of 119 W and 231 W, brown phenomena rarely occurred. In addition, the rehydration ratios of onion under 119 W and 231 W were 4.87 and 4.67, respectively, higher than those under other microwave powers. The microwave drying of onion proved to be a constant speed process and its mathematical model was in line with Page equation.

Physico-chemical and Structural Characterization of Rapeseed Polysaccharide WPS-1
ZHU Jian-fei1 CHEN Gang1 TANG Chun-hong1 WU Mou-cheng2
2010, 31(11):  51-54.  doi:10.7506/spkx1002-6630-201011011
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WPS-1 was found to be a non-starch polysaccharide with white and flocculent appearance, in which the contents of neutral sugar, uronic acid and protein were 83.2 %, 6.1% and 3.4%, respectively. Protein in WPS-1 was composed of 13 different amino acids. The major monosaccharide compositions of WPS-1 as determined through FT-IR and GC analyses were Ara (67.7%), Gal (17.8%) and Glc (14.5%). The methylation analysis indicated that the major fragments of WPS-1 were (1→5) and (1→2) linked by Ara residues of α-arabinoses. Four kinds of substituted arabinosyl residues as verified according to the 13C NMR and 1H NMR spectra existed in arabinan fragments of WPS-1.

Effects of Compound Flour Improvers on the Rheological Properties of Dough
ZHENG Zhi ZHOU Hui-xi ZHONG Xi-yang LUO Shui-zhong PAN Li-jun JIANG Shao-tong*
2010, 31(11):  55-59.  doi:10.7506/spkx1002-6630-201011012
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This paper describes the results of an investigation on the effects of flour improvers such as sodium-stearoyl-2-lactylate (SSL), guar gum and ascorbic acid added separately or together on the farinograph and extenograph properties of dough, in which orthogonal array design was used to determine the optimum amounts of the flour improvers added together. The analysis of variance indicated that the combined addition of SSL, guar gum and ascorbic acid at 0.7%, 0.2% and 0.012% levels, respectively, resulted in a pronounced increase of dough stability time (from 3.6 to 11.7 min, P<0.01), elongation force (from 102.90 to 190.96 g, P<0.05) and elongation area (1884.9 to 2684.1 g·mm, P<0.05). Therefore, the rheological properties of dough can be effectively improved by the addition of compound flour improvers.

Free Radical Scavenging and Antioxidant Activity of Six Potherbs from Guizhou
GONG Jiang-ning1 LIAO Li-ling1,* WANG Zheng-wu2 ZHENG Kui-ling1
2010, 31(11):  60-63.  doi:10.7506/spkx1002-6630-201011013
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Six potherbs including Chenopodium album linn, Pteridum aquilinum var latiusculum, purslane, Picris divaricata vaniot, water cress and Bengal waterdropwort from Guizhou were extracted with ethanol or water and the extracts were tested for their hydroxyl and DPPH free radical scavenging capabilities. Meanwhile, the IC50 values as determined using rapeseed oil and lard as antioxidant models were used to evaluate their antioxidant activity. The results indicated that the 6 potherbs exhibited high hydroxyl and DPPH free radical scavenging capabilities and had excellent antioxidant effects on rapeseed oil and lard. However, added Bengal waterdropwort could accelerate oxidantion of rapeseed oil and lard.

Effect of Drying Methods on the Physico-chemical and Sensory Quality of Salicornia bigelovii Torr.
XU Ming-liang1 ZHOU Xiang2 CAI Jin-long2 YU Zhi-fang1,*
2010, 31(11):  64-68.  doi:10.7506/spkx1002-6630-201011014
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The changes in the contents of chlorophyll, crude fiber, sodium chloride and total sugar, rehydration ratio and sensory quality of Salicornia bigelovii Torr. before and after hot-air drying (80 ℃, 4 h), microwave drying (420 kW, 5 min, then 140 kW, 5 min) or frozen drying (-60 ℃, below 13.48 Pa) were investigated. The results showed that hot air-dried Salicornia bigelovii Torr. exhibited poorer sensory quality, lower rehydration capacity, lower chlorophyll retention and more loss of vitamin C and total sugar. Frozen drying could significantly reduce color change, increase rehydration ratio, maintain more chlorophyll and sugar in Salicornia bigelovii Torr.. Microwave drying was between hot air and frozen drying for drying efficiency. No significant difference in sodium chloride content was observed among the drying methods.

in vitro Antioxidant and Antimicrobial Activity of Polysaccharides Extracted from the Fruits of Evodia lenticellata Huang and Evodia rutaecarpa (Juss.) Beth.
FU Juan1 BIAN Jing-jing1,2 ZHAO Hua1,*
2010, 31(11):  69-72.  doi:10.7506/spkx1002-6630-201011015
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In this paper, it reports the results of an evaluation of in vitro antioxidant and antimicrobial activity of respective polysaccharides (PEL and PER) extracted from the fruits of Evodia lenticellata Huang and Evodia rutaecarpa (Juss.) Beth using hot water extraction and subsequent ethanol precipitation. The contents of polysaccharides were determined by phenol-sulphuric acid method. The scavenging capacities of PEL and PER against hydroxyl free radicals (·OH), hydrogen peroxide (H2O2) and 2,2-diphenyl-2-picrylhydrazyl free radicals (DPPH·) were evaluated using mimic chemical systems in vitro. Minimal inhibitory concentration as determined by liquid dilution method on cell culture plates was used for anti-microbial activity evaluation. The results showed that the EC50 values of PEL for scavenging ·OH, H2O2 and DPPH· were 0.8, 0.25  mg/mL and 0.9 mg/mL, respectively; for PER, the EC50 values were 1.0, 0.1 mg/mL and 0.8 mg/mL, respectively. Both PEL and PER exhibited obvious scavenging effects against H2O2 and ·OH. In addition, they were both more competent to scavenge H2O2 than vitamin C at the same concentrations. PER provided a potential antimicrobial agent with stronger bioactivity when compared to PEL under the same conditions.

Properties of Acetylated Potato Starch: a Study Based on Chemical Gelatinization
HUANG Jun-rong WEN Xing LI Hong-liang ZHANG Pei
2010, 31(11):  73-76.  doi:10.7506/spkx1002-6630-201011016
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The acetylated potato starch was chemically gelatinized at the periphery of granules with aqueous calcium chloride (4 mol/L) at room temperature, and the remnant granules were obtained after removing the gelatinized starch at the periphery of granules. The original and remnant granules were analyzed for their size, substitution degree, crystal properties and thermal properties. The degree of substitution (DS) of acetylated potato starch was correlated with granular size. The smaller the granular size, the larger the DS. Acetyl groups were mainly distributed at the periphery of starch granules. The crystal structure of remnant granules was B-type, the same as that of original granules. The relative crystallinity and the peak gelatinization temperature of remnant granules became larger as the degree of gelatinization increased.

Synthesis of O-Carboxymethyl Chitosan and Its Effect on the Growth of Aspergillus niger
LI Xiao-fang FENG Xiao-qiang YANG Sheng*
2010, 31(11):  77-80.  doi:10.7506/spkx1002-6630-201011017
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O-carboxymethyl chitosan (OCMC) was prepared and characterized by IR spectroscopy. The effect of OCMC on the growth of Aspergillus niger was also investigated. Results indicated that an obvious inhibitory effect of OCMC on the growth of Aspergillus niger was observed after 1 day of cultivation on agar plates with the addition of OCMC. OCMC at the concentration of 1.0 mg/mL exhibited the strongest inhibitory effect. The interaction between chitosan or OCMC and ct-DNA  could result in the structural damage of ct-DNA.

Functional Properties of Proteins from Mulberry Leaves
WANG Fang LIU Hua DONG Mei-hong
2010, 31(11):  81-86.  doi:10.7506/spkx1002-6630-201011018
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Mulberry leaf proteins were obtained via ultrasonic-assisted extraction and subsequent acid precipitation. The effects of pH, NaCl concentration, sucrose concentration and temperature on functional properties of mulberry leaf proteins were investigated. Results indicated that better solubility, water-holding capacity, emulsifying capacity and emulsion stability, foaming capacity of mulberry leaf proteins were observed at pH far away from isoelectric point (pI = 5). The water-holding capacity, solubility and foaming capacity of mulberry leaf proteins had respective positive correlation with NaCl concentration within the range of 0-1.0 mol/L. The highest emulsifying capacity was observed at 0.8 mol/L and the highest emulsion stability at 0.6 mol/L and a higher level of NaCl concentration resulted in a remarkable decline in both of them; as sucrose concentration increased, the water-holding capacity increased but the solubility and foaming capacity decreased and no pronounced changes in the emulsifying capacity and emulsion stability were observed; the oil-absorbing capacity or foaming capacity of mulberry leaf proteins were positively correlated with temperature, while the water-holding capacity, solubility, emulsifying capacity and emulsion stability of mulberry leaf proteins were the best at 60 ℃.

Study on Properties of Arrowhead Starch Paste
ZHAO Li-chao WU Ying-hua LIU Xin LIANG Xiao-ting
2010, 31(11):  87-90.  doi:10.7506/spkx1002-6630-201011019
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In this paper, it describes the physicochemical properties such as retrogradation, frozen-thaw stability, transparency and viscosity of arrowhead starch paste. The results indicated that arrowhead starch paste had lower sedimentation velocity, which was between chestnut starch paste and cassava starch paste. The frozen-thaw stability of arrowhead starch paste was similar to that of cassava starch paste. Exposure to strong acid or strong alkali resulted in a higher transparency of arrowhead starch paste, whereas there was an opposite change in the media of weak acid or weak alkali. A higher viscosity of arrowhead starch paste was observed in the range of pH 7-11. Sucrose and glucose could increase the viscosity as well as the transparency of arrowhead starch paste; however, NaCl and CaCl2 exhibited an opposite effect. Moreover, increasing concentration of arrowhead starch paste resulted in a higher viscosity; whereas longer length of shearing time resulted in a lower viscosity. Therefore, arrowhead starch paste is a typical non-Newtonian pseudoplastic fluid.

Solid-phase Maillard Reaction between L-glutamic Acid and Glucose as Determined by TG-SPME-GC-MS
ZHU Wen-hui1,2 YANG Liu2,* YANG Hong-yan2,3 YANG Ji2,3 DONG Xue-chang1
2010, 31(11):  91-96.  doi:10.7506/spkx1002-6630-201011020
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In order to explore Maillard reaction without aqueous solution, a novel combinatorial system of thermogravimetry-solid phase microextration-gas chromatography-mass spectrometry (TG-SPME-GC-MS) was designed and a glutamic acid-glucose solid phase Maillard reaction pattern was established. Based on sampling in different temperature ranges, the pyrolysis behavior of pure glucose and mixtures of glutamic acid and glucose at different ratios (1:1, 1:2, 1:4, 1:6, 1:8, or 1:10) were investigated and the release tendency of pyrolysis products in different pyrolysis stages was also discussed. The mixture of glutamic acid and glucose exhibited a lower initial pyrolysis temperature (130 ℃) than that of pure glucose (185 ℃). At the initial reaction stage (130-170 ℃) of solid-phase Maillard reaction, the released product was the pyrolysis product of pure glucose. Maillaid products were generated from 170 ℃, which included 2-pyrrolidone, L-pyroglutamic acid methyl ester, 2-(2-oxopyrrolidino) acetamide, and 5-methyl-1H-pyrrole-2-carbaldehyde.

Antibacterial Activity, Antioxidant Effect and Trace Element Determination of Aruncus sylvester Kostel Root
CAI En-bo HAN Jia-hong LI Lei LI Xiao-ye YANG Zhi-hui LEI Bing XU Rui ZHENG You-lan*
2010, 31(11):  97-101.  doi:10.7506/spkx1002-6630-201011021
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Objective: To investigate the antibacterial activity and antioxidant effect of Aruncus sylvester Kostel root and determine trace elements. Methods: The ethanol extract from Aruncus sylvester Kostel root was tested for its antibacterial activity against five common bacteria and minimal inhibitory concentration (MIC) by filter paper method. The effects of temperature, pressure, pH and ultraviolet light on the stability of the extract were also investigated. DPPH free radical scavenging assay was used for evaluating its antioxidant effect. Atomic absorption spectrophotometry was used to determine the contents of trace elements such as iron, manganese, zinc and copper. Data were subjected to statistical analysis using SPSS16.0 software. Results: The MICs of the extract against the tested bacteria were different. The antibacterial activity of the extract exhibited an excellent stability under various external environments. The half maximal inhibitory concentration (IC50) of the extract for scavenging DPPH free radicals was 0.009 mg/mL. The content of iron was higher than that of other detected trace elements. Conclusion: Aruncus sylvester Kostel root has excellent antibacterial activity, antioxidant effect and plentiful trace elements, which will provide promising its exploitation and utilization value.

Effect of Egg Albumin on the Properties of MTGase-induced Silver Carp Surimi Gels
LIU Hai-mei1,2 BAO Jun-jun1 XIONG Shan-bai2 ZHANG Li3
2010, 31(11):  102-104.  doi:10.7506/spkx1002-6630-201011022
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The formed silver carp surimi gels with the addition of egg albumin (EA), microbial transglutaminase (MTGase) or both of them were tested for their properties and SDS-PAGE patterns in order to examine the effect of EA on the properties of MTGase-induced silver carp surimi gels. EA or MTGase could significantly improve surimi gel properties. EA inhibited the formation of MTGase-induced surimi gels, and resulted in a noticeable decrease in their gel strength and breaking force, but had no inhibitory effect on cross-linking of myosin heavy chain.

Microstructural Analysis of Whey Protein Isolate-Pectin Mixture Using Rheological Models
JIANG Yan-feng CHAI Zhi WANG Zhen REN Fa-zheng LENG Xiao-jing*
2010, 31(11):  105-108.  doi:10.7506/spkx1002-6630-201011023
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A comparative analysis of 2 rheological models such as the Cross model and the Carreau model as well as their separate modified expressions and transmission electron microscopic (TEM) examinations were carried out for elucidating the microstructures of pure whey protein isolate (WPI), pure pectin and WPI/pectin mixture in aqueous solutions at pH 7 without added salts. The concentrations (m/m, %) employed for the solutions were: pure WPI, 5%; pure pectin, 0.8%, 5%and WPI/ 0.8% pectin mixture (5%/0.8%). Both the models were obtained from a shear strain-controlled rheometer over the shear rate range of 0.09s-1 to 600 s-1 and at 80 ℃. The pure WPI and the pure pectin solutions showed Newtonian behaviors, which could be well described by the modified Carreau model. The WPI/pectin mixture, on the other hand, showed shear thinning behaviors and the Carreau model provided a best fit.

Formation Mechanism of Corn Slowly Digestible Starch under Annealing Treatment
ZHAO Kai YANG Chun-hua ZHANG Na MIAO Ming
2010, 31(11 ):  109-112.  doi:10.7506/spkx1002-6630-201011024
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This paper describes the results of an exploration into the formation mechanism of slowly digestible corn starch under the condition of annealing treatment. Scanning electron microscope (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to study the changes of granule appearance, enthalpy, and crystal structure of corn starch during the annealing treatment (AT). The results showed that AT had no effect on granule appearance and the crystal structure was still type A with a relatively compact connection. Compared with native corn starch, T0, Tp, Tc and ΔT (Tc—T0) of its annealed counterparts with and without the removal of rapidly digestive corn starch in DSC plot exhibited an obvious increase. These investigations suggested that the formation of slowly digestible corn starch was due to more compact structures as a result of the crystal rearrangement, which increased the resistance to amylase.

Basic Research
Formation Mechanisms of Carbonyl Compounds from Glycerol Pyrolysis
SHU Jun-sheng1 XU Zhi-qiang2 HU Yong-hua2 XIA Wen-shui1,*
2010, 31(11 ):  113-118.  doi:10.7506/spkx1002-6630-201011025
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This paper reports the use of density functional theory (DFT) for exploring the thermodynamic and kinetic properties of bond dissociation reaction and transition state reaction and the subsequent prediction of pyrolysis pathways. Major products such as formaldehyde, acetaldehyde and acrolein were observed during the dehydration reaction of glycerol. The activation energy of dehydration reaction was in the range of 53.64 kcal/mol to 64.98 kcal/mol. The pyrolysis mechanism of glycerol was applied for 1,2-propanediol and 1,3-propanediol, and it was deduced that the major products were propionaldehyde, acetone and acetaldehyde for 1,2-propanediol pyrolysis and formaldehyde, acetaldehyde and acrolein for 1,3-propanediol pyrolysis. The activation energy of propanediol was in the range of 50 kcal/mol to 60 kcal/mol. These experimental data were in a close agreement with previously reported results of theoretical derivation.

Effect of Processing Methods on Garlicin Content and Nitrite Scavenging Capacity of Garlic
ZHAO Gong-ling1 LOU Tian-jun2 YUAN Xue1 CHEN Hui-juan1 CHEN Fang-juan1
2010, 31(11 ):  119-122.  doi:10.7506/spkx1002-6630-201011026
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Crushed, heated or pickled garlic cloves were evaluated for their garlicin content and nitrite scavenging capacity. The results showed that at fixed levels of storage temperature and pH, both garlicin content and nitrite scavenging capacity of crushed garlic cloves exhibited a tendency to first increase and then decrease as the length of storage time increased. An identical change pattern was observed with increasing storage temperature or pH. As the length of heating time or heating temperature increased, both garlicin content and nitrite scavenging capacity decreased and a more obvious decrease was observed for garlic slices when compared to whole garlic cloves. Pickled garlic cloves with vinegar exhibited a decrease in garlicin content with increasing vinegar amount, but the nitrite scavenging capacity initially presented an increase, followed by a decrease. Increasing tea amount resulted in lower garlicin content and higher nitrite scavenging capacity.

Respective Effects of Calcium Chloride and Papain on Lamb Quality
HU Yong-jin1 LU Dong-po1 ZHU Ren-jun1 GE Chang-rong2,*
2010, 31(11):  123-127.  doi:10.7506/spkx1002-6630-201011027
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The respective effects of CaCl2 injection at varying concentrations and papain soaking on pH, color, cooking loss, myofibril fragmentation index (MFI), sarcoplasmic protein and myofibrillar protein degradation of Biceps femoris from Yunling black goats were investigated. A significant difference (P<0.05) in MFI was observed between the control group and the treatment groups. Ultimate pH was presented in the control group after 0 and 6 h of 4 ℃ storage, which was valued at 6.75 and 6.15, respectively. The lengths of storage time for reaching up to ultimate pH, valued at 6.83 and 6.29 for CaCl2 treatment group and 6.90 and 5.89 for papain treatment group were 2 h and 24 h, respectively. CaCl2 injection or papain soaking could promote the degradation of actin, myosin and myomesin. The samples treated with 0.3 mol/L CaCl2 or 0.002g/100mL papain exhibited the maximum MFI, the highest collagen protein content and minimum cooking loss, indicating perfect tenderization.

Bioengineering
Enzymologic Characteristics of Garlic Fructan Exohydrolase
Cheong Kit Leong,XIE Shun-xin,HUANG Xue-song*
2010, 31(11):  128-131.  doi:10.7506/spkx1002-6630-201011028
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Fructans occupy more than 75% of the dry weight of garlic (Allium sativum L.). Understanding of the enzymologic characteristics of garlic fructan exohydrolase (FEH) provides the theoretical basis on inhibition of garlic germination and mass production of high quality garlic fructans. In this experiment, localization of FEH was done by ammonium sulfate precipitation, its enzymatic degradation products were studied by TLC and ion chromatography, enzyme activity was determined by calculating the variance of reducing sugar via DNS assay. Further study of the locus of action of FEH and the effects of temperature, pH level, ionic strength, and substrate concentration on FEH activity was also included. The results showed that FEH was present in the fraction of 0-20% saturated ammonium sulphate. Through the analysis of enzymatic degradations, FEH was confirmed as an excision enzyme. The optimal reaction temperature, pH, ionic strength and substrate concentration were 45 ℃, pH 5.5, 1.5 mol/L and 4 mg/mL, respectively. These investigations demonstrated that the exohydrolase in garlic could impact the quality of garlic processed products and polysaccharide metabolization in the fresh garlic during its storage.

Optimization of Culture Medium Composition for Active Polysaccharide Production from Metarhizium taii
XIAO Dai-min,XIAO Jian-hui*,ZHANG Zhi-min
2010, 31(11):  132-135.  doi:10.7506/spkx1002-6630-201011029
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Matarhizium taii, the anamorph of edible medicinal mushroom Cordyceps taii, can produce polysaccharide with diverse pharmacological effects for the development of functional foods and new drugs. The purpose of this study was to investigate the use of a combinatorial experimental strategy, involving both one-factor-at-a-time and orthogonal array design methods to optimize the fermentation medium composition for active polysaccharide production by submerged fermentation of Matarhizium taii. The results showed that the optimal medium composition for active polysaccharide production consisted of xylose 40 g/L, soybean steep liquor 4 g/L, (NH4)2SO4, 0.2 g/L vitamin A plus D 1 g/L, KH2PO4 1 g/L and MgSO4·7H2O 0.5 g/L at initial pH 6.0. Using such a medium, an exocellular polysaccharide yield of up to (22.72 ± 0.55) g/L was obtained, which was over 30 times higher than that obtained using fermentation basal medium.

PCR-DGGE Analysis of Microbial Community in Shubat from Xinjiang
Nurgul RAHMAN1,2,CHEN Xiao-hong2,DONG Ming-sheng2,*
2010, 31(11 ):  136-140.  doi:10.7506/spkx1002-6630-201011030
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The microbial community structures of traditional fermented camel milk (shubat) from Xinjiang in China were analyzed using PCR-DGGE technique. Bacterial and yeast community exhibited 78%-84% and 80%-92% similarity among shubat samples from different regions, respectively. Through sequence analysis of V6-V8 region of 16S rDNA, the bacterial community in shubat was composed of Macrococcus caseolyticus, Lactobacillus helveticus, Lactobacillus brevis, Weissella hellenica, Lactobacillus sakei, Enterococcus durans, Enterococcus faecium, Leuconostoc lactis and so on. The yeast community was identified to consist of Kluyveromyces marxianus, Kazachstania unispora, Candida ethanolica and Geotrichum sp. by comparing sequence similarity with D1 region of 26S rDNA gene. These results will provide a theoretical foundation for developing culture starter of shubat.

Separation and Purification of Protease from Bacillus licheniformis 2709
MA Yong-qiang1,ZHANG Hao1,YANG Chun-hua1,LIU Ying1,SUN Bing-yu1,ZHANG Yi-fang2,SHI Yan-guo1,*
2010, 31(11):  141-146.  doi:10.7506/spkx1002-6630-201011031
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A procedure comprising alcohol precipitation, ammonium sulfate precipitation, DEAE ion exchange chromatography and gel filtration chromatography was used to prepare electrophoretically pure alkaline protease from the fermentation supernatant of Bacillus licheniformis 2709. Deamidation degree and alkaline protease activity were evaluated to optimize the procedure. The results indicated that the activity of purified protease was 61069 U/mg; final purification factor was 38.7; recovery rate of activity was 19.3%; and deamidation rate was 20.9%. The enzymological properties of alkaline protease were also studied. The optimal reaction conditions for alkaline protease were pH 10.0 and 50 ℃. After incubation at 40 ℃ for 2 h, the protease remained more than 80% activity and was relatively stable at pH 8 - 11.

Identification of Bacteriocin-producing Bacillus thuringiensis and Properties of Its Antibacterial Substances
LI Yun,YANG Sheng-yuan*,LIN Xiao-dong,ZHONG Yu-hong,SU Ting,LIU Xiang-jia
2010, 31(11):  147-152.  doi:10.7506/spkx1002-6630-201011032
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Strain K2 having the ability to produce bacteriocin was isolated from the surface of picked vegetables. The neutralized cell-free fermentation supernatant exhibited an inhibition effect against Gram-positive bacteria, especially strong inhibition effect against Bacillus strains. The inhibition activity of the fermentation supernatant still kept high after ammonium sulphate precipitation and dialysis, and the activity of the dialysis retentate was sensitive to a variety of proteases. These results indicated the protein nature of antibacterial substances contained in the dialysis retentate. Base on morphological, physiological and biochemical characteristics, 16S rDNA sequence and phylogenic analysis, the strain K2 was classified as Bacillus thuringiensis. The antibacterial substance from strain K2 remained strong antibacterial activity after heating treatment at 80 ℃ and pH 6-9 for 30 min, suggesting its excellent thermostable property and pH resistance. The antibacterial activity was generated from midlogarithmic growth phase and reached the maximum activity at mid-stationary phase.

Effect of Energy Level on H-FABP Gene Expression and Pork Quality
BIAN Lian-quan1,XU Yun-he1,2,SU Yu-hong2,LIU Xian-jun1
2010, 31(11):  153-156.  doi:10.7506/spkx1002-6630-201011033
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In order to explore the effect of energy level on H-FABP gene expression and pork quality, 18 DLY pigs (60 kg) were randomly divided into two groups, which were fed food containing high energy (DE 13.85 MJ/kg, CP 14%) and low energy (DE 12.75 MJ/kg, CP 14%), respectively. All the pigs were slaughtered at the body weight of 100 kg to determine H-FABP gene expression and meat quality traits. The results showed that high-energy food increased H-FABP gene expression (P>0.05). Highenergy food also increased intramuscular fat (IMF) content and back fat thickness (BFT) (P<0.05); H-FABP gene expression was positively correlated with IMF (P < 0.05) and IMF was positively correlated with BF (P < 0.05). These investigations suggested that energy level was able to affect FABP gene expression and meat quality.

Cloning and Expression of iap Gene from Listeria monocytogenes and Purification of Protein p60
LU Tian,WU Hai-tao,CAO Zheng-mao,WANG Xiao-hong*
2010, 31(11):  157-161.  doi:10.7506/spkx1002-6630-201011034
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In this study, iap gene of Listeria monocytogenes was amplified by PCR using self-designed primers and genomic DNA of Listeria monocytogengs as the template. Through introducing EcoRⅠand XhoⅠsites to the 5'and 3' ends of iap gene, iap gene was inserted into pMD18-T vector and recombinant pMD-18T-iap plasmid was constructed. After the verification of DNA sequence, the iap gene was subcloned into expression vector pET-28a to obtain pET-28a-iap expression plasmid. Through ITPG induction of pET-28a-iap, the recombinant p60 protein with relatively molecular mass of 60 kD was over-expressed in E. coli BL21(DE3). The p60 protein was composed of soluble protein and inclusion protein and the amount of soluble protein reached up to 76.3%. The soluble protein was purified by Ni2+-chelating affinity column chromatography with an extraction rate of 68.3%, and the purity of recombinant protein was 95.6%. These results will provide a reference for further studies on structure and functions of p60 protein.

Optimization of Fermentation Culture Medium for Enterococcus faecium BC-3 for the Production of Bacteriocin-like Substances
MIN Zhong-man,YUE Xi-qing*,CAI Wei-fan,GUO Chen
2010, 31(11):  162-167.  doi:10.7506/spkx1002-6630-201011035
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The production of bacteriocin-like substances by Enterococcus faecium BC-3 fermentation was optimized with respect to the effects of various fermentation culture medium components. Plackett-Burman (PB) design was employed to evaluate the importance of 10 factors affecting the production of bacteriocin-like substances, and peptone, beef extract and dibasic ammonium citrate were selected as the most significant affecting factors. Subsequently, path of steepest ascent was coupled with response surface analysis based on central composite design to investigate the optimal values of the selected factors. The optimal fermentation culture medium for the production of bacteriocin-like substances was composed of 33.1 g/L peptone, 55.6 g/L beef extract and 4.9 g/L dibasic ammonium citrate. A maximum diameter of inhibition zone of 17.13 mm obtained using such a medium, 50.79% higher than before the optimization.

Biological Activity Analysis of Human Tissue-type Plasminogen Activator in Transgenetic Egg
LI Yin-ju1,CHENG Xiang-chao1,ZHANG Chun-jie1,WU Ting-cai1, DU Rui-ling2,YU Zu-hua1
2010, 31(11):  168-172.  doi:10.7506/spkx1002-6630-201011036
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In order to explore the translocation feasibility of human tissue-type plasminogen activator (t-PA) from liver to egg yolk and develop functional eggs with anti-cardiovascular diseases, a recombinant plasmid pPhosvitin-tPA encoded human tissue-type plasminogen activator was constructed. The pcDNA3-tPA and pPhosvitin-tPA coated with liposome was directly injected into hen s liver. The expression of recombinant t-PA protein in liver and egg yolk was evaluated using Western blot and ELISA, and its biological activity in egg yolk was determined using fibrinolysis test. SDS-PAGE and Western blot confirmed that recombinant t-PA protein was expressed in yolk on the 7th day post-injection; the molecular weight of the expressed protein was approximately 63 kD. The expression rates were 39.16 mg/L and 53.92 mg/L measured in ELISA. Fibrinolysis of t-PA in vitro indicated that the expressed protein had the capability to activate tissue-type plasminogen. Therefore, it was a feasible strategy to obtain transgentic eggs with recombinant t-PA through its expression in hen s liver subjected to the injection of plasmid encoded recombinant t-PA, which provided a novel method to develop functional food with anti-cardiovascular diseases and made it reality to become a new resource of protein drugs from hens.

β-Glucosidase Production under Optimized Fermentation Conditions of Genetically Engineered Bacterial Strain
LIU Chang-jiang1,LIANG Shuang1,ZHENG Yan1,ZONG Xu-yan1,LI Chang-biao2
2010, 31(11):  173-177.  doi:10.7506/spkx1002-6630-201011037
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The fermentation conditions of genetically engineered bacterial strain for β-glucosidase production were optimized using one-factor-at-a-time method and response surface analysis based on central composite design. The optimal procedure for β-glucosidase production was based on 8 h fermentation under the conditions of pH 6.6, 37.9 ℃, 10% inoculation amount, 200 r/min rotation speed followed by 10 h of induction with the addition of 0.5 mmol/L IPTG, which made the enzyme activity and of β-glucosidase reach up to 147.8 U/mL, respectively.

Preliminary Analysis of Bacterial Flora of the Intestinal Tract of Carp
HOU Jin-hui,CHEN Hong-wei,CAO Ze-hong,GAO Zhao-Jian,CAI Kan
2010, 31(11):  178-181.  doi:10.7506/spkx1002-6630-201011038
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In this study, 62 bacterial strains were isolated from the intestinal tract of healthy Carp, Carassius auratus. Totally 18 Gram-positive and 44 Gram-negative strains were identified through Gram-staining. Cellulase and amylase production analysis verified 26 amylase-producing strains and no cellulase-producing strains in the intestinal tract of carp. Amylase-producing strain was 41.94% among all the isolated strains. Several strains were identified to be Aeromonas, Shewanella and Pseudomonas through 16S rDNA gene sequencing analysis. Pathogencity and amylase activity of strain F2 was analyzed to reveal that this strain was nonpathogenic for carp and its activity reached the peak level at pH 7 and 32 ℃.

Effect of Fermentation by Trametes versicolor on the Extraction of Flavonoids from Glycyrrhiza Residues
LI Yan-bin1,2,ZHANG Qin1,2,HE Jiang-zhou1,2,MEN Zhi-li1
2010, 31(11):  182-186.  doi:10.7506/spkx1002-6630-201011039
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Glycyrrhiza residues were used as substrates to conduct solid-state fermentation with Trametes versicolor, followed by the extraction of flavonoids from fermented glycyrrhiza residues. The purpose of this study was to investigate the use of onefactor- at-a-time and orthogonal array design methods to optimize the fermentation of glycyrrhiza residues by Trametes versicolor for the extraction of flavonoids. Fermentation by T. versicolor could significantly improve the yield of flavonoids. Fermentation temperature, water content in materials and fermentation time exhibited obvious effects on the yield of flavonoids. The optimal conditions for the fermentation of glycyrrhiza residues were determined as follows: with addition of 0.2 g/L ammonium tartrate as nitrogen source and water content in materials of 55%, fermentation for 3 days at 28 ℃. Under these optimal fermentation conditions, the yield of flavonoids reached up to 1.18%, which exhibited 90.32% improvement compared to direct ethanol extraction.

Preparation and Characterization of Conjugated Antigen between Human Serum Albumin and Dextrans
FANG Li-sha1,XIE Zhen-ming1,LIANG Da-feng2,ZENG Lian-qiang2,YU Lin1,*
2010, 31(11):  187-191.  doi:10.7506/spkx1002-6630-201011040
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Dextrans were oxidized using sodium periodate (NaIO4) to obtain products with aldehyde groups, which further reacted with amino (-NH2) groups of human serum albumin (HSA) to form unstable Schiff's base, and stable neoglycoprotein was then obtained in the presence of NaCNBH3 as reductant. In this study, the conjugation between human serum albumin and dextrans was investigated with respect to the effects of dextran type, amount of NaIO4 used for dextran oxidization, ratio between oxidized selected dextran and HSA, and reaction time. The optimum reaction conditions for the conjugation between human serum albumin and dextrans were found to be: dextran T40/NaIO4 molar ratio 1:187, environmental pH 9.0, and oxidized dextran T40/HSA molar ratio 4:1 for a reaction duration of 12 h. In addition, larger amounts of NaIO4 were required for the oxidation of dextrans with larger molecular weight; the higher degree of oxidation (DO), the higher degree of grafting (DG).

Preparation and Identification of Anti-sulfadiazine Monoclonal Antibody
WANG Liu-hua,XU Yang*,GUO Jie-biao,ZHANG Hong,HE Qing-hua
2010, 31(11):  192-196.  doi:10.7506/spkx1002-6630-201011041
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In order to generate a monoclonal antibody (McAb) against sulfadianzine (SD), three separate immunogens with SD/BSA conjugation ratios of 9.0, 8.0 and 3.7 were prepared by diazotization method and BALB/c mice were then immunized with the immunogens. An optimum immunization was observed in BALB/c mice immunized with the immunogen with middle SD/BSA conjugation ratio. A McAb (1F6) with high affinity to SD was obtained by hybridoma technique. The titer of the McAb was 1:1.28 ×106 in ascites according to the indirect ELISA determination. IC50 and the lowest detectable limit (LDL) of the McAb in linear range of 14.8-421.5 ng/mL for SD were 79.1 ng/mL and 10.4 ng/mL, respectively. The cross-reactivity ratios of the McAb against sulfamethazine, sulfamonomethoxine and sulfamethoxydiazine were 0.3%, 0.99% and 4.5%, respectively, while no cross-reactivity to sulfamethoxazole, sulfaquinoxaline, 4-aminobenzoic acid, sulfanilamide or sulfanilic acid was observed. The sub-class of the McAb was identified as IgG2b.

Comparison on Fermentation Characteristics of Strawberry Wine by Self-selected Yeasts
LU Hui-wei,SUN Yu-mei*,LU Ming-chun,CAO Fang,ZHANG Li-na,YUE Yong-tang
2010, 31(11):  197-201.  doi:10.7506/spkx1002-6630-201011042
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Yeast strains D, E and H were separated and selected from strawberry broth after spontaneous fermentation. Strain A, Saccharomyces cerevisiae was used as the control. The major flavor components of strawberry wines fermented by various strains were analyzed using gas chromatography. The fermentation characteristics of various strains were compared according to the measurement of degradation rate of reducing sugar, ethanol-producing ability, acid production and sensory quality. The results showed that strain A had the highest ability to produce ethanol and the wine produced by strains H or D exhibited better flavor. Strain H had better fermentation characteristics, which could provide a final reducing sugar content reduced to 18.3 g/L and 12.92% ethanol content in the wine fermented by it. Meanwhile, the contents of isobutyl alcohol, isoamyl alcohol, ethyl lactate and β-phenethyl alcohol in the wine fermented by strain H were higher than those of the wines produced by other strains. Moreover, the wine fermented by strain H exhibited clear and bright color, pure taste and classical flavour style of strawberry wine.

pyrG Gene Cloning and Establishment of Homologous Transformation System for Aspergillus oryzae
WANG Jin-liang,CHEN Hong-wen*
2010, 31(11):  202-205.  doi:10.7506/spkx1002-6630-201011043
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The present paper reports the establishment of homologous transformation system for Aspergillus oryzae based on pyrG gene as the selective marker. pyrG gene was amplified by PCR with A. oryzae genome as a template and connected with pMD-18T vector. The product was transformed into E. coli DH 5α. Recombinant plasmid pMD-pyrG was verified according to blue-white screening, PCR fast screening, enzyme digestion and sequence identification. Sequence analysis exhibited 99.9 % homology with the pyrG gene of A. oryzae KNB 616. The deduced homology for amino acids was 99.6 %. Transformation of A. oryzae pyrG- mutant with recombinant plasmid pMD-pyrG by PEG/CaCl2 method could result in its genetic transformation to become pyrG+ mutant. The establishment of homologous transformation system for A. oryzae makes it possible to introduce exogenous gene and analyze its function in the future.

Preliminary Study on Integration of Growth and Inactivation Models of Clostridium sporogenes Spores
DONG Qing-li,LUO Ting
2010, 31(11):  206-208.  doi:10.7506/spkx1002-6630-201011044
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In order to verify the feasibility of using one model to predict microbial growth and inactivation, the"mirror image" curve of thermal inactivation for Clostridium sporogenes spores was fitted by Gompertz and Baranyi models describing microbial growth, respectively. Both traditional growth models were compared based on mathematical evaluation. Both Gompertz and Baranyi models had better fitting for microbial thermal inactivation and no significant difference was observed according tot-test analysis. Moreover, Gompertz model with lower standard error of prediction (SEP) was superior to Baranyi model. Therefore, we recommend the use of Gompertz model to describe both growth and inactivation of Clostridium sporogenes spores.

Preliminary Detection and Identification of Microorganisms on the Surface of Green Asparagus during Modified Atmosphere Storage
GAO Wen-geng1,CHANG Xiao-yuan2,YU Ya-qiong2,LI Ping-lan2,*
2010, 31(11 ):  209-213.  doi:10.7506/spkx1002-6630-201011045
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This paper reports the observation of changes in total count of bacteria colonies on the surface of scale leaves and on the root cross-section of green asparagus during modified atmosphere (MA) storage and the preliminary isolation and identification of isolated microorganisms. There was a very slow increase in microbial population during the first 10 days of MA storage, followed by a sudden increase, reaching up to 7.40 × 107CFU/g on the 14th day. Subsequently, microbial population decreased slightly with prolonged length of storage time. A total of 24 bacterial strains 8 fungal strains were isolated from the surface of green asparagus that began to decay, which were identified to belong to Pediococcus, Escherichia, Pseudomonas, Erwinia, Micrococcus, Leuconostoc, Staphylococcus, Sporosarcina, Alcaligenes or Acetobacter and to belong to Penicillium, Alternaria, Pythium or Saccharomyces.

Nutrition & Hygiene
Effect of Creatine Pyruvate on Carcass Characteristics and Amino Acid Compositions in Rats
KONG Yi-li,LIU Yi,ZHANG Yuan-shu,SU Xiao-qian,MA Hai-tian*,ZOU Si-xiang
2010, 31(11):  214-220.  doi:10.7506/spkx1002-6630-201011046
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In order to investigate the effect of creatine pyruvate (CrPyr) on metabolic direction of nutritive substances, rats were administered CrPyr to explore carcass characteristics and amino acid compositions in serum and tissues. Forty healthy male SD rats were randomly divided into four groups, which were administered CrPyr at the dosages of 0, 750, 1500 mg/(kg bw·d) and 3000 mg/(kg bw·d), respectively. On the 49th day of the experiments, all rats were scarified after 12 h fasting. The content of amino acids in serum and tissues were determined by reversed-phase high performance liquid chromatography (RP-HPLC). Results showed that relative weight of leg muscle in CrPyr-treated groups was significantly increased (P< 0.05) compared with the control group. Similarly, CrPyr-treated groups exhibited a significant increase in the content of glucogenic amino acid in serum and muscle. However, no obvious difference in amino acid composition in liver was observed. These investigations suggested that CrPyr could improve protein synthesis by elevating the concentration of glucogenic amino acid in serum and muscle of rats.

Protective Effect of Polysaccharides from Ganoderma atrum against Oxidative Stress-induced Cardiomyocyte Injury in Neonatal Rats
LI Wen-juan1,NIE Shao-ping1,YU Qiang1,YAN Yan1,ZHU Shang-bin1,LI Chang1,HE Ming1,2,XIE Ming-yong1,*
2010, 31(11):  221-225.  doi:10.7506/spkx1002-6630-201011047
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Objective: To investigate the protective effect and its mechanisms of polysaccharides from Ganoderma atrum (PSG-1) on oxidative stress-induced cardiomyocyte injury in neonatal rats. Methods: Primary cultures of cardiomyocytes from neonatal rats with PSG-1 pretreatment were exposed to H2O2 and beating rates of cardiomyocytes were monitored under inverted microscope. Cell viability was detected by MTT assay. The activities of lactate dehydrogenase (LDH) and superoxide dismutase (SOD), and the content of malondialdehyde (MDA) were determined by a colorimetric method. The level of intracellular reactive oxygen species (ROS) was determined using flow cytomety. SOD expression was monitored by western blot analysis. Results: PSG-1 significantly decreased LDH activity, ROS generation and MDA content, and greatly increased beating rates of cardiomyocytes, cell viability, protein expression and SOD activity in a dose-dependent manner. Conclusion: PSG-1 protects cardiomyocytes against oxidative stress-induced injury, which is probably related to the attenuation of MDA content and ROS generation and the increase of SOD expression and activity.

Protective Effect of Opuntia milpa alta Polysaccharides on SDS-induced Damage of Human Cell Membrane and Mouse Hepatocyte DNA
WANG Hai-tao1,HE Cong-fen1,DONG Yin-mao1,ZHANG Hui-ming1,2,PI Nan1,LIU Wen-ting1,ZHAO Hua1,*
2010, 31(11):  226-230.  doi:10.7506/spkx1002-6630-201011048
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Objective: To investigate the protective effect of Opuntia milpa alta polysaccharides (OMAP) on human red blood cell (RBC) membrane and mouse hepatocyte DNA damage induced by sodium dodecyl sulfate (SDS). Methods: RBC hemolysis test and Comet assay were used to determine the effect of OMAP on cell membrane damage and DNA damage, respectively. Three groups were designed for the experiments. The positive control group of cell system was given 40μg/mL SDS; OMAP control groups of cell system were cultured in media containing OMAP with varying concentrations (20, 40, 60, 80 μg/mL and 100μg/mL); OMAP + SDS groups of cell system were first treated with OMAP at varying concentrations prior to incubation in media with 40 μg/mL SDS. Results: OMAP presence at all concentration conditions could markedly prevent cell membrane and DNA damage induced by SDS, and an obvious dosage-response relationship was observed. Conclusion: OMAP has good potential to protect SDS-induced cell membrane and DNA damage.

Effect of Soy Isoflavones on the Expression of Bcl-2 mRNA and Bax mRNA in Ovary and Uterus in Young Female Rats
CHI Xiao-xing1,ZHANG Tao2,QIAN Li-li1,SUN Qing-rui1
2010, 31(11):  231-233.  doi:10.7506/spkx1002-6630-201011049
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Objective: This paper focuses on the evaluation of the effect of soy isoflavones on the expression of Bcl-2 mRNA and Bax mRNA in ovary and uterus in youth female rats and the elucidation of anti-aging mechanism of soy isoflavones in youth female rats from the viewpoint of apoptosis. Methods Fifty two-month-old youth female rats were chosen to be divided into five groups of 10 rats each by body weight: control group (basic diet), low-dose group (soy isoflavones 100 mg/(kg bw·d), middledose group (soy isoflavones 200 mg/(kg bw·d), high-dose group (soy isoflavones 300 mg/(kg bw·d), estrogen-treated group (diethylstilbestrol 0.5 mg/kg). The experiments lasted for 7 consecutive weeks. The expression of Bcl-2 mRNA and Bax mRNA in ovaries an uterus were detected by in situ hybridization method. Results: compared with the control group, the expression of Bcl-2 mRNA in ovary and uterus in soy isoflavones-treated groups was significantly increased, while the expression of Bax mRNA was significantly decreased. Conclusions. Soy isoflavones can enhance the expression of contra-apoptosis gene Bcl-2 mRNA and reduce the expression of auxo-apoptosis gene Bax mRNA. This is probably a good explanation of the anti-aging mechanism of soy isoflavones in youth female rats.

Effect of Soybean Meal Derived Phytoestrogen on Biomechanical Characteristics of Femur in Senile Rats
ZHAO Li-ying1,ZHANG Er-qin1,LIU Sheng2,DU Rui-qing1,*,GAO Yun-hai3,HUANG Hao4
2010, 31(11):  234-237.  doi:10.7506/spkx1002-6630-201011050
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Objective: To evaluate the effect of phytoestrogen contained in soybean meal on biomechanical characteristics of bone in senile rats. Methods: Totally 120 senile male SD rats were randomly divided into 4 groups, which were fed common diet (as the control), common diet plus calcium, common diet plus phytoestrogens, and common diet plus calcium and phytoestrogen, respectively. The rats in every group were partially sacrificed after 3, 6 or 10 months of feeding. The biomechanical characteristics of the femur in senile rats were analyzed. Results: The administration of phtoestrogen, could enhance biomechanical characteristics and improve bone quality in rats regardless of length of administration time (3, 6 or10 months), which was superior to the administration of calcium alone. The administration of calcium alone for 3 or even 6 months had no obvious beneficial effects on biomechanical characteristics and bone quality in rats; an improvement in some but not all of biomechanical characteristics in rats, howevers observed when the length of administration time was prolonged to 10 months. In the presence of phytoestrogen, increasing calcium amount resulted in a better improvement in biomechanical characteristics. Conclusion: The intake of calcium alone has a limited effect in preventing osteoporosis and in improving bone quality. Comparatively, the frequent consumption of soybean or soybean products has positive significance for preventing osteoporosis and improve bone quality.

Determination and Nutritional Evaluation of Amino Acids in Esox lucius Muscle
WANG Yong-xing1,QIAN Long2,*,LU Yan1,Abduula ABBAS1
2010, 31(11 ):  238-240.  doi:10.7506/spkx1002-6630-201011051
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In order to evaluate the nutritional quality of Esox lucius muscle, its amino acid composition was determined and analyzed using an automatic amino acid analyzer. The amino acid composition of Esox lucius muscle consisted of 18 common amino acids including 8 essential amino acids that are required in human body. The total content of amino acids in a dried muscle sample was 82.65 g/100g and the content of essential amino acids was 43.58 g/100g. The ratio between essential amino acids and total amino acids was 53 %. The essential amino acid composition in Esox lucius muscle basically met the requirements of the food standard issued by FAO/WHO. The coefficient of amino acids ratio was 86.41. The content of four delicious amino acids in a dried muscle sample was 30.51 g/100g.

Hypolipidemic Effect of Dietary Fibers from Gracilaria sp. in Hyperlipidemic Mice
XIAO Mei-tian,YE Jing,TANG Xu-chong
2010, 31(11):  241-243.  doi:10.7506/spkx1002-6630-201011052
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Kingming mice were fed high fat diet to establish a hyperlipidemic model. In order to explore the hypolipidemic effect of dietary fibers from Gracilaria sp. (GDF), the mice with hyperlipemia were administered GDF at the dosages of 100, 200 mg/(kg bw·d) and 400 mg/(kg bw·d) for 4 consecutive weeks. Oat dietary fiber was used as the control. Blood lipid indicators including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) were determined. GDF could significantly reduce the contents of TC, TG and LDL-C, and increase the content of HDL-C in serum. Therefore, GDF has the potential to regulate lipid metabolism and relieve oxidative injury induced by high fat diet.

Evaluation on Immune-enhancement Effect of Lactoferrin
HU Zhi-he,LI Na,LIU Chuan-guo,PANG Guang-chang,CHEN Qing-sen
2010, 31(11):  244-247.  doi:10.7506/spkx1002-6630-201011053
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The immune regulatory function of lactoferrin was evaluated according to relevant Chinese national standards for evaluation of immune regulatory functional food. Balb/c mice were chosen to establish an immunodeficiency model. The immunodeficiency mice were orally administered lactoferrin at the dosages of 0.1, 1 mg/mL and 10 mg/mL, respectively. The effect of lactoferrin on immune organ weight, cellular immune function, humoral immune function and monocyte macrophages function were determined. The results showed that lactoferrin exhibited positive reaction within the dosage range of 0.1-10 mg/mL, and the strongest immune effect of lactoferrin was 1 mg/mL. Therefore, it can be concluded that lactoferrin exerts immune regulatory function in a dose-dependent manner.

Toxicological Assessment of Peony Seed Oil
ZHU Wen-xue,LI Xin,LIU Shao-yang,BAI Xi-ting,LIU Ke
2010, 31(11):  248-251.  doi:10.7506/spkx1002-6630-201011054
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Objective: To study toxicological safety of peony seed oil. Methods: Acute toxicity test, sub-acute toxicity test and sperm abnormal genetic toxicity of peony seed oil were determined to evaluate its safety. Results: Acute toxicity test in mice demonstrated non-toxicity of peony seed oil due to its LD50 larger than 15 g/kg bw; sperm abnormal genetic toxicity test was negative, suggesting that no mutagenic effect arising from the administration of peony seed oil was observed; healthy rats were by gavage administered peony seed oil for 30 consecutive days and no abnormal changes in health status, biochemical indexes, hematological and blood biochemical indexes and immune organ indexes in the rats were observed after the end of the administration. Based on these results, it was estimated that the maximum non-effective dosage of peony seed oil was more than 5.0 g/kg bw (150 times as high as the recommended dosage for human body). Conclusion: Peony seed oil is excellent edible oil with higher safety.

Effect of Cordyceps militaris on Learning and Memory Capability of D-Galactose-induced Aging Mouse Model
YANG Zhan-jun,ZHANG Jian,TANG Yang,WEN Lu
2010, 31(11):  252-254.  doi:10.7506/spkx1002-6630-201011055
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Objective: To explore the effect of Cordyceps militaris on learning and memory capability of D-galactose-induced aging mouse model. Methods: An aging mouse model was established through the induction of D-galactose, and the experimental mice (assigned to the model group) were by gavage administered with Cordyceps militaris for 6 consecutive weeks and the Cordyceps militaris treated group was obtained. After the end of the administration, the mice were evaluated for their learning and memory capability by dark avoidance test, shuttle-box test and step-down test. Results: Compared with the control group, the learning and memory capability of mice in model group exhibited a significant decrease (P<0.05 or P<0.01); While, compared with the model group, the learning and memory capability of mice the Cordyceps militaris treated group exhibited an obvious recovery (P<0.05). Conclusion: Cordyceps militaris can significantly improve learning and memory capability of aged mice.

Anti-fatigue Effect and Mechanism of Polysaccharides from Eleagnus angustifolius L.
DING Yu-song1,WANG Zhong2,MA Ru-lin1,FENG Gang-ling1,XU Shang-zhi1,LU Feng-lian1,TANG Mei-e1,ZHENG Rong-hua1
2010, 31(11):  255-257.  doi:10.7506/spkx1002-6630-201011056
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Objective: To explore the anti-fatigue effect and mechanism of polysaccharides from Eleagnus angustifolius L. Methods: A total of 192 Kunming mice were randomly divided into 4 batches, each of which consisted of 4 groups: EAP groups at the dosages of low (100 mg/(kg bw·d)), middle (500 mg/(kg bw·d)) and high (1000 mg/(kg bw·d)) levels, and the control group. Each mouse was administered once a day for 30 days. After the end of the administration, all the mice were evaluated for their weight-loaded swimming duration and the contents of hepatic glycogen, blood urea nitrogen and blood lactic acid. Results: EAP at the high and middle dosages could prolong weight-loaded swimming duration, and decrease blood lactic acid level of mice. Hepatic glycogen content exhibited an increase in all groups administered EAP. In addition, a decline of blood urea nitrogen was observed in mice administered EAP at the high and low dosages. Conclusion: EAP could alleviate physical fatigue of mice.

Risk Assessment of Copper in Livestock Products
ZHOU Yan-ming,LIN Cui-cui*
2010, 31(11):  258-262.  doi:10.7506/spkx1002-6630-201011057
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This study focused on the assessment of hazard identification, hazard description, exposure assessment, risk characterization resulting from excessive copper in livestock products in order to improve the safety of livestock products. A risk assessment model for copper was established by risk assessment software RISK4.5. Probability of excessive copper in livestock products from certain city could be deduced from the established model. These investigations will promote food safety, protect the health of customers and provide a guideline for departments in charge of risk assessment.

Hypoglycemic Activity of Polysaccharides from Fruit Body of Grifola frondosa and Its Effect on α -Glucosidase Activity
LEI Hong1,WANG Yi1,CAI Liang-liang1,WU Wu-tong2
2010, 31(11):  263-267.  doi:10.7506/spkx1002-6630-201011058
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A kind of polysaccharide named MT-α-glucan was isolated and purified from the fruit body of Grifola frondosa. The dose-effect and time-effect relationships of MT-α-glucan were studied. The effect of MT-α-glucan on fasting blood glucose, 24 h post-treatment blood glucose, oral blood glucose tolerance, muscle glycogen content in KKay diabetic mice and the activity of α-glucosidase in vitro were investigated. Results showed that MT-α-glucan at the dosages of 112, 225 mg/kg bw and 450mg/kg bw had significant hypoglycemic effect and the strongest hypoglycemic effect was observed at the dosage of 450mg/kg bw at 8 h post-administration. However, blood glucose was restored to original level at 24 h post-administration. Consecutive administrations of MT- α -glucan at the dosage of 450 mg/kg bw and 150 mg/kg bw exhibited an obvious hypoglycemic effect on fasting blood glucose, blood glucose level at 24 h post-administration, and an increase effect on oral blood glucose tolerance and muscle glycogen content of KKay diabetic mice. In addition, MT- α -glucan had significant inhibitory effect onα-glucosidase activity in vitro. Therefore, MT-α-glucan had obvious hypoglycemic effect, which might be related to its inhibitory effect onα -glucosidase activity.

Comparative Study on Bioavailability of Lycopene Liposomes, Lycopene Microcapsules and Soybean Oil-based Preparation of Lycopene
KONG Xiang-hui1,WANG He-ya1,QIAN He2,*
2010, 31(11):  268-272.  doi:10.7506/spkx1002-6630-201011059
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The physical and chemical properties of lycopene have been shown to hamper its biological functions. In this study, the liposome technique, providing one kind of commonly used carriers for drugs, was considered for the production of lycopene liposome with high stability and bioavailability. An ultrasonic-assisted film-forming method was used to prepare lycopene liposomes. Results indicated that low release rate of soybean oil-based preparation of lycopene in mimic gastric or intestinal fluid without bile salt was observed; however, the release of soybean oil-based preparation of lycopene in mimic intestinal fluid with bile salt reached up to 91%. The release of lycopene from liposome and microcapsule preparations was less than 22% in mimic gastric fluid, while its release in two kinds of mimic intestinal fluid was between 80% and 90%. Compared with soybean oil-based preparation of lycopene, lycopene liposomes prepared in our laboratory and commercially-available lycopene microcapsules exhibited longer retention time in body and lower clearance, which provided a prolonged efficiency for lycopene. Moreover, the bioavailability of lycopene liposomes was 154.42%, which was close to lycopene microcapsules and much higher than soybean oil-based preparation of lycopene.

Reviews
Advances in Characterization of Amylose and Amylopectin Starch
LI Hai-pu,LI Bin,OUYANG Ming,ZHANG Sha-sha
2010, 31(11):  273-277.  doi:10.7506/spkx1002-6630-201011060
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As two major constituents of starch, amylose and amylopectin are distinct in both molecular structures and molecular aggregation, which results in dissimilarity in their physico-chemical properties. Consequently, the application performance of starch is variable due to the ratio of amylose and amylopectin. Current progress in characterization such as purity, molecular structure, relative molecular weight, crystal characteristics, thermal enthalpy and viscosity of amylose and amylopectin has been reviewed in this paper, which will provide meaningful references for further investigations of structural and physicochemical characterization as well as the application of amylose and amylopectin.

Research Progress on Evaluation Methods for Quality of Frozen Surimi and Surimi-based Products
LU Ye,WANG Xi-chang*,LIU Yuan
2010, 31(11):  278-281.  doi:10.7506/spkx1002-6630-201011061
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In the last decade, the yield of frozen surim has increased year by year in China. Surimi-based products have become the important aquatic processing products. The quality evaluation of frozen surimi and surimi-based products plays a crucial role in their circulation. Currently, the major methods available to evaluate frozen surimi and surimi-based products are sensory evaluation and instrument measurements. In this paper, evaluation methods were summarized and the future development directions are proposed, which will provide a theoretical basis for future research.

Research Progress of Ergot Alkaloids
LU Chun-xia,WANG Hong-xin*
2010, 31(11):  282-288.  doi:10.7506/spkx1002-6630-201011062
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Ergot alkaloids are mycotoxins, which are produced from fungi in the family of Clavicipitaceae. Toxicity of ergot alkaloids is an important issue to human and animals. However, ergot alkaloids exhibited a therapeutic effect on some forms of migraine, postpartum hemorrhages, mastopathy, Parkinson s disease, cerebrovascular insufficiency and venous insufficiency. This paper reviews the production of ergot alkaloids, physical and chemical properties, biosynthesis, hazards, biological activity, as well as the detection method.

Research Progress of Polysaccharides from Stigma maydis
ZHAO Wen-zhu,YU Zhi-peng,YU Yi-ding,LIU Bo-qun,LIU Jing-bo*
2010, 31(11):  289-292.  doi:10.7506/spkx1002-6630-201011063
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Polysaccharides were major functional components in Stigma maydis. The polysaccharides are high molecular weights and complicated molecular structures. These polysaccharides have functions of blood glucose regulation, tumor inhibition, immune modulation and anti-oxidation. In this paper, current research progress of extraction, purification, structural identification and pharmacological actions of polysaccharides from Stigma maydis is reviewed, which will provide a scientific basis for further study and exploitation of Stigma maydis.

Current Advances in Characteristics of Fungaltoxin and Preparation of Antigen
SUN Ya-ning1,2,HOU Yu-ze1,*,DENG Rui-guang2,HU Xiao-fei2,WANG Lei1,ZHAO Li-na1,ZHI Ai-min2,LIU Qing-tang2,ZHANG Gai-ping2
2010, 31(11):  293-297.  doi:10.7506/spkx1002-6630-201011064
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Fungaltoxins are secondary metabolites with strong toxicity during growth process of fungi. They are dangerous to human health and safety through food or feed chains. The most effective method to control its negative impact is to fully understand their characteristics for conducting accurate and rapid detection. Currently, ELISA detection method has become the major trend for rapid detection of mycotoxins. In this paper, the characteristics, classifications, harmfulness, preparation methods of immunogen and ELISA detection of fungaltoxins is reviewed.

Research Advances in Tetrodotoxin and Its Fermentation
GU Jiang-wen1,XU Shan-liang2,*,YAN Fu-yun1,CHEN Xuan-xiong1
2010, 31(11):  298-302.  doi:10.7506/spkx1002-6630-201011065
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Tetrodotoxin (TTX) is a highly toxic amino hydrogenated quinazoline compound in puffer fish. TTX is one of the most lethal biological toxins. It is also a powerful anesthetic and detoxification agent. Therefore, further studies on preparation technology and high-yield strategies of TTX for extending its medicinal values are being conducted according to the understanding of its generation pathways and TTX-producing strains. In this paper, basic characteristics of TTX including the origin, physical and chemical properties, biological activity are reviewed. In addition, current hot research direction and corresponding issues such as TTX-producing strain and its fermentation are also comprehensively analyzed.

Research Progress in Rare Sugars
YI Yang1,2,ZHANG Ming-wei1,*
2010, 31(11):  303-307.  doi:10.7506/spkx1002-6630-201011066
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Rare sugars are defined as monosaccharides and their derivatives rarely exist in nature. They play an important role in the field of food, health and medicine. In this paper, bioactivities such as anticancer, scavenging free radical and neuroprotective function of several rare sugars are described. Meanwhile, three major synthesis strategies such as ring-closing metathesis, twostep synthesis and Izumoring synthesis, for rare sugars were also introduced. In addition, current research and application perspectives of rare sugars were also proposed.

Research Progress of Angiotensin Converting Enzyme Inhibitory Peptides
YU Zhi-peng,ZHAO Wen-zhu,LIU Bo-qun,LIU Jing-bo*
2010, 31(11):  308-311.  doi:TS253.1
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Angiotensin converting enzyme (ACE) catalyzes the conversion of angiotensin I to potent vasoconstrictor angiotensin II and plays an important physiological role in the regulation of blood pressure. Angiotensin converting enzyme inhibitory peptides derived from animal or plant proteins have attracted extensive attention and have become a hot research topic due to their safety and no side effects. In this paper, current research progress including antihypertensive mechanisms and evaluation methods of ACE inhibitory peptides is reviewed.

Antioxidant Mechanism and Application Prospective of Antibacterial Peptides
XIAO Ming-zhu1,2,JIN Xiao-bao1,2,ZHU Jia-yong1,2,*
2010, 31(11):  312-315.  doi:10.7506/spkx1002-6630-201011068
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Antibacterial peptides have become a research hotspot of great interest in more than two decades. Besides their anti-microbial property, their anti-oxidant and anti-aging effects have been confirmed through current extensive research. In this paper, anti-oxidation mechanisms related to scavenging of free radicals, inhibition of lipid peroxidation and chelating of metal ions are reviewed. In addition, their applications in food, cosmetics and health products are also discussed.

Research Progress of Heating Treatment for Citrus Fruits Postharvest
WANG Qing-yun,GONG Ji-jun,ZHONG Hai-yan
2010, 31(11):  316-319.  doi:10.7506/spkx1002-6630-201011069
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Heating treatment of fruits postharvest to control decay and maintain quality is new technology without pollution and residues, which has gained wide attention these years and been used in various fruits and vegetables. However, heating treatment of citrus fruits has been reported infrequently. In this paper, different heating treatment methods are summarized. The effect of heating treatment on quality characteristics of fruits, and reduction of chilling injury and control of diseases and insect pests is discussed. The commercial prospects and development trends of heating treatments for citrus fruits postharvest are also analyzed.

Degradation and Product Analysis of Ochratoxin A Induced by γ -Irradiation
CHI Lei,HA Yi-ming*,WANG Feng
2010, 31(11):  320-324.  doi:10.7506/spkx1002-6630-201011070
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In this paper, the toxicity of ochratoxin A and its pollution in agricultural products in China are introduced. The advantage of γ -irradiation-induced degradation for ochratoxin A is analyzed through the comparison with various traditional degradation methods. In addition, according to current research progress inγ-irradiation degradation for different kinds of mycotoxin, γ-irradiation degradation methods for ochratoxin A and corresponding product analysis are comprehensively reviewed.

Research Progress of Acid-reducing Techniques for Fruit Wine
WEN Lian-kui,ZHAO Wei,ZHANG Wei,HU Yao-hui*
2010, 31(11):  325-328.  doi:10.7506/spkx1002-6630-201011071
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In order to explore the strategies for reducing acid in fruit wine, physical, chemical and biological methods for reducing acid of fruit wine according to fruit wine species, organic acid types, and acidity requirements of fruit wine are systematically reviewed in this paper. In addition, the application of modern biotechnology in acid-reducing process of fruit wine is also discussed.