Volume 33,Issue 11,2017 Table of Contents

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  • 1  Effect of BPS on the Differentiation of 3T3-L1 Preadipocytes and Its Mechanism
    ZHOU Xing-hua ZHANG Xiao-wei SUN Xin-juan XIAO Xiang ZHAO Yan-sheng ZHU Ying DONG Ying
    2017, 33(11):1-6. DOI: 10.13982/j.mfst.1673-9078.2017.11.001
    [Abstract](797) [HTML](440) [PDF 675.34 K](1122)
    Abstract:
    Bisphenol A (BPA) is restricted for its endocrine disruption and adverse health effects on the human body, so that bisphenol S (BPS) is widely used as a substitute n a variety of food packaging materials. The security of BPS has not been fully studied before its large-scale application.. In this study, 3T3-L1 preadipocytes were used as an in vitro model to investigate the effect of BPS on the differentiation of 3T3-L1 preadipocytes and its mechanism, to evaluate the safety of BPS and provide reference for the prevention of chronic metabolic diseases such as obesity. The results showed that BPS could promote the growth of 3T3-L1 preadipocytes and could significantly inhibit the proliferation of cells when the concentration was over 400 μmol/L. BPS could significantly induce the accumulation of lipid in the differentiated 3T3-L1 cells which showed a non-dose-dependent relationship. Compared with the model group, BPA up-regulated the expressions of PPARγ, C/EBR and aP2 genes, whereas BPS only seems to up-regulate the expression of PPARγ. In addition, BPS and BPA could significantly decrease the expression of GLUT4 gene (p<0.01). In conclusion, the pathways of BPS and BPA acting on adipocytes differentiation were not exactly the same, which might be accomplished under the combined action of various transcription factors.
    2  Effects of 6-Shogoal on the Apoptosis of Human Colorectal Cancer Cells and the Expression of Bax, BCL2, Caspase3 and pARp1
    WANG Yu-feng CHEN Chao YANG Chun LI Hai YANG Yin-xue
    2017, 33(11):7-15. DOI: 10.13982/j.mfst.1673-9078.2017.11.002
    [Abstract](1842) [HTML](267) [PDF 924.22 K](943)
    Abstract:
    In this study, HCT116 and HT29 were directly induced by 6-shogoal through in vitro cell experiment to investigate the effects of 6-shogoal on the apoptosis of human colorectal cancer cells and the expression of associated apoptotic proteins (Bax, BCL2, Caspase3 andPARP1). The changes of cell morphology with the treatment of 6-shogoal were observed by inverted phase contrast microscope. The inhibition rate of HCT116 and HT29 was detected by CCK8 and the cell proliferation curves were drawn.The apoptosis in human HCT116 and HT29 were detected by Annexin V-FITC/PI flow cytometr and the expression of related proteins (Bax, BCL2, Caspase3 and pARp1) was analyzed using western-blot). Compared with the model group, 6-shogoal could inhibit the apoptosis of HCT116 and HT29 in a concentration dependent manner (p<0.05), which also could enhance the expression of Bax, Caspase3 and PARP1 inhibit the expression of BCL2 and increase the ratio of Bax/BCL2 (p<0.05). Therefore, the apoptosis of HCT116 and HT29induced by 6-shogoalmay be related to the activation of Bax, Caspase3, PARP1 expression and the increase of the Bax/BCL2 ratio. This finding can provide references for the clinical treatment and prevention of colorectal cancer.
    3  Hepatocyte-protective Effect of Luteolin
    ZHENG Rui FU Xiong ZHAO Zhen-gang LIU Rui-hai
    2017, 33(11):16-22. DOI: 10.13982/j.mfst.1673-9078.2017.11.003
    [Abstract](942) [HTML](365) [PDF 796.16 K](868)
    Abstract:
    The hepatocyte-protective effect of luteolin was investigated in this study. Human cancer cells HepG2 were used as the liver model and H2O2 was taken as the source of oxidative damage. The experiment was divided into five groups as follows: blank group, damaged group, the protective group with low concentration of luteolin (0.5 μM+300 μM H2O2), the protective group with medium concentration of luteolin (5 μM+300 μM H2O2) and the protective group with high concentration of luteolin (10 μM+300 μM H2O2). Cell viability, reactive oxygen species (ROS) growth rate, cell cycle and apoptosis, as well as lactate dehydrogenase (LDH), superoxide dismutase (SOD) and catalase (CAT) activities were measured. With the protection of luteolin, the cell viability of 10 μM luteolin-protective group reached 84%, and the enzyme activities of LDH, SOD and CAT were significantly lower than those of the damaged group (p<0.05). The increase rate of ROS had no significant differences with the blank group (p>0.05). The results of flow cytometer showed that apoptotic rate decreased in dose-dependent with the increase concentration of luteolin, but there was no significant difference on the cell cycle between the damaged group and the luteolin-protective group (p>0.05). Our study demonstrated that luteolin had a good hepatocyte-protective effect and had the potential for application in food, nutraceuticals and cosmetics industry.
    4  Effects of Extraction Temperature on Physicochemical Properties and Immune Activity of Polysaccharide from Lentinula
    LUO Qi-chang CUI Chun LI Wen-Zhi
    2017, 33(11):23-30. DOI: 10.13982/j.mfst.1673-9078.2017.11.004
    [Abstract](811) [HTML](236) [PDF 752.24 K](795)
    Abstract:
    The effect of extraction temperature on the structure of Lentinan polysaccharide was investigated three kinds of Lentinan polysaccharide samples, including LEP-A, LEP-B and LEP-C, were obtained from Lentinus edodes by hot water extraction method. The extraction conditions were as follows: the ratio of material to liquid was 1:20 and extraction times for 2 with different extraction temperature changing from 100℃ to 140℃. The content of polysaccharide significantly increased with the increase of extraction temperature. High performance liquid chromatography (HPLC) analysis showed that the monosaccharide composition of three crude polysaccharides contained only glucose. Analysis of IR spectrum proved that three kinds of polysaccharides contained the stretching vibration of -OH at 3600- 3000 cm-1, the stretching vibration of -CH at 3000 -2800 cm-1, and the stretching vibration of carboxyl at 1430-1200 cm-1. All of them were the characteristic IR absorption peaks of polysaccharides. In combination with other characteristic absorption peaks, the polysaccharide was confirmed as a pyran polysaccharide. LEP-A, LEP-B and LEP-C immunoreactivity analysis showed that the three kinds of Lentinan polysaccharide samples could improve the phagocytosis of macrophages and stimulate the proliferation rate of T lymphocytes and B lymphocytes. Also, the activities of polysaccharide obtained at low extraction temperature such as 100℃ and 119℃ were higher than that at 140℃.
    5  Effects of κ-Carrageenan on the Rheological Characteristics and Structure of Gluten during the Frozen-thaw Storage
    WANG Ting WANG Kai HU Zhuo-yan ZHAO Lei
    2017, 33(11):31-36. DOI: 10.13982/j.mfst.1673-9078.2017.11.005
    [Abstract](858) [HTML](305) [PDF 681.61 K](1157)
    Abstract:
    In this paper, the effects of κ-carrageenan on the rheological properties, secondary structure and microscopic property of gluten during the frozen-thaw storage were studied by Rheometer, Fourier Transform Infrared Spectroscopy (FTIR) and Confocal Laser Scanning Microscope (CLSM). The results showed that the changes of the storage modulus (G'), loss modulus (G") and the secondary structure of the gluten were divided into three stages during the frozen-thaw storage. The first stage was form 0 d to 30 d, where the G' and G" of the gluten decreased dramatically, and the content of β-sheet (1629 cm-1) increased significantly with decreasing the content of α-helix (1656 cm-1) simultaneously. The second stage was form 30 d to 90 d, where the changes of rheometer parameters and secondary structure were not significant. During the third stage from 90 d to 120 d, the G' and G" of the gluten dropt again, while the content of β-sheet (1613 cm-1) increased significantly with the decrease of α-helixcontent simultaneously (1656 cm-1). CLSM photographs showed that the distribution of carrageenan mainly concentrated on the edge of gluten network on the frozen-thaw 0 d, and then the carrageenan fully mixed with wheat gluten during the storage, which led to enhance gel properties of gluten. However, the gluten network structure was further damaged and a large number of irregular hole emerged up to 90 d.
    6  Screening the Saccharomyces Cerevisiae with High Temperature Toleranceby ARTP Mutagenesis and Genome Shuffling
    ZHAO Yu LIU Shan-shan CHEN Ye-fu HAO Ai-li HONG Kun-qiang FU Xiao-meng WANG Peng-fei XIAO Dong-guang
    2017, 33(11):37-41. DOI: 10.13982/j.mfst.1673-9078.2017.11.006
    [Abstract](900) [HTML](163) [PDF 528.84 K](827)
    Abstract:
    Saccharomyces cerevisiae has the advantages of fast fermentation speed, short fermentation cycle, low viscosity of fermentation raw materials and low production cost during the high temperature fermentation in industrial production, which is more suitable for simultaneous saccharification fermentation technique. Therefore, S. cerevisiae strain with high temperature tolerance is of great significance in the industrial application. In this study, AY12 was used as the starting strain, which was isolated from industrial strains. The strain was mutated by atmospheric and screened at 37 ℃. Then, 150 strains with good colony growth were obtained. By the way, the stains were carried out to achieve genome shuffling by sporulation and hybridization, and 137 strains with good growth performance were obtained by re-screening at 37℃. After fermentation in the corn hydrolysate at 35 ℃, 14 strains were obtained with good fermentation performance. The strains were rescreened by the simultaneous saccharification fermentation at 35 ℃, and the ethanol yield and residual sugar content of each strain were determined. Finally, 7 strains were screened with good tolerance to high temperature fermentation. L-38 was screened as the best fermentation performance strain after the simultaneous saccharification fermentation. Compared with the starting strain AY12, the ethanol yield of L-38 was 16.20% (V/V), which increased by 8.00%., and the residual sugar content was 35.50 g/L, which was 32.38% lower than that by AY12.
    7  Fibrillar Aggregation Behavior and Stability of Soy Globulin
    WANG Jin-mei WANG Meng-ping WEI Cui-lan YANG Xiao-quan QI Jun-ru
    2017, 33(11):42-48. DOI: 10.13982/j.mfst.1673-9078.2017.11.007
    [Abstract](1236) [HTML](304) [PDF 639.01 K](1133)
    Abstract:
    In order to better define fibrillar aggregation behavior of protein, the heat-induced soy globulin (11S) fiber aggregation process under acidic conditions was investigated in the subunit level to monitor the hydrolysis process, structural change and stability of the protein and its subunits by using 11S as raw material. The hydrolysis kinetics results showed that the fibrillar aggregation process of 11S was a multistep process, including the hydrolysis of polypeptide chains, self-assembly into amyloid fibrils aggregates and the gradual accumulation of macroscopically visible fibrous aggregates with twisted helical structures. Compared with the single exponential growth of the 11S fibrosis process, the fibrosis process of the acidic subunits was delayed. The acidic subunits mainly contributed to the nucleation process of fibril aggregation in the early stage, while the addition of basic subunits could change the process of fibril aggregation. The fibril aggregates of protein could increase the solubility of 11S at isoelectric point and decrease the solubility at neutral acidic pH. In addition, the alkaline environment (pH 10.0) would cause 11S fiber aggregates to dissolve completely, and the macroscopic fiber length becomes shorter and the structure changes. The results might provide a theoretical basis for the rational use of soy protein fibril aggregates as a novel functional food ingredient.
    8  Kinetics and Thermodynamics of Pb (Ⅱ) Absorption by Black Seed Coat Superfine Powder of Pepper
    YANG Mo XUE Yuan WANG Xiao-jing LEI Hong-jie XU Huai-de
    2017, 33(11):49-54. DOI: 10.13982/j.mfst.1673-9078.2017.11.008
    [Abstract](711) [HTML](244) [PDF 7.16 M](874)
    Abstract:
    The black seed coat powder of pepper was used as the biological adsorbent in this study. First, the adsorption effects of particle sizes black seed coat powder of pepper on Pb2+ were discussed, and then the adsorption mechanism of the black seed coat superfine powder of pepper, was studied. The adsorption isotherm, thermodynamics and kinetics during adsorption process were investigated. Results showed that the black seed coat superfine powder of pepper exhibited an effective adsorbability of Pb2+among the coarse powder and fine powder, and the maximum adsorption quantity was 15.54 mg/g. When the initial concentration of Pb2+ was 10~90 mg/L, the adsorption equilibrium could be described by the Langmuir isotherm, which indicated that the biosorption of Pb2+ by superfine powder was a monomolecular layer adsorption. The biosorption kinetics was described by the pseudosecond-order model, which could be affected by film diffusion and intra-particle diffusion, and the former was the rate-limiting step. When the temperature was in the range of 25~45 ℃, thermodynamic parameters including the changes of free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were less than 0, suggesting that the adsorption process was spontaneous, exothermic process and belonging to physical adsorption.
    9  Expression and Identification of CP4-EPSPS Gene in Pichia pastoris
    ZHAO Hui MAO Bi-qi LIANG Zhi-cheng GONG Shi-di
    2017, 33(11):55-62. DOI: 10.13982/j.mfst.1673-9078.2017.11.009
    [Abstract](999) [HTML](330) [PDF 668.08 K](822)
    Abstract:
    Constructing the genetically modified (GM) Pichia pastoris stains is the key step forestablishing a new method to assess the safety of foreign protein . Based on the research model of the 5-enolpyruvyl shikinmate-3-phosphate synthase derived from Agrobacterium CP4 strain (CP4-EPSPS), the cp4-epsps gene was chemically synthesized after optimizing thecodon usage bias. The codon adaption index (CAI) of optimized sequence was 0.85, and the GC content of optimized sequence was 52%. Cp4-epsps gene was amplified by PCR and cloned to the expression vector pPICZb of Pichia pastoris GS115 through homologous end-joining, and the recombinant vector pPICZb-EPSPS was constructed. The correct recombinant vector was transferred into GS115 strain through electroporation, and four positive strains were screened through the right site via PCR. Then, those positive strains were induced by 0.5% methanol for four days at 28 ℃, 250~300 r/min. Finally, the expression of cp4-epsps in GS115 was identified from CP4-EPSPS monoclonal antibody and C-MYC monoclonal antibody by SDS-PAGE and western blotting. The results showed that the target gene was expressed in GS115 strain and MW of protein was 50 ku, which coincided with the theoretical results. In conclusion, the construction of transgenic Pichia pastoris GS115 strains is beneficial for the safety assessment of transgenic CP4-EPSPS synthase in GM crops.
    10  Effects of Polyphenols on the Wine Astringency by Phenolic/Protein Interaction Model
    ZHU Yan-yun WANG Xiao-yu DU Guo-rong TIAN Cheng-rui WANG Xue-hui REN Meng-meng ZHANG Juan
    2017, 33(11):63-69. DOI: 10.13982/j.mfst.1673-9078.2017.11.010
    [Abstract](722) [HTML](210) [PDF 541.78 K](759)
    Abstract:
    The difference of the interaction between phenolic compounds and protein with diverse polymerization degrees in different red wines was investigated to find out the key components of astringency for improving the wine-making process and selecting grape varieties. Using the different varieties of red wines as material, the phenolic substances of wine were divided into three parts by C18 solid phase extraction column: monophenols, oligomers and polymers. The contents of total phenols and total flavanols were determined. The interactions of different phenolics and protein were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fluorescent spectrometry. There were significant differences in total phenols and total flavanols contents in red wines. The contents of total phenols and total flavanols of phenolic fragments with different degrees of polymerization in red wines were as follows: monophenols < oligomer < polymer. The results of SDS-PAGE and fluorescence spectrometry showed that the effect of high polymers on the protein was the strongest, and the effects of monophenols and oligomers in different wines on the protein presented variance. The composition with different degrees of polymerization in the wine had different effects on the wine astringency. In the process of selecting grape varieties and improving the wine-making process, the control of the phenolic substance could be considered, especially for the regulation of the polymer.
    11  Nutrition Component Contents and Carbon Nitrogen Isotope Characteristics of Different Varieties of Vegetables
    YU Li-mei LIU Xiao-jing NONG Zhong-wen CHEN Hai-guang BU Jian-zhen ZHOU Shu-yi
    2017, 33(11):70-74. DOI: 10.13982/j.mfst.1673-9078.2017.11.011
    [Abstract](722) [HTML](198) [PDF 581.73 K](1059)
    Abstract:
    The nutrition components and carbon nitrogen isotope characteristics in organic vegetable and ordinary vegetable were investigated to classify their differenceof, by the chemical analysis and stable isotope mass spectrometry method in this study. The results showed that the moisture contents of the organic vegetables were slightly lower than those of ordinary vegetable. Meanwhile, the contents of phenolic, protein, total sugar and vitamin C of organic vegetables were higher than those of ordinary vegetables. Among them, the contents of vitamin C of 7 kinds of organic vegetables was 1.11~2.90 times of ordinary vegetables, titrated acid content of organic vegetables was 1.1~1.5 times higher than that of the ordinary vegetables, and total sugar content of organic vegetables was 1.09~1.34 times higher than that of the ordinary vegetables. The Carbon Nitrogen Isotope had different values among seven vegetables, the δ15N values of organic corn and eggplant are 5.36 and 4.62 higher than those of the ordinary one, respectively, which contributed to the different plant models. According to comprehensive analysis, the nutrients and carbon nitrogen isotope characteristics of organic vegetables are different form ordinary vegetables, which are caused by the different cultivation environment and fertilization standards between vegetables.
    12  Effects of Ultrasound-Assisted Salting on the Quality and Microstructure of Dried Grass Crap
    WANG Teng NING Zheng-xiang ZHANG Ye-hui ZHANG You-sheng
    2017, 33(11):75-82. DOI: 10.13982/j.mfst.1673-9078.2017.11.012
    [Abstract](780) [HTML](330) [PDF 595.13 K](843)
    Abstract:
    The grass carp salting was treated with ultrasound to reduce the salting and drying time. The effects of ultrasound treatment on the saline temperature , moisture content, salinity, texture, microstructure and sensory evaluation of dried grass crap were investigated after salting treatment assisted with different ultrasound power (0 W, 120 W, 240 W, 360 W and 480 W) at 40 kHz and then dried with low temperature heat pump operated at 20 ℃ with 50% humidity. Results showed that the ultrasound had an obvious heat effect. Compared to the ambient temperature, the temperature of saline could be increased by 4~16 ℃with ultrasound treatment (180 min) in an open salted container. The salinity, elasticity and sensory scores increased from 3.58%, 0.70 g, 29.00 to 5.21%, 0.84 g and 43.00, respectively, after treated with ultrasound-assisted salting 120 min and then dried with heat pump for 50 h, and the moisture content and hardness decreased from 27.04% and 2355 N to 24.88% and 1582 N, respectively. Results of paraffin sections and scanning electron microscopy showed that the ultrasound-assisted salting treatment completely destroyed the connective tissues among the muscle fibers, and a quick salt could enter into the muscle fiber cells, which made muscle tissues more full. Consequently, ultrasound-assisted salting could accelerate the rates of salting and drying of grass crap, which improved the quality of dried grass crap product.
    13  Characteristics of Enzymatic Hydrolysis of Defatted Peanut Meal with Different Substrate Concentrations
    LI Lu-fang ZHAO Mou-ming ZHANG Jia-nan SU Guo-wan
    2017, 33(11):83-88. DOI: 10.13982/j.mfst.1673-9078.2017.11.013
    [Abstract](786) [HTML](257) [PDF 432.00 K](808)
    Abstract:
    Defatted peanut meal is the main byproduct during peanut oil production, while high degree of denaturation in the press process leads to lower protein utilization. In this study, the peanut meal was hydrolyzated by proteases from Aspergillus oryzae induced by fermentation technology. The protein recovery rate, degree of hydrolysis, total sugar recovery, molecular weight (MW) distribution and free amino acid composition of hydrolysate with different substrate concentrations were compared. At the same time, the sensory evaluation of the hydrolyzate containing flavor peptide was carried out by the electronic tongue to investigate the characteristics of enzymatic hydrolysis of defatted peanut meal with different substrate concentrations and select the appropriate enzymatic concentration. The results showed that the protein recovery rate of the defatted peanut meal was between 70.68% and 84.14% and the degree of hydrolysis was between 30.04% and 40.05%. The peptides fractions <1 ku were the main component of the total peptides (87.57%~90.21%). The hydrolysate was rich in taste peptides and showed good umami tastes. In addition, when the ratio of material to liquid was 1: 5, the hydrolysate showed higher protein recovery and degree of hydrolysis, more small peptides and better umami taste.
    14  The Changes of Bacterial Community Structure of Hot Air Dried Daqu during the Storage
    WANG Hong LUO Hui-bo ZHOU Ping HUANG Dan DENG Bo SHEN Cai-ping WU Jie-feng
    2017, 33(11):89-95. DOI: 10.13982/j.mfst.1673-9078.2017.11.014
    [Abstract](689) [HTML](200) [PDF 640.81 K](783)
    Abstract:
    Bacterial community structure of hot air dried Daqu in the storage period was researched by high-throughput sequencing technology. The results showed that the bacterial abundance of hot air dried Daqu increased firstly and then reduced with increasing the storage time, while bacterial community diversity increased all the time. Firmicutes was the absolute dominant phyla, and Weissella was the absolute dominant genera. Hot air drying for Daqu stored in Daqu room could promote the growth of Staphylococcus bacteria, and inhibit the growth of Lactobacillus bacteria. Hot air drying for Daqu stored under laboratory conditions could promote the growth of Kroppenstedtia bacteria and Bacillus bacteria. With increasing the storage time, laboratory conditions could promote the abundance of Paenibacillus, Pseudogracilibacillus, Kroppenstedtia, Melghirimyces bacteria of hot air dried Daqu. The bacterial biomass of hot air dried Daqu stored in Daqu room tended to be stable with increasing the storage time.
    15  Effects of Raising Fragrant Time on the Physico-Chemical Quality of Yuan’an Yellow Tea
    YE Fei TENG Jing GONG Zi-ming GAO Shi-wei GAO Zhi-ming LIU Pan-pan WANG Xue-ping ZHENG Peng-cheng WANG Sheng-peng ZHENG Lin
    2017, 33(11):96-101. DOI: 10.13982/j.mfst.1673-9078.2017.11.015
    [Abstract](753) [HTML](181) [PDF 513.89 K](884)
    Abstract:
    The sensory quality, color, physico-chemical quality and aroma components of Yuan’an yellow tea were investigated using a new designed machine at 130 ℃with different time (12.5min, 15min, 17.5min, 20min and 22.5 min). The results indicated that as the raising fragrant time increased, the sensory quality of tea increased and then decreased; the total color difference was not obvious; but the hue (a/b) of dry tea, tea brew and infused leaves were yellowed obviously (p<0.01) and the brightness of tea brew and infused leaves (L) decreased (p<0.01). The content of polyphenols decreased significantly (p<0.01) and the amino acids increased first and then decreased. The content of baked aroma components including 2-methylfuran increased. When the raising fragrant time was 20min, the qualities of sensory and catechin (p<0.01) were the highest and the contents of polyphenols and amino acids were the lowest .The content of baked aroma components such as hexaldehyde, benzaldehyde, nerol, limonene, indole and longiborneol were also the highest. Consequently, the utilization of the new designed machine for 20 min would be an effective method to improve the quality of Yuan’an yellow tea.
    16  Toxicological Safety Evaluation of Royal Jelly Acid Lyophilized Powder
    BAI Bing-yao ZHOU Qian YANG Guang DONG Xiao-han YAN Chen-jing HAN Xue CAI Dong-wei ZHAO Wen
    2017, 33(11):102-109. DOI: 10.13982/j.mfst.1673-9078.2017.11.016
    [Abstract](755) [HTML](256) [PDF 556.04 K](853)
    Abstract:
    The safety of lyophilized powder of royal jelly acid was studied for the reasonable utilization and development of eleutheroside. According to the national standard procedures and methods in food safety and toxicological evaluation, a series of toxicological studies on the ingestion of eleutheroside were conducted, including the acute oral toxicity test in mice, genetic toxicity tests (salmonella typhimurium reverse mutation test (Ames test), mouse bone marrow cell micronucleus test and mouse sperm malformation test) and a 30-day feeding test in rats. Oral acute toxicity test showed that the medium lethal dose (LD50) of the powder was above 20 mg/kg·bw for both male and female mice. The results of Ames test, mouse bone marrow micronucleus test and spermabnorinality test were negative. The 30-day feeding test showed that the physical appearance and indices of hematology, biochemistry, organ coefficients and histological observations of rats had no significant differences as compared with the control group.
    17  Synthesis of Diacylglycerol in Soy Sauce Residue Oil Catalyzed by Immobilized Lipase
    LIU Fang MIAO Jian-yin HUANG Zao-cheng ZHENG Zhong-mu DAI Wei-jie ZHOU Cong CAO Yong
    2017, 33(11):110-118. DOI: 10.13982/j.mfst.1673-9078.2017.11.017
    [Abstract](704) [HTML](337) [PDF 659.42 K](761)
    Abstract:
    Soy sauce residue oil was was extracted with free fatty acids content of 61.50% by a novel continuous phase transition extraction method at low temperature, and the self-made immobilized lipase HMIM with Sn-1, 3 specificity was used to catalyze the synthesis of diacylglycerol. The enzyme dosage the content of glycerin, reaction temperature, metal ions and auxiliary acid treatment methods were optimized, and the optimal conditions were determined as follows: immobilized lipase dosage 1%, content of glycerol 1.2 times of the required, reaction temperature: 65 ℃, vacuum degree; 0.098 MPa, K+ concentration 2 mmoL, stirring speed 20 r/min and reaction time 10 h. Under these conditions, the free fatty acid esterification rate was 96.36% and the content of diglyceride was 48.65% (43.65% of 1,3-DG, 5.00% of 1,2-DG). The contents of FFA, MG and TG were 2.24%, 9.31% and 39.80%, respectively. Results showed that esterification reaction would not change the fatty acid composition of soy sauce residue oil. Process of Enzymatic esterification not only reduced the acid value of soy sauce residue oil but also increased the contents of functional diacylglycerol, which provided a new method for the development and utilization of soy sauce residue.
    18  Extraction and Purification of Flavonoids from Buckwheat Bran and Preparation of Chitosan Composite Membrane
    WANG Yu-ru YUE Tian-li YUAN Ya-hong CAI Rui WANG Zhou-li
    2017, 33(11):119-126. DOI: 10.13982/j.mfst.1673-9078.2017.11.018
    [Abstract](700) [HTML](189) [PDF 536.88 K](735)
    Abstract:
    In order to improve the utilization of buckwheat and prolong the shelf life of fresh cut fruits and vegetables, the industrial waste residue of buckwheat bran was used as raw materials to extract flavonoids by ultrasonic-assisted alcohol dissolution method. The extraction process was as follows: ethanol 70% (volume fraction), the extraction temperature 50℃, the ratio of material to liquid 1: 40 (m/V) The ultrasonic frequency was 2500 Hz and the extraction time was 40 min. The yield of flavonoids in buckwheat bran was 29.3 mg/g. The bacteriostatic effect of buckwheat bran flavonoids on the two kinds spoilages of fresh fruits and vegetables was studied, the results showed that the minimum inhibitory concentration (MIC) of buckwheat bran flavonoids on Escherichia coli and Pseudomonas fluorescens were 0.595 and 1.19 mg/mL, respectively. The minimal bactericidal concentration (MBC) of Escherichia coli and Pseudomonas fluorescens were 1.19 and 2.38 mg/mL, respectively. The extracted flavonoids were mixed with chitosan and Freeze-dried to prepare composite membrane. The reparation process was as follows: flavonoid-chitosan ratio 27%, and glycerol-chitosan ratio 1: 3. The composite film had a good antibacterial effect and was safe, simple operation, and low-cost.
    19  Microwave Extraction Process and Anti-oxidization of Active Components from Cinnamomi Cortex
    LIU Lin-qi ZHAO Chen-xi LI Jing-feng PENG Yu-jiao LUO Jin-hua TANG Wei-zhuo ZHENG Qun-yi
    2017, 33(11):127-133. DOI: 10.13982/j.mfst.1673-9078.2017.11.019
    [Abstract](702) [HTML](229) [PDF 575.70 K](1086)
    Abstract:
    The microwave extraction process, the correlation of antioxidant abilities and active components from Cinnamomi cortex were investigated in this study. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging rate and ferric reducing antioxidant power (FRAP) were used as the evaluation indexes. The chemical antioxidants butylated hydroxytoluene (BHT) and ethoxyquine (EMQ) were used as positive control. Based on the single-factor tests, the microwave extraction process of active components from Cinnamon cortex was optimized by orthogonal experimental design. The ultra performance liquid chromatography (UPLC) separation method was established for active components extracted from Cinnamomi cortex and the correlation of antioxidant capacity of the extract and active components was elucidated by UPLC-DPPH coupled method. The results showed that the optimized extraction process of Cinnamomi cortex was as follows: ethanol 70%, ratio of liquid-solid was 10:1 (mL/g), extracting temperature 65℃ and extraction time 10 min. And the extracts obtained from Cinnamomi cortex showed much higher DPPH radical scavenging rate of 92.18% and FRAP value of 32.90 μmol/L. The IC50 of Cinnamomi cortex extract on DPPH radical scavenging rate was 55.0 mg/L, which was almost equal to seven times of that of BHT (IC50=390 mg/L) and equivalent to that of EMQ (IC50=55.0 mg/L). Analysis of DPPH radical scavenging rates and UPLC chromatograms of 10 batches of Cinnamomi cortex extracts showed that the anti-DPPH free radicals were due to the interaction of various active components such as cinnamaldehyde and coumarin, but not linearly related to the content of cinnamaldehyde. It was not comprehensive to evaluate the quality of Cinnamomi cortex only with cinnaldehydum.
    20  Preparation and Adsorption Properties of Enrofloxacin MolecularImprinted Polymer Film
    LV Chun-hui FANG Guo-zhen WANG Shuo
    2017, 33(11):134-139. DOI: 10.13982/j.mfst.1673-9078.2017.11.020
    [Abstract](587) [HTML](222) [PDF 553.48 K](915)
    Abstract:
    The enrofloxacin molecular imprinted polymer film was directly synthesized on the surface of polystyrene microtiter plate by surface imprinting technique using the enrofloxacin (ENRO) as template, methacrylic acid (MAA) as functional monomer and ethyleneglycol dimethacrylate (EDMA) as cross-linker. The enrofloxacin molecular imprinted polymer film was characterizedby FT-IR, scanning electron microscope, adsorption-equilibrium experiments, scatchard analysis and adsorption kinetic experiments. The results showed that the imprinted film exhibited good imprinting effect, high specific adsorption ability and fast mass transfer rate. Scatchard analysis indicated that the imprinted film contained two types of binding sites with specific binding properties. The dissociation constant (Kd) and maximum binding capacity (Qmax) of the two linear curves were 19.49μg/mL, 12.98 μg/mL for the higher affinity sites and 277.78 μg/mL, 98.14 μg/mL for the lower affinity sites, respectively, and the heterogeneous of MIP could be ignored in MIAs. The enrofloxacin- specific polymer film synthesized by the proposed method could be used as a biomimetic antibody to determine the enrofloxacin residues in food by competitive immunosorbent assay.
    21  Effects of Drying Methods and Raw Material Ratio on the Quality of Restructured Carrot-Potato Chips
    HOU Chun-hui YI Jian-yong BI Jin-feng LIU Chang-jin ZHOU Lin-yan PENG Jian
    2017, 33(11):140-147. DOI: 10.13982/j.mfst.1673-9078.2017.11.021
    [Abstract](816) [HTML](286) [PDF 675.16 K](947)
    Abstract:
    The effects of drying methods and raw material ratio on drying characteristics and quality of restructured carrot-potato chips were investigated using hot air drying (AD), freezing drying (FD), combined hot air and instant controlled pressure drop drying (AD-DIC), combined freezing drying and instant controlled pressure drop drying (FD-DIC) respectively. The results showed that the hardness and crispness, glass transition temperature, contents of total sugar and vitamin C of the restructured chips decreased gradually with the increase of the carrot ratio \with the same drying mode, while the ‘a*’ value, ‘b*’ value and the total carotenoid content increased gradually. Compared with AD or FD, the values of ‘a*’, ‘b*’, hardness, total content of carotenoid and vitamin C in restructured chips prepared by AD-DIC and FD-DIC were lower but the crispness was higher at the same raw material ratio.AD-DIC and FD-DIC could be used as the appropriate drying methods for preparation of restructured carrot-potato chips in terms of production cost or product quality. High quality of the products prepared by FD-DIC was achieved at potato-carrot ratio of 1:1 (m/m), followed by the ratio of 3:7 (m/m).
    22  Hot Air Drying Characteristics and Dynamics Model of Areca Catechu
    ZHAO Zhi-you XIAO Dong CHAO Yu-zhou FU Xiao-mei XIA Yan-bin
    2017, 33(11):148-155. DOI: 10.13982/j.mfst.1673-9078.2017.11.022
    [Abstract](832) [HTML](206) [PDF 620.82 K](847)
    Abstract:
    The relationships between the parameters of drying characteristics, effective moisture diffusion coefficient, apparent activation energy and the drying kinetics equations of Areca catechu in different temperatures were studied using the Fick’s second law and the mathematical model of betel nuts drying. The results showed that the drying curve of betel nuts at 70 ℃ and 75℃ had a significant difference; and the hot air drying was a process of falling-rate drying of internal moisture diffusion control. The variation range of water diffusion coefficient of Areca catechu (65℃~85℃) was as follows: friut areca catechu Deff =6.45×10-9~1.17×10-8 m2/s Smoke areca catechu Deff =7.47×10-9~1.21×10-8 m2/s. Apparent activation energy was: friut areca catechu Ea = 30.32 kJ/mol, smoke areca catechu Ea = 23.38kJ/mol. The constant coefficient of the single diffusion model and the Page model was significantly affected by temperature(p<0.05) and single diffusion drying model was the best mathematical model for describing edible areca (Friut areca catechu: R2avg =0.97, RMSEavg =0.023; Smoke areca catechu: R2avg=0.98, RMSEavg=0.025); The drying models of hot air drying at 65℃-85℃ were described as : MR Friut areca catechu =(2×10-4T2- 0.037T+2.54)exp-(3×10-5T3-0.0064T2+0.51T-13.06)t; MR Smoke areca catechu=(3×10-4T2-0.0616T+3.67)exp- (-4×10-4T2+0.061T-2.027)t.
    23  The Processing of Enzymatic Liquefaction of Pitaya Juice
    ZHANG Yue-ying LI Guo-sheng BAI Xin-peng YANG hui-qiang
    2017, 33(11):165-170. DOI: 10.13982/j.mfst.1673-9078.2017.11.024
    [Abstract](692) [HTML](224) [PDF 476.86 K](921)
    Abstract:
    The effects of enzymatic hydrolysis on the fruit pulp were investigated in this study. The optimum conditions were investigated based on the viscosity and juice yield of the pitaya juice. On the base of single factor analysis, the suitable temperature, time, enzyme dosage and the best value range of pH value were determined, and then the best choice of single enzyme and compound enzymes were confirmed. Eventually, the optimum technical conditions for liquidizing pitaya juice were confirmed by L9 (34) orthogonal analysis and the optimum technological conditions were verified. The combination of pectinase, cellulase and hemicellulase was used under the conditions of temperature 50℃, time 45 min, enzyme adding quantity 0.07% and pH value 4.3. Under these conditions, the pitaya purees viscosity was sharply decreased by 170.5 mpa·s and juice yield was obviously increased by 14.8%. Besides, the pitaya juice had good color and acceptable taste.
    24  Effects of Drying Temperatures on the Volatile Flavor Compounds in White Tea
    QIAO Xiao-yan WU Hua-ling CHEN Dong
    2017, 33(11):171-179. DOI: 10.13982/j.mfst.1673-9078.2017.11.025
    [Abstract](686) [HTML](185) [PDF 445.04 K](980)
    Abstract:
    The volatile flavor compounds (VFC) in a white tea Danxia 2 was analyzed at different drying temperatures by headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) method. The results showed that the relative contents of alcohols and esters decreased with the increase of drying temperature, while ketones, aldehydes, hydrocarbons and furans increased. The results of principal component and cluster analysis of VFC were consistent with the results of sensory evaluation in white tea. The results showed that the aroma profiles revealed stages changes and the critical temperature points of the aroma profile change were 60℃, 100℃ and 120℃. Aromatic hydrocarbons, C10 mono-terpenes and esters were the representational VFC in white tea at different temperatures. Aldehydes and ketones had additive effect on the aroma of white tea; the positive effect of aldehydes on the aroma was greater than that of ketones. However, alcohols had a negative effect on the aroma of white tea. Esters were the key reasons of why the aroma of white tea changed from unpleasure to pleasure. The increasing contents of the C10-C11 aromatic hydrocarbons and C10 mono-terpene led to a further aggravation of scorch odour and the bitter smell.
    25  Effect of the Thermal Packaging on Preservation of PuCheng ChuanToumo
    ZHOU Wen-li ZHANG Jian-xin CAO Zhi-yong LI Sai-jie LI Chun-hua
    2017, 33(11):180-190. DOI: 10.13982/j.mfst.1673-9078.2017.11.026
    [Abstract](660) [HTML](228) [PDF 566.02 K](823)
    Abstract:
    The effect of thermal packaging on the quality of Chuan Toumo was studied for prolonging the shelf-life of Pu cheng Chuan Toumo. . The changes of microorganism, physicochemical indexes and sensory evaluation indexes were measured at 25°C using the product packaged at room temperature as a control. The results showed that the total number of bacterial colony changes in thermal packaging was smaller than that in the control group during the storage. The control group got mouldy in 6 days, and no mould was detected in the experimental group within 15 days. The hardness, adhesiveness and chewiness of Chuan Toumo increased during the storage, while the moisture content, water holding capacity and cohesiveness decreased. Compared with the control group, the moisture content, water holding capacity and cohesiveness were higher within the 6 days, while the hardness and adhesiveness were lower. There were 26 kinds of volatile compounds in Chuan Toumo, and the content of esters, alcohols and acids decreased during the storage, while the content of aldehydes, ketones and hydrocarbons increased. The total number of bacteria in the experimental group increased during the storage of 6~15 d, the sensory quality decreased gradually, and the sensory score was 65.19 in thirteen day. Considering the microorganisms, physicochemical indexes and sensory evaluation indexes, the thermal packaging could prolong the shelf-life of ChuanTouMo for about 13 days.
    26  Preparation of a Compound Beverage with Ganoderma Lucidum and Black Tea
    LIU Jin FANG Jun XIE Yan-hua LI Meng-dan CHEN Li-li XIA Zhi-lan
    2017, 33(11):191-200. DOI: 10.13982/j.mfst.1673-9078.2017.11.027
    [Abstract](697) [HTML](268) [PDF 714.80 K](885)
    Abstract:
    A compound tea beverage was developed by using Ganoderma lucidum enzymolysis solution and black tea extract as the basic raw material and adding proper auxiliary material. The extract of Ganoderma lucidum was obtained by enzymolysis, and the black tea extract was obtained by extraction. Then, the optimum formula was obtained by single factor test and orthogonal test according to sensory evaluation standard and fuzzy mathematics evaluation method. The results showed the best formula was as follows: Ganoderma lucidum extract/black tea extract/water 42.5/22.5/35, β-cyclodextrin 3%, sugar 1.4%, maltodextrin 1.4%, sodium alginate 0.04%, D-sodium ascorbate 0.024% and CMC-Na 0.18%. Under these conditions, the sensory evaluation score of Ganoderma lucidum and black tea compound tea was the highest and shelf life could reach 120 d. 24 kinds of volatile components were identified and confirmed by gas chromatography-mass spectrometry (GC-MS). The relative contents more than 2% among them were 2-ethylhexan-1-ol (78.27%), isoamyl alcohol (9.30%), isoamyl acetate (3.88%) and undecane (2.82%). The aroma components of Ganoderma lucidum and black tea were retained in this beverage.
    27  Effect of Packaging on the Buffering Capacities of Hami Melon during Dropping Process
    CAI Mei-hui LI Bin MA Yue ZHAO Xiao-yan ZHANG Chao
    2017, 33(11):201-205. DOI: 10.13982/j.mfst.1673-9078.2017.11.028
    [Abstract](627) [HTML](194) [PDF 395.49 K](684)
    Abstract:
    The effect of packaging on the buffering capacities of hami melon during dropping process was evaluated. The hami melon was packaged by the 3, 5, and 7-layer corrugated carton, or filled by 5 different fillers. And the gravity acceleration of the packaged melon was measured during the dropping process. The 7-layer corrugated carton presented the lowest acceleration, 3.6% and 2.1% lower than the 3-layer and 5-layer corrugated carton, respectively. The acceleration presented the negative correlation with its thickness and edgewise compressive strength with the correlation of -0.987 and -0.994, respectively. The bulk pearl cotton presented the lowest acceleration, being of 27.1%, 23.2%, 11.5% and 3.9% lower than the EPE pearl cotton, bubble column, corrugated paper and bubble film, respectively. The strongest buffering capacity of the bulk EPE pearl cotton was caused by the porous structure. Moreover, the porous structure facilitated the air circulation of the Hami melon. Hence, the bulk EPE pearl cotton is a potential package for the Hami melon.
    28  Residue and Dietary Risk Assessment of Pyrimethanil in Strawberry
    FU Yan ZHANG Liang WU Yin-liang
    2017, 33(11):206-211. DOI: 10.13982/j.mfst.1673-9078.2017.11.029
    [Abstract](1014) [HTML](269) [PDF 438.13 K](858)
    Abstract:
    In order to assess the dietary exposure risk of pyrimethanil residue in greenhouse strawberry, the final residues and decline trends of pyrimethanil used in strawberry were studied. A risk assessment was performed using the risk quotient (RQ). The results indicated that the dissipation rate of pyrimethanil in strawberry fruits followed the first-order kinetics. The half-life of pyrimethanil was 4.28 d. The pyrimethanil (400 g/L suspension) was sprayed on strawberries grown under greenhouse conditions at the dosage of 562.5 and 843.75 g a.i./ha with the preharvest interval of 3, 5, 7 d. The ultimate residue levels for pyrimethanil in strawberry fruits were lower than the established MRLs in China (3 mg/kg). The dietary exposure and risk assessment were conducted based on the supervised field trial data. The results indicated that the dietary intake of pyrimethanil from strawberry consumption for all groups Chinese consumers were acceptable. This study would provide more understanding of residue behavior and dietary intake risk by pyrimethanil used under greenhouse conditions.
    29  Quality-Risk Prediction of Veterinary Drugs by Data Mining
    TIAN Xing-guo CHEN Jiang-tao LV Jian-qiu
    2017, 33(11):212-218. DOI: 10.13982/j.mfst.1673-9078.2017.11.030
    [Abstract](644) [HTML](193) [PDF 462.98 K](868)
    Abstract:
    Veterinary drug residues had become one of the source problems for food security at present. It was difficult for farmers to identify the fake veterinary drugs, which resulted in the risks of veterinary drugs quality. To improve the identification ability of the farmers and reduce the utilization of unqualified veterinary drugs, the data mining classification prediction model, established by C5.0, Logistic, neural network, was used to classify and predict the quality of veterinary drugs by sorting the sampling data of Chinese Veterinary Drug Administration based on SPSS Modeler software. Results showed that the classification accuracy of the three models was low, which resulted in optimizing the model by combination of classifier, and the neural network, binary logic regression - neural network, decision tree-neural network were compared. The overall performance of decision tree - neural network was the best in classification accuracy and generalization performance. Finally, the model for predicting the veterinary drugs quality in decision tree-neural network was established and further optimized, and the prediction accuracy reached 74.34%..
    30  Distribution of Enterobacteriaceae on Kumquat Surface by MALDI-TOF-MS
    WEI Chao GUO Ling-an DAI Xiao-hang
    2017, 33(11):219-223. DOI: 10.13982/j.mfst.1673-9078.2017.11.031
    [Abstract](677) [HTML](229) [PDF 493.55 K](890)
    Abstract:
    To evaluate the consumption risk of kumquat, MALDI-TOF-MS was adopted to investigate the distribution of Enterobacteriaceae on kumquat surface by screening the pathogenic microorganisms, which were identified by biochemical identification and 16S rDNA sequencing identification to confirm the results. Six species of Enterobacteriaceae were isolated and identified as Enterobacter gergoviae, Klebsiella pneumonia, Enterobacter sakazakii, Pantoea dispers, Enterobacter cloaca and Enterobacter cancerogenus, among which Klebsiella pneumonia, Enterobacter cancerogenus and Enterobacter sakazakii had high detection rates. The results of MALDI-TOF-MS were consistent with those of the two other methods on genus but partly different on species. The cluster analysis of isolated microorganisms by MALDI-TOF-MS showed that the microorganisms of the same genus were comparatively close relatives; however, microorganisms of the same species had some differences in mass spectrums. The results indicated that there were Enteropathogens on the surface of kumquats, which resulted in a consumption risk. Enhancing the routine detection and risk assessment of pathogens in agricultural products was suggested. , MALDI-TOF-MS could be used for rapid detection of agricultural microorganisms with the advantages of high resolution and classification analysis on the basis of protein level.
    31  Principal Components Analysis and Cluster Analysis of Physicochemical Properties of Starch from Different Cultivars of Millet
    ZHANG Gui-ying ZHANG Xi-wen YANG Bin ZHANG Guo-quan LI Ping DU Wen-juan JIANG Long-bo
    2017, 33(11):224-229. DOI: 10.13982/j.mfst.1673-9078.2017.11.032
    [Abstract](1256) [HTML](223) [PDF 374.77 K](1002)
    Abstract:
    The size, chemical composition, iodine blue value, light transmittance and pasting properties of starch granules were analyzed with 17 cultivars of starch, and principal components analysis and cluster analysis were used to evaluate the millet starch properties. The results showed that the correlation between the millet starch properties indicators was significant, and the absolute values of 79% were more than 0.30The relationship between indicators was analyzed by principal components analysis and the comprehensive evaluation of millet starch properties were investigated by analysis of principal components. Two obtained components reflected 86.976% information of the original variability based on the total variance by principal components analysis. According to the comprehensive scores of principal components, Datong 29, A3, A1, Yugu1 and Yugu9 were in the top five by comprehensive principal components score, and the starch quality was better; comprehensive score of Jingu21, Jigu11, Xia1, JiGu21 and A2 was low, and the starch quality was poor. 17 millet varieties were divided into 3 groups by cluster analysis, the results of cluster analysis were consistent with comprehensive scores, and the correlation between millet starch characteristics was significant. These results could provide theoretical basis for further processing of millet.
    32  Analysis of Volatile Chemical Components of Guava Fruit by HS-SPME-GC-MS
    BAI Li-li DAI Hua KONG Du-lin ZHANG Wan-ke LI Juan
    2017, 33(11):230-234. DOI: 10.13982/j.mfst.1673-9078.2017.11.033
    [Abstract](885) [HTML](217) [PDF 419.82 K](1015)
    Abstract:
    The volatile chemical components of guava fruit were analyzed by HS-SPME-GC-MS. The relative content of each component was calculated using the peak areas to determine the chemical compositions compared with computer retrieval and standard spectrogram. 71 compounds were separated from guava fruit and 38 of them were identified, which accounted for 76.55% of the volatile chemical components. Comparison of the relative contents of those volatile chemical components showed that: terpenes>aldehydes>esters>alkanes> other compounds. The main components with higher relative mass fraction were hexanal (22.91%), (-) - β- caryophyllene (15.31%), cis-3-hexenyl acetate (8.52%), (E)-2-hexenal (6.45%), α-copaene (4.56%), D-limonene (3.84%), (+) -δ-cadinene (2.11%), (+)- aromandendrene (1.93%), Z,Z,Z-1,5,9,9- tetramethyl-1,4,7,-cycloundecatriene(1.54%), (-)-caryophyllene oxide (0.95%), (4E, 6Z)-2, 6-dimethylocta-2,4,6-triene (0.89%) and so on. The present study can provide scientific evidence for the further development and utilization of the biological activity of guava fruits.
    33  Rapid Detection of Salmonella in Shrimp by Immunomagnetic Separation Combined with Real-time PCR
    LI Ya-ru ZHOU Dong-gen XIA Xing-zhou CAO Yi-fang YANG Hui-ning HU Shuang-fang XIAO Xing-long
    2017, 33(11):235-242. DOI: 10.13982/j.mfst.1673-9078.2017.11.034
    [Abstract](880) [HTML](202) [PDF 486.78 K](784)
    Abstract:
    A rapid and sensitive detection method of immunomagnetic separation (IMS) combined with real-time PCR for Salmonella in shrimp was established. The immunomagnetic beads were prepared by coupling anti-Salmonella polyclonal antibody to magnetic beads and the reaction conditions were optimized to establish the IMS method, and a probe and primers were synthesized for ttr gene of Salmonella to construct the real-time PCR system. The specificity and sensitivity of four representative Salmonella strains were examined. The results showed that the optimal dosage of immunomagnetic beads was 100 μL, and the optimal reaction time of immunomagnetic beads with sample bacteria was 30 min. The proposed IMS-real time PCR had a high specificity and the limits of detection were 5×101 CFU/25 g for Salmonella typhimurium, 5×102 CFU/25 g for Salmonella choleraesuis and 1×102 CFU/25 g for both Salmonella enteritidis and Salmonella paratyphi A, respectively, and the detection process could be completed within 6 h. The test results of IMS-real time PCR were same with those of the national standard for 40 collected shrimp samples. The established IMS-real time PCR need less time and had a high sensitivity, which provided technical support for the rapid detection of Salmonella in aquatic products as well as the practical significance for the prevention and control of foodborne diseases caused by Salmonella.
    34  Identification and Analysis of Volatile Components of Xinjiang Pepper Chicken Soup by GC-MS
    GENG Qiu-yue TIAN Hong-lei ZHAN Ping WANG Peng
    2017, 33(11):243-250. DOI: 10.13982/j.mfst.1673-9078.2017.11.035
    [Abstract](701) [HTML](270) [PDF 468.13 K](842)
    Abstract:
    The gas chromatography–mass spectrometry (GC-MS) was used to isolate and identify the volatile compounds of 8 pepper chicken samples from different restaurants in Shihezi for investigating the characteristic volatiles of Xinjiang pepper chicken soup , meanwhile and the correlation models of volatile compounds in 8 pepper chicken samples were established to obtain the key differences among the samples by hierarchical cluster analysis (HCA) and principal component analysis (PCA). Results showed that 74 kinds of volatile flavor compounds that had been detected were classified into 8 categories, including hydrocarbons (30), alcohols (10), aldehydes (10), esters (6), ketones (8), heterocyclic compounds (8), ethers (2) and sulfoethers (2). The contents of hydrocarbons (17.27%~74.22%)were the highest, followed by alcohols (14.77%~56.75%),esters (0.50%~22.31%) and heterocycles (0.55%~11.36%). Compounds with higher contents were linalol (3.03%~37.31%) and D-limonene (5.60%~25.72%). Consequently, linalol, D-limonene and 2,4-decadienal played a key role in the formation of characteristic flavor of Pepper Chicken was identified.
    35  Simultaneous Determination of Four Individual Alternaria Toxins by Ultra-high Performance Liquid Chromatography-tandem Mass Spectrometry in Flour
    CHEN Bei ZHU Feng LI Fang LIU Hua-liang JI Wen-liang
    2017, 33(11):251-256. DOI: 10.13982/j.mfst.1673-9078.2017.11.036
    [Abstract](844) [HTML](208) [PDF 533.84 K](966)
    Abstract:
    A sensitive and rapid method based on solid phase extraction (SPE) and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS /MS) was developed for the determination of four individual Alternaria toxins in the wheat flour. The samples were extracted with the mixture of 0.05 mol/L NaH2PO4 (pH3.0)-acetonitrile-methanol (450+450+100, V/V) by ultrasound, and then purified by HLB solid-phase extraction column. The separation used Waters CORTECS C18 (4.6×100 mm, 2.7 μm) column gradient elution with 1.0 mmol/L ammonia solution (pH 8.3) and methanol as the mobile phase. The electrospray negative ion (ESI-) and multiple reaction monitoring mode (MRM) pattern were used to detect and the matrix additive standard was used toquantify the Alternaria Toxins. The tenuazonic acid(TeA) and alternariol (AOH) in concentration range of 2.0~100 μg/L, as well as tentoxin (TEN) and alternariol methyl ether (AME) in concentration range of 0.2~10.0 μg/L, had a good linear relationship with the correlation coefficient (R2) of > 0.998. The average recovery was 76.3%~107.5%. The detection limit and the quantitative limit of TeA, AOH, TeA and AME were 1.0 μg/kg and 3.0 μg/kg, respectively. The detection limit and the quantitative limit were 0.1 μg/kg and 0.3 μg /kg, respectively. Therefore, the method is suitable for the determination of Alternaria toxins in flour.
    36  Determination of Rutin in Ginkgo leaf by Capillary Electrophoresis-Electrochemiluminescence
    WEI Ruo-nan CHEN Zhi-yuan GENG Jing-zhang
    2017, 33(11):257-263. DOI: 10.13982/j.mfst.1673-9078.2017.11.037
    [Abstract](671) [HTML](203) [PDF 529.77 K](782)
    Abstract:
    A rapid and efficient separation method was established for the determination of rutin by capillary electrophoresis- electrochemiluminescence (CE-ECL). Tertiary amine compounds, obtained by derivatization reaction of rutin and five secondary amines, were screened by UV, and then detected by CE-ECL. Ginkgo leaf samples were extracted with 70% ethanol aqueous solution by ultrasonic-assisted extraction. The influences of detection potential, concentration and pH of separation buffer and running buffer, separation voltage, injection voltage and injection time on the separation and detection of rutin were investigated. Under the optimal conditions, rutin was separated in 5 minutes, and the linear concentration range for rutin was 0.002~2 μg/mL. Besides, the regression equation was y=1958.4x+7600.4, with a correlation coefficient of 0. 994 and a detection limit of 0.0004 μg/mL (S/N=3). The relative standard deviations (RSD) of migration time, peak height and peak area for seven continuous injections of 0.2 μg/mL rutin were 1.1%, 1.2% and 2.0%, respectively. The proposed method was applied to the determination of the rutin in Ginkgo leaf with the recoveries of 92% -103%.
    37  Quantitative Analysis of Hydrolyzed Vegetable Protein (HVP) Adulterated Milk by Near Infrared Spectroscopy
    FAN Rui SUN Xiao-kai CHEN Jie YANG Chen LIU Dong-wu NIU Jin-ye SUN Fa-zhe KONG Ling CHEN Zhi-wei
    2017, 33(11):264-271. DOI: 10.13982/j.mfst.1673-9078.2017.11.038
    [Abstract](890) [HTML](223) [PDF 496.99 K](960)
    Abstract:
    Hydrolyzed Vegetable Protein (HVP) was a typical adulterated compound that was used as an inexpensive protein by criminals to increase the nitrogen content in milk. Different concentrations of HVP adulterated samples were prepared in this study and were scanned directly with the near-infrared spectrometer (NIRs). Samples pretreated with trichloroacetic acid were analyzed by Transmission Analyzer, and the quantitative analysis models were established by TQ software to compare the difference between the two methods. Results showed that, the optimized quantitative analysis model by Fiber Optic Module was established with 10 principle components factors through preprocessing method of first derivative & Norris derivative filter in the spectral region of 8000~5000 cm-1. The root mean square error of cross (RMSEC), root mean square error of prediction (RMSEP) and correlation coefficient (R) of the model were 0.224, 0.214 and 0.98414 respectively with a recovery of 93.2479%., The optimized quantitative analysis model by transmission analyzer was established with 10 principle components factors through preprocessing method of first derivative & Norris Derivative Filter in the spectral region of 10000~7000 cm-1. RMSEC, RMSEP and R of the model were 0.175, 0.138 and 0.99036 respectively with a recovery of 98.7351%. The quantitative analysis model pretreated with tricholoroacetic acid was accurate and stable, which could be used in rapid quantitative analysis of HVP in milk and provide reference for milk quality control.
    38  Analysis of Internal Moisture Changes of Nectarine during Drying Process Using LF-NMR Technology
    TANG Mei LUO Jie-ying GAO Yang-wen LIU Jian-liang WANG Qin
    2017, 33(11):272-278. DOI: 10.13982/j.mfst.1673-9078.2017.11.039
    [Abstract](844) [HTML](212) [PDF 571.90 K](829)
    Abstract:
    The objective was to provide new ideas for the preservation and processing of nectarine by studying the moisture distribution and migration during drying process. The relationship between signal intensity and moisture content and moisture distribution of nectarine were determined using LF-NMR technology. The transverse relaxation time (T2) changes of nectarine with different drying methods were measured simultaneously, and then the characteristics of internal moisture state and changes were analyzed. The results showed that the water content and the signal intensity of nectarine were positively correlated and the regression equation was y = 12.415x-596.67 (R2 = 0.9822). MRI images could clearly reflect the structures of nectarine pulp, core shell and nucleolus son and the distribution of water. There were three kinds of water in fresh nectarine, bound water (about 90%), immobilized water (1%) and free water. The drying process could reduce the free degree of water with the decrease of T2, and the air drying was faster than the vacuum drying. During the air drying process, the immobilized water transferred into free water and free water lost, while a part of free water lost and the other transferred into immobilized water during the vacuum drying. This research can provide theoretical basis for the industrial production and preservation of nectarine.
    39  Development and Application of Rapid Determination Kit for Sodium Thiocyanate in Liquid Milk
    LIU Feng-yin WANG Shu-juan LI Xuan LI Jia-wei WANG Zi-wei ZENG Si-min LIANG Yue MU Hong-tao
    2017, 33(11):279-284. DOI: 10.13982/j.mfst.1673-9078.2017.11.040
    [Abstract](728) [HTML](312) [PDF 488.64 K](776)
    Abstract:
    Sodium thiocyanate (NaSCN), a chemical raw material with preservative effect, was often used in dairy products to extend the shelf life, which increased the safety risk. The rapid detection methods for sodium thiocyanate that had been reported had several drawbacks such as serious background interference and low sensitivity. A NaSCN semi-quantitative rapid detection method was established in this study with the principle of sanguineous complex reaction induced by SCN- and Fe3+ by selecting the chromogenic agent, optimizing chromogenic reaction conditions, simulating milk matrix, pretreating samples and the chromogenic reaction. The rapid determination kit for sodium thiocyanate residues in liquid milk samples was developed. The optimum conditions were as follows: the chromogenic agent, 2 mol/L iron nitrate (2 mol/L nitric acid as the solvent); reaction time, 2 min. The reaction was complete in room temperature under the optimum conditions. The detection limit of the kit for sodium thiocyanate residues in liquid milk was 5 mg/kg, and the color gradient was well distinguished in the NaSCN concentration of 5~100 mg/kg. The proposed kit was accurate, sensitive, rapid (5 min), stable and not in need of instrument assistance, and wad suitable for on-site screening a large quantities of liquid milk samples for small and medium-sized enterprises and basic units.
    40  Research Progress and Application of Plant Antimicrobial Peptides
    TIAN Ye WANG Gui-feng ZHANG Xiang-qian
    2017, 33(11):285-291. DOI: 10.13982/j.mfst.1673-9078.2017.11.041
    [Abstract](873) [HTML](624) [PDF 458.04 K](1647)
    Abstract:
    Antimicrobial peptides (AMPs) are an important part of innate immune system of organisms, which are isolated from a wide range of organisms, including bacteria, plants and animals. In the past 20 years, the number of antimicrobial peptides has been increasing rapidly and their broad spectrum antimicrobial activity is also being studied in depth with the continuous discovery of antimicrobial peptides, Plant AMPs are isolated from plants, showing many differences with other life forms of AMPs. Common types of plant AMPs include thionins, plant defensins, Heveins, Knottins, lipid transfer proteinsand and Snakins. Because of the increasing antibiotic resistance of pathogenic microorganisms, there is an urgent need to find alternatives of traditional antibiotic agents. Plant AMPs have the potential to be the drug candidates of animal and human’s infection caused by pathogens for their wide range of biological activities including antibacterial, antifungal, antiviral, anticancer and insecticidal.. The mechanism of antibacterial activity of plant AMPs is an important direction of our research, which is helpful to find a new therapy for disease. In this study, we provide an overview of all plant AMPs with their classification types, distribution, function, mechanism of microbial resistance to plant AMPs and development prospects.

    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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