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Table of Content

15 October 2011, Volume 32 Issue 19
Basic Research
Meaty Flavors Derived from a Reaction System Consisting of Oxidized Chicken Fat and Cysteine and Formation Mechanisms
JIN Lin-xi,PAN Cui-fang,WANG Shi,XIE Jian-chun,SUN Bao-guo
2011, 32(19):  1-6.  doi:10.7506/spkx1002-6630-201119001
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Oxidized chicken fat was prepared based on controlled oxidization. After the optimal reaction temperature and time were selected, meaty flavor products were obtained by thermal reaction between cysteine and oxidized chicken fat and analyzed by solid-phase micro-extraction and gas chromatography-mass spectrometry (GC-MS). Through retention index alignment with the NIST08 library, 42 flavor compounds including sulfur compounds, pyridines, aliphic aldehydes, ketones, alcohols and furans were identified in the reaction products. Using 1,2-dichloro-benzene as the standard, 2-pentylfuran was qualified as the most abundant, followed by 2-pentylpyridine, nonanal, 5-methyl-2(5H)-thiophenone and 2-pentyl-2-cyclopenten-1-one. Compared with the controls (oxidized chicken fat with or without cysteine), cysteine degradation and fat oxidation in the oxidized chicken fat with cysteine were both inhibited; whereas, new heterocyclic flavor compounds such as 2-pentylpyridine and 2-pentylthiophene resulting from the Maillard reaction were achieved to reveal the desired meaty flavor.
Comparison and Analysis of Rheological Properties of Three Kinds of Fermented Dairy Products
WANG Song-song,CHEN Qing-sen
2011, 32(19):  7-11.  doi:10.7506/spkx1002-6630-201119002
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A rheometer was used to measure the rheological properties of three fermented dairy products, which were made of milk, soybean milk and both of them, respectively. The results showed that all three kinds of fermented dairy products were thixotropic fluid with a hysteresis loop area ratio of 1: 0.56: 0.69 and a viscosity index ratio of 1: 0.63: 0.91. Under the conditions of constant temperature and rotate speed, the initial apparent viscosity ratio was 1: 0.99: 1.28. The slowest decrease rate of apparent viscosity was observed in fermented soybean milk. In strain sweep experiments, fermented soybean milk was found to be the most stable, followed by fermented milk and complex fermented milk. In temperature sweep experiments, fermented soybean milk had the strongest tolerance to temperature and fermented complex milk had maximum apparent viscosity. By comparing their rheological properties, fermented soybean milk revealed the strongest stability and the highest apparent viscosity. Complex fermented milk had a higher apparent viscosity and a higher stability than single fermented milk.
Effects of Cu2+, Co2+ and Mg2+ on Interaction between Farrerol and DNA
FU Peng,ZHANG Guo-wen,WANG Lin,HU Ming-ming
2011, 32(19):  12-15.  doi:10.7506/spkx1002-6630-201119003
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The interaction between farrerol and calf thymus DNA (ctDNA) was explored by UV-visible spectrophotometry, fluorescence spectroscopy, and melting-point technique in combination with methylene blue (MB) competition in the presence of Cu2+, Co2+ and Mg2+ in physiological buffer (pH 7.4). The results revealed that farrerol could be intercalatively bound to DNA. Cu2+, Co2+ and Mg2+ had different effects on the absorption spectrum of farrerol and could increase the fluorescence intensity of DNA-MB complex. A gradual increase in Cu2+ concentration could result in an initial decrease followed by an increase in the binding constant of DNA-farrerol complex. In the presence of higher Mg2+ concentration, the binding constant of DNA-farrerol complex tended to initially increase and then decrease. However, Increasing Co2+ concentration revealed little effect on the binding constant of DNA-farrerol complex. Therefore, the effect of metal ions on the binding between farrerol and DNA mainly depends on the relative affinity between metal ions and farrerol, DNA basic groups or phosphate groups.
Fractionation and Identification of Ethyl Ecetate Extract from Rhizoma Fagopyri Cymosi
ZHAO Li-qin,ZHANG Xiao-ping,ZHANG Chao-feng
2011, 32(19):  16-22.  doi:10.7506/spkx1002-6630-201119004
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Objective: To fractionate the ethyl ecetate extract from Rhizoma Fagopyri Cymosi and identify the resulting fractions. Methods: Silica gel column chromatography, Sephadex LH-20 column chromatography and recrystailization were employed to fractionate the ethyl ecetate extract. According to physiochemical properties and spectral data, the fractions obtained were identified. Results: Thirteen compounds were separated from the ethyl ecetate extract and elucidated as glutinone (1), isorhametin (2), quercetin (3), quercetin-3-O-α-L-rhamnoside (4), eriodictyol (5), catechin (6), 3,5-dimethoxy benzene carbonic acid-4-O-glucoside (7), syringic acid (8), p-hydroxyl-benzaldehyde (9), succinic acid (10), N-trans-coumaroyl tyramine (11), sitosterol (12) and daucosterol (13). Conclusion: For the first time, compounds 5, 7 and 11 have been isolated from the genus of Fagopyrum, and compound 8 from Fagopyrum dibotrys (D.Don) Hara.
Effect of Fasting on Technological Quality of Chicken during Postmortem Rigidity
JIA Xiao-cui,LI Chun-bao,XU Xing-lian,ZHOU Guang-hong
2011, 32(19):  23-27.  doi:10.7506/spkx1002-6630-201119005
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In order to explore the effect of fasting on the technological quality of chicken, three-yellow chicken with fasting 0, 8, 16 h and 24 h were killed, and the breast meat was harvested, minced after postmortem rigidity for 0, 3 h and 24 h and then processed into sausages. The pH, cooking loss, pressure loss, shear force, meat color and textural characteristics of the chicken sausages obtained were measured. The results showed that prolonged fasting time could result in a decrease in pH and shear force (P<0.05) and an increase in pressure loss and cooking loss. At pre-rigor state, the control group had better textural properties than fasting groups, which revealed the highest hardness, elasticity, cohesiveness, gumminess and chewiness. The group with fasting for 16 h had higher texture than other two fasting groups. As time went on, the pH, water-holding capacity and textural quality of chicken sausage became smaller during postmortem rigidity.
Properties of Beta-limit Dextrin Prepared by Enzymatic Hydrolysis of Waxy Corn Starch
SHAO Lan-lan,ZHAO Yan,TU Yong-gang,YANG You-xian,LI Jian-ke,LI Xin,DONG Pan,DENG Wen-hun
2011, 32(19):  28-32.  doi:10.7506/spkx1002-6630-201119006
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The particle morphology, crystallinity and some properties of β-limit dextrin prepared by enzymatic hydrolysis of waxy cornstarch with β-amylase were studied. The results showed that the particles of β-limit dextrin were angular, irregular and non-crystal. The dextrin revealed low retrogradation and more remarkable improvement on solubility, swelling power, transparency and freeze-thaw stability when compared with raw waxy cornstarch. Its hygroscopicity was a little lower than that of raw waxy cornstarch. Due to its unique properties and excellent processing performance, the application prospect ofβ-limit dextrin in the food processing industry is promising.
Purification and Monosaccharide Composition Analysis of Tartary Buckwheat Polysaccharides
YAN Jun,SUN Xiao-chun,XIE Zhen-jian,HE Gang,YI Yong,FANG Chen,GOU Xiao-jun
2011, 32(19):  33-36.  doi:10.7506/spkx1002-6630-201119007
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Tartary buckwheat polysaccharides (TBPs) were extracted by boiling water, precipitated by alcohol and purified by ion-exchange column chromatography. The purity and molecular weight of TBPs were determined by high performance gel filtration chromatography (HPGFC). Polysaccharide samples were hydrolyzed with sulfuric acid solution, and derivatized with 1-phenyl-3-methyl-5-pyrazolone (PMP). The monosaccharide composition of the hydrolysates obtained was analyzed by RP-HPLC. The results showed that TBPs could be obtained by water extraction and alcohol precipitation after protein removal by Savag method. Three polysaccharides, named as TBP-1, TBP-2 and TBP-3, were obtained by DEAE-cellulose column chromatography with molecular weights of 144544, 445656 and 636795, respectively. Liquid chromatographic analysis based on pre-column derivatization showed that TBP-1 and TBP-2 were composed of glucose and TBP-3 of mannose, rhamnose, glucuronic acid, glucose, galactose and arabinose in a molar ratio of 4.32:2.41:1.00:39.8:9.64:2.02.
Change of Antioxidant Activity in Persimmon Vinegar during Brewing Process
SUN Lu-hong,LU Zhou-min,BAO Rong,ZHAO Nan,BAI Wei-dong
2011, 32(19):  37-41.  doi:10.7506/spkx1002-6630-201119008
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Objective: To reveal the change regularity of antioxidant activity and material basis in persimmon vinegar during brewing process. Methods: One-step fermentation method was applied for brew vinegar from persimmon pulp. The major change in antioxidant contents and antioxidant activity as well as their correlation were explored. Results: The content change of total polyphenols, total flavonoids and vitamin C exhibited an initial increase and a final decrease during the fermentation process and a slow ascending trend during the aging stage. An obviously positive correlation among the three components was observed (P<0.01). The total antioxidant activity of persimmon vinegar revealed a rapid increase during fermentation process. Meanwhile, a significantly positive correlation between total antioxidant activity and total acid was also observed (P<0.01). Moreover, a remarkable positive correlation was also observed between the DPPH radical-scavenging capacity of persimmon vinegar and the contents of total flavonoids, total acid or vitamin C (P<0.05) and between the hydroxyl radical-scavenging capacity and the content of total polyphenols (P<0.01). Conclusion: Persimmon vinegar has significant antioxidant activity and its antioxidant activity is attributed to many kinds of components.
Effects of Exogenous Factors on the Content of Vitamin C in Germinated Soybean
ZHAO Jie-chang,LI Xiao-mei
2011, 32(19):  42-45.  doi:10.7506/spkx1002-6630-201119009
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Raw soybean does not have vitamin C, but it can generate vitamin C during the germination process. Moreover, the content of vitamin C reveals an increase with prolonged germination time. The content of vitamin C was measured by 2,6-dichlorophenol indophenol method and the effects of exogenous factors such as glucose, L-galactose, D-mannose, potassium iodide and UV irradiation on vitamin C were explored. The results showed that glucose, L-galactose, potassium iodide and UV irradiation could accelerate the synthesis of vitamin C. L-galactose treatment revealed the most obvious effect on the content of vitamin C, resulting in an increase of 8.43 mg/100 g when compared with untreated soybean. Similarly glucose treatment also exhibited a stronger effect on the content of vitamin C, which was improved by 4.23 mg/100 g. Prolonged soaking in these solutions at a lower concentration was better than short-time soaking in these solutions at a higher concentration. Moreover, UV irradiation on the 5th day could obviously accelerate the synthesis of vitamin C.
Water Content Change of Surimi Products Explored by NMR during Storage
LIN Jing-jing,LIN Xiang-yang,WU Jia,BIAN Zhi-ying,YE Nan-hui,ZHU Rong-bi
2011, 32(19):  46-49.  doi:10.7506/spkx1002-6630-201119010
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The spin-spin relaxation time T2 and water content change in surimi products were measured by NMR in this study. The change of water spatial distribution and mobility in two kinds of surimi products at -18 ℃ (normal storage temperature) and 4/-18 ℃ (enlarged temperature change during storage) was explored. The results indicated that both kinds of surimi products had four kinds of water mobility, which were T21, T22, T23, and T24. T21 and T22 were bound water and exhibited little change during storage. T23 and T24 revealed higher mobility, which was the critical water change during storage. Water change of surimi products under the condition of 4/-18 ℃ was stronger than under the condition of -18 ℃ and even most closely bound water (corresponding to T21) showed a change.
Stability of Chlorophyll from Tumorous Stem Mustard Leaves
LI Min,YOU Xiong-ying,ZHAO Chang-qiong
2011, 32(19):  50-53.  doi:10.7506/spkx1002-6630-201119011
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The effects of light, temperature, pH, oxidants, reductants, and metal ions on the stability of leaf chlorophyll from tumorous stem mustard were explored. Chlorophyll was extracted by acetone and determined by U-3010 ultraviolet and visible spectrometer. The results showed that the stability of chlorophyll from the leaves of tumorous stem mustard was affected by many factors including light, H2O2, vitamin C, acid, alkali and several metal ions. The chlorophyll was stable when temperature was 10-70 ℃, and temperature over 80 ℃ could result in a decrease of its stability. In addition, neutral condition and Na2SO3 revealed a hyperchromic effect on the chlorophyll.
Stability and Biological Activity of Intracellular Red Pigment from Fusarium momiliforme
SUN Yue-e,SHAO Ying,CHEN An-hui,LIU Xiao-juan,FAN Mei-zhen
2011, 32(19):  54-59.  doi:10.7506/spkx1002-6630-201119012
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In order to explore the stability and biological activity of intracellular red pigment from Fusarium momiliforme RCEF4029, spectrophotometry was used to determine the stability of the red pigment and DPPH-microplate assay was used to evaluate its free radical scavenging activity. Meanwhile, a resazurin cytotoxicity assay model of Chinese hamster ovary (CHO) cells was employed to study anti-tumor activity of the pigment. The results showed that the red pigment had good thermal and light stability. Metal ions such as Zn2+ and Ca2+ had no obvious effect on the stability of the red pigment, while Na+, Mg2+ and Al3+ revealed hyperchromic effect on the red pigment; in contrast, Fe3+ had destructive effect on its stability. Oxidants, reductants, vitamins, acidity regulators and food additives had little effect on the stability of the red pigment. Citric acid, sodium hydrate, VE, gelatin and sodium benzoate had slight hyperchromic effect on its stability. Furthermore, the red pigment also exhibited some free radical scavenging activity. Therefore, the intracellular red pigment is a kind of stable natural pigment with wide utilization potential.
Modification of Casein Hydrolysate by Alcalase-catalyzed Plastein Reaction and ACE-inhibitory Activity of Modified Products
SUN Hui,ZHAO Xin-huai
2011, 32(19):  60-65.  doi:10.7506/spkx1002-6630-201119013
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Casein hydrolysate with a hydrolysis degree of 10.9% and an ACE-inhibitory IC50 of 52.6 μg/mL was prepared by hydrolyzing casein with alcalase and then modified by alcalase-catalyzed plastein reaction. When the reaction time was fixed at 6 h, the optimal reaction conditions were achieved by response surface methodology to be enzyme dosage of 3.1 kU/g protein, reaction temperature of 25 ℃ and substrate concentration of 50 g/100 mL. Nine modified casein hydrolysates with different modification degrees were prepared. The results indicated that each modified casein hydrolysate had enhanced ACE-inhibitory activity. The IC50 of the modified hydrolysate with the highest activity was 14.9μg/mL. This modified hydrolysate was centrifuged into two fractions, a supernatant and a precipitation fraction. The supernatant and precipitation fractions revealed a reduced and enhanced ACE-inhibitory activity when compared with their suspension, suggesting that the precipitation fraction accounted mainly for the improved activity of the modified hydrolysate. Tricine-SDS-PAGE electrophoresis analysis also showed that some new peptides with higher molecular weights were generated in the modified hydrolysate and the precipitation faction. The further enzymatic hydrolysis of the supernatant and precipitation fractions could result in the impairment of ACE-inhibitory activity.
Structure-Antioxidant Activity Relationship of Polysaccharide WCP3a Isolated from Coprinus comatus
LIU Na-nu,ZHANG Jing,SUN Run-guang,DU Ke,LI Lian-qi,QU Jia-kuan
2011, 32(19):  66-69.  doi:10.7506/spkx1002-6630-201119014
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The in vitro antioxidant activity and structure- antioxidant activity of polysaccharide WCP3a isolated from Coprinus comatus were explored in this study. The polysaccharide revealed an obvious scavenging effect against superoxide anion free radicals generated from pyrogallol self-oxidation. Meanwhile, the polysaccharide at the concentration of 0.6 mg/mL had the strongest scavenging activity against superoxide anion free radicals. The single-helix structure of the polysaccharide was determined by Congo red test and atomic force microscopy. Moreover, the polysaccharide WCP3a treated with NaOH at various concentrations could generate WCP3a-0.2 and WCP3a-0.4 with different spatial configurations. The scavenging capacity of WCP3a-0.2 and WCP3a-0.4 against superoxide anion free radicals was much stronger than that of WCP3a. The atomic force microscopy (AFM) revealed that NaOH treatment could damage the spatial structure of the polysaccharide. Therefore, the antioxidant activity of WCP3a in vitro is highly correlated with its spatial structure.
in vitro Antioxidant Activity of Cucumber Polysaccharides
HE Nian-wu,YANG Xing-bin,TIAN Ling-min,ZHAO Yan
2011, 32(19):  70-74.  doi:10.7506/spkx1002-6630-201119015
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Objective: To determine total carbohydrate content in cucumber, isolate polysaccharides from it and analyze uronic acid content, monosaccharide composition and in vitro antioxidant activity of extracts obtained. Methods: Phenol-sulfuric acid and sulfuric acid-carbazole methods were employed to evaluate total carbohydrate content and uronic acid content, respectively. In addition, high performance liquid chromatography (HPLC) based on pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) was employed to analyze the monosaccharide composition of cucumber polysaccharides. Moreover, the scavenging activity of cucumber polysaccharides against 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion (O2- ·) and hydroxyl ( ·OH) free radicals and total reducing power (TRP) of cucumber polysaccharides were evaluated in vitro. Results: The total carbohydrate and uronic acid contents in cucumber polysaccharides were 63.5% and 10.6%, respectively. The monosaccharide composition of cucumber polysaccharides was made up of D-mannose (Man), L-rhamnose (Rha), D-glucuronic acid (GlcUA), D-galacturonic acid (GalUA), D-glucose (Glc), D-xylose (Xyl), D-galactose (Gal), L-arabinose (Ara) with a molar ratio of 4.08:2.78:1.00:5.82:6.07:2.78:8.48:6.58. Cucumber polysaccharides revealed high antioxidant activity, and the scavenging rates at the concentration of 20 mg/mL against DPPH, superoxide anion and hydroxyl free radicals were 92.31%, 83.57% and 77.59%, respectively. Moreover, cucumber polysaccharides also exhibited strong reducing power. Conclusion: Cucumber polysaccharides are typically heteropolysaccharides with stronger antioxidant activity.
Separation, Purification and Identification of Antibacterial Components in Rape Bee Pollen
SUN Li-ping,DU Xia,CHEN You-gen,XU Xiang,AN Zhong-yao,LI Chun-yan
2011, 32(19):  75-78.  doi:10.7506/spkx1002-6630-201119016
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The bioassay-guided fractionation was used to isolate antibacterial components from aqueous extract of rape bee pollen. The MICs and MBCs of antibacterial components isolated against Bacillus subtilis, Escherichia coli, Staphylococcus aureus rosenbach and Pseudomonas aeruginosa were determined. An active component with strong antibacterial activity was obtained and identified as kaempferol by ESI-MS and NMR spectroscopy. Therefore, rape bee pollen is a natural antibacterial plant source and has promising application potential.
Antioxidant Activity of Total Flavonoids from Different Mango Varieties
WEN Liang-juan,LIU Hao,WANG Wei
2011, 32(19):  79-82.  doi:10.7506/spkx1002-6630-201119017
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Three commercially available mango varieties including Jinhuang mango, Xiangya mango and Tainong mango were determined for the contents of total flavonoids. Meanwhile, the antioxidant activity of these mango varieties was evaluated using hydroxyl, superoxide anion and DPPH radical scavenging systems and compared with that of vitamin C. The results showed in decreasing order of the hydroxyl free radical scavenging activity of total flavonoids in the concentration range of 40-200μg/mL, three commercially available mango varieties and vitamin C could be ranked as follows: Tainong mango, Xiangya mango, Jinhuang mango and vitamin C. In terms of the superoxide anion free radical scavenging activity, the deceasing order was vitamin C, Tainong mango, Xiangya mango and Jinhuang mango in the concentration range of 10-200 μg/mL. In the concentration range of 1-20 μg/mL, vitamin C exhibited the highest scavenging activity against DPPH free radicals, followed by Tainong mango, Jinhuang mango and Xiangya mango. Total flavonoids from all the three mango varieties had obvious antioxidant activity in a dose-dependent manner. Total flavonoids from Tainong mango revealed a better antioxidant capacity than those from other two varieties.
Effect of High-pressure Homogenization on Structure and Functional Properties of Soybean β-Conglycinin
GUO Li,WANG Peng,ZHAO Dong-jiang,WANG Guang-hui,ZHOU Feng-chao,MA Xue
2011, 32(19):  83-87.  doi:10.7506/spkx1002-6630-201119018
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The structure and functional properties of high-pressure homogenized β-conglycinin were investigated by differential scanning calorimetry (DSC), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The denaturation temperature of the β-conglycinin was determined by DSC to be (74 ± 1) ℃. The particle size of the protein after high-pressure homogenization became much smaller. FTIR spectroscopy showed the protein structure was changed significantly after homogenization at 20 MPa and 30 MPa. Moreover, the protein exhibited a high solubility, emulsifying activity and emulsion stability and low whey precipitation after homogenization. The β-conglycinin revealed an increase of its water-holding capacity at the pressure levels of 20 MPa and 35 MPa, and an enhanced oil-holding capacity at 25 MPa and 30 MPa of homogenization pressure.
Isolation, Purification and Monosaccharide Composition Analysis of Citus reticulata Peel Polysaccharides
CHEN Si,HUANG Qing-hua,LI Rao-ling,GAN Wei-fa,YUAN Han-qi
2011, 32(19):  88-91.  doi:10.7506/spkx1002-6630-201119019
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Polysaccharides were extracted from dried powder of Citus reticulata peel with acidic water, followed by pigment removal on D-201 ion exchange resin, protein removal by Sevag,s method, dialysis and freeze-drying. The CPA-I fraction was achieved by sequential column chromatographies on DEAE-sepharose fast flow and Sephadex G-100. Monosaccharide composition analysis of CPA-I was carried out by HPLC based on pre-column derivatization with 1-phenyl-3-methy1-5-pyrazolone (PMP). High performance size exclusion chromatography (HPSEC) was used for purity analysis and relative molecular weight determination. UV-visible and infrared (IR) spectral analyses were conducted for structural characterization. The results showed that the molecular weight of CPA-I with high purity was 7.96×104, and the monosaccharide composition of the polysaccharide was composed of galacturonic acid and arabinose. The IR spectrum indicated that CPA-I was a galacturonic acid polysaccharide esterified by carboxylic acid.
Antioxidant Properties of Polysaccharides from Phellinus igniarius in vitro
ZHU Zi-ping, LI Na
2011, 32(19):  92-95.  doi:10.7506/spkx1002-6630-201119020
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The antioxidant properties of intracellular polysaccharides (IPS) and exopolysaccharides (EPS) from Phellinus igniarius were evaluated in vitro by chemical simulation. The results indicated that the EC50 of Phellinus igniarius IPS and EPS were 1.09 mg/mL and 1.52 mg/mL for scavenging DPPH radicals, 0.78 mg/mL and 0.23 mg/mL for scavenging hydroxyl radicals, 29.97μg/mL and 20.31μg/mL for scavenging superoxide anion radicals and 1.36 mg/mL and 1.66 mg/mL for chelating Fe2+, respectively. An excellent linear relationship between the reducing power and concentrations of both polysaccharides was observed in the tested concentration ranges. The antioxidant capacity of both polysaccharides was in a dose-dependent manner but showed an obvious difference.
Bile Salt-binding Capacity and Lipid-lowering Mechanisms of Water Extracts from Fresh Tea Leaves and Tea Flowers
DENG Zhi-hui,HUANG Hui-hua
2011, 32(19):  96-99.  doi:10.7506/spkx1002-6630-201119021
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The bile salt-binding capabilities of water extracts from fresh tea leaves, fixed fresh tea leaves and tea flowers were compared. Meanwhile, the correlation between tea polyphenol content and bile salt-binding capacity in vitro in a simulated human digestive environment was also explored. The results revealed a significant correlation between bile salt-binding capacity and tea polyphenol content. Water extract from fixed fresh tea leaves exhibited the strongest bile salt-binding capability, followed by water extracts from tea flowers and fresh tea leaves. Therefore, water extracts from fresh tea leaves and tea flowers have functional components that can reduce blood lipid.
Antioxidant Activity of Soluble Dietary Fiber from Crab Apple Pomace
NIU Guang-cai,ZHU Dan,XIAO Dun,WEI Wen-yi,WANG He-lin
2011, 32(19):  100-103.  doi:10.7506/spkx1002-6630-201119022
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Objective: To explore the antioxidant activity of soluble dietary fiber (SDF) prepared by fermenting crab apple (Malus asiatica) pomace with mixed strains. Methods: The scavenging rates of SDF derived from crab apple pomace against hydroxyl, superoxide anion and DPPH radicals and its inhibitory effect against lipid peroxidation in soybean oil were evaluated. Results: The SDF revealed strong scavenging capacity against hydroxyl and superoxide anion free radicals with an EC50 of respectively 4.63 mg/mL and 8.84 mg/mL, but the scavenging capacity against DPPH free radicals was weaker. The antioxidant effect of the SDF on soybean oil was similar to that of BHA. Conclusion: SDF derived from crab apple pomace has a strong scavenging capacity agaisnt hydroxyl, superoxide anion free radicals and an obvious antioxidant effect on soybean oil. Therefore, it can be applied as a food antioxidant, which will have promising application prospects.
Antibacterial Activity of Lipid Antibiotic Substances in Adults of Tenebrio molitor L.
WANG Jun,LIN Hua-feng,LI Shi-guang,LI Mao-ye,ZHANG Song-ying
2011, 32(19):  104-107.  doi:10.7506/spkx1002-6630-201119023
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The adults of Tenebrio molitor were extracted with ethyl acetate, and then the resulting crude extract was separated by silica gel column chromatography to obtain lipid antibiotic substances in the ethanol eluate. The inhibitory effect of the antibiotic substances gainst bacteria and fungi was also investigated. The results showed that the lipid antibiotic substances with and without heating in 100 ℃ water bath for 20 min had a significant inhibitory effect on G- bacteria, suggesting their good thermal stability. The lipid antibiotic substances also had a significant inhibitory effect on three species of pathogenical fungi. When the concentration was 50 mg/mL, the decay rates of apples and pears were reduced by 13.24% and 16.90%, respectively. The lipid antibiotic substances also could prolong the shelf life time of bean curd.
Rheological Properties of Wheat Starch-Ionic Liquid
LUO Zhi-gang,LU Xuan-xuan
2011, 32(19):  108-111.  doi:10.7506/spkx1002-6630-201119024
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The rheological properties of wheat starch-[AMIM]Cl solution were studied by using HAAKE rheometer. The results showed that wheat starch-[AMIM]Cl solution was a typical pseudoplastic fluid. The apparent viscosity of starch-[AMIM]Cl solution exhibited an obvious decrease with increasing shear rate and shear thinning nature became more obvious with increasing starch concentration. The thixotropy dropped with increasing temperature .
Infrared Spectral Properties of Melanin from Black-bone Silky Fowl and Its Degradation Products
QIAO Juan-juan,TIAN Ying-gang,XIE Ming-yong,LI Xin,ZHANG Pan,ZHU Sheng,WANG Chun-yan
2011, 32(19):  112-115.  doi:10.7506/spkx1002-6630-201119025
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Melanin from black-bone silky fowl (BSFM) was degraded by NH4OH-H2O2 and K2CO3-H2O2 methods. BSFM and its soluble degradation products were studied by Fourier transform infrared spectroscopy. The results showed that the infrared spectra of BSFM and its soluble degradation products were much similar, and had characteristic absorption peaks in the ranges of 3600-3100 cm-1, 2950-2850 cm-1, 1680-1630 cm-1, 1570-1515 cm-1 and 1240-1200 cm-1. From the absorption peak near 1650 cm-1, it could be speculated that backbone structure fragments of BSFM are present in its soluble degradation products derived from the action of H2O2 and that amide groups and cyclic-alkenes may be the major groups of BSFM backbone structure.
Alpha-Amylase Inhibitors in Galla Chinensis
SONG Yan-xian,MIN Yu-tao,XU Feng-cai,MA Qing-yi
2011, 32(19):  116-119.  doi:10.7506/spkx1002-6630-201119026
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In order to separate the inhibitory factors of α-amylase in Galla Chinensis, crude methanol extract of Galla Chinensis was fractionated by sequential Soxhlet extraction with petroleum ether, ethyl ether, ethyl acetate and methanol. Meanwhile, the residue left after methanol extraction was extracted with acetone-water (1:1, V/V) and the extract obtained was further separated by pH gradient extraction, polyamide column chromatography and Seaphadex LH-20, respectively. The inhibitory activity of all samples against α-amylase was determined. The results showed that the inhibitory rates of ethyl ether fraction, ethyl acetate fraction, acetone-water extract, methanol faction (obtained from secondary extraction by Soxhlet method), petroleum ether fraction and crude methanol extract were 91.04%, 90.38%, 80.09%, 66.48%, 34.14% and 23.96%, respectively. The α-amylase inhibitors in petroleum ether fraction were lauric acid, myristic acid and palmitic acid with corresponding inhibitory rates of 34.34%, 31.71% and 31.01%, respectively. Tannic acid and gallic acid were the α-amylase inhibitors in ethyl ether fraction, with corresponding inhibitory rates of 66.7% and 21.3%, respectively. The α-amylase inhibitor composition in acetone-water extract was complicated and consisted of partially methyl-esterified fatty alcohols according to preliminary purification and GC-MS analysis.
Bioengineering
A Method for Screening Angiotensin I Converting Enzyme Inhibitory Peptides
JIN Qing,WU Jian-ping, ZHANG Gui-chuan,DENG Ya-fei4,YUAN Lu-jiang
2011, 32(19):  120-124.  doi:10.7506/spkx1002-6630-201119027
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A rapid and highly efficient method for identifying angiotensin I converting enzyme inhibitory peptides from protein hydrolysates was established based on quantitative structure activity relationship (QSAR) and protein sequence. First, a small peptide library was constructed by protein sequence searching according to the hydrolysis sites of a specific enzyme. Then, the activities of peptides in the library were predicted using QSAR model. Target peptides were synthesized and their IC50 values were measured. Finally, a real protein hydrolysate was prepared and HPLC was employed to analyze the target peptides in the hydrolysates. Totally 34 tripeptides with an IC50 of less than 10 μmol/L were predicted from rapeseed protein, wheat protein and rice protein and 11of them with higher activity were synthesized. LRL with the lowest IC50 of 3.42μmol/L located in rapeseed cruciferin BNC1 (P33523) sequence 347-349 was characterized from the synthesized peptides.
Screening of Lactic Acid Bacteria with Antioxidant Activity
LIU Tian-yi,PAN Dao-dong
2011, 32(19):  125-129.  doi:10.7506/spkx1002-6630-201119028
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In order to achieve lactic acid bacteria with high antioxidant activity, 20 lactic acid bacterial strains were isolated from kimchi juice, goose intestines and chicken crop. Strains L8 and L17 with high antioxidant activity were picked out through preliminary screening based on DPPH and superoxide anion free radical scavenging activity and secondary screening based on total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD) activity. Both strains were identified as Lactobacillus casei by carbohydrate fermentation, physiological and biochemical tests and 16S rDNA sequence analysis.
Antibacterial Susceptibility and Subtypes of Salmonella Isolates from Retail Chicken in Xi,an in 2007-2008
YANG Bao-wei,SHEN Jin-ling,XI Mei-li,ZHANG Xiu-li,CUI Sheng-hui,WANG Xin,MENG Jiang-hong
2011, 32(19):  130-136.  doi:10.7506/spkx1002-6630-201119029
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Objective: The antibacterial susceptibility, and serotype and genotype of 260 Salmonella isolates from retail chicken in Xi,an district of Shaanxi province were determined to explore the microbial safety of retail chicken. Methods: The antibacterial susceptibility was tested using agar dilution method recommended by the Clinical and Laboratory Standards Institute. Serotyping was performed using slide agglutination method according to WHO guidelines. DNA fingerprinting profiles of Salmonella were determined using pulse field gel electrophoresis (PFGE) developed by the US Centers for Disease Control and Prevention, and analyzed using the BioNumerics Software. Results: The drug resistance rates of 260 Salmonella isolates to nalidixic acid, ciprofloxacin, levofloxacin, gatifloxacin, ampicillin, amoxicillin-clavulanic acid, cefoperazone, ceftriaxone and cefoxitin were 81.4%, 29.2%, 22.4%, 21.8%, 34.6%, 37.7%, 32.6%, 23.1% and 1.9%, respectively. Twenty-one serotypes were identified in the Salmonella isolates, and the common serotypes were Salmonella Enteritidis, Salmonella Shubra, Salmonella Indiana, Salmonella Typhimurium, Salmonella Djugu, Salmonella Derby, Salmonella Virchow, Salmonella Othmarschen and Salmonella II, respectively. The isolates of serotypes Salmonella Indiana (22.6%) and Salmonella Shubra (6.1%) were resistant to at least 15 antibiotics, which were the most resistant ones. PFGE profiles of Salmonella Enteritidis, Salmonella Shubra, Salmonella Indiana and Salmonella Typhimurium isolates were genetically diverse. The epidemiological regularity of the different serotypes of Salmonella Exhibited differences along with sampling time and places. Conclusion: Salmonella isolates from retail chicken in Xi,an are diverse in serotypic and genotypic characteristics and many of them are resistant to multiple antibiotics commonly used in the treatment of humans and animals.
FTIR Characterization of Lignin Degradation Products from Soybean Straw Fermented by Phanerochaete chrysosporium Burdsall
WANG Li-ting,XU Wei,ZHANG Yu-qiang
2011, 32(19):  137-140.  doi:10.7506/spkx1002-6630-201119030
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The degradation conditions of soybean straw lignin by Phanerochaete chrysosporium fermentation were studied in this paper. The results showed that addition of 5 g of soybean straw power to 12 mL of synthetic medium for fermentation at an initial pH of 4.5 and an inoculum size of 0.8 mL (8.6 × 106 CFU/mL spore suspension concentration) for 10 d proved optimal and the resultant degradation rate of lignin was 45.96%. Also, Fourier transform infrared spectroscopy (FTIR) was employed to changes in functional groups arising from lignin degradation. The results showed that the relative intensity of spectral peaks associated with lignin (1099cm-1and 1057-1038 cm-1) was weakened, whereas the relative intensity of spectral peaks associated with benzene (1643-1608 cm-1 and 1510-1508 cm-1) was enhanced. These results suggest the degradation of lignin into small molecules or lignin monomers. Moreover, the contents of benzene and cyclic compounds in lignin were decreased according to comparisons with the changes of other spectral peaks.
Optimization of Fermentation Conditions for Genetically Engineered Recombinant Bacterium with Amylomaltase Gene
HU Yao-hui,WANG Dan,PIAO Chun-hong,YU Han-song,LIU Jun-mei
2011, 32(19):  141-146.  doi:10.7506/spkx1002-6630-201119031
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The optimal fermentation conditions for the genetically engineered recombinant bacterium with amylomaltase gene conserved in our laboratory were explored in this study. One-factor-at-a-time investigations showed that the optimal fermentation culture medium was composed of 0.025 g/mL molasses, 0.015 g/mL tryptone, MgSO4 ·7H2O/K2HPO4 ratio of 7:1, and 0.5 g/L FeSO4 ·7H2O. The optimal fermentation conditions determined based on gucose oxidase activity were 100 mL of medium in a 250 mL flask, shaking speed of 200 r/min, inoculum amount of 5%, initial pH of 7.0, fermentation temperature of 37 ℃, addition of the inducer IPTG at OD600nm = 0.6, induction temperature of 30 ℃, induction period of 5 h and inducer concentration of 1 mmol/L. Under the optimal conditions, the amylomaltase activity was 950 U/mL, which was improved by 7 times compared with non-optimization conditions.
in vitro Fermentation Characteristics of Modified Dietary Fiber from Grape Pomace
LING Bo,CAI Yu-jie,WU Hong-bin,ZHAO Guo-hua,MING Jian
2011, 32(19):  147-151.  doi:10.7506/spkx1002-6630-201119032
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Human excrement extract was used as the inoculum to modify grape pomance dietary fiber in a mimic human intestinal environment by in vitro fermentation. The pH and the content of short-chain fatty acids (SCFAs) in modified dietary fiber obtained after different times of fermentation were determined. The results indicated that grape pomance dietary fiber was one of ideal carbon sources that could be exploited by intestinal microflora. SCFAs including acetic acid, propionic acid, butyrate acid and isobutyrate acid were produced during fermentation in vitro. Meanwhile, no obvious pH change in the fermentation broth of modified grape pomace dietary fiber was observed. However, the contents of total SCFAs and each SCFA were affected due to fermentation treatment.
Fermenting Water Extract from Young Alfalfa Stems and Leaves with Lactobacillus acidophilus for Protein Precipitation
QU Min,YANG Da-peng,LIANG Jin-zhong,ZHANG Yue-xue
2011, 32(19):  152-156.  doi:10.7506/spkx1002-6630-201119033
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In the present work, we investigated the growth regularity of Lactobacillus acidophilus, screened out a high yield acid-producing strain and used the strain to ferment water extract from the young stems and leaves of Medicago sativa (alfalfa) cv. Zhaodong to precipitate alfalfa leaf protein by produced acids. The precipitation of alfalfa leaf protein from water extract from the young stems and leaves of Medicago sativa (alfalfa) cv. Zhaodong was studied by adjusting its pH. The effects of fermentation time, inoculum size, material/liquid ratio in raw material extraction on alfalfa leaf protein yield were explored. pH 3.0-3.7 proved optimal for precipitating alfalfa leaf protein. The optimal conditions for preparing alfalfa leaf protein were extraction material/liquid ratio of 1:20, fermentation time of 11 h, and inoculum amount of 107 cells/mL. Under the optimal extraction conditions, the extraction yield of alfalfa leaf protein was up to 45.08%.
Thermodynamics of 10-23 DNAzyme Cleavage Reaction Evaluated by Microcalorimetric Method
ZHOU Guo-yan,LI Xuan-chen,WANG Ai-min,LAN Hao,XING Hua
2011, 32(19):  157-160.  doi:10.7506/spkx1002-6630-201119034
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The sequence of 2031 site in anterior HBV C/C area was selected as the substrate RNA fragment to synthesize the corresponding 10-23 DNAzyme. Under mimic physiological conditions, the thermodynamics of 10-23 DNAzyme was evaluated by microcalorimic method. Heat-flow curves were plotted to obtain the initial reaction rate (v0) at various concentrations of the substrate RNA. The maximum rate (vmax), Michaelis-menten constant (Km) and catalytic constant (Kcat) of 10-23 DNAzyme were obtained from the established Lineweaver-Burk plot of 1/v0 against 1/[S] to be 2.5 × 10-9 mol/(L ·s), 0.045 nmol/L and 0.107 min-1, respectively.
Batch and Fed-batch Fermentation of High Yield Gamma-aminobutyric Acid-producing Lactobacillus brevis BS2 Capable of Enriching Zn
XIE Xiao-yang,YUAN Wei-jing,LI Kun-tai,GUO Xiao-yan,LIU Zhi-wen,XU Bo
2011, 32(19):  161-164.  doi:10.7506/spkx1002-6630-201119035
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In this study, Lactobacillus brevis BS2, a high yield gamma-aminobutyric acid (γ-GABA)-producing strain capable of enriching Zn, was used to conduct batch and fed-batch fermentation in a 15-L fermenter for exploring the biotransformation of γ-GABA. An initial pH of 5 was used for batch fermentation with and without holding pH at 5. As a result of holding pH, the production ofγ-GABA was considerably increased and sodium glutamate and glucose were almost all consumed at the time points of 32 h and 44 h, respectively. When the initial pH of 5 was held during the fermentation, adding 200 mL of 630 g/L sodium glutamate and 200 mL of 550 g/L glucose (18 min needed at the same flow rate of 11.1 mL/min) was necessary at the time points of 32 h and 44 h, respectively. As a result, the glucose and sodium glutamate in the medium were both over 18 g/L at the end of their additions, which basically reached their initial levels before the fermentation. At 56 h, almost all glutamate was depleted and the production of γ-GABA reached 22.5 g/L. Finally, the second addition of sodium glutamate was done as described above at 56 h. The production of γ-GABA was over 33 g/L at 104 h.
Identification of a Lactic Acid Bacteria Strain Rich in Surface (S)-Layer Protein and Its Tolerance to Digestive Enzymes
XIAO Rong,FAN Yu-bing,WANG Yuan-liang,LI Zong-jun,
2011, 32(19):  165-169.  doi:10.7506/spkx1002-6630-201119036
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A strain of lactic acid bacteria was isolated from fresh milk by plate streaking method. The isolated strain was named as M8, which was rich in S-layer protein according to sodium dodecyl sulfonate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The strain was identified as the species of Lactobacillus brevis via morphological observation, physiological and biochemical characteristics, and phylogenetic analysis of 16S rRNA sequences. Its excellent tolerance was found during sequential suspension at 37 ℃ in a mimic gastric juice (pH 2.5) containing pepsin (3 g/L) and citric acid-phosphate buffer (100 mmol/L) and then in a mimic small intestinal juice (pH 8.0) containing trypsin (10 g/L) and Tris-HCl buffer (25 mmol/L). Therefore, S-layer protein may function as a protective barrier and resist the invasion of digestive enzymes.
Effect of Propyl p-Hydroxybenzoate on SOD Gene Expression of in Drosophila melanogaster
JIANG Fang-ping,YING Qiong-qiong,GU Wei
2011, 32(19):  170-173.  doi:10.7506/spkx1002-6630-201119037
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In order to explore the effect of propyl p-hydroxybenzoate (PP) on superoxide dismutase (SOD) gene expression in Drosophila melanogaster, PP was used to feed Drosophila melanogaster at the concentrations of 0, 0.20, 0.50, 1.00 g/L and 2.00 g/L for 10 consecutive days, respectively. Total RNA was extracted from Drosophila melanogaster and RT-PCR was used to investigate the impact of PP on mRNA expression level of SOD gene in Drosophila melanogaster. The results suggested that PP could significantly suppress Cu, Zn-SOD and Mn-SOD in comparison with the control group (P<0.05). As the PP concentration increased, the expression level of Cu, Zn-SOD gene in female flies and Mn-SOD gene in males revealed a decrease; however, the expression level of Mn-SOD gene in female flies exhibited an obvious improvement. These results indicated that the toxicological effect of PP may be related to the inhibition of SOD gene expression in Drosophila melanogaster, which shows differences between males and females.
Optimization of Tryptic Hydrolysis Conditions for Preparing Milk-derived Immune Peptides by Response Surface Methodology
XU Xin ,HE Jia-yi,LIU Guo-yan,CAI Li-li,WEI Xiao-rui,MAN Qi-qi,ZHANG Jun
2011, 32(19):  174-179.  doi:10.7506/spkx1002-6630-201119038
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Objective: To optimize the tryptic (PTN 6.0S) hydrolysis conditions of sodium caseinate for preparing peptides with high-immune activity. Methods: One-factor-at-a-time experimental design combined with response surface methodology was employed systematically to develop optimal hydrolysis conditions of sodium caseinate. The effect of hydrolyzed sodium caseinate on proliferation degree (stimulation index, SI) and ammonia nitrogen (AN) of mouse spleen cells was measured by tetrazolium salt-based colorimetric (MTT) assay. Results: The optimal hydrolysis conditions were substrate concentration of 3.5 g/100 mL, enzyme/substrate ratio of 3.8:1000, hydrolysis time of 15 h, hydrolysis temperature of 55.0 ℃ and hydrolysis pH of 7.0. Under the optimal hydrolysis conditions, the maximum SI was achieved to be 0.184±0.002 and the ammonia nitrogen content was up to (0.795±0.012) g/L. Conclusion: Enzymatic hydrolysis is a better way to prepare high-immune activity peptides from sodium caseinate
Kinetics for Phenyllactic Acid Production by Lactobacillus paracasei W2 in Batch Fermentation
SUN Jiang,ZHENG Li-xue,WANG Li-mei
2011, 32(19):  180-183.  doi:10.7506/spkx1002-6630-201119039
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The cell growth, phenyllactic acid (PLA) production and sugar consumption of Lactobacillus paracasei W2 throughout the batch fermentation were investigated and corresponding kinetic models were proposed according to Logistic and Luedeking-Piret equations. The experimental data was processed by Matlab 7.0 software, and the batch fermentation kinetics model parameters were achieved. The R2 of each of the proposed models was greater than 0.955, suggesting that the experiment data were fitted well with these models. Therefore, the established models can provide a reasonable description for the batch fermentation process.
Biofilm-forming Capabilities of Lactobacillus bulgaricus and Streptococcus thermophilus
WANG Kun,YAN Ying-juan,JIANG Mei,CHEN Xiao-hong,LI Wei,DONG Ming-sheng
2011, 32(19):  184-187.  doi:10.7506/spkx1002-6630-201119040
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The biofilm-forming capabilities of Streptococcus thermophilus and Lactobacillus bulgaricus on different carriers (coconut, stainless steel mesh, plastic sheet, glass sheet or ceramic parts) was studied by using placed slice and plate culture count methods. The results showed that stainless steel mesh and coconut were suitable carriers for biofilm formation. During 7 days, the CFU (colony-forming units) of the single-species biofilm on coconut and stainless steel mesh initially reached 1 × 107 CFU/cm2 and then was kept at 3.2 × 106 CFU/cm2. The mixed-species biofilm was stable at approximately 1 × 107 CFU/cm2 in continuous seven days. In addition, scanning electron microscope was used to observe mixed-species biofilm formed by S. thermophilus and L. bulgaricus, and a typical mixed-species biofilm was observed on coconut and stainless steel mesh.
Optimization of Ethanol Precipitation of Exopolysaccharides Produced by Lactobacillus plantarum 70810 by Response Surface Methodology
FENG Mei-qin,QIU Yuan,ZHANG Qi,Mahinur·MUTUVULLA,CHEN Xiao-hong,DONG Ming-sheng
2011, 32(19):  188-192.  doi:10.7506/spkx1002-6630-201119041
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The optimal conditions of ethanol precipitation for exopolysaccharides (EPS) produced by Lactobacillus plantarum 70810 were investigated by one-factor-at-a-time experiments and response surface methodology. A mathematical model was developed to reveal the significant effects of each factor and their interactions on the yield of EPS. The optimal parameters for ethanol precipitation of EPS from Lactobacillus plantarum 70810 were 12.56 h precipitation time, 3.9:1 ethanol/fermentation supernatant ratio (V/V) and 3.54-fold condensation of fermentation supernatant. Under the optimal conditions, the model-predicted and experimental values of EPS yield were 323.11mg/L and 320.17 mg/L, respectively, with a relative error of 0.91%.
Optimization of Enzymatic Catalysis Conditions of Alliinase by Response Surface Methodology
ZHAO Yu-hui,WANG Jing,HU Qiu-hui,XIN Zhi-hong
2011, 32(19):  193-197.  doi:10.7506/spkx1002-6630-201119042
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The effects of different factors on the activity of alliinase purified from garlic cloves were investigated to optimize the reaction conditions of alliinase. On the basis of one-factor-at-a-time experiments, four factors affecting the activity of alliinase, including [E]/[S]ratio, pH, reaction temperature and ion concentration, were optimized by response surface methodology to maximize the reaction rate. Analysis of the experimental data conducted using Design Expert software indicated that optimal parameters were [E]/[S] ratio of 0.20, reaction temperature of 36 ℃, pH 6.4 and Mn2+ concentration of 8.15 mmol/L. Under these optimal conditions, the activity of alliinase was (0.156 ± 0.0053) U/mL. However, Cu2+ at the concentration of 10 mmol/L could reduce the initial activity of alliinase by 50%.
Nutrition & Hygiene
Protective Effect of Zinc Threonine against Liver Injury in Diabetic Rats
LI Chuan,ZHU Ke-xue,NIE Shao-ping,HU Xiao-bo,HUANG Dan-fei,XIE Ming-yong
2011, 32(19):  198-200.  doi:10.7506/spkx1002-6630-201119043
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Objective: To observe the effect of zinc threonine on antioxidant activity and function of liver in streptozotocin (STZ)-induced diabetic rats and probe the underlying mechanisms. Methods: Wistar rats were subjected to caudal vein injection of STZ to induce a diabetic model. The model rats were randomly divided into diabetic control group, metformin positive control group, and low-, middle- and high-dosage zinc threonine groups, and normal group. The activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and nitric oxide synthase (NOS) and the content of malondialdehyde (MDA) and nitric oxide (NO) in the liver homogenates of each group were determined after 8 weeks of administration carried out once a day. Meanwhile, the activities of serum ALT and AST and the content of TP were assayed. Results: Compared with the diabetic control group, MDA, NO, SOD, GSH-Px and liver index in the high-dosage zinc threonine group were obviously improved (P <0.05), and the effect of zinc threonine on ALT, AST, AST/ALT and TP were in a dose-dependent manner. Conclusion: Zinc threonine can protect the liver from oxidative damage and improve the liver function of diabetic rats.
Protective Effect of Chondroitin Sulfate from Sea Cucumber against Alcohol-induced Gastric Ulcer in Rats
LIU Yan-qing,LI Guo-yun,GAO Yan,MA Min,TANG Qing-juan,CHANG Yao-guang,XUE Chang-hu, LI Zhao-jie,
2011, 32(19):  201-204.  doi:10.7506/spkx1002-6630-201119044
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Objective: To explore the protective effect of chondroitin sulfate from sea cucumber against alcohol-induced gastric ulcer in rats. Methods: Thirty-two rats were randomized into 4 groups including model group, low dose group, medium dose group and high dose group. At the end of the 3rd day of administration, the ulcer bleeding, ulcer index, incidence rate and histological characteristics of each rat were evaluated. Results: Compared with the model group, the administration of chondroitin sulfate at low, medium and high doses could reduce bleeding area and ulcer index. Conclusion: Chondroitin sulfate from sea cucumber can significantly reduce bleeding area and ulcer index so that it has excellent preventive function of gastric ulcer.
Protective Effect of Water Extract from Mactra chinensis against Acute Hepatic Injury of Mice
WANG Xiao-jie,SHI Qian,ZHANG Chen-chen,WANG Shou-hai,LIU Xiao-chen,LIU Xin-sheng,QU Yan-qing
2011, 32(19):  205-208.  doi:10.7506/spkx1002-6630-201119045
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Objective: To explore the protective effect of water extract from Mactra chinensis muscle (WEMC) on CCl4-induced acute hepatic injury of mice. Methods: Mice were administered orally with the extract at the daily doses of 0.15, 0.45 g/(kg ·d)and 0.90 g/(kg ·d). Eight days later, 6% CCl4 were intraperitoneally injected at the dose of 1 mL/kg. At 24 h after the injection, liver index and the contents of serum alanine aminotransferase (ALT), total protein (TP), albumin (Alb) and globulin (Glb) as well as A/G were investigated. On the other hand, the pathological changes in the hepatic tissues of each group were determined. Results: WEMC at each dose significantly lowered ALT in serum (P <0.01). Meanwhile, the hepatic histology was also improved in three WEMC groups. Moreover, a significant increase in A/G was observed in each WEMC group when compared with the model group (P <0.01). WEMC had a pronounced promoting effect on the recovery of mouse liver function but had little effect on liver index. Under a light microscope, it could be observed that WEMC had a marked effect on improving hepatic injury in mice. Conclusion: EMC can protect CCl4-induced liver damage of mice.
Antioxidant Activity of Ablmoschus manihot Flower Ethanolic Extract and Its Inhibitory Effect on the Growth of Hela Cells
QIU Yan,SONG Jian-jun,WANG Shao-jie
2011, 32(19):  209-213.  doi:10.7506/spkx1002-6630-201119046
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Objective: To explore the antioxidant activity of Ablmoschus manihot flower ethanol extract (AFEE) and its growth inhibitory effect on HeLla cells. Methods: Fenton reaction, pyrogallol auto-oxidation and DPPH radical-scavenging systems were used for antioxidant evaluation of AFEE in vitro. The reducing power was evaluated by potassium ferricyanide assay. Growth inhibitory effect of AFEE on Hela cells was assessed by MTT assay. Results: The scavenging activity of AFE on hydroxyl, superoxide anion and DPPH free radicals increased as the total flavonoids concentration increased. The EC50 of AFEE in scavenging hydroxyl, superoxide anion and DPPH free radicals were 170, 20 mg/L and 8.7 mg/L, respectively. The reducing power of AFE was two-fold higher than that of vitamin C. The growth of HeLa cells was remarkably inhibited by AFEE in a dose-dependent manner and the IC50 of AFEE in inhibiting Hela cell growth was 228 μg/mL. Conclusion: AFEE shows strong antioxidant activity and good inhibitory effect against the growth of Hela cells, suggesting a potential to be used as a natural antioxidant agent.
Comparative Analysis and Evaluation of Nutritional Composition of Two Types of Maca Tablets
SUN Xiao-dong,DU Ping,SHAN Yun,YANG Jun, ZHANG Xian-jun,YAO Min,YANG Yong-wu,ZHANG Jing
2011, 32(19):  214-216.  doi:10.7506/spkx1002-6630-201119047
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Objective: To evaluate the difference and similarity of nutritional composition of two types of commercially available Maca tablets, processed using maca root tubes grown in Peru and Lijiang in Yunnan, respectively. Methods: The nutrients such as protein, amino acid, fat, fatty acid, crude fiber, vitamin and 10 kinds of mineral substances in both maca tablets were subjected to comparison according to the international standards. Results: Similar nutritional composition and contents in both maca tablets were observed. However, Lijiang Maca tablets revealed significantly lower contents of fat and iron than Peru maca tablets, and Peru maca tablets had higher levels of unsaturated fatty acids and arginine. Conclusion: Maca has a high nutritional potential so that it can be introduced and further exploited.
Anti-mutagenic Effect of Water-soluble Polysaccharide from Hippophae rhamnoides Leaves
LI Fang-liang,GAO Yang,LIU Ying,YANG Xin-yuan,WANG Rui
2011, 32(19):  217-219.  doi:10.7506/spkx1002-6630-201119048
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In order to explore the anti-mutagenic effect of water-soluble polysaccharides from Hippophae rhamnoides leaves (WPHL), the inhibitory effect of WPHL on bone mouse marrow cell micronuclei, abnormal sperm and hepatic DNA damage induced by cyclophosphamide (CP) was studied. The results show that WPHL at the dose of 50 mg/kg ·d significantly inhibited the frequency of micronucleus (P <0.05) and sperm abnormality (P <0.05). In addition, WPHL could also significantly decrease the number and tail length of hepatic comet cells (P <0.05). Therefore, WPHL has anti-mutagenic potential.
Anti-atherosclerotic Effect of Soybean Isoflavones in Rabbits
YIN Xue-zhe,XU Hui-xian,JIN Ai-hua,QUAN Ji-shu
2011, 32(19):  220-223.  doi:10.7506/spkx1002-6630-201119049
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The inhibitory effect of soybean isoflavones (ISF) on lipid peroxidation of serum lipoproteins in rabbits with atherosclerosis was studied. An atherosclerotic model was established by feeding rabbits high-fat diet. ISF at dosages of 100 and 50 mg/(kg ·d) and was added to the high-fat diet to create high dosage and low dosage treatment groups, and simvastatin at 2 mg/(kg ·d) added as a control. After 8 weeks of feeding, all rabbits were killed and aorta was collected, then HE staining was used to examine the pathological change during the formation of atherosclerosis. Serum lipoproteins were isolated to investigate the cholesterol (CH) level, lipid peroxidation (LPO) and the oxidation susceptibility of low-density lipoprotein (LDL). The results showed that ISF administration suppressed the formation of atherosclerotic plaques, reduced the levels of plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-CH) in atherosclerotic rabbits, decreased the LPO level of serum lipoproteins, and prolonged the lag phage of LDL oxidation in vitro. These results suggested that ISF could reduce cholesterol level, decrease the lipid peroxidation of LDL, and promote resistance to LDL oxidation, which may be useful in the prevention and treatment of atherosclerosis.
Anti-fatigue Effect of Polysaccharides from Campanumoea javanica B1 in Mice
PENG Mei,ZHANG Zhen-dong,YANG Juan
2011, 32(19):  224-226.  doi:10.7506/spkx1002-6630-201119050
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The anti-fatigue effect of polysaccharides from Campanumoea javanica B1 (CJPs) was explored. Random mice grouping was carried out to create 4 groups including control group and polysaccharide groups at low, medium and high doses (100, 200, 400 mg/(kg ·d)). All groups were treated by gavage for 21 consecutive days. The pole-climbing time, loaded swimming time, and the contents of blood lactic acid, blood urea nitrogen and liver glycogen were measured. The results showed that CJPs could significantly prolong the pole-climbing time and loaded swimming time of mice, reduce the contents of blood lactic acid and blood urea nitrogen, and improve the content of liver glycogen when compared with the control group (P<0.05). Therefore, CJPs have an excellent anti-fatigue effect.
Effect of Sphallerocarpus gracilis Polysaccharides on Proliferation Inhibition and Apoptosis of Sarcoma HepG2 and Mouse Lymphocyte Leukemia P388
JIA Lei,NIE Xiu-juan,FANG Mei
2011, 32(19):  227-231.  doi:10.7506/spkx1002-6630-201119051
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Objective: To explore the effect of Sphallerocarpus gracile polysaccharides (SGP) on apoptosis induction and proliferation inhibition of HepG2 and P388 cells as well as the lifespan extension of mice treated with SGP. Methods: HepG2 and P388 cells were co-cultured in the presence of SGP in this study. The inhibitory effect of SGP at different concentrations on the proliferation of HepG2 and P388 was evaluated by MTT assays. The SGP-induced apoptosis and cell cycle change of HepG2 and P388 were analyzed by flow cytometry. Meanwhile, the extension of lifespan of P388 mice treated with SGP was determined. Results: SGP revealed a significant anti-proliferation effect on HepG2 and P388 in vitro. The inhibition rate of SGP treatment for 48 h at the concentration of 200 mg/(kg ·d) against HepG2 was 37.5% (P<0.01). The inhibition rates against P388 at 150 and 200 mg/(kg ·d) after 48 h of treatment were both over 38% (P<0.01). In addition, SGP obviously inhibited the growth of implanted HepG2 in mice with an inhibitory rate of higher than 40%. Moreover, SGP induced the apoptosis of HepG2 and block HepG2 at the G1 phase. Furthermore, SGP prolonged the life of P388-bearing mice with a lifespan extension rate of 10%. Conclusion: SGP has an outstanding anti-cancer effect in mice and can effectively inhibit the proliferation of HepG2 and P388 cells and induce the apoptosis of HepG2 cells.
Effect of Ganoderma lucidum Spore Oil on Activities of SOD and CAT and mRNA Expression Levels of C3 and P21 in Mice
HU Shun,YI You-jin,, XIONG Xing-yao, XIA Yan-bin,ZHONG Ying-li,WANG Xiu
2011, 32(19):  232-235.  doi:10.7506/spkx1002-6630-201119052
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Objective: To explore the immunoregulation effect of Ganoderma lucidum spore oil in aged mouse models induced by D-galactose and its anti-aging mechanisms. Methods: Aged mice were intragastrically administered with Ganoderma lucidum spore oil for 45 consecutive days to examine the change of SOD activity, CAT activity, spleen index and thoracic gland index. Meanwhile, the mRNA expression levels of C3 and P21 in mouse spleen and thymus were determined by semi-quantitative RT-PCR. Results: The SOD activity and CAT activity in DB (D-galactose + Ganoderma lucidum spore oil) group were much higher than those in DY (D-galactose + corn oil) group (P≤0.05). The spleen index and thoracic gland index in DB group were higher than those in DY group (P≤0.01). The mRNA expression levels of C3 in spleen and thymus was significantly higher in DB group than those in DY group (P≤0.05); similarly, the thymus mRNA expression levels of C3 in SB (normal saline + Ganoderma lucidum spore oil) group was significantly higher than that in SY (normal saline + corn oil) group (P≤0.05). Spleen P21 mRNA expression level was significantly lower in DB group compared with DY group (P≤0.05) and in SB group compared with SY group (P≤0.05). Conclusion: Ganoderma lucidum spore oil can improve spleen index and thoracic gland index, SOD activity and CAT activity. It also can stimulate the expression of C3 and inhibit the expression of P21, which may be one of the antioxidant mechanisms of Ganoderma lucidum spore oil.
Hypoglycemic Effect of Refined Corn Bran with Different Treatments in STZ-induced Diabetic Mice
LI Qin-qin, GENG Xin
2011, 32(19):  236-239.  doi:10.7506/spkx1002-6630-201119053
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Objective: To explore the preventive effect of refined corn bran with different treatments on hyperglycemia in diabetic mice induced by streptozocin (STZ). Methods: Refined corn bran (RCB) after removing starch and protein was treated by acid and alkali, respectively to obtain an acidic hydrolysate (HAC) and an alkaline hydrolysate (HAL). After being fed standard diet alone or with the respective additions of RCB, HAC and HAL for 21 consecutive days, mice were subjected to multiple low-dose STZ injections for creating a diabetic mouse model except the normal group. The body weight, food intake, blood glucose, physical activity and liver index in each mouse were examined. Results: Compared with the control group, HAC and HAL could significantly suppress the reduction of body weight (P<0.05), increase physical activity, and delay fatigue in diabetic mice. In addition, HAC could significantly decrease blood glucose in the liver of diabetic mice (P<0.05), whereas, GSH and SOD levels were obviously increased. Moreover, HAC could also increase glycogen level remarkably and decrease MDA level in the liver. Conclusion: HAC can effectively prevent the increase of blood glucose and the reduction of body weight in STZ-induced diabetic mice and the mechanisms might be correlated to the increase of antioxidant activity and maintenance of liver glycogen in diabetic mice.
Anti-oxidative Stress Effect of Water-soluble Soybean Dietary Fiber on the Kidneys of Hyperlipemic Mice
JIANG Su-wei,PAN Li-hua,XU Xue-ling,LUO Jian-ping
2011, 32(19):  240-243.  doi:10.7506/spkx1002-6630-201119054
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Objective: To explore the anti-oxidative stress effect of water-soluble soybean dietary fiber (WSSDF) prepared by ultrasound-assisted extraction (UAE) or alkali extraction (AE) on the kidneys of hyperdipemic mice. Methods: Kuming male mice were randomly divided into 8 groups. The mouse groups were fed a normal diet or a high fat diet alone or supplemented with WSSDF (400, 200mg/(kg ·d) and 100 mg/(kg ·d)) derived from UAE and WSSDF (400, 200 mg/(kg ·d) and 100 mg/(kg ·d)) derived from AE, respectively. After 15 consecutive days of intrasgastric SDF administration, serum TC, TG, HDL-C and LDL-C and kidney MDA, H2O2, GSH, GST, SOD and CAT were determined. Results: Compared with the model group, both WSSDFs derived from UAE and AE could decrease the contents of GST, MDA and H2O2, increase the activities of GSH, SOD and CAT in the kidneys of hyperdipemic mice. Conclusion: WSSDF can improve antioxidant stress in kidney of hyperdipemic mice in a dose-dependent manner and UAE results in a slight increase of the activity of WSSDF when compared with AE.
Effects of trans-Fatty Acids on Damage of Human Umbilical Vein Endothelial Cells
YU Hua-hong,LIANG Zhong-shuang,LI Xiang-mei,QIU Bin,LIU Rong,LI Jing,DENG Ze-yuan
2011, 32(19):  244-247.  doi:10.7506/spkx1002-6630-201119055
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The effects of trans-linoleic acid and trans-oleic acid on survival rate, nitric oxide synthase (NOS) activity, nitric oxide (NO) production and lactate dehydrogenase (LDH) leakage of human umbilical vein endothelial cells was studied to explore the mechanisms by which trans-fatty acids promote atherosclerosis. The results showed that both trans-fatty acids could inhibit cell proliferation through reducing NOS activity and NO secretion, increasing LDH leakage, and decreasing the vasodilation capability, thus affecting the cell oxidative stress level. Moreover, trans-linoleic acid revealed stronger cell damage than trans-oleic acid.
Separation and Purification of Black Soybean Peptide and Its Hypolipidemic Effect in Mice
LIU En-qi,WU Yong-hua, ZHANG Jian-ping, CHEN Zhen-jia, LI Yu-e
2011, 32(19):  248-252.  doi:10.7506/spkx1002-6630-201119056
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Macroporous adsorption resin DA201-C was used for the isolation of hypolipidemic peptides from black soybean protein hydrolysate. The inhibitory rates of cholesterol micelle solubility (CMSIR) by all fractions were determined, and the hypolipidemic effect of the fraction with the highest CMSIR was evaluated in mice. The results showed that black soybean peptides were eluted from DA201-C resin according to its hydrophobicity through gradient ethanol elution. The peptide fraction eluted by 75% ethanol displayed the highest CMSIR of 62.1% when the concentration of peptide fraction was 5 g/L. After administration of the peptide at the dose of 1000 mg/(kg ·d) for 30 days in mice, the levels of serum TC, TG and LDL-C and VLDL-C were obviously decreased (P <0.01) when compared with the mice fed hypercholesterolemia diet.
Effects of N-Carbamyl-L-glutamic Acid and Arginine in Diet on Growth Performance of Weaning Mice
HUANG Xin-qiu,WANG Yuan-xing,YANG You-xian,LI Chang,ZHU Ke-xue,SHU Xiang,ZHU Sheng
2011, 32(19):  253-257.  doi:10.7506/spkx1002-6630-201119057
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Objective: To investigate the positive effect of N-carbamyl-L-glutamic acid (NCG) and arginine in diet on the growth performance of weaning mice. Methods: First, 0.025%, 0.05% and 0.1% NCG was added in the diet of weaning mice to explore the effect of NCG on the growth performance of weaning mice. Moreover, the diet containing 0.05% NCG combined with arginine at the concentrations of 0.025%, 0.05% and 0.1% was also used to explore the growth performance of weaning mice. Results: The addition of 0.1% NCG in the diet of weaning mice could increased the average daily weight gain by 12.40% and reduce the feed/gain ratio by 14.65% when compared with the control group. Simultaneous additions of 0.05% NCG and 0.025% arginine could result in a 10.53% increase of average daily weight gain when compared with the control group. Conclusion: The addition of 0.1% NCG in diet can significantly improve the growth performance of weaning mice. Simultaneous additions of 0.05% NCG and 0.025% arginine can also significantly improve the growth performance of weaning mice, with the same efficiency as that of 0.1% NCG alone.
Composition Analysis and Immunological Functions of Enzymatic Hydrolysates of Lentinus edodes and Oyster Mushroom Prepared with Papain
AI You-wei,LIU Chao-qun,CHEN Yan-li,WANG Hong-xun
2011, 32(19):  258-261.  doi:10.7506/spkx1002-6630-201119058
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On the basis of our previous work concerning the preparation of edible fungi beverage, the composition and immunological functions of Lentinus edodes hydrolysate and oyster mushroom hydrolysate prepared by papain hydrolysis were investigated. The results showed that after the hydrolysis, the yields of proteins, polysaccharides and amino acids in hydrolysates from both mushroom species were all over 74%, especially polysaccharides with the highest yield. The immunological function experiments showed that both hdyrolysates could notably increase phagocytic index, thymus index and spleen index when compared with the blank control group. This suggests that the they have immunological functions due to the presence of polysaccharides. This study preliminarily indicates that edible fungi beverage can partially replace edible fungi intake.
Toxicological Studies on Compound Theanine Preparation
TAN Jun-feng, LIN Zhi,LI Liang
2011, 32(19):  262-267.  doi:10.7506/spkx1002-6630-201119059
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The edible safety of theanine was investigated according to Standard of Health Food Test and Assessment. Acute toxicity test in mice showed that the maximum tolerance dose (MTD) was higher than 20 g/kg. All three genetic tests including Ames test, mouse bone marrow micronucleus test and mouse teratospermia test showed negative results. Thirty-day feeding test showed that physical appearance and the indices of hematology, biochemistry and organ coefficients of rats had no significant difference when compared with those in the control group. All these results suggest that compound theanine preparation is highly safe with neither acute toxicity nor genotoxicity.
Inhibitory Effect of Ethanol Extract from Propolis on Maltase and Sucrase in Rat Intestinal Tract
WANG Guang-xin, DONG Jie, ZENG Xiao-xiong, ZHANG Hong-cheng
2011, 32(19):  268-272.  doi:10.7506/spkx1002-6630-201119060
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In order to explore the control effect of ethanol extract from propolis (EEP) on postprandial blood glucose, propolis was extracted by ethanol with various concentrations. The contents of total flavonoids and total phenols in EEPs were analyzed by high performance liquid chromatography (HPLC). The inhibitory effect of EEPs on sucrase and maltase in rat intestinal tract was also investigated. The results indicated that EEP extracted by 75% ethanol revealed the highest content of total flavonoids, which was (697.36 ± 6.15) mg rutin/g EEP. However, EEP extracted by 25% ethanol had the highest content of total phenols, which was (386.50 ± 17.40) mg gallic acid/g EEP. Moreover, the EEP extracted by 75% ethanol showed the highest anti-sucrase activity with IC50 of (32.30 ± 0.60) μg/mL. In contrast, the aqueous extract of propolis exhibited the highest anti-maltase activity with IC50 of (32.60 ± 0.20 )μg/mL). Compared with the positive control group, the IC50 of each EEP against sucrase from rat intestinal tract exhibited a significant decrease (P < 0.05).
Functional Evaluation of Complex Codonopsis pilosula/Accinium vitis-idaea Drink in Protecting Mitochondria against Damage in vitro
LI Xing-tai,DU Chun-yu,LIU Yu-qing,LIU De-wen,JIN Feng-xin,ZHANG Ya-kui,KUANG Hai-xue
2011, 32(19):  273-278.  doi:10.7506/spkx1002-6630-201119061
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Objective: To explore the health benefits of Codonopsis pilosula/Vaccinium vitis-idaea drink (CVD) through evaluating its reactive oxygen species (ROS) scavenging capacity and protective effect on mitochondrial damage. Methods: The functional factors of CVD total flavonoids and Codonopsis polysaccharide were determined by AlC13 colorimetry and sulfuric acid-phenol method respectively. Lipid peroxidation in liver and brain mitochondria was induced by Fe2+-vitamin C in vitro. TBA colorimetry was used to measure the content of thiobarbituric acid reactive substance (TBARS). The scavenging activities of CVD against superoxide anion free radicals (O2- ·) generated in reduced nicotinamide adenine dinucleotide (NADH)-N-methylphenazonium methyl sulfate (PMS) system and hydroxyl free radicals ( ·OH) generated in hydrogen peroxide (H2O2)-Fe2+ system were measured by NBT reduction and Fenton reaction colorimetry, respectively. The Na2S2O3 titration method was used to measure the H2O2 scavenging activity of CVD. Permeability transition (PT) of liver mitochondria in rats was induced by Ca2+ in vitro and measured spectrophotometrically. Results: The contents of total flavonoids and Codonopsis polysaccharide in CVD were (95.2 ± 6.3) μg/mL and (7.5 ± 0.4) mg/mL, respectively. Mitochondria incubated at a given temperature with Fe2+-vitamin C system couldresult in an obvious increase of TBARS. CVD could inhibit TBARS production and significantly scavenge O2- ·, ·OH and H2O2 in a dose-dependent manner within a certain concentration range. CVD could protect mitochondria from PT induced by Ca2+. Conclusion: The protective effect of CVD on mitochondrial damage can be achieved by antioxidation and scavenging ROS. Therefore, CVD has a heath-promoting effect.
Reviews
Research Progress in Physiological Functions and Stability of Lycopene
LUO Jin-feng,REN Mei-yan,CHEN Jing-xin,DING Xiao-wen
2011, 32(19):  279-283.  doi:10.7506/spkx1002-6630-201119062
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As a natural pigment, lycopene has a variety of physiological activities. Currently, lycopene is a hot research point in the functional food, pharmaceutical, cosmetic fields and others. However, lycopene has a special unsaturated structure and poor stability so that it is easy to degrade and isomerize, which reveals the limitation of lycopene. In this paper, basic properties, physiological functions and stability of lycopene are summarized. Meanwhile, some methods for providing lycopene stability are also proposed with the aim of provide useful information for the application of lycopene.
Relationship between Post-harvest Physiological Disorders and Ultra-structural Change of Citrus Peel
CUI Wen-jing,LIU Li-dan,ZENG Kai-fang
2011, 32(19):  284-287.  doi:10.7506/spkx1002-6630-201119063
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Due to inappropriate environmental factors causing physiological metabolism disorders, post-harvest citrus fruits during storage can produce a number of physiological disorders including chilling injury, oleocellosis, rind pitting and edema. These physiological disorders can reduce the sensory quality, storability and edible quality of fruits. In this paper, the relationships between major physiological disorders of citrus peel and the changes of cell membrane, cell wall and subcellular structures are reviewed. Meanwhile, the ultra-structural changes of citrus peel during the occurrence of these physiological disorders are discussed for the purpose of providing a theoretical basis for exploring the mechanisms and control methods of physiological disorders in citrus fruits.
An Overview of Standards and Techniques for Beef Grading
TANG Xiao-yan WANG Min QIAN Yong-zhong MAO Xue-fei SUN Bao-zhong ZHOU Guang-hong
2011, 32(19):  288-293.  doi:10.7506/spkx1002-6630-201119064
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The beef industry has a relatively late start in China compared with developed countries. The quality of our native beef is low and high-grade products are too few to meet the increasing requirements of today,s domestic market. The lack of a practical uniformed beef grading system also results in a poor system for beef marketing so that beef products with good quality and favorable price are still not commercially available. All of these issues largely limit the development of our native beef industry. However, the beef industry in developed countries has a better grading system for fitting well with domestic manufacturing conditions, which can ensure the healthy development of beef industries for dozens or even hundreds of years. In this paper, the research progress in beef grading system and corresponding automatic techniques adopted in developed countries is discussed. Meanwhile, some suggestions are also proposed for the research and development of beef grading system suitable for our current conditions in China.
Graphic Expression Methods of Food Flavor
ZENG Fan-bin,PAN Si-yi
2011, 32(19):  294-297.  doi:10.7506/spkx1002-6630-201119065
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In order to explore the relationship between the concentrations of flavor compounds in foods and their sensory scores. The geometric figures of main flavor components in foods are usually established through mathematical modeling. The food flavor can be expressed more intuitively. Five flavor figures are discussed in this article. The change of flavor substances can be studied qualitatively and quantitatively. The flavor compounds corresponding to foods with the best flavor can be explored by mathematical methods. The advantages and disadvantages of geometric figures for flavor are also evaluated.
Research Progress in the Quality of Rabbit Meat and Its Factors
CHEN Li-qing,HAN Jia-dong,MA Liang,ZHANG Yu-hao
2011, 32(19):  298-301.  doi:10.7506/spkx1002-6630-201119066
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Based on a summary of the nutritional quality of rabbit meat, we analyze the effects of varieties, sex, age, body weight, feeding management, slaughtering process, post-mortem storage and cooking conditions on the quality of rabbit meat in order to provide beneficial guidance for the quality control and consumption of rabbit meat, rabbit breeding and meat product manufacturing.
Recent Advances in Pollution Situation and Novel Detection Technology of Four Foodborne Pathogenic Bacteria
WEI Ling,WU Hui-juan,LI Bao-ming,LI Yue,JIANG Su-juan
2011, 32(19):  302-306.  doi:10.7506/spkx1002-6630-201119067
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E. coli O157:H7, Listeria monocytogenes, Staphylococcus aureusenes and Salmonella are important foodborne pathogens with high environmental resistance. Foodborne infection has become a very important hygienic problem because of the rapid expansion of food trade and highly increased mobility of today,s populations. Therefore, the detection of these bacterial contaminatants in foods is very important for public health. Traditionally, the detection of foodborne pathogens involves sample collection, enrichment, and isolation of the target organism on selective and/or indicator media. Such culture-based approaches are less sensitive, less specific and time-consuming, which require 48-96 h from sample collection to final results. Therefore, a sensitive, specific and rapid assay for the detection of these pathogens is highly desired. In this paper, the current pollution situation of the four pathogenic bacteria above is reviewed, and seven novel detection technologies such as PCR, SPR, biosensor, immune identification, immunomagnetic separation and capillary electrophoresis are summarized.
Research Advance in Hypolipidemic Effect and Mechanism of Dark Tea
WU Chao-bi,HUANG Jian-an,LIU Zhong-hua,WANG Jun
2011, 32(19):  307-311.  doi:10.7506/spkx1002-6630-201119068
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Dark tea is a traditional and unique tea product in China and has become a research topic of high interest in recent years due to its significant hypolipidemic effect. Meanwhile, dark tea also has the capability to regulate hyperlipidemia; however, its hypoliplidemic mechanism is complex. In this paper, the regulation of hyperlipidemia and the hypolipidemic mechanism of dark tea are reviewed.
Research Advance in Biotransformation and Utilization of Citrus Peels
SUN Jin-hui,CHEN Hai-gui,LU Yan-gang,SHANG Yong-biao
2011, 32(19):  312-315.  doi:10.7506/spkx1002-6630-201119069
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Citrus peels have a great biological transformation value for producing fuel ethanol, methane, feed, foods and food additives. Their biological transformation by organisms or enzymes can result in the re-use of resources, improve the utilization of citrus byproducts, and also can make a contribution to the development of new biotransformation products. In this paper, the current biotransformation and utilization of citrus peels are introduced. Meanwhile, new research directions are also discussed.
Research Progress of Determination Methods for β-Glucanase Activity
ZHANG Yong-qin,ZENG Fan-wei
2011, 32(19):  316-320.  doi:10.7506/spkx1002-6630-201119070
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In this paper, the present determination methods for β-glucanase activity are reviewed, which includes viscometric method, chromomeric method, agar diffusion method, and commonly used end-reducing methods such as DNS, Somogyi-Nelson and BCA methods, as well as novel MBTH method. In addition, the end-reducing methods are classified as end-point method, multiple-point method, microplate method, and flow injection analytic method according to the operation procedures. Meanwhile, current problems with these methods are discussed, and the future development trends of the determination methods are proposed.