Volume 30,Issue 6,2014 Table of Contents

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  • 1  Sol - gel Transition Properties of Soy Protein -dextran Blend Based on Color Dynamic Monitoring
    ZHU Jian-hua YANG Xiao-quan QI Jun-ru YANG Xiao-min
    2014, 30(6):1-6.
    [Abstract](1334) [HTML](0) [PDF 696.83 K](769)
    Abstract:
    A novel method to quantitatively analyze initial gelation time, whole gelation time and gelation velocity of GDL induced soy protein isolate (SPI)/dextran (DEXT) blends solution sol-gel transition process was proposed with dynamic luminance determination. A Boltzmann function model depending on blends luminance (L*) - gelation time(t) was established as L*=L*2+(L*1-L*2)/{1+exp[(t-tg)/dt]},which had a clear physical meaning for parameters of this equation. The effect of -SPI-g-DEXT amount (0-0.50%) on sol-gel transition properties of SPI/DEXT was investigated with the above equation. Compared to the control sample,incorporation of 0.20% (m/m) SPI-g-DEXT led to the delay of the initial gelation point by 1.07±0.21 min and extend the time threshold of sol-gel transition process to1.34±0.16 min, while reduce the average gelation velocity amplitude about 10.5%. Further increase in the SPI-g-DEXT amount to 0.30%~0.50% (m/m) shorted the initial gelation point and the time threshold of sol-gel transition process, but increased the average gelation speed, which was mainly due to space steric hindrance beyond compatibilizing effect produced by relatively higher SPI-g-DEXT amount. In addition, the trends of the above three parameters could be exacerbated with the SPI-g-DEXT amount increase.
    2  Apoptotic Mechanism in Human HT-29 Colon Cancer Cells Induced by Total Flavones from Trollius chinensis Bunge
    SONG Jia-le LI Gui-jie ZHAO Xin
    2014, 30(6):7-12.
    [Abstract](1340) [HTML](0) [PDF 552.04 K](743)
    Abstract:
    The mechanism of the ethanol extract of the total flavones from Trollius chinensis Bunge (TFETC) inducing apoptosis in HT-29 human colon cancer cells was investigated. MTT assay, which is used to determine the anti-proliferation effect to cancer cells, showed that TFETC inhibited the proliferation of HT-29 cells in a dose-dependent manner, and the inhibitory rate was 81% when treated with 200 μg/mL TFETC. 4,6-diamidino-2-phenylindole (DAPI) staining. Flow cytometry analysis showed that 200 μg/mL TFETC induced apoptosis of HT-29 cells and the sub-G1 DNA content was 28.9%. Reverse transcription polymerase chain reaction (RT-PCR) was applied to evaluate the impact of TFETC on mRNA expression levels of Bcl-2, Bcl-xL, Bax, caspase-9, caspase-3 and COX-2 in HT-29 cells. The results showed that TFETC reduced the mRNA expression levels of anti-apoptosis genes Bcl-2 and Bcl-xL, and up-regulated the mRNA expression of pro-apoptosis genes Bax, caspase-9, and caspase-3 in HT-29 cells. Moreover, TFETC down-regulated the mRNA expression of COX-2 in HT-29 cells in a dose-dependent manner. These results indicated that TFETC could induce the apoptosis through an intrinsic mitochondria pathway in HT-29 cells. Meanwhile, TFETC could reduce cell proliferation through down-regulating the gene expression of COX-2.
    3  Intervention Effect of Chimonanthus nitens Oliv. Leaf Extract on the Adipose Tissue of Mice
    CHEN Lan LI Guang-nan HE Lei LI Xiao-fei DING Hong
    2014, 30(6):13-17.
    [Abstract](1209) [HTML](0) [PDF 596.18 K](663)
    Abstract:
    The in vitro screening experiment found that Chimonanthus nitens Oliv. leaf alcohol extract and volatile oil significantly inhibited the activity of fatty acid synthase (FAS). During the in vivo experiments, mice were divided into normal group, intake-control group, high-dose of alcohol extract group, low-dose of alcohol extract group and volatile oil group whose weight and food intake were recorded every two days. The mice were killed after 30 days and a series of obesity indicators were measured to calculate Lee’s index, fat index and index of each viscera. The fat in mice was studied through hematoxylin-esoinstaining. Results indicated that Chimonanthus nitens Oliv. leaf extract affected the synthesis of body fat, which probably due to the inhibition of FAS and interference in the accumulation of fat. High-dose of alcohol extract group and volatile oil group greatly decreased by 7.19% and 6.96% respectively compared with normal group, fat index decreased by 42.04% and 36.73% respectively, TG decreased by 41.34% and 32.96% respectively, and TC decreased by 20.83% and 14.58% respectively. Moreover, the visceral index showed that the extracts had no significant toxic effects to the mice.
    4  Antitumor Activity of Glycosaminoglycan from Crassostrea rivularis
    WU Hong-mian FAN Xiu-ping HU Xue-qiong LIU Qian JIANG Yang
    2014, 30(6):18-23.
    [Abstract](918) [HTML](0) [PDF 677.04 K](610)
    Abstract:
    The anti-tumor activity of glycosaminoglycan from Crassostrea rivularis (CG) in vivo and in vitro was studied in this paper. MTT method was used to detect the effect of CG on the growth of K562, CNE-2Z and Hela cells in vitro. Through the method of animal transplant tumor screening in vivo, the effects of CG on the growth of S180, EAC and L 1210 tumors in mice were observed. The results showed that the fractions of CG, CGIa and CGIIa could inhibit the growth of K562, CNE-2Z and Hela cells (p<0.05), and when combined with 5-Fu the efficiency of anti-tumor increased. IC50 of CGIa on K562 and CNE-2Z cells in 72h were 1.95 mg/L and 7.36 mg/L respectively. In vivo, CG had remarkable inhibitory effect on growth of S180 tumor. The inhibitory ratio increased from 44.66% to 67.96% when combination with CTX. The immune injury by CTX could be repaired by CG. The life prolonging rate of mice transplanted with EAC and L1210 tumor while treated by CG combination with CTX were 50.27% and 55.27%. The results showed that glycosaminoglycan from Crassostrea rivularis had anti-tumor activity.
    5  Isolation, Determination and Antibiotic Resistant of Food-born Providencia spp.
    SHI Lei LIANG Si-si Shima A Yamasaki S YAN He
    2014, 30(6):24-29.
    [Abstract](1111) [HTML](0) [PDF 523.77 K](1036)
    Abstract:
    The objective of this study was to identify the Providencia spp. that isolated from three kinds of different meat and their antibiotic resistance performance was also investigated. API20E system was used to determine and identify the isolates from pork, chicken and beef. And Kirby-Bauer was applied to detect the antibiotic resistance of Providencia spp. Subsequently, Providencia spp. was screened by PCR for class ? integron. The results showed that 38 samples were Providencia spp. positive in 85 samples, and the relevance ratio was 44.70%. Moreover, 44.74% of positive Providencia spp. was multiple resistant and some of them resisted up to six kinds of antibiotics. Two isolates showed class ? integrase positive, and one isolate of Providencia rustigianii was found carrying gene cassette. These isolates with multiple resistances in the food may be transferred to human by food chains, and then become a potential threat for human health.
    6  Spectroscopic Studies on the Interaction of Rutin and Lysozyme
    CUI Li-jian QU Ling-ling YANG Wen-yue DOU Yu-hong JIAO Ning HUANG Yun
    2014, 30(6):30-35.
    [Abstract](1372) [HTML](0) [PDF 718.02 K](860)
    Abstract:
    The interaction of rutin with lysozyme (LYZ) was studied in simulating physiological condition (pH 7.40) at 298 K, 304 K and 310 K by ultraviolet-vis (UV) absorption and fluorescence spectroscopy. The results showed that rutin quenched the endogenous fluorescence of LYZ via a static quenching procedure and the interaction between them was a spontaneous process. The number of binding sites was approximately 1. Van der Waals' forces and hydrogen bonds played major roles in stabilizing rutin-LYZ complex, and the distance between the donor and acceptor was 4.02 nm (298 K). The UV absorption, synchronous fluorescence and three-dimensional fluorescence spectra showed that the conformation of LYZ became more tightly packed. The turbidimetric analysis showed that rutin decreased LYZ activity. Rutin may be bad for the hydrogen-bonding receptor catalysis activity of Asp-52 by affecting the micro-environment of lysozyme activity site (Asp-52).
    7  Effects of Wheat Gluten Protein Peptides on the Fermentation Performance of Yeast under Super High Gravity Brewing
    ZHAO Mou-ming MO Fen ZHAO Hai-feng LIU Feng-yuan
    2014, 30(6):36-41.
    [Abstract](1219) [HTML](0) [PDF 655.33 K](853)
    Abstract:
    Effects of wheat gluten protein peptides with different molecular weights (Mws) on propagation and fermentation performance of brewer’s yeast were studied. Results showed that peptides with different Mws varied in propagation and fermentation-promoting activity for yeast strains under the super high gravity brewing. Peptides WGP-III (Mw < 3 ku) showed the highest propagation-promoting activity and promoted yeast fermentation significantly. The initial free amino nitrogen (FAN) of WGP-? (Mw = 5~10 ku), WGP-II (Mw = 3~5 ku) and WGP-III increased by 27%, 33% and 47% respectively compared with CK. WGP-III increased the maximum FAN level, and at the end of the fermentation, FAN utilization was 58%, which was increased by 11% compared with the CK. Supplement of these peptides during fermentation resulted in the increase of biomass,fermentation ethanol yield and the utilization rate of FAN by 30%, 5% and 11%, respectively. Moreover, the small molecular peptides (Mw < 3 ku) had more reasonable proportion amino acids, and the total alcohols increased by 68%, the total esters decreased by 17%, which made them bring more harmonious taste.
    8  Storage Quality Changes and Correlation Analysis of Rice after Low Temperature Released
    ZHOU Xian-qing WANG Ling-zhao ZHANG Yu-rong LUN Li-fang ZHANG Zhi-chao CUI Yan-ke
    2014, 30(6):42-46.
    [Abstract](1212) [HTML](0) [PDF 536.87 K](928)
    Abstract:
    In order to investigate the quality changes of rice after low temperature storage, the quality indexes, such as malondialdehyde content (MDAC), fatty acid value (FAV), falling number, electrical conductivity rate (ECR), peroxidase (POD) and polyphenoloxidase (PPO) were measured for samples stored in the stimulated high temperature environments of the typical rice storage areas in China (35 ℃, 80% RH and 30 ℃, 70% RH), and rice stored at ambient temperature was used as the control. Then the correlation between quality indexes and eating quality of rice were analyzed and a prediction model for eating value was established. The results showed that after low temperature storage was released, the activity of POD and PPO decreased with the time prolonging, while the FAV, ECR and the falling number increased. The MDAC of rice increased at first and then decreased. Under the stimulated conditions, the rice quality changed fast, which was not suitable for rice storage. The shelf-life of rice in the 35 ℃ with 80% RH, 30 ℃ with 70% RH conditions and ambient temperature was 75 d, 100 d and 175 d, respectively. The verification test of rice quality showed that the model was credible.
    9  Effect of Storage Microenvironment on the Variation of Wheat Protein
    WANG Ruo-lan LIU Xiao-lin ZHAO Yan LIU Li MA Yu-jie
    2014, 30(6):47-51.
    [Abstract](1498) [HTML](0) [PDF 532.08 K](724)
    Abstract:
    Wheat was stored in four different storage microenvironments, which were simulated the four main wheat-growing areas, Meng-Xin, north China, central China, south China (15 ℃, 50% RH; 20 ℃, 65% RH; 28 ℃, 75% RH, 35 ℃, 85% RH), the variation law of wheat protein composition and content of sulfhydryl and disulfide was explored in this paper. It was showed that in each treatment group, the impact of storage time on the total protein content was not significant (P> 0.05). At the end of storage period (240 d), compared to the low temperature and humidity (15 ℃, 50% RH) condition, wheat gliadin and sulfhydryl content stored under the other three storage conditions were reduced 2×10-4, 1×10-4, 1.2×10-3 g/g and 0.13, 0.55, 0.75 mol/g, respectively, while gluten and disulfide content were increased 5×10-4, 1.3×10-3, 2.4×10-3 g/g and 0.22, 0.27, 0.42 mol/g, respectively. Under high temperature and humidityconditions (35 ℃, 85% RH), the gliadin, gluten, sulfhydryl and disulfide content of wheat changed significantly (P <0.05), leading to the increase of gluten/gliadin proportion and oxidate more free sulfhydryl to disulfide bond. At low temperature and humidity (15 ℃, 50% RH), the wheat protein was more stable and might store safely.
    10  Fatty Acids and Stable Carbon Isotope Ratios in Cordyceps militaris
    GUO Lian-xian LIANG Fu-rui LIANG Yi WANG Jiang-hai
    2014, 30(6):52-58.
    [Abstract](1569) [HTML](0) [PDF 736.96 K](912)
    Abstract:
    This paper aims to study the fatty acid composition and stable carbon isotope ratios as well as their variational trends of several substitutes of Ophiocordyceps sinensis. Firstly, the stable carbon isotope ratios of eight substitutes of Ophiocordyceps sinensis, including six kinds of Cordyceps militaris and two kinds of Cordyceps mycelium, and one stroma sample of Ophiocordyceps sinensis were determined by elemental analysis-isotope ratio mass spectrometry (EA-IRMS). Then, the neutral and polar lipids were effectively extracted from the samples by a chemical saparation method, and their fatty acid compositions were measured by chromatography mass spectrometry (GC-MS). Finally, the measured data was compared with our previously-published data of Ophiocordyceps sinensis. Evident differences were found among different substitutes of Ophiocordyceps sinensis in their stable carbon isotope ratios, fat contents and fatty acid compositions. The contents of fat and unsaturated fatty acids in the substitutes were lower than those of Ophiocordyceps sinensis, exhibiting the irreplaceability of Ophiocordyceps sinensis. Results also showed that the stable carbon isotope ratios and fatty acid composition might be two important markers to discriminate the adulteration among the substitutes of Ophiocordyceps.
    11  Homology Modeling of Anti-carbaryl ScFv and Molecular Simulation Study between ScFv and Its Antigen Carbaryl
    HE Kuo ZHANG Xiu-yuan DU Xin-jun WANG Jun-ping ZHOU Xiao-nan
    2014, 30(6):59-63.
    [Abstract](1149) [HTML](0) [PDF 525.87 K](714)
    Abstract:
    Functions of antibody are determined by its structure. However, the interaction mechanism is still not known since no carbaryl antibody crystallization was analyzed, which severely affects its application in ELISA detection. This study aimed to predict the 3D structure and binding mode of anti-carbaryl scFv with antigen. The molecular modeling and docking technology were employed by utilizing relative bioinformatics tools and on-line resources. The results showed a hydrophobic groove was formed by H-CDR2, H-CDR3 and L-CDR2, which block in carbaryl firmly. The binding site was composed of Ala51, Ser52, Ile51, Gly54, Ser56, Arg98 and Gly100, etc. These data highlighted the mechanism of interaction between anti-carbaryl antibody and antigen. Furthermore, it provides guidance for in vitro affinity maturation of anti-carbaryl antibody.
    12  Effects and Mechanisms of Sodium Fluoride on Assay of Acid Trehalase Activity
    TAN Hai-gang GUO Xue-wu WANG Ya-zhou XIAO Dong-guang
    2014, 30(6):64-69.
    [Abstract](1505) [HTML](0) [PDF 612.22 K](843)
    Abstract:
    The effect of sodium fluoride on the determination of acid trehalase activity in baker’s yeast was investigated in this study. The recombinant baker’s yeast stains TL-105(hxt14?) and TL-106(gal2?) with deleted genes encoding the hexose transporters were constructed. The acid trehalase activity, the secretion of neutral trehalase and acid trehalase, the secretion of glucose and trehalose and the uptake of extracellular glucose of BY6-9α (parental strain), TL-103(ath1?), TL-104(agt1?), TL-105(hxt14?) and TL-106(gal2?) were measured. It was found that sodium fluoride had less effect on the secretion of neutral trehalase, acid trehalase and trehalose, although it had obvious effect on the assay of acid trehalase activity. Thus, sodium fluoride was not related to the secretion of intracellular trehalase or trehalose in the assay of acid trehalase activity. The acid trehalase activity, examined by citrate procedure, of strains TL-105(hxt14?) and TL-106(gal2?) at the stationary phase was 17.06% and 300.23% higher than those of the parental strain, respectively. However, the acid trehalase activities of the three strains examined by citrate and sodium fluoride method showed less difference. Furthermore, the extracellular glucose concentration of strains BY6-9α and TL-103(ath1?) at the exponential phase, which was incubated at 30 ℃ for 30 min with sodium fluoride before the acid trehalase activity was assayed, was 108.53±1.39 and 30.53±1.02 mg/L in the reaction mixture, respectively. These results indicated that sodium fluoride significantly affected the uptake of extracellular glucose and led to the secretion of intracellular glucose. Hence, the acid trehalase activity of the strains treated with sodium fluoride was higher than those without sodium fluoride treatment.
    13  Construction and High Expression of β-glucosidase I Gene from Aspergillus aculeatus NO.F 50 in Pichia pastoris
    CHEN Wen-yong HU Xia-yan KANG Ya-jun ZHENG Sui-ping
    2014, 30(6):70-75.
    [Abstract](1422) [HTML](0) [PDF 682.91 K](935)
    Abstract:
    β-Glucosidaseiswidely used in synthesis of alkyl glucosides and aryl glucosides,as well asdegradation of cellulose. The β-glucosidaseI gene from Aspergilus aculeatus No.F50 was cloned, andmultiple copies of expression cassette 5’AOX-ABGL-TT was inserted intosecreted expression vector pHKA, which could cut apart by the restriction enzymes Bgl II and BamH I. And thenthey were connected together by the use of DNA ligase. The constructed pHKA-(ABGL)3 recombinant plasmid was linearized and integrated into Pichia Pastoris GS115 strain by electroporation. Esculin high-throughput screening method was used to detect positive clones which were cultured in shake flask. In the methanol induction of 120 hours, the supernatant activity was detected using pNPG as substrate. The strain had the maximum supernatant activity of 83.15 U/mL, 3.35 fold higher than previous report. Then it was selectedto realize high-density fermentation using 50 L fed-batch fermentor. The supernatant hydrolytic activity of fermentation in 50 L fermentor wasup to 979 U/mL, which was 2.94 fold higher than control, and protein expression level reached 12.0 mg/mL.
    14  Measurement Analysis of Contact Pressure Distribution of Apple under Compression
    FENG Zhe WU Jie SUN Hui-jie LI Fan
    2014, 30(6):76-81.
    [Abstract](1138) [HTML](0) [PDF 630.56 K](685)
    Abstract:
    In this study, the pressure distribution of apple subjected to static loading was measured by the pressure sensitive film technique. The effects of apple maturity and curvature radius at contact location of fruit on pressure area were focused on. The results were calculated by Hertz equation; meanwhile, the calculation accuracy of the equation on contact pressure area was analyzed. The result showed that the contour of pressure distribution was near elliptical, and the discontinuous distributed pressures had the variation feature of rising and falling. The pessure less than 0.2 MPa occupied at the edge of the contact region, while the area of pressure over 0.5 MPa distributed at tiny spots. When the apple was loaded over 100 N, the pressure areas of two different maturity apples showed significant difference. With the increase of curvature radius, the pressure areas of apple at same load increased to varied extent due to maturity difference. Compared with film measurements of apple pressure area, the calculations with Hertz equation showed larger deviation. Hence, a correction coefficient (λ=1.5780 -0.0042F) was introduced to modify the equivalent elastic modulus in the Hertz equation. As a result, there was a good agreement between the measured contact areas and the predications using the modified Hertz equation. This indicated that the modified Hertz equation could precisely estimate pressure area of apple under static load.
    15  The Screening and Identification of a Cellulose Degrading Fungus and Its Straw Degradating Capability
    LIU Qi-li ZHANG Jian-xin GE Wen-jiao WANG Xiao-hui LI Chun-xi ZHANG Yan-zi YU Xiao-feng
    2014, 30(6):82-86.
    [Abstract](1520) [HTML](0) [PDF 540.69 K](774)
    Abstract:
    Numerous semi-decomposed straws, half decayed wood and soil with rich humus collected from different regions of China were studied to screen and characterize novel fungus with powerful cellulose degradation capability on corn straws. 120 strains were isolated from these resources by standard separation methods. A fungus (CM-1) with high-yield cellulase was obtained after a three-step screening by cellulose congo red medium culturing, evaluation of FPA and carboxymethyl cellulose (CMC) activities and weight loss rate of straws powder degraded. The corn straw degradation capabilities of MC-1, the control strain Trichoderma spp. and their mixed fermentation liquor HJ-1 were compared. Results showed that the cellulose hydrolysis circle diameter of MC-1 cultivated in Congo red culture medium for 72 h was 8.52 cm. After cultivated for 48 h, the CMC enzyme activity of MC-1 was 96.31 U/g and filter paper enzyme activity was 8.68 U/g. The results of indoor straw decay test showed that straw weightlessness rate and cellulose decomposition rate rose rapidly within the starting 15 days, and then the speed begun to reduce. After 45 days, the straw weightlessness rate of MC-1 reached 46.84 %. The weightlessness rate and cellulose decomposition rate of straw treated with HJ-1 was higher than single fungus agent.
    16  Molecular Structure and in vitro Digestibility of Germinated Oat Starch
    TIAN Bin-qiang DENG Qian-chun XIE Bi-jun
    2014, 30(6):87-91.
    [Abstract](1352) [HTML](0) [PDF 633.56 K](691)
    Abstract:
    The Jinyan Ⅷ oat was geminated in the dark, and then starches were extracted from different germination periods. The intrinsic viscosity, molecular weight and chain length distribution of samples were characterized by Ubbelohde viscometer, gel permeation chromatography and ion exchange chromatography, respectively. It was found that the amylose content and intrinsic viscosity of germinated oat starches increased compared to raw oat starches, and a significant positive correlation presented between them. The degree of polymerization (DP) in segments 27~33 dominated raw and malted oat starches, occupying more than 60%. The segments with DP≤31 decreased continually, while the segments with DP≥33 increased, indicating that energy conversion during germination depended on utilizing short-chain starch. The in vitro digestibility of raw and germinated oat starches showed that the germination process reduced the hydrolysis index and the glycemic index of oat starch, and intermediate fractions of oat starch played obviously impact on in vitro digestion index, with a significant positive correlation coefficient of 0.82.
    17  Atoxigenic Aspergillus flavus Competitively Reduce Aflatoxin Production by the Toxigenic Aspergillus flavus
    WEI Dan-dan ZHOU Lu ZHANG Chu-shu LIU Yang
    2014, 30(6):92-97.
    [Abstract](1390) [HTML](0) [PDF 565.17 K](658)
    Abstract:
    Six Aspergillus flavus isolates were collected from Guangdong, Shandong, Liaoning and Hubei Provinces in China, and identified through morphology and molecular biology. The aflatoxin production ability of these isolates was detected by HPLC. The results showed that GZ-6 was a toxigenic isolate, while GZ-15, WF-5, WF-20, JZ-2 and YC-8 were atoxigenic. To analyze the inhibitory effect of the atoxigenic strain on the toxigenic strain, the atoxigenic strain with the toxigenic strain were co-inoculated at t he spore concentration ratio of 104:105 or 105:105 on peanuts and maize, respectively. The results showed that the inhibitory effect of the atoxigenic strain on the toxigenic strain was significantly enhanced as the spore concentration increased. At the ratio of 105:105 (atoxigenic: toxigenic), the five atoxigenic A. flavus reduced 34.55~75.94% aflatoxin production by GZ-6 on maize and 38.03% ~83.03% aflatoxin production by GZ-6 on peanuts. WF-5, WF-20 and GZ-15 could prevent more than 75.00% aflatoxin production by GZ-6 and could probably be exploited as effective agents for aflatoxin control in field.
    18  A QSAR Study on Antibacterial Activity of P-hydroxybenzoate Esters
    QIU Song-shan JIANG Cui-cui ZHOU Ru-jin WANG Deng-ju
    2014, 30(6):98-102.
    [Abstract](1203) [HTML](0) [PDF 502.85 K](814)
    Abstract:
    The molecular structures of eleven kinds of p-hydroxybenzoate esters were optimized by using density functional theory (DFT) B3LYP method of quantum chemistry, and the quantitative structure-activity relationship (QSAR) of these compounds was studied. Stepwise multiple linear regression was used to select the descriptors and to generate the best prediction model that relates the structural features to inhibitory activity. The results suggested that ELUMO and had positive correlation on the activities of p-hydroxybenzoate esters, with correlation coefficient of 0.9910. The results showed that the lowest unoccupied molecular orbit ELUMO and the increase of dipole moment were the main independent factors contributing to the antifungal activity of the compounds. The antifungal activity increased with the increase of ELUMO and . The obtained QSAR model could provide theory reference to design p-hydroxybenzoate esters with stronger antibacterial activity.
    19  Tissue Distribution and Pharmacokinetics of Diethylstilbestrol and Its Metabolite Dienestrol in Ctenopharynodon idellus
    XU Ying-jiang SUN Yan REN Chuan-bo XUE Jing-lin LIU Hui-hui TIAN Xiu-hui HUANG Hui GONG Xiang-hong
    2014, 30(6):103-109.
    [Abstract](958) [HTML](0) [PDF 670.15 K](687)
    Abstract:
    Diethylstilbestrol and its metabolite dienestrol in Ctenopharynodon idellus by oral administration were investigated in their tissue distribution and pharmacokinetics, and they were quantified by UPLC-MS. Diethylstilbestrol concentrations-versus-time was well described by a two-department open model with first-order absorption. For example, after single oral of 1.0 mg/kg (b.w.) diethylstilbestrol, the highest concentration of it was detected in liver, followed by muscle and plasma. The average elimination speed was 12.02 μg/(L·h), 1.33 μg/(kg·h) and 3.59 μg/(kg·h), respectively, for plasma, muscle and liver. No diethylstilbestrol was detected after oral administration of 10 h, 192 h and 168 h. The variation of dienestrol concentrations in plasma, muscle and liver of Ctenopharynodon idellus was similar to that of diethylstilbestrol, which was increased first and then decreased. Concentrations of dienestrol in plasma, muscle and liver reached the peak after oral administration of 1 h, 6 h and 6 h, and no detection after 8 h, 168 h and 144 h. The relevant pharmacokinetic parameters of diethylstilbestrol were calculated by using DAS 2.0. Taking the concentration of 1.0 mg/kg b.w. diethylstilbestrol as example, it was indicated that area under concentration-time curve (AUC) differed greatly and the tissues had different accumulation capability. The overall clearance rate was 1.434 L/(h·kg), 0.126 L/(h·kg) and 0.099 L/(h·kg), indicating diethylstilbestrol was widely distributed and fast eliminated in tissue. It was recommended the eliminated period should be 6 d, 8 d and 10 d. The concentrations versus time curve of diethylstilbestrol provided useful information for studying decontamination of Ctenopharynodon idellus that was contaminated by diethylstilbestrol.
    20  Expression of Vitreoscilla Hemoglobin Improves CALB Production in Pichiapastoris
    LU Jun-yu LIN Ying LIANG Shu-li YE Yan-rui
    2014, 30(6):110-115.
    [Abstract](1222) [HTML](0) [PDF 532.37 K](760)
    Abstract:
    To alleviate the dissolved oxygen (DO) limitation and improve Candida antarctica lipase B (CALB) production during high-cell density fermentation, the CALB gene and Vitreoscilla hemoglobin (VHb) gene vgb were co-expressed in Pichiapastoris under the AOX1 and YPT promoter control, respectively. In addition, to detect the effect of signal peptide, GFP was expressed on the surface of peroxide, while RFP was expressed in the peroxide matrix. Finally, GFP or RFP was replaced by VHb protein to find out the impaction of the different positions. SDS-PAGE and Western Blot analysis results indicated that VHb and CALB were successfully co-expressed in recombinant strains. Compared with the control strain, expression of CALB in GS115/ExVHb and GS115/VHbSKL under oxygen limitation was improved by 27.57% and 20.52%, respectively. Therefore, expression of VHb in P. pastoris is an effective strategy to improve CALB production.
    21  Screening of Beany-flavor Removement Yeast from Fermented Soybean Meal
    TANG Qiao HU Mao-feng LIU Su-chun
    2014, 30(6):116-120.
    [Abstract](1408) [HTML](0) [PDF 615.13 K](746)
    Abstract:
    A new method for removing beany-flavor effectively and safely during the process of soybean powder was developed in this research A yeast Y03was screened from the fermented dough, grape skin and wine yeast, which can remove beany-flavor effectively. By SPME-GC-MS analysis and sensory evaluation, the result showed that hexanal, the main components of volatile beany-flavor, and a variety of ingredients causing beany-flavor such as (E)-2-hexenal, dimethylamine, 3-hexanol, cyclohexanone were removed completely after 2 h fermentation by Y03, meanwhile a multiple aromatic alcohols, aromatic esters, such as phenylethanol, matsutake alcohol, ethyl octanoate, and ethyl laurate were generated. This strain was identified as Saccharomyces cerevisiae by 26S rDNA sequence analysis.
    22  Changes of Physicochemical Properties of Superfine Grinding Starch from Castanea henryi
    XIE Tao YANG Chun-feng KANG Ling-tao TANG Zheng-hui GAO Juan
    2014, 30(6):121-125.
    [Abstract](1206) [HTML](0) [PDF 645.71 K](810)
    Abstract:
    Effects of superfine grinding on physicochemical properties of Castanea henryi starch were studied. The results demonstrated that along with prolonging the superfine grinding time, particle diameters, crystallinity degrees, dilatations, gelatinization temperature ranges and gelatinization enthalpies of C. henryi starches decreased, while their solubilities and enzymatic hydrolyzation rates increased. When the superfine grinding time was up to 60 min, starch granules were shattered to limit, their crystalline structures destroyed and all became amorphous structures; the gelatinization temperature range was from 35 ℃ to 62 ℃, solubilities were close to 60% and enzymatic hydrolyzation rates were beyond 70%. Moreover, when the superfine grinding continued to 75 min, more fine particles got together, particle size of 0~5 μm decreased significantly, while particle size greater than 25 μm increased. Superfine grinding destroyed the apparent structure and crystalline structure of starch granules. Therefore, the saccharification and alcohol fermentation ability of superfine grinding starch could be greatly improved. With C. henryi starch superfine grinded for 60 min as material, its alcohol concentration reached 13.64% after 96 h using liquefaction and saccharification fermentation technology, while direct saccharification fermentation technology only achieved 12.32% after 108 h.
    23  Homogeneous Synthesis of Tapioca Starch Succinate in Ionic Liquid
    XI Yong-kang LUO Zhi-gang LI Yao-rong CHENG Jian-hua LIN Yong-peng HONG Sheng-quan LONG Si-cai ZHENG Hua-sheng
    2014, 30(6):126-130.
    [Abstract](1008) [HTML](0) [PDF 624.11 K](765)
    Abstract:
    Tapioca starch succinate was homogeneously synthesized using ionic liquid (ILs) 1-butyl-3-methylimidazolium (AMIMCl) as reaction medium without any catalyst. The starch was dissolved in AMIMCl at 105 ℃ for 30 min before reaction, which could provide feasible reaction environment for starch functionalization. The results of turbidimetric measurement suggested that the solubility of starch dissolved in AMIMCl at 105 ℃ was 10.2%. Tapioca starch succinate achieved the highest DS of 0.518 under the following conditions: succinic anhydride/ anhydroglucose unit molar ratio of 4:1, reaction temperature of 110 ℃, and reaction time of 3 h. FT-IR result showed the peak at 1733 cm-1 attributed to the stretching vibration of ester carbonyl group , which indicated that the esterification of corn starch with succinic anhydride was successfully accomplished. The results of SEM showed that tapioca starch succinate lost individuality and smoothness which native starch granules had. XRD of starch succinate with high DS had new diffraction peaks at 8°, which suggested that the new crystalline pattern was formed.
    24  Drying Characteristics and Mathematical Modeling of Yacon Pulp by Vacuum Foam Mat Drying
    SHI Qi-long ZHAO Ya PAN Wang-ying
    2014, 30(6):131-139.
    [Abstract](1137) [HTML](0) [PDF 717.29 K](662)
    Abstract:
    The purpose of the present study was to illuminate the effect of whey protein isolate on the foam properties of yacon pulp and determine the drying characteristics and mathematical model of vacuum foam mat drying. Effects of total solid content of yacon pulp, types and mass fractions of foaming agent, and whipping time on the foam expansion, foam stability and foam density were investigated. The optimum for stable foam formation was yacon pulp with total solid content of 5%~7%, with 15% whey protein isolate as foaming agent and 1% carboxymethylcellulose sodium as foam stabilizer, and whipping time of 20min. Drying characteristics of foamed yacon pulp at different temperatures (55, 65 and 75 ℃) and vacuum degrees (0.075 and 0.095 MPa) were investigated. Drying rate increased with increasing drying temperature and vacuum degree. Compared with non-foamed pulp, foam mat treatment significantly increased the effective moisture diffusivity coefficients and decreased the activation energy for the diffusion of the moisture associated with yacon pulp and therefore increased the drying rate and lowered the drying time of yacon pulp. Midilli et al. model achieved the best fit and can be used to describe the foam mat vacuum drying process of yacon pulp.
    25  Inhibition of the Freeze-denaturation of Protein in Litopenaeus vannamei by Trehalose, Alginate and its Oligosaccharides
    MA Lu-kai ZHANG Bin WANG Qiang DENG Shang-gui WANG Bin
    2014, 30(6):140-145.
    [Abstract](1338) [HTML](0) [PDF 543.22 K](753)
    Abstract:
    The aim of this work was to evaluate the inhibition of saccharides from seaweed on the freeze-denaturation of protein in Litopenaeus vannamei, compared with sodium pyrophosphate as anti-freeze agent. The results indicated that the thawing loss (5.00~5.54%) of shrimp were significantly (p<0.05) decreased by 0.5% and 1.0% trehalose and alginate oligosaccharides (500~600 Da) treatments after six weeks storage (-18 ℃), which showed little significant difference from that by sodium pyrophosphate treatment (5.02~5.48%, p > 0.05). The L* values of shrimp were not significantly affected by 0.5%, 1.0% trehalose, alginate and its oligosaccharides (p>0.05) during the whole storage, which indicated they had good protective effect on the lightness of the shrimp. In addition, the activity of Ca2+-ATPase, contents of myofibrillar and salt-soluble proteins in shrimp were also decreased in all treated-groups after six weeks storage, while the protective effect on protein by trehalose/alginate oligosaccharides treatments were more significant than the other control groups (p<0.05). The study can lay the foundation for developing a kind of safe, natural and harmless non-phosphate additive which is suitable for the frozen shrimp.
    26  Weibull Distribution for Modeling Med- and Short- Wave Infrared Radiation Drying of Kiwifruit Slices
    ZENG Mu-cheng BI Jin-feng CHEN Qin-qin LIU Xuan WU Xin-ye JIAO Yi
    2014, 30(6):146-151.
    [Abstract](1246) [HTML](0) [PDF 784.60 K](655)
    Abstract:
    In this study, the kiwifruit was selected as raw material to investigate the effect of drying conditions on the parameters of Weibull distribution. The experiment was conducted at different levels of med-and short-wave infrared radiation drying temperature (50, 60, 70, 80 ℃) and infrared power (675, 1350, 2025 W). The result showed that the Weibull distribution function was good in simulating the process of med-and short-wave infrared radiation drying of kiwifruit slices. The scale parameter (α) was found to be related with the drying temperature and infrared power, and was decreased with increasing drying temperature and infrared power. However, the drying conditions had little influence on the shape parameter (β). The estimated moisture effective diffusivity (Dcal) of kiwifruit samples were calculated to be in the range from 1.061×10-7 to 3.51×10-7 m2/s, which increased with increasing drying temperature within the ranges tested. The activation energy determined from Arrhenius equation was 32.55, 27.02 and 28.07 kJ/mol at 675 W, 1350 W and 2025 W, respectively.
    27  Preparation and Identification of Gentamicin and Its Polyclonal Antibody
    XU Yao-xin GONG Yun-fei CHEN Zong-lun XI Xi DAI Ming-yan WU Ying-ying LIU A-ming ZHANG Ming-zhou
    2014, 30(6):152-157.
    [Abstract](994) [HTML](0) [PDF 564.50 K](745)
    Abstract:
    To develop immunoassay for gentamicin, the artificial antigen and polyclonal antibody were prepared in this study. Identified through ultraviolet spectrum (UV) and SDS-PAG, the immunogen (GM-BSA) and coating antigen (gm-ova) of gentamicin were synthesized by the method of carbodiimide successfully. GM-BSA was used to immune New Zealand white rabbits, and the antiserum was obtained. In this study, we utilize a notive method to immune animal and obtained serum volume much more than conventional method’s. One indirect competitive ELISA method has been developed to detect the titer and sensitivity of the antiserum. The results show that the titer of antiserum was continuously improving and the IC50 was nearly 3ng/mL. On this basis, With an concentration range from 0.3 to 243 ng/mL, the IC50 is 2.954 ng/mL, and the IC10 is 0.056 ng/mL. The results of this study provide a basis for the breakthrough of serum volume, and also is a good start for the development of gentamicin ELISA kit.
    28  Effects of Carbon Sources on Production of Leucine Aminopeptidase and Activities of Sugar Metabolic Enzymes Produced by Bacillus cereus CZ
    CUI Tang-bing JIANG LI-xiang HAN Qian LI Jun-xia
    2014, 30(6):158-167.
    [Abstract](945) [HTML](0) [PDF 456.12 K](677)
    Abstract:
    Leucine aminopeptidase (LAP) produced by Bacillus cereus CZ was investigated in this study. Results indicated that L-arabinose was the best carbon source for producing LAP, followed by D-galactose and lactose, whereas glucose, maltose, sucrose and sodium bicarbonate obviously inhibited LAP production. The production of LAP was also reduced largely when L-arabinose was mixed with other simple sugars, or Lactose/ D-galactose was mixed with glucose. The mixture of lactose and glucose was the optimal carbon sources for cell growth.When using 2% lactose, D-galactose and L-arabinose as carbon sources, LAP activities did not reach the maximum values after 48 h fermentation. For the sugar metabolic enzymes, β-galactosidase can be strongly induced by lactose. L-Arabinose had certain induction effect, while D-galactose had a strong depression effect. Galactokinase was induced significantly by D-galactose, followed by L-arabinose and lactose. L-arabinoseisomerase was induced strongly by L-arabinose, moderately by other simple sugars and mixed sugars. LAP production reached the highest with 4% L-arabinose and D-galactose. Extracelluar galactokinase decreased with increasing the sugar concentration, but intracellular enzymes showed the reverse trend. L-arabinoseisomerase increased with increasing concentration of L-arabinose. LAP production reached the highest when fermentation for 56 h with 4% L-arabinose. However, its production increased continuously with fermentation time when 4% D-galactose was used.
    29  Effect of Different Dosage Rates on Radical Content and Volatile Compounds of Irradiated Yeast Extract
    GENG Sheng-rong XIONG Guang-quan XIA He-zhou LIAO Tao LI Xin
    2014, 30(6):168-173.
    [Abstract](934) [HTML](0) [PDF 682.53 K](722)
    Abstract:
    Yeast extract (YE) was irradiated respectively by γ-rays with dosage rate of 60 and 480 Gy/min and electron beams of 12000 Gy/min. The volatile compounds from irradiated YE and five kinds of target amino acid-water solutions were detected by gas chromatograph- mass spectrometer-computer (GC-MS), the composition of YE volatile compounds and their amino acid source were investigated. The radical characteristics of irradiation YE were researched by electron sin resonance (ESR) and the mechanism of dosage rate on reducing irradiation damage was studied. Results showed that the six same volatile compounds from three irradiation treatments were acetone, acetic acid, methyl disulfide, toluene, 2,6-dimethyl-pyrazine and benzaldehyde. The number of volatile compounds and YE content increased during the first 14 days and then decreased during 14~35days after irradiation. The essential constitutes of amino acids were Met, Ala and Phe from YE degradation. The order of volatile content of YE with same absorbed dosage was: 60 Gy/min γ-rays>480 Gy/min γ-rays>electron beams. The ESR spectrum of YE was a double peak and the peak changed with dosage and dosage rate. YE irradiated by 60 Gy/min γ-rays was detected by ESR and showed that the ESR signal intensity was positively correlated with absorbed dosage and the linear fitting equation was: A=4363.5D+4873.9, R2=0.9826. The sequence of ESR signal intensity of YE with same absorbed dosage was: 480 Gy/min γ-rays < electron beams <60 Gy/min γ-rays. Therefore, high dosage rate irradiation can produce low radical intensity and reduce the volatile content production.
    30  A Comparative Study on Quality of Chilled and Quick-frozen Pork During the Storage Period
    XIA Lie JIANG Ai-min LU Yan LI Jun-guang WEN Xiao-long ZHANG Da-lei
    2014, 30(6):174-180.
    [Abstract](1222) [HTML](0) [PDF 496.93 K](689)
    Abstract:
    Porcine longissimus muscle was processed by air-blast cooling and immersion-frozen to make its center temperature decreased from 10 ℃ to 0 - 4 ℃ (air-blast cooling), -5 ℃ and -18 ℃ (immersion-frozen) after 12 h. Then 0 ~ 4 ℃ and -18 ℃ chilling meats were preserved in the refrigerator with 0 ~ 4 ℃ and -18 ℃, while -5 ℃ processed meat was preserved in the -5 ℃ (one-stage frozen) and -18 ℃ (two-stage frozen) refrigerator respectively. Besides, a comparative study between these four preserved meats was carried out in terms of conductivity, water retention, drip loss, cooking loss, textural characteristics, TVB-N, the total number of colonies, pH and color (L*, a*, b*). The experimental result showed that: one-stage frozen meat had better quality than two-stage frozen one among immersion-frozen process. Immersion-frozen meat (-18 ℃) that stored for 4 weeks or less had the same quality with cooling meat which stored for 4 days or less. However, the water retention, texture features and color of cooling meat were superior to the immersion-frozen groups, but in aspects of TVB-N and the total number of colonies, it showed a reverse result.
    31  Identification of the Thermal Denature of Pork Protein by SDS-PAGE and the Qualities of the Pork
    HAN Zhong LUO Man TANG Xiang-wei ZHANG Tian-yi ZHANG Bin LI Yan ZENG Xin-an GAO Wen-hong SUN Da-wen
    2014, 30(6):181-185.
    [Abstract](1090) [HTML](0) [PDF 538.94 K](682)
    Abstract:
    The application of microwave heating in food cooking can not only save time but also make food with more nutrition and less off-flavors, which is an ideal method for cooking. The longest back muscle of pig was cut into 5 cm × 5 cm × 1.5 cm cube, and three pieces of pork were studied each time, then the SDS-PAGE method was applied in appraising protein thermal denature. Meanwhile, cooking loss, chromatic aberration, water-holding capacity, shearing force and power consumption during heating of the processed samples were analyzed. Variance and significant analysis of the results were also conducted. The results showed that for the variable frequency microwave oven, the heating time of the pork under the power of 900 W and 700 W were both 70 s, and the heating time for the power of 500 W was 120 s. For the non variable frequency microwave oven, heating time was 80 s, 100 s, 140s for the power of 100%, 80%, and 50%, respectively. Finally, it was concluded that the quality of the samples heated by the power of 700 W was best, and the consumption of electricity was the lowest.
    32  Subcritical Water Preparation and Properties of Low Molecular Citrus Pectin
    CHEN Jian-bing YIN Ying LU Sheng-min XIA Qi-le ZHANG Jun
    2014, 30(6):186-190.
    [Abstract](1018) [HTML](0) [PDF 602.53 K](800)
    Abstract:
    To obtain the satisfied physical preparation of low molecular citrus pectin, effects of high pressure homogenization and subcritical water treatment on citrus pectin molecular weight were studied in this paper. The results showed that both of them reduced the pectin molecular weight. Average molecular weights of homogenized pectin were 140 ku, 130 ku and 120 ku under the pressure of 50 MPa, 100 MPa and 150 MPa respectively; while those of subcritical water treated samples were 50 ku, 20 ku and 10 ku under 105 ℃, 120 ℃ and 135 ℃ respectively. Taking a comprehensive consideration of molecular weight, yield and quality, subcritical water treatment at 120 ℃ was selected as a suitable method to produce low molecular citrus pectin. Compared with those properties of non-treated sample, monosaccharide composition of the treated citrus pectin changed little and their contents (especially for galactose) were decreased at a certain degree. The content of galacturonic acid was increased from 74.23% to 87.92%, while degree of esterification decreased from 70.32% to 62.47% in the citrus pectin after treated with subcritical water at 120 ℃. The content of heavy metal in the treated sample was increased slightly, but still within the safe range.
    33  Effects of Temperature on the Quality of Antarctic Krill (Euphausia superba) during Frozen Storage
    LI Xue-ying LIU Hui-xing YANG Xian-shi CHI Hai HUANG Hong-liang LI Ling-zhi RAO Yu-lin
    2014, 30(6):191-195.
    [Abstract](1397) [HTML](0) [PDF 559.79 K](844)
    Abstract:
    Antarctic krill was stored at -20, -30, -40, -50±1 ℃ and their quality was studied based on the indicators of sensory score, water-holding capacity (WHC), salt soluble protein (SSP), thiobarbituric acid-reactive substance (TBARS). Significant differences (P<0.05) in the quality changes of Antarctic krill were observed during frozen storage at different temperatures. The results showed that the higher the frozen temperature, the worse the sensory quality and the water-holding capacity of Antarctic krill. Severe protein denaturation and fat oxidation were observed with prolonging frozen time. The trend of Antarctic krill deterioration basically kept constant in the process of freezing storage. When stored at -20, -30, -40, -50 ℃ after 180 d, WHC and SSP of Antarctic krill decreased by 18.27%, 15.00%, 16.04%, 12.92% and 32.66%, 33.99%, 24.95%, 21.84%, but TBARS increased by 76.38%, 78.09%, 65.71%, 53.55%, respectively. Sensory quality deteriorated the fastest when stored at -20 ℃ for 200 d, yet it was acceptable when stored at -30 ℃ after 200 d. The sensory quality was much better when stored at -40 ℃and -50 ℃. It showed that the lower the frozen storage temperature, the slower the deterioration rate of Antarctic krill. In consequence, the storage temperature below -30 ℃ was recommended for the storage of Antarctic krill.
    34  Physicochemical Characteristics of High-temperature Soy Meal Hydrolysates with Different Degrees of Hydrolysis
    HUANG Li-hua ZHANG Ye-hui LI Hai-bin
    2014, 30(6):196-201.
    [Abstract](1172) [HTML](0) [PDF 601.77 K](720)
    Abstract:
    High-temperature soybean meal was hydrolyzed by Alcalase and papain, respectively. Six kinds of hydrolysates were obtained with the degrees of hydrolysis (DH) of 5%, 10%, and 15%. Effects of Alcalase and papain on physicochemical properties of these different hydrolysates were evaluated. The results showed that Alcalase and papain were all produced six kinds of hydrolysates with different ranges of molecular weight. The proportions of hydrolysates from different enzymes had significant differences (P<0.5), and the average molecular weight of hydrolysates was gradually decreased with increasing the DH. Alcalase included more peptides that less than 2562 Da compared with papain at the same DH. The significant difference of amount between exposed and destruct of hydrophobic groups in enzymatic reactions resulted in surface hydrophobicity decreased firstly with the increasing DH and then increased. Therefore, the hydrolysates with DH of 10% had the minimum surface hydrophobicity than the others. The absolute values of zeta potential increased with increasing DH, and the intermolecular repulsion of molecules increased synchronously. The effect of Alcalase and papain on zeta potential had no significant difference at the same DH. Moreover, at pH 3, 5, 7 and 9, the solubility of the hydrolysates increased gradually with increasing DH, and the emulsifying activity index and emulsion stability index exhibited decreasing trends with increasing DH.
    35  Effects of Different Sugar Osmosis on the Quality and Tissue Cells of Preserved Mango
    SHENG Jin-feng LI Li SUN Jian LI Chang-bao LI Jie-min ZHENG Feng-jin LIU Guo-ming HE Xue-mei LIAO Fen ZHANG Ya-yuan
    2014, 30(6):202-206.
    [Abstract](960) [HTML](0) [PDF 519.86 K](763)
    Abstract:
    At room temperature, mango slices were immersed in sugar solution assisted by ultrasonic, microwave and vacuum to produce the preserved mangoes. Color, texture, total sugar content and rehydration rate were analyzed. Meanwhile, the histiocyte of mango was examined using microscope. The results showed that color and texture of the preserved mango assisted by vacuum changed obviously in comparison with atmospheric sugar osmotic, while its color, hardness, conglutination and chewiness showed significant difference from those of the control (P<0.05). Ultrasonic and microwave assisted treatments exhibited little effects on color and texture of mango. Ultrasonic enhanced infiltration rate of sugar and the total sugar content was the highest in ultrasonic-assisted preserved mango. Rehydration behavior was reduced by three kinds of new methods to some extent, and the rehydration rate of the preserved mango was among 189.27%~191.10% after being immersed for 150 min in water. By examining mango tissue section using microscope, it was found that ultrasonic infiltration method obviously reduced mango cellular structure damage during sugar osmosis.
    36  Effect of Preharvest Sprayed Treatment with Chlorine Dioxide on Preservation of Blueberry during Storage
    XIE Guo-fang WANG Rui LIU Xiao-yan
    2014, 30(6):207-213.
    [Abstract](1341) [HTML](0) [PDF 603.69 K](753)
    Abstract:
    The effects of preharvest treatment with chlorine dioxide on physiological, biochemical and preservation mechanisms of modified atmosphere packaged blueberry during near-freezing point storage were analyzed. ‘Powder blue’ blueberry fruit were sprayed with 0, 20, 40 and 60 mg/L ClO2 before harvest, respectively. They were packaged in perforated polyethylene plastic box, then moved into a polyethylene film bag with a slackened tie and stored at -1±0.1 ℃. The colony clearance rate on fruit surface, flavor index, decay rate, weight loss, total soluble solids, soft fruit rate, respiration rate, anthocyanin, polyphenols, titratable acids and pH value were measured. Meanwhile, the activities of some free radical scavenging and formation-related enzymes such as polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonialyase (PAL) were investigated. The result showed that the appropriate concentration of chlorine dioxide treatment could effectively remove colonies on fruit surface, reduce total soluble solids, decay rate and weight loss, inhibit fruits soften, decrease respiration rate, increase the activities of POD and PAL, and maintained low level PPO activity. By comparative analysis of different concentrations, the best sprayed concentration of chlorine dioxide was determined as 40 mg/L, which can effectively increase preservation and considerably extend the storage period.
    37  Effect of Freezing Method and Temperature on the Quality of Abalone
    OUYANG Jie TAN Jia-yu SHEN Jian
    2014, 30(6):214-218.
    [Abstract](1250) [HTML](0) [PDF 425.82 K](755)
    Abstract:
    In order to study the influence degree and mechanism of different freezing methods?and temperatures on the quality of abalone during freezing, two freezing methods (air freezing, liquid freezing), three freezing temperatures (-20 ℃, -40 ℃, -60 ℃) were used for fresh abalone freezing. Frozen denaturation degree, muscle tissue structure, springiness were used as the evaluation indexes. The results showed that the liquid freezing rate was 10 times higher than air freezing rate, while decline rate of salt-soluble protein solubility was 2% lower. The decreasing speed of Ca2+-ATPase activity and increasing speed of Mg2+-ATPase activity were very slow. Frozen denaturation degree of protein and salt-soluble protein loss were low. The space between muscle tissues was smaller and more flexible than that without thawing. During freezing process, lowering freezing temperature, improved the freezing rate,but decreased salt soluble protein loss. No obvious change between frozen denaturation degree and flexible was observed. Base on general consideration of factors such as freezing rate, quality, and energy, liquid freezing at -60 ℃ was considered suitable for abalone freezing.
    38  Chemical Constituents from the Root Bark of Morus atropurpurea
    HE Xue-mei WU Dong-ling ZOU Yu-xiao WANG Guo-cai ZHANG Xiao-qi LIAO Sen-tai SUN Jian YE Wen-cai
    2014, 30(6):219-228.
    [Abstract](1447) [HTML](0) [PDF 847.60 K](874)
    Abstract:
    Mulberry root bark (Sang Bai Pi) was a kind of traditional Chinese medicine which showed hypotensive, antiviral bacteriostatic and anti-inflammatory activities. In order to explore the material basis of pharmacological activity of mulberry root bark, the chemical constituents of the root bark from Morus atropurpurea was studied in this paper. Fifteen compounds were isolated from the root bark by silica gel, Sephadex LH-20, ODS and PHPLC column chromatography. Their structures were identified by physicochemical properties and spectral analysis as kuwanon A (1), kuwanon B (2), kuwanon C (3), kuwanon T (4), cyclomorusin (5), moracin M (6), moracin O (7), moracin P (8), mulberrofuran L (9), albanin A (10) , australone A (11), 5'-(1',1'-dimethylallyl)-8-(3',3'-dimethylallyl)-2',4',5,7-tetrahydroxyfla-vone (12), 5,7-dihydroxycoumarin (13), oxyresceratrol (14) and β-daucosterol (15), respectively. Fifteen compounds contained eight prenylflavonoids, four 2-arylbenzofuran, one coumarin, one stilbene and one sterol. Moreover, compounds 1-4 and 7-13 were firstly found from Morus atropurpurea.
    39  Determination of the Toxic Elements As, Cd, Hg and Pb in Food Grade Dimethicone by Inductively Coupled Plasma Mass Spectrometry
    NIE Xi-du FU Liang
    2014, 30(6):229-232.
    [Abstract](1649) [HTML](0) [PDF 575.13 K](760)
    Abstract:
    A method of inductively coupled plasma mass spectrometry (ICP-MS) was established to determine As, Cd, Hg and Pb toxic elements in dimethicone after diluted by kerosene. The condensation and deposition of high concentrations of carbon in mass cone interface and ion lens, which will decrease the sensitivity of element analysis, can be avoided effectively by introducing O2 to plasma. The mass spectral interferences of polyatomic ions to As element were corrected by collision?reaction?cell and the matrix matching method was used to eliminate matrix interference. On the other hand, the memory effect of Hg was corrected by the addition of Au in sample solution and standard solution. The detection limit of As, Cd, Hg and Pb was 0.58, 0.16, 0.87, 0.12 ng/L, respectively, with a correlation coefficient higher than 0.9999. The recovery rate was 93.25%~102.70%, with a relative standard deviation less than 4.61%. These four toxic elements were all detected in practical analysis, and their content was very low, which had no harm to human body. The method can be applied for the quality control and safety evaluation of food grade dimethicone.
    40  Rapid Non-destructive Testing for K Values of Silver Carps based on the Olfactory Visualization Technique
    HUANG Xing-yi YAO Li-ya HAN Fang-kai GUAN Chao
    2014, 30(6):233-237.
    [Abstract](1079) [HTML](0) [PDF 532.74 K](789)
    Abstract:
    In this study, the olfactory visualization technique was used to predict the K values of silver carps quantitatively. The samples stored at 4 ℃ for several days were detected by the olfactory visualization technique non-destructively. The signals of the colorimetric sensor array respond to the volatile compounds were obtained. Meanwhile, the content of adenosine triphosphate related compounds in the samples was measured by HPLC and K values were calculated. Finally, the partial least squares (PLS) and genetic algorithm-partial least squares (GA-PLS) quantitative prediction models were established based on the odor characteristic information and K values. The results showed that the original variables reduced from 48 to 18 and the sensors reduced to 11 after the GA optimization. The performance of GA-PLS model was better than that of PLS. The root mean square error of prediction was 0.04 and the correlation coefficient of prediction was 0.93. The correlation between the measured and predicted K values of the silver carps was very high, therefore, the olfactory visualization technique could be used to predict the silver carp freshness quantitatively. This study provided an accurate, fast, low-cost and non-destructive testing method for fish freshness detection.
    41  Chemical Constituents and Antioxidant Activities in vitro of Essential Oils from Osmanthus fragrans Fruits
    BI Shu-feng ZHANG Ling-jie GAO Hui CHENG Chong-yan CHEN Chong-mei SHAO Ya-nan
    2014, 30(6):238-243.
    [Abstract](1471) [HTML](0) [PDF 570.24 K](672)
    Abstract:
    The essential oils from Osmanthus fragrans fruits were extracted by water-steam distillation. Their chemical components were analyzed by gas chromatography-mass spectrometry, and the relative contents of the chemical components were determined with peak area normalization method. The antioxidant activities of essential oils in vitro were evaluated by total reducing power, metal chelating ability, and scavenging capacity against ABTS· and DPPH· with Vc or EDTA as the positive control. The results showed that 44 compounds, which occupied 89.12% of total constituents, were identified from the essential oils. The esters and acids were the dominant components in the essential oils, which occupied 47.28% and 15.67% of total constituents, respectively. The major compounds in the essential oils were 5-vinyl-3-pyridinecarboxylic acid methyl ester, methyl-4-formylbenzoate, palmitic acid, 1, 21-docosadiene and 1, 2-epoxyoctadecane. The essential oils exhibited significant antioxidant activities in vitro in a concentration-dependent fashion. The ED50 values of total reducing power, metal chelating ability, and scavenging capacity against ABTS· and DPPH· were 147.63, 41.25, 33.51, and 50.94 L, respectively.
    42  Determination of Four Estrogens Residues in Milk Samples by Liquid Chromatography-tandem Mass Spectrometry
    ZHAO Chao-min YUE Zhen-feng WU Hui LAI Fu-rao
    2014, 30(6):244-249.
    [Abstract](1209) [HTML](0) [PDF 739.76 K](838)
    Abstract:
    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of four estrogens residues (estrone, 17 β-estradiol, 17α-estradiol, estriol) in milk samples. The milk samples were extracted by oscillation with acetonitrile, dehydrated with NaCl and defatted under freezing condition, and then purified by solid-phase extraction using C18 cartridges. The analytes were separated using Hydrosphere C18 chromatographic column with gradient elution of acetonitrile/water. Finally, the eluents were qualitatively and quantitatively determined by mass spectrometer with electrospray ionization in negative multiple reaction monitoring mode. The parameters of the liquid chromatography (mobile phase, flow rate, temperature of column) and mass spectrometry were also optimized to enhance detection sensitivity. Using matrix matched external standard method, good linearity in response could be obtained with correlation coefficients larger than 0.999. All quantification limits of estrone, 17β-estradiol, 17α-estradiol and estriol were 0.2 μg/kg. At the spike levels of 0.2 μg/kg, 0.4 μg/kg and 1.0 μg/kg for each estrogen, the recoveries of estrogens were within the range of 69.7%~108.0%, and the relative standard deviation were from 4.3% to 10.5%. The above results showed that the method was accurate and reliable, and suitable for the determination of estrogens residues in milk samples.
    43  Comparison of Different Pretreatments for GC Determination of L-Borneol, Isoborneol, and Camphor Contents in Blumea balsamifera (L.) DC. Leaves
    WANG Yuan-hui ZHAO Dan-dan WANG Hong-xin ZOU Chun-li
    2014, 30(6):250-256.
    [Abstract](1539) [HTML](0) [PDF 532.75 K](731)
    Abstract:
    The efficiencies of hydrodistillation-solvent extraction (HDSE), simultaneous distillation and extraction (SDE), solvent extraction (SE), ultrasonic assisted extraction (UAE), microwave assisted extraction (MAE), and simultaneous ultrasonic-microwave assisted extraction (UMAE) in the extraction of L-borneol, isoborneol, and camphor from leaves of Blumea balsamifera (L.) DC. were compared. Three compounds in leaves were determined by GC with six pretreatments, respectively. UMAE was the most rapid pretreatment method (extraction time 30 s). The precisions of six pretreatments all met the standard, with RSDs of less than 3%. GC combined with six pretreating was accurate in the determination of L-borneol (recoveries 86%~100%). However, HDSE-GC was the only method for detecting all three compounds (recoveries 100%~105%). The leaves of B. balsamifera from harvest period were determined by HDSE-GC and UMAE-GC, and it was found that L-borneol contents in leaves harvested from mid-October to next mid-January were high, suitable for raw material in L-borneol production. The study provides an accurate and reliable pretreatment method for the rapid analysis of L-borneol in B. balsamifera leaves and the best harvest period of leaves.
    44  Nondestructive Detection for Internal Qualities of Tan-sheep Meat Using NIR Hyperspectral Imaging Technique
    WANG Jia-yun WANG Song-lei HE Xiao-guang HE Jian-guo WU Long-guo LIU Gui-shan
    2014, 30(6):257-262.
    [Abstract](1587) [HTML](0) [PDF 543.32 K](709)
    Abstract:
    In this paper, protein and fat content, pH value of Tan-sheep meat was nondestructively detected using near infrared hyperspectral imaging technology. Spectral information of 69 samples was collected by hyperspectral image system (900~1700 nm). The partial least squares regression (PLSR) models under full-wave spectrum established by the original spectrum were compared with pretreatment?ones, and the best pretreatment algorithms were selected. In addition, the characteristic wavelengths were selected through β weight coefficient?of PLSR, then the PLSR models of protein and fat content, pH value under the characteristic wavelengths were set up, and the prediction effects of models were analyzed. The results showed that: the best pretreatment algorithms for models of mutton protein and fat content , pH value were Baseline, MSC+ SG and the original spectrum; the determination coefficient (RP2) of models built under characteristic wavelengths were 0.83, 0.86 and 0.72, and the predict root mean square error (RMSEP) were 0.57, 0.09 and 0.12, which could replace the full-wave modeling. Thus, it is feasible for testing internal qualities of mutton quickly and nondestructively using NIR hyperspectral imaging technology.
    45  Rapid Determination of Diarrhetic Shellfish Poisoning in Shellfish by Colorimetric Protein Phosphatase Inhibition Assay
    GUO Meng-meng WU Hai-yan XUE Rui-yu TAN Zhi-jun LI Zhao-xin ZHAI Yu-xiu
    2014, 30(6):263-267.
    [Abstract](1436) [HTML](0) [PDF 518.18 K](736)
    Abstract:
    Okadaic acid (OA) and its derivatives, the components of diarrhetic shellfish poisoning (DSP), are potent inhibitors of protein phosphatases. Based on the mechanism of action, a protein phosphatase 2A (PP2A) inhibition assay for the rapid determination of DSP toxins in bivalve was developed. In this study, p-nitrophenyl phosphate (p-NPP) was used as the substrate and hydrolyzed by PP2A, then the product was measured at 405 nm. The total DSP content (calculated by OA) in samples could be detected according to the standard dose-effect curve developed with a series of OA standard solutions. The experimental conditions of sample preparation were optimized, and shellfish matrix loading limits for the protein phosphatase inhibition assay were established according to the shellfish species. The detection limit was 80 μg/kg, andthe spiked recoveries for OA in shellfish samples were between 90.43% and 118.52%, with relative standard deviations (RSD) ranged from 6.85% to 13.93%. The colorimetric protein phosphatase inhibition assay was simple, rapid and showed good recovery and reproducibility, demonstrating this proposed method could be used as an efficient analysis tool for rapid screening of DSP in shellfish and suit for daily monitoring to control shellfish toxicity.
    46  Effect of Alicyclobacillus acidoterrestris on Volatile Compounds and Color of Corn Juice Beverage
    XU Can LI Er-hu WANG Lu-feng FAN Gang XU Xiao-yun PAN Si-yi
    2014, 30(6):268-277.
    [Abstract](1413) [HTML](0) [PDF 630.30 K](802)
    Abstract:
    Thermoacidophilic bacterium were selected and screened from commercial maize beverage with smoky, antiseptic or disinfectant like flavor taints. A strain of Alicyclobacillus was isolated from spoilage samples with an optimum growth temperature of 45~50 ℃ and optimum growth pH of 3.5~4.0. The strain was identified as Alicyclobacillus acidoterrestris by 16S rDNA sequencing and inoculated to normal samples. Then inoculated samples were cultured at 45 ℃ for 30 days. Volatile compounds and colorimetric characteristics of the beverage were studied by gas chromatograph-mass spectrometer and colorimeter. Total amount of volatile compounds was similar among normal and inoculated samples but showed variation on key aromas. The concentrations of 14 volatile compounds in inoculated samples were significantly higher than normal samples. Among them, guaiacol and o-ethoxyphenol had an offensive smelling and their odor activity values were 1696.58 and 398.40, respectively. Colorimetric analysis showed that the white intensity increased in inoculated samples and the L value was significantly improved.
    47  Development of a Colloidal Gold Labeled Strip for the Rapid Detection of Bisphenol A
    WU Pan-pan LI Yue-ming ZHANG Jun ZHOU Li-hua ZHANG Kun ZHAO Su-qing ZHAO Feng-yi
    2014, 30(6):278-280.
    [Abstract](1295) [HTML](0) [PDF 517.57 K](692)
    Abstract:
    To establish a rapid method for detection of Bisphenol A (BPA), colloidal gold-based immune chromatographic assay (GICA) was used. After using artificial antigen of BPA to immune Balb/C mice, monoclonal antibodies against BPA were prepared by normal hybridoma technology. The monoclonal antibody was purified by precipitation of Caprylic Acid-Ammonium Sulfate (CA-AS) and it was identified as IgG2b subtypes. Colloidal gold was prepared through the reduction of gold chloride by sodium citrate acid, UV-Vis spectrum and transmission electron microscope (TEM) were performed, the results indicated that the colloidal gold had a single 530 nm absorption peak and its particle size was about 30 nm. The colloidal gold-antibody was produced by monoclonal antibody of BPA labeled with colloidal gold. In this study, the GICA sensitivity was about 100 ng/mL and the detection time was about 10 min. The cross-reactions showed that there was no cross-reaction between test strip and BPA analogues, but had good reproducibility. This method was convenient, rapid and effective for detecting BPA, and the development of GICA was applicable for the rapid determination of BPA in the field.
    48  A Method for Fast Quantitative Analysis of Major Wine Volatile Compounds Based on Liquid-liquid Extraction
    ZENG You DING Yi PENG Cheng
    2014, 30(6):281-288.
    [Abstract](1064) [HTML](0) [PDF 564.20 K](750)
    Abstract:
    In this paper, 3 mL wine was diluted with water (7 mL) and internal standard solution (60 μL 0.02% (V/V) 4-Methyl-2-pentanol), salted with 4.5 g ammonium sulfate and then extracted with 0.5 mL dichloromethane. After scrolled for 10 min and centrifuged for 10 min, the extract was injected in a GC system. ZB-WAX capillary column (30 m × 0.25 mm × 0.25 μm) used with the temperature program was as follows: 40 ℃ for 5 min, then raised at 3 ℃/min up to 190 ℃ for 10 min. N2 was used as carrier gas with flow rate of 1.5 mL/min, injection volume and input temperature were 0.5 mL and 200 ℃, and the injection mode was splitless. The results were detected by FID. The method could isolate 63 compounds from wine, and 30 of them were analyzed qualitatively. They included nine alcohols, eleven esters, eight organic acids, two aldoketones. Repeatability of 28 of them was less than 10% (as RSD) with the recoveries from 85% to 120%. The quantitative analysis by using internal standard solution was accurate. This method has the advantages of simple operation, little pollution, short time of pretreatment and good repeatability and accuracy, which satisfies the further demand of wine fingerprinting analysis technology.
    49  Identification of the Quality of Dried Shark Fins Products Based on Stable Isotope Ratio
    XIAN Yan-ping LUO Hai-ying GUO Xin-dong WU Yu-luan LUO Dong-hui DONG Hao
    2014, 30(6):289-293.
    [Abstract](1356) [HTML](0) [PDF 598.40 K](793)
    Abstract:
    By determining stable carbon and nitrogen isotope composition of large quantities of real dried shark fins products, the δ13C and δ15N value scopes were obtained. The samples can be identified by the comparison of carbon, nitrogen isotope compositions between real shark fins products and them. The carbon and nitrogen isotope ratios of 24 dried shark fins products were determined by element analyzer- isotope ratio mass spectrometry (EA-IRMS). Obvious difference in carbon and nitrogen isotope ratios was between real dried shark fins products and fake ones. The δ13C and δ15N values of real shark fins products ranged from -16.553‰ to -11.065‰ and 8.803‰ to 19.122‰, respectively, while those of fake shark fins products ranged from -18.122‰ to -16.507‰ and 6.253‰ to 7.313‰. Eleven samples were distinguished as fake shark fins products from all the 24 samples by the comprehensive judgment of the two indicators. This method is fast and convenient, and can be used to evaluate the quality of dried shark fin products. In addition, for those fake dried shark fins products made by leftover material of shark, which cannot be judged by PCR technique, this method can be applied to clearly differentiate real dried shark fins products with them, thus can remedy the defect of PCR method.
    50  The Contamination Investigation and ERIC-PCR Typing of Yesinia enterocolitica in Foods
    HU Hui-juan WU Qing-ping ZHANG Ju-mei PAN Li GUO Wei-peng WANG Hui-xian
    2014, 30(6):294-300.
    [Abstract](1326) [HTML](0) [PDF 590.31 K](738)
    Abstract:
    The contamination of Yesinia enterocolitica in seven kinds of food from 17 cities across the country was investigated for Y. enterocolitica distribution and genotypic diversity analysis. The microbiological examination of food hygiene--examination of Y. enterocolitica (GB/T4789.8-2008) and GB/T4789.8-2003 were slightly modified and used as the Y. enterocolitica detection methods. The ERIC?PCR fingerprinting of Y. enterocolitica was carried to typing. Fifty positive samples of Y. enterocolitica were detected from 946 food samples, and the total Y. enterocolitica contamination rate was 5.29%. Among the 50 positive samples, the raw meat, frozen food and edible fungi were 24 (12.06%), 25 (16.89%) and 1 (0.74%) respectively. The positive samples detected by GB/T4789.8-2003 method were 34 (3.59%) while were 25 (2.64%) by GB/T4789.8-2008. Cluster analysis showed that 72 Y. enterocolitica strains from 50 samples were divided into four groups and the type C was the main genotype, which initially established the Y. enterocolitica ERIC-PCR fingerprinting database .
    51  Application of Loop-mediated Isothermal Amplification on Pathogens Rapid Detection Key words:
    LI Lin ZHOU Rong LI Bing ZHAO Xi-hong BIAN Hua-wei
    2014, 30(6):301-307.
    [Abstract](1392) [HTML](0) [PDF 428.02 K](873)
    Abstract:
    Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method with many fragment amplification products according to specific region of target genes. Currently, precipitation, electrophoresis and fluorescence are the main methods to detect amplification products. Compared with PCR, amplification and detection process can be achieved in one step without template thermal denaturation, long time cycle and complex electrophoresis. Therefore, LAMP has been reported and applied in the field of bacteriological detection with advantages of rapid, easy operating, low-cost, highly sensitive and specific detection. In future, it is convinced that LAMP will replace PCR assays, contributing to more rapid, simple, specific and accurate detection method. Nowadays, LAMP has been applied on detection of various pathogenic microbes and embryo sexing, and the microbes include pathogenic bacterial, fungi, virus and parasites. This detection has been employed in different fields, such as food safety, clinical medicine and fishery. This paper described the features of LAMP and its application on rapid detection of bacterial, viruses, parasites and aquatic animal pathogens.

    Editor in chief:李琳

    Inauguration:现代食品科技

    International standard number:ISSN 1673-9078

    Unified domestic issue:CN 44-1620/TS

    Domestic postal code:46-349

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