Table of Content

15 April 2013, Volume 34 Issue 7
Microbial Esterification of Organic Acids in Yellow Water by Monascus purpureus and Yeasts: A Comparative Study
CHEN Shuai1,ZHAO Jin-song1,ZHENG Jia1,LIU Kun-yi1,HUANG Jun1,ZHOU Rong-qing1,2,3,*
2013, 34(7):  1-5.  doi:10.7506/spkx1002-6630-201307001
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Comparison of Monascus purpureus AS 3.972 and Pichia anomala 2.10 and Saccharomyces cerevisiae 2.178 was carried out for the microbial esterification of organic acids in yellow water as a by-product of Chinese liquor making. The fermentation products were analyzed by GC-MS. These three microbial strains showed different esterification efficiencies for organic acids in yellow water and resulted in the formation of different products; the esterification efficiency of Monascus purpureus AS 3.972 was 56.81% and 80.85% higher than Pichia anomala 2.10 and Saccharomyces cerevisiae 2.178, respectively and resulted in the formation of 13 esters such as ethyl hexanoate and ethyl caprylates and a similar volatile profile to luzhou-flavor liquor. PCA and OAV analysis suggested that Monascus purpureus AS 3.972 was more suitable for the bioconversion of yellow water than yeasts.
Antioxidant Activity of Hydrogen-Reduced Alkali Lignin Prepared Using Palladium/Carbon (Pd/C) as Catalyst
PU Wei,REN Shi-xue,MA Yan-li,FANG Gui-zhen*
2013, 34(7):  6-10.  doi:10.7506/spkx1002-6630-201307002
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In this study, commercial and laboratory-prepared Pd/carbon catalysts were used for the reduction of industrial alkali lignin by hydrogen under high pressure conditions in order to increase lignin activity. The chemical composition and antioxidant activity of alkali lignin and its reduced products were analyzed. The contents of alcohol hydroxyl groups and phenolic hydroxyl groups in commercial Pd/carbon activated alkali lignin were 5.01% and 3.64%, respectively, compared to 5.35% and 3.82% for laboratory-prepared Pd/carbon activated alkali lignin. Thus, the laboratory-prepared Pd/carbon has better catalysis performance than the commercial Pd/carbon. Both alkali lignin and its reduced products had strong radical scavenging activity against DPPH and hydroxyl radicals at a concentration ranging from 0.025 to 0.6 mg/mL in a concentration-dependent manner. The maximum scavenging rates of commercial Pd/carbon activated alkali lignin and laboratory-prepared Pd/carbon activated alkali lignin were 80.91% and 82.43% for DPPH free radical and 23.12% and 26.21% for hydroxyl free radical, respectively.
Influence of Frequency Signal on Electrical Property of Peach Fruits
DU Guang-yuan1,2,TANG Yan1,GUO Ai-guang1,*,ZHANG Ji-shu1
2013, 34(7):  11-15.  doi:10.7506/spkx1002-6630-201307003
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The purpose of this study was to examine the effect of frequency on electrical parameters of peach fruits. The electrical impedance properties of nectarine ‘Qinguang 2’, including fourteen electrical parameters, were investigated using HIOKI 3532-50 LCR HiTester. Nonlinear curve fitting using SPSS resulted in the establishment of mathematical models which depict the quantitative relationships between these parameters and frequency. All these parameters with the exception of Q factor presented regular changes with increasing frequency while an inverse cubic correlation with frequency was observed on impedance (Z), equivalent serial resistance (Rs), equivalent parallel resistance (Rp) and reactance (X). Equivalent serial capacity (Cs) showed a similar pattern to that of equivalent parallel capacity (Cp).The change in impedance phase angle (θ) with frequency was a U-shaped curve while a W-shaped curve was observed for loss coefficient (D). Electrical excitation frequency admittance (Y), susceptance (B), equivalent series inductance (Ls), parallel equivalent inductance (Lp) and conductance (G) presented an exponential increase with excitation frequency.
Effects of High Pressure Processing on Physical and Chemical Quality of Beef
CHANG Hai-jun1,ZHOU Wen-bin1,YU Xiao-ling2,MA Han-jun2,ZHOU Guang-hong3
2013, 34(7):  16-19.  doi:10.7506/spkx1002-6630-201307004
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The main objective of this study was to investigate the changes in the main physical and chemical quality of beef semitendinosus muscle after high pressure processing (HPP) (with different pressures and lengths of dwell time). Muscle samples were processed under high pressure from 200 to 600 MPa for 10 min and 20 min, respectively. The changes in collagen contents, solubility, cooking loss and meat tenderness were analyzed for beef semitendinosus muscle during processing. The results indicated that with increasing pressure, the shear force of beef tended to decrease, and this reduction was significant when the dwell time was 20 min. Under pressure up to 600 MPa, the shear force was reduced to 39.59 N and 31.36 N when treated for 10 min and 20 min, respectively. The contents of total collagen, soluble collagen and collagen solubility increased with rising pressure. Significant correlation was observed between the changes of collagen characteristics and meat quality.
Interaction of Epigallocatechin-3-gallate with Porcine Pancreas Lipase
FAN Zhi-fei,ZENG Wei-cai,DAI Ji-ling,HE Qiang*
2013, 34(7):  20-23.  doi:10.7506/spkx1002-6630-201307005
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The interaction between epigallocatechin-3-gallate (EGCG) and porcine pancreas lipase (PPL) was studied by fluorescence spectroscopy, and the mechanism was investigated according to molecular docking. Results showed that EGCG could quench PPL fluorescence and inhibit its catalytic activity, while the inhibition was weakened in the presence of Ca2+, Mg2+, Cu2+ or Fe2+. Molecular docking suggested that EGCG might be bound to PPL through hydrophobicity, hydrogen bonds and Pi-Pi interaction, and blocked the entry of substrate into the active center, thus inhibiting the catalytic activity of PPL.
Changes in Microorganism Populations during Storage of Ozone-Treated Paddy
ZHOU Jian-xin,LIN Jiao,ZHANG Rui,ZHANG Du-juan
2013, 34(7):  24-27.  doi:10.7506/spkx1002-6630-201307006
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In the present study, the changing patterns of water content, total bacterial count and mould count during simulated storage of ozone-treated paddy at different temperatures were explored. The counts of microorganisms in paddy could significantly be decreased by ozone treatment. The water content of ozone-treated paddy revealed a slight increase in the first 40 days of storage followed by a general downtrend and declined more obviously at higher storage temperature. Total bacterial count and mould count of ozone-treated paddy basically remained stable during storage at 15 or 20 ℃, but fell more at 25, 30 or 35 ℃ than before storage. Furthermore, at the beginning of storage, both microbiological indicators showed a rebound. Analysis of variance demonstrated that both storage temperature and time had a very significant effect on changes in total bacterial count and mould count, and further statistical analysis using SPSS suggested the linear relationships for total bacteria count or total mold count as a function of storage temperature and time.
Grade Identification of Sausages Based on Instrumental Texture Parameters
ZHAO Gai-ming1,HAO Hong-tao1,2,TIAN Wei3,LI Miao-yun1,HUANG Xian-qing1,LIU Yan-xia1
2013, 34(7):  28-33.  doi:10.7506/spkx1002-6630-201307007
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In this study, texture standards for sausage grading were proposed and validated. Both sensory scores and textural values of texture characteristics were measured. The standard ranges of hardness, frangibility, adhesiveness, springiness, cohesiveness and chewiness were established based on the developed linear regression equations for sensory scores as a function of corresponding textural values. Fisher linear functions were obtained based on the instrumental texture characteristics of different sausage brands. Under the specific testing conditions, the hardness, frangibility, adhesiveness, springiness, cohesiveness and chewiness standard ranges of premium ham sausages were 8690.162 to 9357.137 g, 8929.995 to10963.274 g, -102.467 to -35.005 g, 0.836 to 0.951, 0.226 to 0.279 and 1766.990 to 2232.348 g, respectively. In addition, these parameters of excellent sausages were 7441.334 to 9188.980 g, 6700.973 to 8929.995 g, -102.467 to -66.644 g, 0.741 to 0.833, 0.200 to 0.247 and 1368.863 to 1737.272 g, and there parameters of ordinary sausages were 6734.754 to 8690.162 g, 4441.556 to 6700.973 g, -257.264 to -159.397g, 0.633 to 0.698, 0.148 to 0.183 and 736.838 to 951.339 g. All the Fisher linear functions exhibited an accuracy higher than 94.5% in grade discrimination of different sausage brands. These results indicated that the established textural value standards and functions could be used to guide product development and quality evaluation of sausages.
Comparative Study of Properties of Raw Milk with Different Somatic Cell Counts
CHEN Jian-po1,CHEN Shu-xing1,*,LI Li-li2,WEI Hui-juan1,REN Fa-zheng3
2013, 34(7):  34-37.  doi:10.7506/spkx1002-6630-201307008
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Five raw milk samples with different somatic cell counts (SCC) were analyzed for major chemical composition, fat decomposition degree (lipase activity, free fatty acid content and its ratio to total fat), and protein decomposition degree (water soluble nitrogen, ratio of non-protein nitrogen to total nitrogen, and casein profile) with the aim of understanding the effect of SCC on raw milk quality. The results showed that: 1) There was no significant difference (P > 0.05) in major components and properties for raw milk with SCC lower than 4.0 × 105 cells/mL; 2) fat decomposition was positively related to SCC level and showed no significant difference between two raw milk samples with SCC lower than 4.0 × 105 cells/mL (P > 0.05); 3) casein profile of raw milk varied with SCC, the ratios of water soluble nitrogen and none-protein nitrogen to total nitrogen, WAN/TN and NPN/TN, increased with increasing SCC, while no significant difference was observed between the raw milk samples with SCC lower than 4.0 × 105 cells/mL.
Correlation Analysis between Meat Quality and Serum Biochemical Parameters from Qinghai Datong Young Yak
JING Yuan1,YU Qun-li1,*,HAN Ling1,FENG Yu-cheng2
2013, 34(7):  38-41.  doi:10.7506/spkx1002-6630-201307009
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In order to explore the correlation between meat quality of beef and serum biochemical parameters, Qinghai Datong young yak and Haibei young calf were determined for beef chroma, pH1, pH24, shear force, warping loss and cooking loss as well as serum biochemical parameters. It was found that Qinghai Datong young yak had darker beef color, higher tenderness and higher water-holding capacity than Haibei young calf. The contents of K, Na, Cl, Mg and high density lipoprotein (HDL), and the activity of alkaline phosphatase (AKP) and lactic dehydrogenase (LDH) in serum of Qinghai Datong young yak was significantly higher than Haibei young calf, whereas the content of low density lipoprotein (LDL) and the activity of glutamic-oxaloacetic transaminase (GOT) were significantly lower. The content of serum creatinine had a significantly positive correlation with cooking loss, and had a significantly negative correlation with water loss. The GOT had a significantly positive correlation with pH24.
Total Phenol and Favonoid Contents and Antioxidant Activity of Houttuynia cordata Thunb.
CAI Wen-guo,WU Wei*,DAI Sha,ZHANG Ping-wu,ZOU Jian
2013, 34(7):  42-46.  doi:10.7506/spkx1002-6630-201307010
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Leaves of sixteen H. cordata cultivars including H. emeiensis Z.Y. Zhu et S. L. Zhang were extracted with 95% ethanol by ultrasonic-assisted method. The contents of total phenolic acids and flavonoids were determined spectrometrically, and their antioxidant capacities were evaluated. The results showed that total phenol contents in dried leaves of H. cordata were in the range of 7.01-15.0 mg/g, and flavonoid contents varied from 3.56 to 11.0 mg/g. DPPH radical scavenging rates of the leaf extracts of H. cordata varied from 84.7 to 248 μmol/g, and ABTS radical scavenging rates from 78.4 to 218 μmol/g. Cluster analysis based on the contents of polyphenol and flavonoid as well as antioxidant activity in vitro indicated that 16 H. cordata cultivars could be classified into two subgroups. The group I included 11 H. cordata cultivars with relatively low total phenol content, flavonoid content, and DPPH and ABTS radical scavenging capacity, while group Ⅱ showed higher contents of polyphenol, flavonoid, and antioxidant activity in vitro. The chromosome number did not show any significant correlation with the contents of polyphenol and flavonoid or antioxidant activity in vitro, while total phenolic acid and flavonoids contents had an obvious correlation with antioxidant activity.
Effect of Inoculum Amount of Staphylococcus xylosus on Quality Characteristics of Fermented Beef Kebabs
XIA Xiu-fang,ZHANG Jin-duo,KONG Bao-hua*
2013, 34(7):  47-50.  doi:10.7506/spkx1002-6630-201307011
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The effect of different inoculum levels of Staphylococcus xylosus on physic and chemical properties and sensory characteristics of fermented beef kebabs was explored. Lactobacillus casei and Staphylococcus xylosus were mixed as composite starters at different ratios for the fermentation of beef kebabs. The physicochemical parameters (pH, aw, a* and TPA) and sensory evaluation of fermented beef kebabs were analyzed. The results showed that the flavor of fermented beef kebabs with 108 CFU/g Staphylococcus xylosus was the best, but the color, texture and total acceptance of fermented beef kebabs with 106 CFU/g or 108 CFU/g Staphylococcus xylosus were poorer than that of the fermented beef kebabs with 107 CFU/g Staphylococcus xylosus. When the inoculum amount of Staphylococcus xylosus was 107 CFU/g, the fermented products had better sensory evaluation, color, flavor and taste, which exhibited a significant difference from two other groups (P ≤ 0.05).
Phenolic Contents and Antioxidant Activity of Lily Flower Petals
YAN Lin-mao1,GUO Yu-long1,ZHANG Yan-long1,*, NIU Li-xin2, JIN Lei2
2013, 34(7):  51-55.  doi:10.7506/spkx1002-6630-201307012
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The contents of phenols including 15 phenol monomers and antioxidant activity of four cultivated varieties of liliy flower petals were tested. The antioxidant activity of petal extracts was evaluated by measuring scavenging ability against ABTS+·, DPPH and hydroxyl free radicals, reducing power and metal-chelating ability. Flower petals of “Sorbonne” was found to contain the highest phenol content followed by “Siberia”, “Manissa” and Lilium regula. Different types of polyphenol monomers were found in the studied varieties of lily petals and catechin, epicatechin, pcoumaricacid, delphinidin, rutin, dihydromyricetin, dihydroquercetin and kaempferol were simultaneously present in them. In addition, phenols from 4 varieties showed strong radical scavenging activity against ABTS+·, DPPH and hydroxyl free radicals, copper ion reducing power and metal-chelating capacity. Our results indicate that these selected lilies can be developed and utilized in practice as promising sources of natural antioxidants.
Preparation by Antisolvent Recrystallization Method and Characterization of Coenzyme Q10 Microparticles
SANG Mei,SUI Xiao-yu,SONG Zhen,ZHAO Xiu-hua,ZU Yuan-gang*
2013, 34(7):  56-61.  doi:10.7506/spkx1002-6630-201307013
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Coenzyme Q10 microparticles with improved hydrophilicity were prepared by antisolvent crystallization method. We investigated the effects of Coenzyme Q10 concentration, system temperature, stirring speed and stirring time on average micro-particle size. In addition, the preparation conditions were optimized. Properties of coenzyme Q10 and micro-particles were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) analysis. The results showed that powder particle size could be adjusted by changing the process conditions. The optimal preparation conditions were 50 mg/mL, 1:6, 4 ℃, 4000 r/min and 10 min for substrate concentration, solvent/anti-solvent volume ratio, system temperature, stirring speed and stirring time, respectively. Under these conditions, the average diameter of micro-particles was 1.84 μm. The chemical structure of coenzyme Q10 microparticles did not reveal an obvious change when compared with coenzyme Q10, but the melting point and decomposition temperature revealed a decrease, and the intensity of crystal diffraction peak became weaker.
Effect of Sodium Tripolyphosphate on Properties of Beef Muscle
DUAN Chang-sheng,ZHAO Shuang-juan,HUANG Wen,WANG Yi*
2013, 34(7):  62-66.  doi:10.7506/spkx1002-6630-201307014
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The effects of soaking in different concentrations of sodium tripolyphosphate solutions and cold storage time on the properties of duck muscle such as color, water-holding capacity (WHC) and TPA parameters were investigated. The results showed that the WHC and TPA parameters of duck muscle were increased by soaking in 3 g/100 mL sodium tripolyphosphate solution. Meanwhile, the total phosphorus residue did not exceed the limit and good eating quality was obtained.
Removal of Anti-nutritional Factors from Soybean by Microwave Processing
SUN Xin-yao,SUN Bo*,MA Wen-juan,REN Jing,ZHAO Xiao,QI Yu
2013, 34(7):  67-69.  doi:10.7506/spkx1002-6630-201307015
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In this study, soybean anti-nutritional factors and protein solubility were determined to explore the feasibility of applying microwave for dry processing of soybeans. The results indicated that microwave could effectively remove soybean anti-nutritional factors, and the removal rates of trypsin inhibitor and urease were over 80% when soybeans were treated by microwave at a power of 3400 W for 120 s. In addition, protein solubility of the microwave-treated soybeans was about 40%, and the soybean flour prepared from them could be used as a special base material for instant soybean beverage.
Functional Properties of Bitter Almond Protein
XUE Lei1,LI Da-wen1,WEI Qin1,*,ZHAO Zhong1,MA Xi-han2
2013, 34(7):  70-75.  doi:10.7506/spkx1002-6630-201307016
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In this study, bitter almond protein was prepared through the combined use of diluted salt solution extraction and isoelectric point-salt precipitation. The effects of pH, NaCl concentration, protein concentration and temperature on functional properties (solubility, water-holding capacity, oil-absorbing capacity, emulsifying capacity, emulsion stability, foaming capacity and foam stability) of bitter almond protein were investigated systematically. The results showed that the solubility, water-holding capacity, emulsifying capacity and emulsion stability, foaming capacity of bitter almond protein were the lowest around isoelectric point (pI 4.1). The solubility, emulsifying properties and foaming properties could be improved with increasing NaCl concentration from 0 to 0.8 mol/L. However, higher level of NaCl concentration had a negative effect on these properties. The emulsifying and foaming properties of bitter almond protein were improved by increasing the protein concentration, but at a level of 3-4 g/100 mL, no obvious change in emulsifying capacity, emulsion stability, foaming capacity or foam stability was observed. Functional properties were significantly improved by suitable heating, but exposure to excessive heat caused a continuous decrease in the various functional properties.
Digestive Stability of Protein in Transgenic Rice Expressing Lysine-rich Fusion Protein Gene
ZHAO Xiang-xiang1,HU Xiao-lan1,LU Chang-li1,JI Li-lian1,LIU Qiao-quan2,TANG Tang1,LIU Fu-xia1
2013, 34(7):  76-81.  doi:10.7506/spkx1002-6630-201307017
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Lysine-rich rice was a transgenic rice produced by inserting lysine-rich fusion protein gene into rice seeds. According to the standard of the People’s Republic of China, the in vitro digestibility of the protein extracted from transgenic rice seeds was investigated in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Results showed that total protein was completely digested at 5 g/L within 2 min in SGF and at 2 g/L from 15 s to 2 min in SIF, respectively. When the total protein concentration was increased to a 5-fold level (25 g/L and 10 g/L in SGF and SIF, respectively) of the standard concentrations, total protein was rapidly degraded in SIF but was hard to digest in SGF because some indigestible protein fragments were still detected after 60 min incubation. However, these indigestible protein fragments could be completely digested by SGF after treatment with SIF for 5 min. These results suggested that the proteins in transgenic GL gene rice revealed no digestive stability in SGF/SIF.
Effect of Glycosylation on Gelling and Physicochemical Properties of Egg White Powder
CHI Yu-jie1,XU Wei1,HONG Yu-miao2
2013, 34(7):  82-85.  doi:10.7506/spkx1002-6630-201307018
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Molecular characteristics of glycosylated egg white proteins (GEWP), including gelling properties, the number of sulfhydryl groups, hydrophobicity, molecular flexibility and Zeta potential were investigated. The results showed that gel strength and water holding capacity of glycosylated egg white proteins increased by 112.51% and 18.89%, respectively, when compared to control. After glycosylation, the protein molecules were partially unfolded, thus exposing the internal hydrophobic groups. At the same time, inter- and intra-protein disulfide bonds were formed, resulting in decreased total sulfhydryl content. In addition, glycosylation decreased the number of free ε-NH2 on the surface of egg white protein molecules, reducing the positive charges, and thus, the isoelectric point of egg white proteins.
Comparative Study on Chemical Components and in vitro Antioxidant Capacity of Essential Oil from Different Parts of Perilla frutescens
WANG Jian1,XUE Shan1,ZHAO Guo-hua1,2,*
2013, 34(7):  86-91.  doi:10.7506/spkx1002-6630-201307019
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The volatile oils extracted from perilla leaves, buds, stems and seeds by simultaneous distillation extraction (SDE) were analyzed for chemical composition by gas chromatography-mass spectrometry (GC-MS) and their antioxidant activity in vitro was compared. The results showed that the highest extraction rate of volatile oil, 8.21‰, was obtained from perilla leaves. Totally 40, 53, 29 and 26 volatile components were identified in perilla leaves, buds, stems and seeds, respectively, accounting for 99.85%, 99.25%, 96.73% and 97.51% of the total essential oils. Only five volatile compounds were simultaneously found in the essential oils from the different parts perilla, including 2-hexanoylfuran, 4-(2-methylcyclohex-1-enyl)-but-2-enal, caryophyllene, linalool and caryophyllene oxide. Among these compounds, 2-hexanoylfuran had the highest content. In in vitro antioxidant evaluation, the essential oils from all the different parts had antioxidant activity. Perilla leaves had the highest DPPH radical scavenging activity, whereas the highest OH radical scavenging activity was observed in perilla seeds.
Effects of Particle Size and Addition Level of Wheat Bran on Texture Properties of Dry White Chinese Noodle
CHEN Jian-sheng,GUO Qi-fang,CUI Jin-long,ZHANG Yong-xiang,LI Xing-cui,YAN Zuo-chen,TIAN Ji-chun*,XU Hui,LIU Kai
2013, 34(7):  92-98.  doi:10.7506/spkx1002-6630-201307020
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Wheat bran is one of the major dietary fibre sources widely used in food. The effects of particle size and addition level of wheat bran on the texture properties of dry white Chinese noodle (DWCN) were investigated in this study. Noodles were made of Shannong 2 wheat flour mixed with wheat bran at four different levels (5%, 10%, 15% and 20%) and of four different particle sizes (0.16-0.43 mm, 0.43-1.0 mm, 1.5-2.0 mm and 2.0-2.5mm). The results showed that the addition level and particle size of wheat bran had considerable influence on noodle texture properties. In general, the breaking strength, flexibility and area integrals of the strength curve decreased obviously as wheat bran particle size and addition level increased. The dry noodle breaking strength (DNBS) showed a downtrend with increasing addition level when the bran size was larger than 0.43 mm. At 5% addition level, there were no differences in DNBS, which was obvious when more than 10% wheat bran was added. For the fine bran (size < 0.43 mm), there was only a slight decrease in dry noodle flexibility (DNF) when the addition level of wheat bran was less than 10%. But for coarse bran, there was obvious effect of addition level on DNF even though the addition was less than 5%. With increasing particle size and addition level of wheat bran, the hardness, gumminess and chewiness of cooked noodle decreased and adhesiveness increased. However, the changing trends of springiness and cohesiveness were not consistent. For fine bran, there was no significant decrease in hardness when the addition level was less than 10%, but for coarse bran, there was a remarkable decrease. For medium and coarse bran, addition of wheat bran had no effect on cohesiveness, springiness or resilience of noodles at 5%-15% addition levels. We suggest that 10% and less fine bran or 5% and less medium bran should be required to produce fibre-rich DWCN.
Physicochemical and Functional Properties of Defatted Legume Flour
NIE Li-jie,DU Shuang-kui*,WANG Hua,CAI Meng
2013, 34(7):  99-103.  doi:10.7506/spkx1002-6630-201307021
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In order to improve the development and utilization of legume resources, the physicochemical and functional properties of dehulled and defatted legume flour from large white kidney bean, light speckled kidney bean, small white kidney bean, cowpea, mung bean, small red bean, lentil and pea were analyzed and compared with those of soybean. The results showed that the legumes had higher bulk density, water-absorbing index and gelation capacity, and lower water solubility index, water-absorbing capability and oil-absorbing ability. Legume flour was significantly different from soybean flour in foaming capacity and stability, and did not revealed significant differences in emulsification and emulsion stability. Significant differences in physicochemical and functional properties of legume flour were also observed. Big white kidney bean exhibited higher water-absorbing index, oil-absorbing ability, emulsion stability and lower bulk density. Small white kidney bean displayed higher water-absorbing capability, emulsification, foaming capacity and foaming stability. Pea flour exhibited higher gelation and foaming capacity but lower emulsion stability.
Effect of Maturity on Structure and Physical and Chemical Properties of Yutian Waxy Corn Starch
YIN Xu-min1,ZHAN Xiao-wan2,ZHAO Guo-hua 2,MING Jian2,ZENG Shun-de1,*
2013, 34(7):  104-110.  doi:10.7506/spkx1002-6630-201307022
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The structure, physical and chemical properties of Yutian waxy corn with different degrees of maturity were determined by scanning electron microscope, X-ray diffraction, Fourier transform infrared spectrometer, differential scanning calorimeter and Brabender Viscometer. The results showed that the granules of Yutian waxy corn starch had a round or polygonal shape, and the number of polygonal particles increased with the elevated maturity. Yutian waxy starch presented A-type crystalline structure and the 2θ values were around 15.15°, 17.50° and 23.00°. With rising maturity, the diffraction intensity of starch granule crystalline increased. The structure of Yutian waxy corn starch consisted of pyrantype α-type glucose. Thermal properties showed minimum differences in To, Tp, Tc and ΔH among the 5 degrees of maturity. To ranged from 70.00 to 72.00 ℃, Tp from 74.90 to 76.80 ℃ and Tc from 80.90 to 83.40 ℃. Brabender viscosity curves showed that the starch from waxy corn collected 30 d after pollination contained the highest content of amylopectin while the starch from waxy corn collected 25 d after pollination had peak viscosity. The starch from waxy corn collected 23 d after pollination had good thermal stability whereas the best cold stability of waxy corn starch was obtained 30 d after pollination.
Antioxidant Activity of Isoquercitrin and Caffeoylquinic Acid Derivatives from Sweet Potato Stems and Leaves
LI Jia-yin1,2,YU Huan2,SHI Bo-yang1,2,LI Mi-lu2,LU Ying1,2,*
2013, 34(7):  111-114.  doi:10.7506/spkx1002-6630-201307023
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The antioxidant activity of four major polyphenolic compounds, namely quercetin-3-O-β-D-glucoside (Q-Glu), 4,5-di-O-caffeoylquinic acid (4,5-diCQA), 3,4-di-O-caffeoylquinic acid (3,4-diCQA) and 3,5-di-O-caffeoylquinic acid (3,5-diCQA) derived from sweet potato stems and leaves were evaluated based on reducing power, DPPH, hydroxyl and superoxide anion free radical scavenging, and anti-lipidperoxidation assays and compared with that of VC. These four polyphenolic compounds demonstrated strong antioxidant activity in a concentration-dependent manner. The IC50 values of Q-Glu, 3,5-diCQA, 3,4-diCQA, 4,5-diCQA against DPPH and hydroxyl free radicals were 47.27, 41.61, 43.55, 46.02 μmol/L, and 190.99, 151.20, 151.24, 217.31 μmol/L, respectively, whereas the IC50 values of Q-Glu3, 5-diCQA, and 3, 4-diCQA against superoxide anion free radical were 0.81, 0.46, 0.71 mmol/L, respectively. In anti-lipidperoxidation assay the IC50 values of 3,5-diCQA, 3,4-diCQA, and 4,5-diCQA were 4.44, 2.53, 3.13 mmol/L, respectively. Within the studied concentration range, however, 4,5-diCQA and Q-Glu did not reach 50% superoxide anion free radical scavenging and lipidperoxidation. Among these compounds, 3,5-diCQA showed the strongest reducing power and radical scavenging activity, and the antilipidperoxidation activity of 3,4-diCQA was the highest. These results show that these four polyphenolic compounds from sweet potatoes stems and leaves have significant antioxidant effects and are promising natural antioxidants.
Structural Characterization and Anti-α-glucosidase Activity of Polysaccharides from Leaves of Gynura davaricata (L.) DC
LIU Wei-wei,LIU Xu,CAO Xue-li*,LUO Jing-jie
2013, 34(7):  115-120.  doi:10.7506/spkx1002-6630-201307024
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The primary structure of polysaccharides from leaves of Gynura davaricata (L.) DC (GDPs) was characterized by gas chromatography, periodate oxidation reaction, Smith reaction, partially acid hydrolysis and 13C-NMR. Congo red test and X-ray diffraction were applied to explore their advanced structures. The inhibitory activity against α-glucosidase of GDPs was also investigated. GC analysis revealed that GDPs-1 was composed of D-Fru, L-Rha, L-Ara, D-Xyl, D-Man, D-Glu and D-Gal with a molar ratio of 0.2:0.4:1:1:1:2:7 and GDPs-2 of L-Ara, D-Man, D-Glu and D-Gal with a molar ratio of 0.4:2:2:0.1. Periodate oxidation reaction, Smith reaction, partially acid hydrolysis and 13C-NMR suggested that GDPs-1 had a backbone of α-(1→2)-linked galactose residues with branches composed of α-(1→3)-linked-Xyl, α-(1→2)-linked-Glu, α-(1→3)-linked- Man and Me-α-Araf, while GDPs-2 had a backbone of α-(1→3)-linked mannose residues with branches composed of α-(1→2)- linked-Glu and α-(1→6)-Glu. The results of Congo red test and X-ray diffraction showed that there was a stable triple spiral structure in GDPs-2 and both polysaccharides had poor molecular regularity. The polysaccharides showed extremely low inhibitory activities against α-glucosidase, which suggest that it is not relevant to the mechanism of glucose modulation.
Effect of Ambient Temperature on Properties of Gelatin-Pullulan-Based Edible Films
MA Yue1,ZHANG Chao1,GAO Dan-dan2,WANG Dan1,JIANG Lian-zhou2,ZHAO Xiao-yan1,*
2013, 34(7):  121-124.  doi:10.7506/spkx1002-6630-201307025
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The effect of ambient temperature on mechanical properties, water-vapor permeability, oxygen permeability, oil permeability, color and water solubility of gelatin-pullulan-based film, gelatin film and pullulan film was comparatively studied. The mechanical properties of gelatin-pullulan-based film were improved at higher ambient temperature, while neither the barrier properties nor water solubility was influenced. Moreover, the color was slightly yellowed. The tensile strength of gelatin-pullulan-based film was stronger than that of gelatin film and pullulan film.
Chemical Composition and Antifungal Activity against Penicillium digitatum of Essential Oil from C. reticulate Blanco
YANG Yan-song
2013, 34(7):  125-128.  doi:10.7506/spkx1002-6630-201307026
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Essential oil of Shatangju (C. reticulate Blanco) was extracted from the fruit peel by hydro-distillation and analyzed by GC-MS. As a result, 17 different components were identified. The major components were limonene (77.99%), followed by β-myrcene (3.74%), β-phellandrene (2.78%), ocimene (2.64%), β-linalool (2.35%), α-pinene (1.60%), 1-octanol (1.54%), decanal (1.24%), 4-terpineol (1.10%) and 4-undecene (1.04%). The antifungal activity of the essential oil at different concentrations (0.16, 0.31, 0.63, 1.25, 2.5, 5.0 μL/mL and 10.0 μL/mL) against the spore germination and mycelia growth of P. digitatum was determined. Results showed that the oil at lower concentrations (< 2.5 μL/mL) had no obvious or even stimulatory effect on the spore germination of P. digitatum, but slightly inhibited the mycelia growth of P. digitatum. In contrast, the oil at a higher concentration (10 μL/mL) remarkably inhibited both the spore germination and mycelia growth of P. digitatum. This study indicates that Shatangju essential oil plays a positive role in controlling P. digitatum.
Effect of Electrodialysis Desalination on Physicochemical Properties of Salted Duck Egg White
DONG Hua-wei,HE Hui*,CHEN Bo-yong,ZHAO Ning-ning,WANG Zhen-zhen
2013, 34(7):  129-134.  doi:10.7506/spkx1002-6630-201307027
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Purpose: The aim of this study was to evaluate the effect of electrodialysis desalination on functional and nutritious properties of duck egg white. Results: The gel hardness of desalted duck egg white was not significantly different from that of fresh one at lower protein level (5-8 g/100 mL). At a protein concentration of 3-9 g/100 mL, both emulsifying activity and foaming capacity of desalted duck egg white increased compared to those of salted eggs. In addition, the foaming capacity of desalted egg was better than that of fresh duck egg while no significant difference in the emulsifying activity was observed between them. SDS-PAGE, DSC and amino acid analysis revealed that the relative molecular mass of salted duck egg white before and after desalination remained constant. The amino acid composition, thermal denaturation temperature and color of desalted duck egg white were very close to those of fresh duck egg white. Conclusion: The functional and nutritious properties of salted duck egg white are little affected by electrodialysis desalination and thereby, can be used as a favorable food material and ingredient.
Influence of Water Content on Chemical Composition of Pu-erh Tea during Pile Fermentation Process
FENG Chao-hao,LIU Tong-xun*
2013, 34(7):  135-139.  doi:10.7506/spkx1002-6630-201307028
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To obtain the rational water content of pu-erh tea for pile-fermentation, variations in the contents of main components of Pu-erh tea were systematically investigated and the process of pile fermentation was simulated under varying water contents. The results showed that at the end of pile fermentation, the contents of tea polyphenols, catechins, heaflavin, thearubigins and amino acids showed a downtrend while the contents of water-soluble sugar, theabrownins and theine appeared to increase. Different water contents of tea led to differences in the species of microorganisms involved in the fermentation process and pile temperature, which eventually affected the quality of tea significantly. In sensory evaluations, the products with 45% water content showed better quality.
Effect of High Pressure Processing on the Sensory Quality of Fresh-Cut Iceberg Lettuce
ZHANG Xue-jie1,YE Zhi-hua2,*
2013, 34(7):  140-143.  doi:10.7506/spkx1002-6630-201307029
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Five sensory attributes (including browning, water , flavor, texture and taste) of fresh-cut iceberg lettuce subjected to high pressure processing (HPP, 50-200 MPa and 1-20 min) were evaluated by a 5-person sensory panel, and comprehensive assessment of the data obtained was carried out using grey correlation degree analysis. The sensory attributes of fresh-cut iceberg lettuce were affected by HPP to different extents. Samples subjected to HPP at 50 MPa for 5 min showed the highest grey correlation degree between the observed and desired sensory quality and were found to have improved sensory quality and higher sweetness. The sensory quality of iceberg lettuce deteriorated with increasing pressure and with prolonged time; an unpleasant odor, high toughness and serious wateriness and browning were obtained when fresh-cut iceberg lettuce was subjected to HPP at 200 MPa for 20 min.
Expression of Bile Salt Hydrolase Genes from Two Different Origins in Escherichia coli Rosetta
YANG Shi-qin1,MAN Chao-xin2,QU Xing-guang1,LI Bin1,XIE Kun-hao1,JIANG Yu-jun1,2,*
2013, 34(7):  144-147.  doi:10.7506/spkx1002-6630-201307030
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Bile salt hydrolase (BSH) gene of Bifidobacterium bifidum ATCC 29521 and Lactobacillus acidophilus NCFM was amplified by gradient PCR using genome DNA as template and cloned into pET28a (+) expression vector. The expression vector was then transfected into E. coli Rosetta and expression of BSH was induced by IPTG. SDS-PAGE analysis showed the presence of three target proteins estimated to be 40, 43 kD and 45 kD, respectively. Ninhydrin analysis revealed that the recombinant BSH hydrolyzed sodium glycocholate to glycine, showing its hydrolysis activity on conjugated bile salts.
Effects of Quality Modification Factor from Stalk on Biomass and Antioxidant Systems of Liquid-Cultivated Mycelia of Pleurotus ostreatus
WANG Cui-ping1,SHENG Ji-ping2,*,SHEN Lin1,*
2013, 34(7):  148-151.  doi:10.7506/spkx1002-6630-201307031
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This study aimed to investigate the effect of different concentrations of stalk-derived quality modification factor (QMF) solution on the biomass of Pleurotus ostreatus mycelia over a 7-day culture period and the effects of 0.5% QMF solution on dynamic changes in DPPH and hydroxyl radical scavenging capacity, total antioxidant activity (T-AOC) and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX). The results showed that the 0.5% QMF treatment led to an increase in the mycelial dry weight of Pleurotus ostreatus by 19.31% on the 7th day compared with the control group. Additionally, despite no marked change in the DPPH radical scavenging activity, there was an 8%—11% increase in the hydroxyl radical scavenging activity after cultivation for 5, 6, 7 days, and an increase in the total antioxidant capacity up to 32% on the fifth day was also found during the first 5 days of cultivation compared with the control group. Moreover, the activities of SOD, POD, CAT and APX after cultivation for 3, 4, 5 days showed increased levels compared with the control group (P < 0.05). These observations show that treatment with 0.5% QMF solution can increase the mycelial biomass while apparently enhancing the antioxidant activity of Pleurotus ostreatus mycelia.
Isolation and Identification of a 3-Phenoxybenzoic Acid-Degrading Fungus and Its Degradation Characteristics
YUAN Huai-yu,LIU Shu-liang*,WANG Zhi-long,ZHAO Nan,LAI Wen
2013, 34(7):  152-156.  doi:10.7506/spkx1002-6630-201307032
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Six mould strains capable of degrading 3-phenoxybenzoic acid (3-PBA) were screened from traditional fermented foods following gradient acclimation by different concentration of 3-PBA. Among these strains, YAT1 isolated from black tea could completely degrade 100 mg/L 3-PBA in PD medium in 22 h. Based on its morphological characteristics and ITS sequences (GenBank Accession No. JQ366070), YAT1 was identified as Aspergillus niger. Kinetic research indicated that the degradation of 3-PBA by YAT1 could be described by a first-order kinetics model. The degradation half-life of 3-PBA ranged from 5.635 to 12.160 h, which was far below its natural degradation half-life (180 d), and the reaction was less affected by pH but significantly influenced by substrate concentration and temperature.
Antioxidant and Cholesterol-reducing Properties of Enterococcus gallinarum m661
LIU Chang-jian,LIU Qiu,JIANG Bo,YAN Jian-fang,SUN Tian-zhu
2013, 34(7):  157-161.  doi:10.7506/spkx1002-6630-201307033
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An enterococcal strain named as m661 was isolated from porcine gastric juice. Strain m661 was found to be capable of producing lactic acid, Gram-positive and catalase-negative. Based on phylogenetic analysis, cellular and colonial morphology and biochemical test, m661 was identified as Enterococcus gallinarum. This strain had antioxidant potential, and its scavenging activity against hydroxyl, DPPH and superoxide anion radicals was in a cell density-dependent manner. At a cell density of 5 × 108 CFU/mL, the scavenging rates of stain m661 against hydroxyl, DPPH, and superoxide anion radicals were 1.58%, 36.6% and 57.1%, respectively. In addition, m661 was found to reduce cholesterol by 34.4% in the culture medium and produce 89.9 mg/L phenyllactic acid, suggesting excellent health-benefiting effects. The results of this study demonstrate that strain m661 has great potential to be developed as a new probiotic resource.
Rapid Isolation and Identification of β-Lactamase-Producing Strains in Raw Milk
XIE Kun-hao1,2,MAN Chao-xin1,LU Yan1,LIU Shan-shan2,FANG Yu-guo1,YANG Shi-qin2,DONG Xin-yue2,JIANG Yu-jun1,2,*
2013, 34(7):  162-165.  doi:10.7506/spkx1002-6630-201307034
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Penicillin-Micrococcus luteus-TSA medium plates were used to establish a method for the rapid isolation of β-lactamase-producing bacteria in raw milk. This method revealed a more convenient and simpler observation than conventional methods, and could provide highly specific isolation. 16S rRNA gene sequence analysis allowed the assignment of the β-lactamase-producing bacterial isolates obtained in this study. As a result, Escherichia coli was the dominant β-lactamase-producing strain in raw milk.
Purification and Partial Characterization of Lipoxygenase in Cherry-valley Duck Breast Muscle
HE Li-chao1,ZHAO Jian-ying2,TIAN Tian2,ZHANG Jian-hao2,*
2013, 34(7):  166-170.  doi:10.7506/spkx1002-6630-201307035
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Crude lipoxygenase (LOX) from Cherry-valley duck breast muscle was purified through 20%-40% ammonium sulfate fractionation and DEAE-Sepharose column chromatography. LOX was separated by gradient elution of DEAESepharose column with 0.3-0.35 mmol/L NaCl solution, resulting in a purification factor of 54.3. The molecular weight of the purified LOX was measured by SDS-PAGE to be 96 kD. Slight differences in enzymatic properties between the crude LOX and the purified LOX were observed. Using linoleic acid as the substrate, the optimal substrate concentrations, reaction temperatures and pH values were 6.4 mmol/L and 10 mmol/L, 40 ℃ and 30 ℃, and 5.0 and 5.5, respectively, and the Michaelis constant (Km) and maximum velocity (Vmax) for the purified LOX were 1.139 mmol/L and 0.07608 U/min, respectively. The purified LOX had a higher affinity for the substrate than the crude LOX.
Factors Affecting α-Dextranase Fermentation and Its Enzymatic Activity
MA Shao-ying,LU Hai-qin,HANG Fang-xue,LI Kai*,SU Jia-ting,GUO Hai-rong
2013, 34(7):  171-174.  doi:10.7506/spkx1002-6630-201307036
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The main factors influencing α-dextranase production by Chaetomium gracile in liquid-state fermentation (including pH, medium volume in a shaking flask, inoculum size and fermentation time) were studied. Meanwhile, the effects of pH, temperature and time on α-dextranase activity were investigated. The optimal fermentation conditions for α-dextranase production were 5.5, 20 mL/250 mL, 3% and 92 h for pH, medium volume in a shaking flask, inoculum size and fermentation time, respectively. Under these conditions, the α-dextranase activity of fermentation broth was 231.5 U/mL, which was 193% higher than the 79.0 U/mL before optimization. The highest α-dextranase activity was observed under the optimal reaction conditions of pH 5.5, 60 ℃ and 10 min.
Characterization of Acetaldehyde Metabolism of Saccharomyces cerevisiae during Wine Fermentation
HAO Rui-ying1,ZHAO Jie1,LIU Yan-lin1,2,*
2013, 34(7):  175-179.  doi:10.7506/spkx1002-6630-201307037
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This study examined dynamic changes in acetaldehyde production during the fermentation of dry white wine and dry red wine by one of 4 indigenous (G3-3, NX8423, D3-4 and NX349) and 2 commercial (X16 and F15) S. cerevisiae strains. Besides, each strain was analyzed for characteristics of acetaldehyde production. The indigenous strains showed similar dynamic changes in acetaldehyde production to the commercial strains despite significant differences in characteristic parameters of acetaldehyde production (P < 0.05). The indigenous strain D3-4 exhibited the lowest acetaldehyde peak of 58.60 mg/L and the lowest final acetaldehyde concentration of 39.96 mg/L during the fermentation of dry white wine, which were decreased by 25.62% and 25.92% compared with those of the commercial strain X16, respectively. X16 presented the fastest acetaldehyde production rate, while NX8423 showed the fastest acetaldehyde degradation rate of 5.90 mg/ (L?d), 2.09-fold higher than that of X16. The commercial strain F15 presented the lowest peak value of 89.33 mg/L, while the indigenous strain G3-3 showed the fastest acetaldehyde production rate of 65.04 mg/L, 45.63% higher than that of F15. In addition, NX349 exhibited the fastest acetaldehyde degradation rate of 25.62 mg/(L?d) and the lowest final concentration of 29.65 mg/L. In conclusion, the indigenous strains have better characteristics of acetaldehyde metabolism than the commercial strains, thus allowing optimization of acetaldehyde production during wine fermentation.
Induction of Bacteriocin Synthesis in Lactobacillus plantarum KLDS1.0391 by Some Lactic Acid Bacteria Strains
MAN Li-li1,2,MENG Xiang-chen1,*,ZHAO Ri-hong1
2013, 34(7):  180-184.  doi:10.7506/spkx1002-6630-201307038
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The aim of this study was to determine the effects of 76 lactic acid bacteria strains on bacteriocin production by L. plantarum and the relationship between bacteriocin production and cell number. Lactobacillus plantarum KLDS1.0391 was co-cultured with one of 76 lactic acid bacteria strains for the determination of antimicrobial activity and live cell populations. Significantly (P < 0.01) increased antimicrobial activity in the supernatants was obtained by the co-culture of Lactobacillus plantarum KLDS1.0391 with L. plantarum KLDS1.0706, L. plantarum KLDS4.0315, L. plantarum KLDS4.0351 or L. reuteri KLDS1.0736. There was a significant positive correlation between the cell density of Lactobacillus plantarum KLDS1.0391 and the antimicrobial activity of the supernatant of co-culture with L. reuteri KLDS1.0736. We also found that bacteriocin production was induced only when L. plantarum KLDS1.0391 was co-cultured with living cells of inducing strains.
Optimization of Fermentation Conditions for Exopolysaccharide Production by Bacillus amyloliquefaciens LPL061
LI Yan-yan,ZHANG Cai,FAN Yi,LIU Li-sha*,LI Ping-lan,HAN Yu-zhu
2013, 34(7):  185-189.  doi:10.7506/spkx1002-6630-201307039
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In order to improve expolysaccharide (EPS) production by Bacillus amyloliquefaciens LPL061, the medium and fermentation conditions were optimized by one-factor-at-a-time design and response surface analysis. The optimal culture medium consisted of 22 g/L sucrose and 18.4 g/L yeast extract at pH 7.0. The optimal fermentation conditions were 28 ℃, 220 r/min shaking speed, 3% inoculum size and 24 h. Under these conditions, the EPS yield was 4.46 g/L, 1.51-fold higher than before the optimization.
Enzymatic Preparation of Antihypertensive Peptides from Loach (Misgurnus anguillicaudatus) Protein
LI Ying1,ZENG Xiao-xiong2,ZHOU Jian-zhong1,HUANG Kai-hong1,HU Bing2
2013, 34(7):  190-195.  doi:10.7506/spkx1002-6630-201307040
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The aim of this study was to prepare antihypertensive peptides by enzymatic hydrolysis of loach protein. Bromelain was found to be the best protease for the preparation of peptides with high antihypertensive activity (IC50 = 0.65 mg/L) among nine proteases. Based on one-factor-at-a-time experiments, Box-Behnken experimental design coupled with response surface methodology (RSM) was employed to optimize the hydrolysis process of loach protein. The ACE inhibitory rate of antihypertensive peptides was investigated with respect to three hydrolysis parameters including enzyme/substrate ratio, temperature and time. The optimum hydrolysis conditions for preparing antihypertensive peptides were determined as 4.9‰, 6.5, 30%, 54.4 ℃ and 5.9 h for enzyme/substrate ratio, pH, substrate concentration, hydrolysis temperature and hydrolysis time, respectively. Under these conditions, the ACE inhibitory rate of loach protein hdyrolysate was 88.92%.
Screening of Fungal Elicitor for Fermentative Production of Natamycin and Optimization of Induction Conditions
WEI Bao-dong,PAN Ya-hui,WANG Ya-nan,WANG Li-yan
2013, 34(7):  196-200.  doi:10.7506/spkx1002-6630-201307041
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Preliminary screening was carried out to obtain fungal elicitor that induces natamycin production by Streptomyces chattanovgensis. The optimal induction conditions were established by mathematical modelling mathematical modelling based on Box-Behnken experimental design and response surface analysis. The potent inducing effect of the fungal elicitors on natamycin production was confirmed. When fungal elicitor from Aspergillus niger was added to a final concentration of 122 μg/mL after 18.3 h natamycin fermentation and incubated for 78.5 h, the observed average yield of natamycin in fermentation broth was 2.89 g/L, 1.68 times higher than the blank control.
Process Conditions for L-Lactic Acid Production by Corncob-immobilized Rhizopus oryzae
ZHAO Long,JIANG Xue-wei*,BIAN Jia-wei,SHEN Jun-xiu,CHEN Yong-fa
2013, 34(7):  201-205.  doi:10.7506/spkx1002-6630-201307042
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The process conditions for L-lactic acid fermentation with immobilized Rhizopus oryzae R-1 using corncob as immobilization carrier and a partial substitute for carbon source were studied. The utilization rate of corncob as a carbon source substitute and its mass ratio to glucose and optimal grinding granularity were investigated. The utilization rate of corncob by Rhizopus oryzae R-1 was 14.9%, and the optimal mass ratio between corncob and glucose was 1:4, yielding a conversion rate of glucose into L-lactic acid was 82.5%, 14.6% higher than that obtained from pure glucose fermentation. A granularity of 40 mesh was found optimal for corncob powder, resulting in an L-lactic acid yield as high as 34.68 g/L in mixed carbon source fermentation and with immobilized mycelial pellets with excellent continuous fermentation performance and a diameter ranging from 0.5 to 1.0 mm. After sixth repeated fermentation, the average conversion of glucose into L-lactic acid was 83.1%. From these result, we conclude that corncob can be a good carrier and base material for the production of lactic acid.
Randomly Amplified Polymorphic DNA (RAPD) Analysis of Lactic Acid Bacteria from Yak Milk Cheese
YANG Ji-xia1,CHEN Zhi-lan2,YANG Hai-yan3,HUANG Ai-xiang4,CHEN Zong-dao1
2013, 34(7):  206-211.  doi:10.7506/spkx1002-6630-201307043
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Objective: To explore the application value of randomly amplified polymorphic DNA (RAPD)-PCR for the genotype evaluation of lactic acid bacteria isolated from yak milk cheeses. Methods: In order to establish a reliable RAPD protocol with primer M13, factors such as annealing temperature, Mg2+ concentration, primer amount, Taq polymerase and DNA template for affecting the quality and reproducibility of RAPD profiles were investigated. The optimal PCR procedure and reaction reagent concentration were employed for RAPD amplification of 39 isolates from yak milk cheese on the basis of previous identification of 16S rRNA sequence analysis. The electrophoretic profiles were analyzed using NTsys2.10e software, genetic similarity coefficients were calculated and a cluster dendrogram was plotted. Results: Genetic similarity coefficients of 39 strains ranged from 0.47 to 0.98. The cluster dendrogram showed that 39 isolates were classified into 10 groups using the similarity coefficient of 0.78 as a cut-off point. The discrimination of groups was consistent with the assignment of the species based on 16S rRNA sequence analysis, except for strains X23, Y36 and Y37. Conclusion: RAPD technique is useful in taxonomy of lactic acid bacteria isolated from yak milk cheese. The accuracy of species identification can be improved by the combination of RAPD with other kinds of genotypic methods.
Effects of Glycine Betaine and Complex Cellulase on the Fermentation of Soy Sauce
WEI Lu-ning1,LI Fen-fang2,HU Wen-feng1,*, WU Hui-ling3,ZHOU Zhao-hui3,LI Tie-qiao3,HAN Chun3, HUANG Zao-cheng3,CHEN Yong-quan1
2013, 34(7):  212-216.  doi:10.7506/spkx1002-6630-201307044
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The microorganisms and inherent or exogenous enzymes have very low activity because of high osmotic pressure during the traditional fermentation of high-salt liquid state soy sauce, which results in a low conversion rate of raw materials and a prolonged fermentation period. Glycine betaine is one of the compatible solutes synthesized by microorganisms under high osmotic pressure which protects the microorganisms and enzymes. In this study, glycine betaine was used added at different time points (0 d or 30 d) in the fermentation of high-salt liquid state soy sauce to protect microorganisms and external complex cellulase. The results showed that simultaneous addition of 0.20% or 0.30% glycine betaine and 0.15% complex cellulose (105 EGu/100 g sauce mash) before and after 30 d soy sauce fermentation obviously improved protein conversion rate by 2.26%-7.92%. Glycine betaine improved the quality of soy sauce effectively, and shortened the fermentation period by about15 d. Average protein conversion rate was increased by 3.17% when adding glycine betaine and complex cellulase after 30 d fermentation than before the beginning of fermentation.
Optimization of Extraction of Pepsin-soluble Collagen from Anglerfish Skin
WANG Pei,SU Xiu-rong*,ZHANG Yong-fei,LI Xing-bo,SUN Jing
2013, 34(7):  217-222.  doi:10.7506/spkx1002-6630-201307045
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Response surface methodology was applied to establish the optimum conditions for extracting pepsin soluble collagen (PSC) from anglerfish skin. Three independent variables including liquid-to-solid ratio, enzyme loading and hydrolysis time were primarily investigated by one-factor-at-a-time design. Further, Box-Behnken optimization design was used to optimize three different levels of these experimental variables. Additionally, this study characterized physiochemical properties of PSC from anglerfish skin. The optimum process conditions for PSC extraction from anglerfish skin were found to be extraction at 4 ℃ for 48 h with an enzyme loading of 3% and a liquid-to-solid ratio of 18:1. Under the optimized conditions, the extraction efficiency of PSC from anglerfish skin was 2.11%. The PSC extract obtained were determined to contain 16% Arg and 18% Tyr. DSC showed a shrinkage temperature of 48.9 ℃ from the PSC extract. SDS-PAGE suggested that the triplehelical structure of collagen basically remained intact. The PSC exhibited a multiporous network structure under SEM.
Effect of Endogeneous Proteinases on Autolysis of Squid Hepatopancreas
CHEN Zhao,TIAN Yuan-yong*,MA Chun,ZHU Bei-wei
2013, 34(7):  223-226.  doi:10.7506/spkx1002-6630-201307046
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Functional properties of endogeneous proteinases from squid hepatopancreas and their role in the autolysis of squid hepatopancreas were studied. Proteinases activity was analyzed by determining TCA soluble peptides using azocasein as a substrate. The results indicated that the optimal pH and temperature were 5.0 and 40 ℃ for crude endogeneous proteinases, respectively. The enzyme activity remained stable over the pH range of 3.0 to 8.0. The autolysis inhibitory effect of E-64 proved that the cysteine proteinase played a dominant role in autolysis of squid hepatopancreas. Moreover, other endogeneous enzymes such as serine proteinase and metallo proteinase also demonstrated varying impacts on the autolysis.
Preparation and Characterization of Anti-leucomalachite Green Polyclonal Antibody
LIANG Li-tian,LIU Zhi-guo*,FU Yun-jie,YIN Huan,MA Yin-zhong,LI Kui
2013, 34(7):  227-230.  doi:10.7506/spkx1002-6630-201307047
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Preparation of anti-leucomalachite green polyclonal antibody allows indirect determination of leucomalachite green (LMG), a major metabolite of malachite green (MG). Carboxyleucomalachite green (CLMG) was chemically synthesized and then coupled to bovine serum albumin (BSA) by the carbodiimide method so as to obtain leucomalachite green-BSA immunogen. The immunoantigen was injected into rabbits according to routine immunity procedure to product anti-leucomalachite green antibody. The specific antibody of leucomalachite green was identified by indirect enzyme-linked immunosorbent assay (iELISA). It was proved that the working concentration of the specific antibody was 1: 32000 and therefore could be applied for the immunodetection of leucomalachite green.
Mutation Breeding of a High Polygalacturonase-Producing Aspergillus niger Strain
ZHANG Yuan-yuan,HAO Lin*,WANG Qian
2013, 34(7):  231-233.  doi:10.7506/spkx1002-6630-201307048
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Aspergillus niger strain SH312-26 was isolated by apparent circle method from strain SH312. A mutant strain named as SH312-26-19 was obtained by UV radiation using SH312-26 the original strain. The polygalacturonase activity of SH312-26-19 was 113.68 kU/mL, a 1.44-fold increase than that of strain SH-312-26. The pectin esterase activity was 14.34 kU/mL, a 0.14-fold increase than that of the original strain. After 5 passages on slant culture medium, the mutant remained genetically stable.
Optimization of Enzymatic Preparation of Antibacterial Peptides by Response Surface Methodology
SUN Chang-jiang,ZHANG Jian-xin*,WANG Xuan,SONG Zhen-zhen
2013, 34(7):  234-239.  doi:10.7506/spkx1002-6630-201307049
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Objective: To determine the optimal conditions for enzymatic preparation of Tenebrio molitor antibacterial peptides. Methods: Antibacterial peptides were prepared by hydrolyzing the protein extracted from Tenebrio molitor by alkaline extraction and acid precipitation. The antibacterial activity of the peptides was evaluated by agar diffusion method. One-factor-at-a-time method and response surface analysis based on Box-Behnken design were used to explore the effects of hydrolysis temperature, pH, hydrolysis time, enzyme dosage and substrate concentration on antibacterial activity of Tenebrio molitor antibacterial peptides. Results: Alkaline protease was the most efficient protease for the preparation of Tenebrio molitor antibacterial peptides, and the optimum hydrolysis conditions were found to be hydrolysis at 54 ℃ and pH 9.5 for 4.4 h with an enzyme dosage of 440 U/g pro and a substrate concentration of 810 g/100 mL. The predicted maximum inhibition circle diameter was 15.17 mm, close to the actual value of 15.04 mm. Conclusion: Peptides with high antibacterial activity can be prepared by hydrolyzing Tenebrio molitor protein with alkaline protease, and the optimized process conditions allow accurate theoretical prediction.
Characterization of Enzymatic Properties of High Homoserine Dehydrogenase-Producing Mutant D206G from Corynebacterium pekinense AS1.299
XU Jin-kun1,2,MIN Wei-hong1,2,*,ZHAN Dong-ling1,2,FANG Li1,2,LIU Jia1,2,SHEN Shu-xia1,2,GUO Yong-ling1,2
2013, 34(7):  240-244.  doi:10.7506/spkx1002-6630-201307050
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Homoserine dehydrogenase (HSD), a key enzyme involved in the biosynthesis of the aspartic acid family of amino acids, plays an important role in the synthesis of threonine and methionine. High HSD-producing mutant D206G from Corynebacterium pekinense AS1.299 was successfully constructed and heterologously expressed in E.coli BL21(DE3). Molecular docking and homologous alignment demonstrated that site 206 was a highly conservative sequence bound with substrate. The optimal pH, temperature and half-life of HSD from the mutant were 7.5, 37 ℃ and 4 h, respectively. In addition, it showed high resistance to metal ions and organic solvents. Compared with its wild-type counterpart, the Km of mutant D206G decreased, possibly due to a reduction in side-chain functional groups and consequent decrease in steric hindrance, thus promoting the enzyme-substrate binding.
Effect of Grape Seed Proanthocyanidin Extract (GSPE) on Type Ⅱ Diabetic Retinopathy in Rats
LI Yu-jie,ZHANG Zhao-feng,DAI Xiao-qian,DING Ye,MA Xiao-tao,JIANG Yan-fei,BAO Lei,LI Yong*
2013, 34(7):  245-249.  doi:10.7506/spkx1002-6630-201307051
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Objective: To investigate the effect of grape seed proanthocyanidin extract (GSPE) on type Ⅱ diabetic retinopathy in rats. Methods: To establish type Ⅱ diabetic rat models, male SD rats fed high fat diet for 4 weeks were injected with streptozotocin (STZ, 0.01 mol/L, 30 mg/(kg?d)). The diabetic rats were randomly divided into diabetes-vehicle group (DM control group), three GSPE-treated groups. Normal rats were enrolled as normal control group. The low, medium and high-dose GSPE-treated groups were administrated at 125, 250 mg/(kg?d) and 500 mg/(kg?d), respectively. DM control group and normal control group were given equal volume of distilled water. After 16 weeks, body weight, fasting plasma glucose (FPG), advanced glycation endproducts (AGEs), ICAM-1 and VCAM-1 were measured. HE stain retina paraffin section was examined under a microscope. Receptor for RAGEs was detected by SP immunohistochemical method. Results: There was no difference (P > 0.05) between DM control group and GSPE-treated groups. Compared with DM control group, AGEs in GSPE high dose group were decreased (P < 0.05), ICAM-1 (all GSPE-treated groups) and VCAM-1 (GSPE low and high dose groups) were decreased (P < 0.05). The retina of GSPE-treated groups had fewer damaged areas and lower RAGE expression in histology. Conclusion: GSPE has a positive effect on type Ⅱ diabetic retinopathy in rats.
Immunoregulatory Function of Verbascose on Macrophage Cell Line RAW264.7
SU Di,ZHANG Yun,DAI Zhu-qing,YE Hong,HU Bing,ZENG Xiao-xiong*
2013, 34(7):  250-253.  doi:10.7506/spkx1002-6630-201307052
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Objective: To investigate the immunoregulatory function of verbascose on macrophage cell line RAW264.7. Methods: RAW264.7 cells were cultured in a 96-well plate with different concentrations of verbascose (25, 50, 100, 200 μg/mL and 400 μg/mL), and the role of verbascose was evaluated based on the proliferative activity of cultured splenocytes as determined by MTT assay, nitric oxide (NO) production and cytokines (IL-6, IL-1β, IFN-α and IFN-γ) expression levels, neutral red phagocytosis. In the present study, lipopolysaccharide (LPS, 10 μg/mL) was used as a positive control, and treatment without verbascose or LPS was used as a negative control. Results: Verbascose significantly improved the proliferation, phagocytosis, NO level and cytokines expression levels when RAW264.7 cells were cultured for 24 h in the studied concentration range. Verbascose at a dose of 200 μg/mL showed the highest effect. Conclusion: Verbascose has an immunomodulatory effect on macrophage cell line RAW264.7 as a potential immunomodulatory enhancer.
Protective Role of CGMP in Intestinal Mucosal Barrier Function in Rats
WANG Jin-feng,CHEN Qing-sen*,YAN Ya-li
2013, 34(7):  254-257.  doi:10.7506/spkx1002-6630-201307053
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Objective: To explore the effect of caseino glycomacropeptide(CGMP) intervention on the expression of trefoil factor and vascular endothelial growth factor in the colon and deduce the effect of CGMP on key factors of intestinal mucosal barrier function in rats with colorectal cancer. Methods: A total of 40 Wistar rats were randomly divided into five groups including control group, model group, low-dose CGMP group, middle-dose CGMP group and high-dose CGMP group. Except the control group, all the rats were intraperitoneally injected with dimethyl hydrazine at a dose of 30 mg/kg. At the same time, the rats from CGMP groups were injected with 1,2-dimethylhydrazine dihydrochloride and administered with CGMP at dosages of 10, 50, 100 mg/(kg?d), respectively. After eight weeks, all the rats were killed to harvest colon tissues for determination of the expression of ITF and VEGF by immunohistochemical method. Results: HE staining revealed that CGMP might regulate damaged intestinal barrier function in rats. Meanwhile, IHC staining confirmed that CGMP could reduce the expression of VEGF, but had no effect on the expression of TFF3. Conclusion: CGMP may repair damaged intestinal barrier function in rats.
Effect of Capsaicin Dose on Intestinal Fermentation in Rats
LI Ming-ze,SU Xin-feng,PENG Lin,Lü Jiao,LIU Xiong*
2013, 34(7):  258-261.  doi:10.7506/spkx1002-6630-201307054
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Objective: To study the effect of capsaicin dose on intestinal fermentation in rats. Methods: A total of 48 Sprague- Dawley rats were randomly divided into 4 groups (six male and six female rats in each group) by body weight. The groups were given 0, 2.5, 5 or 7.5 mg/(kg·d) for 28 days, respectively and had free access to a basal diet and water during the experimental period. Body weight gain, cecal tissue weight, and the amounts of free ammonia and short-chain fatty acids (SCFAs) in cecal contents were determined. Results: Capsaicin administration increased the amount of food intake, and free ammonia (FA) concentration and pH in cecal contents in a dose-dependent manner while the body weight gain and SCFAs concentration in cecal contents were decreased. Conclusion: Capsaicin has an apparent inhibitory effect on fermentation in SD rats in a dosedependent manner.
Effect of Long-Term Intervention with Proanthocyanidin on Oxidative Stress in Type Ⅱ Diabetes
JIANG Yan-fei,ZHANG Zhao-feng,BAO Lei,JING Lu-lu,DING Ye,DAI Xiao-qian,MA Xiao-tao,LI Yu-jie,CAI Xia-xia,LI Yong*
2013, 34(7):  262-265.  doi:10.7506/spkx1002-6630-201307055
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Objective: To observe the oxidative stress in Type Ⅱ diabetic rats after long-term feeding of grape seed proanthocyanidin extract (GSPE) and the effect of GSPE intervention on oxidative stress. Methods: Forty-eight Type Ⅱ diabetic rats that were successfully induced were randomly divided into 4 groups: three GSPE-treated groups and one diabetic model group. Twelve rats fed on normal forage were served as normal control group. GSPE-treated groups were administered with GSPE by gavage at doses of 125, 250, 500 mg/(kg·d). Diabetic model group and normal control group were administered with deionized water also by gavage. After 24 weeks, all rats were killed and blood and organs were acquired. Oxidative indicators (SOD, GSH-Px and MDA) of all tissues were detected. Results: Compared with the normal control group, SOD activity in the serum and liver tissue of the diabetic model group was significantly decreased, so was the GSH-Px activity in liver and muscle tissue, but the amount of MDA in the brain of the diabetic model group was increased; compared with the diabetic model group, SOD activity in the serum, liver and spleen and GSH-Px activity in the serum, liver, muscle and spleen from the intervention groups was significantly increased (P < 0.05). Conclusion: The level of oxidative damage in different tissues from Type Ⅱ diabetic rats is different. Long-term intervention with GSPE can reduce oxidative damage to tissues.
Protective Effect of Selenium-Enriched Polysaccharides from Cordyceps militaris against Rotenone-Induced Oxidative Damage in Drosophila melanogaster
SUN Jun-de,HOU Jing,YANG Yi
2013, 34(7):  266-269.  doi:10.7506/spkx1002-6630-201307056
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Objective: To explore the protective effect of Cordyceps militaris polysaccharide (CPS) and selenium-enriched polysaccharide (SE-CPS) on rotenone-induced oxidative stress and neurotoxicity in Drosophila melanogaster. Methods: Rotenoneinduced fruit fly damage models were divided into basic medium with or without CPS and Se-CPS to evaluate oxidative stress and neurotoxity. Seven antioxidant indicators including malondialdehyde (MDA), protein carboxyl (PC), glutathione content (GSH and GSSG), superoxide dismutase (SOD) and glutathione-S-transferase (GST) were measured. Meanwhile, acetylcholinesterase (Ache,) and butyrylcholinesterase (Bche) activities were also analyzed to evaluate the neuroprotective role of both polysaccharides. Results: Both CPS and Se-CPS could reduce oxidative stress indicators and neurotoxicity. Se-CPS had better protective effect at equal concentrations; 1% Se-CPS could restore the damage to 85% level of control group. Moreover, some oxidative stress indicators and enzyme activity were also restored to the control level.
in vitro Immunoregulatory and Antitumor Activity of Sulfated Polysaccharides from Sargassum kjellmanianum
MA Wei-wei,LI Li,ZHOU Ge-fei*
2013, 34(7):  270-274.  doi:10.7506/spkx1002-6630-201307057
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The in vitro immune-regulatory and anti-tumor activities of sulfated polysaccharides from Sargassum kjellmanianum (SKP) were investigated in this study. Polysaccharides were first extracted from Sargassum kjellmanianum by hot water. Crude extract was then treated with TCA to remove proteins and dialyzed to remove small molecule impurities. Three different types of polysaccharides, SKP1, SKP2 and SKP3, were collected through DEAE-52 ion exchange column. Chemical analysis showed that the polysaccharides were composed of fucose, galactose, xylose and mannose. All three types of polysaccharides were sulfated. Sulfate group accounted for 3.4%, 25.6% and 29.9% in SKP1, SKP2 and SKP3, respectively. SKP2 and SKP3 significantly enhanced immune function of immunocytes, and SKP2 increased the proliferation rate of spleen lymphocytes and peritoneal macrophages up to 53.56% and 51.41%. Cell culture showed that all SKP1, SKP2 and SKP3 inhibited the proliferation of HT-29 and HeLa cells, showing their anti-tumor activity.
Antioxidant Activity of Polypeptides with Different Molecular Weights from Wheat Germ
WANG Cai-li,ZHANG Zhi-guo,WANG Cheng-zhong*,YANG Ai-hua
2013, 34(7):  275-278.  doi:10.7506/spkx1002-6630-201307058
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In this study, the antioxidant activity of polypeptides with different molecular weights from wheat germ was investigated. Ultrafiltration and nanofiltration were used to sub-classification and purification of wheat germ peptides prepared by composite enzymatic hydrolysis. Meanwhile, oxidative damage mouse models were established and 170 mice were randomly divided into 17 groups (normal control group, model control group, wheat germ polypeptide groups with different molecular weights and different concentrations. Except the normal control group, all the mice were injected with D-galactoseat a dosage of 600 mg/(kg?d) to establish oxidative damage model. The mice in polypeptides groups were administered with polypeptides with five molecular weights at low, medium and high doses. Forty days later, the mice were sacrificed and exsanguinated from eyeballs, and superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, malondialdehyde (MDA), and total antioxidant capacity (T-AOC) in serum and liver were determined to explore antioxidant activity of wheat germ peptides. The results showed that wheat germ peptides could improve the activities of SOD and GSH-Px as well as T-AOC in serum and liver, and reduce MDA level in serum and liver, suggesting good antioxidant activity. In addition, increasing the peptide concentration could also improve the antioxidant activity. Moreover, wheat germ peptides with molecular weight of 2000 D revealed better antioxidant activity.
Protective Effect and Mechanism of Angiotensin Converting Enzyme 2(ACE2) against Diabetes-Induced Liver Oxidative Stress Injury in Rats
LI Ya-xin,XU Chen-yang,ZHANG Dong-hui,HAN Dong-ning,ZHANG Yuan-shu*
2013, 34(7):  279-283.  doi:10.7506/spkx1002-6630-201307059
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This study aimed to investigate possible protective effect and mechanism of ACE2 against diabetes-induced liver oxidative stress injury in rats. A total of 24 male healthy SD rats were used in this study. Eight rats without any treatment were used as negative control, and 16 others were administrated with STZ solution (60 mg/kg) via the ip route to induce diabetic hepatic oxidative stress injury model and then divided into 2 groups: diabetes group and insulin (3.7 × 10-8 mol/d) treatment group. After 30 days of administration, all the rats were sacrificed and blood and hepatic tissues were harvested to measure the content of AGEs in serum, the contents of MDA, H2O2 and the activity of SOD and GSH-Px in hepatic tissues. The contents of AngⅡ and Ang1-7 were also investigated as well as the activities of ACE and ACE2 in hepatic tissues. Results showed that the average fasting blood glucose level in normal control group was (5.39 ± 0.30) mmol/L, compared to (28.24 ± 2.51) mmol/L (much higher than the hyperglycemia index of 16.6 mmol/L) in diabetes group. The average fasting blood glucose level of measurements at intervals of 5 days during the administration period was significantly reduced to (11.18 ± 1.26) mmol/L, which, however, was still significantly higher than normal control group (P < 0.05), and reached a level lower than 10.0 mmol/L and even close to the normal level at the end of the administration period. The serum content of AGEs in diabetes control group was significantly higher than that in normal control group and insulin treatment group (P < 0.05). Compared with normal control group and insulin treatment group, there were significant increases in the serum content of AngⅡ, the activity of ACE and the contents of MDA and H2O2 in hepatic tissues of diabetes group but reductions in the activities of SOD, GSH-Px and ACE2 and the content of Ang1-7. In summary, the liver of the diabetes rats had a local increase in AngⅡ content but a decrease in ACE2 content and underwent oxidative stress. Following insulin treatment, the enhancement in ACE2 activity resulted in degradation of AngⅡ, thus relieving the oxidative stress of liver. These results suggest that ACE2 might have some protective effect against hepatic oxidative stress in diabetes rats and the mechanism appears to be related to the enhanced degradation of AngⅡ.
Effect of Polysaccharides from Lycium barbarum on Cisplatin-Induced Apoptosis of Human Embryonic Kidney Cells
GUO Pei-pei,GAO Li-ping*,LENG Hong-tao,GUO Zhuo-yu,LU Zheng
2013, 34(7):  284-288.  doi:10.7506/spkx1002-6630-201307060
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This study aimed to explore the effect of polysaccharides from Lycium barbarum (LBP) on the cisplatin-induced apoptosis of human embryonic kidney cells and to investigate its possible mechanism. MTT method was used to observe the effect of LBP and cisplatin on the cell viability of HEK293 cells. CDDP-induced apoptosis was analyzed by flow cytometry and Western blotting was applied to determine the expression of apoptotic gene Bax and anti-apoptosis gene Bcl-2. LBP was able to antagonize cisplatin-induced cytotoxicity in a concentration-dependent manner. Flow cytometry revealed that increasing LBP concentrations led to a decrease in the apoptosis rate and pro-apoptotic Bax gene expression while antiapoptotic gene Bcl-2 expression was enhanced. LBP demonstrated a preventive effect on cisplatin-induced injury in EK293 cells. The mechanism may be related to its capacity of enhancing anti-apoptotic gene Bcl-2 expression and inhibiting proapoptotic gene Bax expression.
Comparative Study of Hematinic Function of Celery Sodium Iron Chlorophyllin and Other Hematinics
CHI Cui-cui1,ZHAI Er-lin1,LI Chun-yan1, Lü Dan1,2,ZHUANG Gui-dong1,CHI Yu-sen1,*
2013, 34(7):  289-292.  doi:10.7506/spkx1002-6630-201307061
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Objective: To investigate the therapeutic effects of sodium iron chlorophyllin and other hematinics on iron deficiency anemia (IDA) model rats. Methods: IDA model rats were established by feeding an iron-deprived diet. Sodium iron chlorophyllin, heme iron, NaFeEDTA and FeSO4 were given to the model rats via gastric administration. A blood cell automatic analyzer was used to analyze hemoglobin (Hb), red blood cells (RBC) and hematocrit (HCT). Results: The Hb, RBC and HCT contents of model rats administrated with sodium iron chlorophyllin increased significantly compared to blank model and FeSO4 administrated mode after 30 days of administration (P < 0.05), but did not differ from those of heme iron and NaFeEDTA administrated model rats. Conclusion: Celery sodium iron chlorophyllin is effective in treating iron deficiency anemia.
Anti-aging Effects of Concentrated Powder of Borojo Fruit on Aging Mice Induced by D-Galactose
ZHAN Jing1,2, JIAO Hong1,*, WANG Jia-ji3, CHEN Xiao-yi3, MENG Ping1
2013, 34(7):  293-295.  doi:10.7506/spkx1002-6630-201307062
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Objective: To study the anti-aging effect of concentrated powder of Borojo fruit on aging mice induced by D-galactose. Methods: Kunming male mice were treated with 50 mg/kg D-galactose to create aging model by intraperitoneal injection. Mice were fed Borojo fruit concentrated powder by gavage continuously for 30 days. The activities of SOD and GSH-Px and the content of MDA in mouse serum and liver were determined. Results: Borojo fruit concentrated powder at middle dose (4.0 g/(kg·d) and high dose (6.0 g/(kg·d) improved SOD activity and significantly decreased MDA content in the serum and liver of mice, and at high dose significantly improved GSH-Px activity in the serum and liver. Conclusion: Borojo fruit concentrated powder has strong in vivo anti-aging effects. It can be applied for the development of health functional food.
Research Progress of Natural Preservatives Modified by Maillard Reaction
WANG Ying-ying,XU Duo-xia,JIAO Qiong,YUAN Fang,GAO Yan-xiang*
2013, 34(7):  296-301.  doi:10.7506/spkx1002-6630-201307063
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Natural preservative was biodegradable, edible and nontoxic, which was one of the major research directions of preservatives. Compared with chemical and enzymatic modification methods, Maillard reaction modification method had better safety. Natural preservative derivatives produced by Maillard reaction had excellent emulsifying properties, heat stability and antibacterial activity. Chitosan as a monosaccharide derivative produced by Maillard reaction not only exhibited antimicrobial and antioxidant properties, but also had good water-solubility. It was a promising commercial substitute for acid-soluble chitosan. Therefore, research and development should be focused on the novel derivatives of natural preservative through Maillard reaction to develop multiple functional food additives.
in vitro Research Methods of Interaction between Harmful Substances in Foods and DNA
GUAN Yu-fang1,LEI Dan-dan1,TAN Yu-rong1,ZHAO Guo-hua1,2,*
2013, 34(7):  302-306.  doi:10.7506/spkx1002-6630-201307064
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The research methods such as electrochemical, UV-visible, fluorescence, SCGE and viscosity methods for the interaction between harmful substances in foods and DNA have been reviewed. A number of techniques and methods such as 32P-postlabelling, immunoassay, immuno-CE/LIF and LC/MS have also been developed for the quantitative detection of interaction between harmful substances in foods and DNA. Based on the research of recently 10 years of related literature, the detection technique and analytic methods regarding in vitro investigation of DNA interaction have been also briefly discussed in this article, which will provide valuable references for the studies of interaction between food harmful substances and DNA.
Role of Rutin in Modern Civilization Diseases
MA Rong,PANG Guang-chang*
2013, 34(7):  307-311.  doi:10.7506/spkx1002-6630-201307065
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As a major representative component of flavonoids, rutin has gained high attention in the scientific field. At present, the studies of rutin have achieved remarkable results. In this article, the sources, structures, physicochemical properties, biological activity, and extraction and determination methods of rutin from a variety of raw materials are summarized. Meanwhile, the roles of rutin in several typical civilization diseases such as gout, obesity, cardiovascular diseases and diabetes are also discussed. In order to strengthen the function of rutin on the body, the role of rutin in signal transduction in vivo is also proposed.
Present State of Vitamin D Fortification and Its Stability
YANG Jing-yan1,2,DENG Qian-chun1,HUANG Feng-hong1,*,XU Ji-qu1
2013, 34(7):  312-315.  doi:10.7506/spkx1002-6630-201307066
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In recent years, more and more attention has been paid on Vitamin D deficiency in human all over the world. This paper reviewed the current vitamin D supplement, fortification, its carrier as well as stability in the carrier, to provide a reference for development of vitamin D fortified foods and to increase vitamin D intake efficiency.
Advances in Active Oxygen Generation and Antioxidant System of Fresh-Cut Fruits and Vegetables
MA Jie1,2,HU Wen-zhong2,*,BI Yang1,JIANG Ai-li2
2013, 34(7):  316-320.  doi:10.7506/spkx1002-6630-201307067
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After cutting fresh fruits and vegetables, the generation of active oxygen including superoxide anion free radical, H2O2 and hydroxyl free radical is induced, which can destroy the normal metabolism of active oxygen. However, fresh-cut processing stimulates the antioxidant system of fruits and vegetables to result in a positive defense. In this paper, the generation of active oxygen including superoxide anion free radicals and H2O2 as well as the change of antioxidant system including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and antioxidants such as ascorbic acid, polyphenols and reduced glutathione (GSH) is summarized, which can provide the reference for the reaction mechanism against mechanical damage of fresh-cut fruits and vegetables.
Research Progress in Antimicrobial Effects of Berberine and Its Derivatives
ZHONG Ci-ping 1,QIAN Yu2,SHU Chang1,SUO Hua-yi1,LI Lin1,*
2013, 34(7):  321-325.  doi:10.7506/spkx1002-6630-201307068
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Berberine is an isoquinoline alkaloid extracted from Chinese herb such as Coptidis rhizome. It has a variety of biological activities, and revealed a wide spectrum of clinical applications. On the other hand, due to its low bioavailability, its functional characteristic studies were limited to medical applications. Therefore, by chemical modification or transformation of chemical structure of berberine, a series of derivatives could improve its bacteriostasis. In this paper, the synthesis, inhibitory effect and mechanism progress of berberine and its derivatives could be used as preservatives or mixed with chitosan coating on fruits and vegetables for disease-preventing and fresh-keeping. In order to provide certain references for berberine, the preservative effects of berberine derivatives on preservative effect in foods.
A Review: Determination of Chlorothalonil in Food
WANG Ling-ling1,2,HOU Yu-ze1,*,ZHI Ai-min2,LI Wen-jun1,HU Xiao-fei2,DENG Rui-guang2
2013, 34(7):  326-329.  doi:10.7506/spkx1002-6630-201307069
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Chlorothalonil (CTN) is abroad-spectrum, protective organic chlorine bactericide, commonly used to control fungus diseases of vegetable, fruit, peanuts, rice, wheat and other crop. For its hazards to environment and human health, determination of CTN residue has attracted increasing attention of people. The physical and chemical properties, application and detection methods of CTN are reviewed here, in order to provide some reference for further development of CTN detection methods.
Research Progress of Chemical Components in Monofloral Honey
ZHAO Li-fu1,2,XU Yun-you3,DONG Rui1,LI Hui-ping1,ZHANG Jing1,*
2013, 34(7):  330-334.  doi:10.7506/spkx1002-6630-201307070
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Because of various pharmacological activities, chemical components in honey are being extensively studied. In this paper, chemical components including saccharides, flavonoids and phenolic acids in monofloral honey have been systematically summarized, which will provide the references for identifying geographic origins and species of honey, improving the quality of honey and ensuring food safety.
Structure, Biosynthesis and Application of Exopolysaccharides by Lactic Acid Bacteria
DAN Tong,WANG Jun-guo,ZHANG He-ping*
2013, 34(7):  335-339.  doi:10.7506/spkx1002-6630-201307071
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Exopolysaccharides (EPS) are secreted outside cell wall of producing microorganism. Because of unique rheological properties and molecular structure, these polymers are widely used in foods as a stabilizer, thickener and emulsifier. In this article, chemical structure, biosynthesis and application of exopolysaccharide produced in bacteria have been reviewed, and new advances in exopolysaccharides produced by lactic acid bacteria (LAB) were discussed. Moreover, the results provide a new theoretical basis for increasing exopolysaccharide production of LAB.
Historical Evolution and Development of the Threshold (TTC) of Toxicological Concern
ZHU Zhou-hai,ZENG Wan-li,GUAN Ying,GAO Qian,LI Xue-mei,MIAO Ming-ming,YAO Jian-hua*
2013, 34(7):  340-344.  doi:10.7506/spkx1002-6630-201307072
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The threshold of toxicological concern (TTC) is a concept that refers to the establishment of a level of exposure for all chemicals, below which there would be no appreciable risk to human health. The TTC method has been applied for nearly half a century since it was proposed, and has experienced a continuous improvement and development process. The establishment, development and improvement of TTC method were discussed. TTC method was originally developed to determine the threshold of safety in food materials. Since then, the non-carcinogenic oral toxicity endpoint of no significant effect level (NOEL) was analyzed to develop a structural class-based multi-scale TTC which was then adopted by Food Additives of FAO/World Health Organization (FAO/WHO) Joint Expert Committee (JECFA) and the European Food Safety Authority (EFSA) with development and improvement. The TTC approach is in wide application to assess the risk of chemicals at low exposure levels, which avoids multiple unnecessary, overly detailed studies, as well as a wide range of toxicological experiments. The TTC method also provides a feasible way for the risk assessment of chemical substances that the amount is very low but lack of a complete toxicity data.
Green Manufacturing Technology: A Challenge and Opportunity for the Meat Industry
PENG Zeng-qi,Lü Hui-chao
2013, 34(7):  345-348.  doi:10.7506/spkx1002-6630-201307073
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This article reviews the development of green chemistry and green manufactury in both China and abroad. The risk of the hazardous chemicals to human body and the environment produced by traditional meat processing technologies, such as grilling, frying, smoking and boiling, was discussed here. In view of modern science and technology as well as the sustainable development of food industry, the concept of meat green manufacturing technology was defined and successful applications of green chemistry in China’s meat industry were summarized.
Research Progress of Exopeptidases in Foods
Fu Jing
2013, 34(7):  349-354.  doi:10.7506/spkx1002-6630-201307074
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Exopeptidases are divided into two subclasses including amino-peptidases and carboxy-peptidases, which can hydrolyze peptide bonds of polypeptides to form the products with less bitter taste, or produce free amino acids or small peptides as pleasant-tasting flavor compounds or as flavor precursors. Exopepetidases may be active during postharvest processes such as fruit ripening, malting and meat aging. They may also be active during food processing such as drying, thermoprocessing, or fermentations. An important role of exopepitdases in foods is the hydrolysis of hydrophobic and bitter peptides. The classification, structure, detection methods, purification methods of exopeptidases, as well as their debittering methods on protein hydrolysates are discussed.