Volume 32,Issue 5,2016 Table of Contents

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  • 1  Effects of Probiotic-Fermented Soymilk on the Hypolipidemic Activity and on Ameliorating Liver Injury in Hyperlipidemic Mice
    ZHANG Xiao-lei WU Yan-feng PIAO Chun-hong YU Han-song LIU Jun-mei JIA Dong-mei HUA Xiao-man WANG Yu-shan WANG Xin-zhe WANG Yu-hua
    2016, 32(5):1-8. DOI: 10.13982/j.mfst.1673-9078.2016.5.01
    [Abstract](1197) [HTML](0) [PDF 749.90 K](1738)
    Abstract:
    The in vitro cholesterol removal ability of Lactobacillus casei, Lactobacillus plantarum, and Bifidobacterium bifidum and the effects of probiotic-fermented soymilk on the blood lipid level and liver injury in mice fed a high-fat diet were investigated. The O-phthalaldehyde method was used to determine the in vitro cholesterol removal ability of probiotics. C57BL/6N mice were randomly divided into seven groups: normal chow group, high-fat group, L. casei-fermented soymilk intervention group, L. plantarum-fermented soymilk intervention group, B. bifidum-fermented soymilk intervention group, probiotic-fermented soymilk intervention group (a mixture of the three types of probiotics), and non-fermented soymilk intervention group. After seven weeks of treatments, the related serum and liver lipid parameters were measured and the histopathological changes in the liver were observed. The in vitro cholesterol removal abilities of L. casei, L. plantarum, and B. bifidum were 43.14%, 46.27%, and 40.53%, respectively. The treatment using the soymilk fermented with the three types of probiotics significantly reduced the abdominal and perirenal fat indexes as well as the serum total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL) levels, while elevating the serum high-density lipoprotein (HDL) level. The liver TC, TG, alanine aminotransferase (ALT), and aspartate aminotransaminase (AST) levels were also reduced. In addition, the accumulation of fat in the liver was improved significantly.
    2  Detection of Surface Glycosylation of CD8+ T Lymphocytes in Glatiramer Acetate-treated Mice, Using Agrocybe aegerita Lectins
    WU Wei-peng HUANG Bi-xia GUAN Xin WEN Yu-di LIANG Yi
    2016, 32(5):9-13. DOI: 10.13982/j.mfst.1673-9078.2016.5.02
    [Abstract](862) [HTML](0) [PDF 709.07 K](1454)
    Abstract:
    Glatiramer acetate (GA) is a first-line agent for the treatment of multiple sclerosis, and it exerts an immunomodulatory function by inducing regulatory CD8+ T cells. In order to investigate GA-induced CD8+ T cells, the lectins AAL (Agrocybe aegerita lectin) and AAL2 were used to analyze the glycosylation level and cytokine expression in CD8+ T lymphocytes in the spleen and inguinal lymph nodes in GA-induced, immune-tolerant mice, by biotin-labeling and flow cytometry. The results showed that the percentages of AAL+CD8+ and AAL2+CD8+ T lymphocytes in the spleen were 8.46 ± 3.1% and 9.08 ± 2.8%, respectively; and the percentages of AAL+CD8+ and AAL2+CD8+ T lymphocytes in the inguinal lymph nodes were 10.65 ± 4.6% and 8.25 ± 5.9%, respectively. Moreover, the percentages of AAL+ cells in CD8+ T lymphocytes in both the spleen and inguinal lymph nodes were significantly higher than those in the CD8- T lymphocytes (p <0.05). In the inguinal lymph nodes, the proportion of AAL+CD8+ T cells expressing IFN-γ was significantly higher than that of AAL-CD8+ T cells, and the proportion of cells expressing IFN-γ+ and perforin in AAL2+CD8+ T cells was also significantly higher than that in AAL2-CD8+ T cells. These studies provide preliminary data for studies on the surface glycosylation of CD8+ T lymphocytes, and indicate that glycosylation level is associated with cytokine secretion.
    3  Molecular Mechanism Underlying the Amelioration of Dextran Sulphate Sodium (DSS)-induced Colitis in Mice by Oryzanol
    CHEN Ya-ya LUO Fei-jun TIAN Yuan-yuan LI Xin-hua SHI Li-min YAN Ming ZENG Lin-na LIU Bo LIN Qin-lu
    2016, 32(5):14-21. DOI: 10.13982/j.mfst.1673-9078.2016.5.03
    [Abstract](1207) [HTML](0) [PDF 1.00 M](1397)
    Abstract:
    Oryzanol is one of the important active substances in rice bran. A mouse model of ulcerative colitis was established by feeding C57BL/6 mice continuously with 1.0% sulphate sodium D (DSS), and the anti-inflammatory effect of oryzanol and its molecular mechanism were evaluated. The results showed that the symptoms of DSS-induced colitis in the mice from oryzanol group were significantly alleviated. The thickness of bowel wall, colon length, colon weight, inflammatory cell infiltration, disease activity index (DAI) and other important pathological indicators were improved significantly. Oryzanol could also significantly improve important biochemical indicators of inflammatory injury in colonic tissues, such as myeloperoxidase (MPO) and malondialdehyde (MDA) contents, and reduce the plasma nitrite content. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis found that the mRNA expression levels of inflammatory factors, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-1, and IL-6 were significantly reduced in colonic tissues. Western blotting further confirmed that oryzanol suppressed the protein expression of inflammatory factors in colonic tissues. It was concluded that oryzanol had an inhibitory effect on DSS-induced colitis in mice and its molecular mechanism may involve the down-regulation of the expression of inflammatory factors.
    4  Sedative-hypnotic Effects of Aqueous Extract of Ziziphora tenuior Linn. and Its Impact on Immune Function in Mice
    SHA Ai-long MENG Qing-yan HAO Hai-yan
    2016, 32(5):22-26. DOI: 10.13982/j.mfst.1673-9078.2016.5.04
    [Abstract](917) [HTML](0) [PDF 567.85 K](1292)
    Abstract:
    The impact of sedative-hypnotic effects of aqueous extract of Ziziphora tenuior Linn. on the immune function in mice was investigated in this study. The effects of the aqueous extract of Z. tenuior on spontaneous activity, dormancy-number, and dormancy-time of mice induced by pentobarbital sodium were observed and compared with that in the physiological saline-treated groups. Further, the thymus index, spleen index, activities of ACP and LYZ, and the concentration of IgG in the sera of mice treated with three doses of the aqueous extract of Z. tenuior were determined. For acute toxicity tests, the aqueous extracts were orally administered. The results showed that in the medium- and high-dose groups for the aqueous extract of Z. tenuior, spontaneous activity was significantly inhibited, and both dormancy-number and -time were significantly increased in the mice induced by pentobarbital sodium, when compared with those in the physiological saline-treated groups. Moreover, these effects were dose-dependent. The three doses of the aqueous extract of Z. tenuior also significantly increased the thymus index, spleen index, activities of ACP and LYZ, and the concentration of IgG in the mice sera. The aqueous extract of Z. tenuior was nontoxic, and showed a large safety range. The results indicated that the aqueous extract of Z. tenuior had obvious sedative and hypnotic effects in mice, and there was a synergistic effect between the extracts and pentobarbital sodium, which could significantly strengthen immune function in mice.
    5  Structure and Cold-adaptation Mechanism of Trypsin Purified from the Krill (Euphausia superba Dana, 1852)
    ZHOU Ting-ting WANG Xi-chang LI Yan
    2016, 32(5):27-32. DOI: 10.13982/j.mfst.1673-9078.2016.5.05
    [Abstract](1096) [HTML](0) [PDF 1.02 M](1755)
    Abstract:
    The molecular characterization of trypsin purified from Euphausia superba (Dana, 1852) was investigated in this research. Aspects such as thermodynamic activation parameters, sequence alignment, and molecular model allowed an in-depth understanding of its activity at low temperatures. Conserved residues were compared between cold-adapted trypsin and its warm-adapted counterparts, and the results showed that their active cores were almost identical. Strategies adopted by trypsin for molecular adaptation to low temperatures may be as follows. A higher proportion of hydrophobic residues and lower proportion of charged residues in the enzyme probably diminish the number of intramolecular interactions, resulting in improved structural flexibility. Increased number of loose random coils may also contribute to improve structural flexibility. Reduced steric hindrance is also a key factor that allows the substrate to easily access the active site, thus promoting the catalytic reaction.
    6  Effects of Gelatin from Fish Skin on Ultraviolet Irradiation-induced Skin Photoaging
    CHEN Tie-jun HOU Hu LU Jiao-han SI Lei-lei LI Ba-fang
    2016, 32(5):33-39. DOI: 10.13982/j.mfst.1673-9078.2016.5.06
    [Abstract](872) [HTML](0) [PDF 828.20 K](1401)
    Abstract:
    The protective mechanism of gelatin against ultraviolet irradiation-induced photoaging of skin was investigated in this study. Gelatin derived from pacific-salmon skin (SG) was extracted using hot water and the molecular weight and amino acid composition analyzed. Institute of Cancer Research (ICR) mice were randomly divided into five groups, with ten mice per group: normal group (NC), model group (MC), vitamin C group (PC), low dose SG treatment group (SG-L), and high dose SG treatment group (SG-H). The activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were measured in skin tissues, as were the levels of malondialdehyde (MDA) and hydroxyproline (HYP). The protective effects of SG on photoaging were evaluated by haematoxylin and eosin staining and Masson’s trichrome staining. The results indicated that the average molecular weight of SG was 81.31 Ku. Glycine accounted for approximately one-third of the total amino acids in SG, and 49.57% of amino acids were hydrophobic. Cysteine and tryptophan were not detected in SG. SG could protect collagen fibers against UV irradiation-induced photodamage. Compared with the control group, the SG-H group exhibited significantly enhanced activity of T-SOD (P < 0.05), increased levels of HYP (P < 0.01), and reduced levels of MDA(P<0.05). In addition, average activities of CAT and GSH-Px increased by 23.70% and 28.30%, respectively, in the SG-H group. This study shows that SG can effectively protect mouse skin from UV irradiation-caused photodamage.
    7  Effects of Mung Bean Hull Nanocrystalline Cellulose on the Performance of Whey Protein Concentrate Edible Film
    MA Zhong-su WANG Ya-jing CHEN Shan-shan ZHANG Ning SUI Si-yao ZHANG Li-ping
    2016, 32(5):40-45. DOI: 10.13982/j.mfst.1673-9078.2016.5.07
    [Abstract](983) [HTML](0) [PDF 770.57 K](1338)
    Abstract:
    Mung bean hull cellulose was used as the raw material to obtain nanocrystalline cellulose by sulfuric acid hydrolysis, which was applied to prepare a whey protein concentrate film. The morphology and crystalline structure of mung bean hull nanocrystalline cellulose and the effects of the amount of added mung bean hull nanocrystalline cellulose on the tensile strength, elongation at break, oxygen permeability, water vapor permeability, transmittance, and microstructure properties of whey protein concentrate films were evaluated. The results showed that the mung bean hull cellulose nanocrystals had a rod-shaped structure with the length ranging from 100 to 200 nm and the diameter ranging from 10 to 20 nm. In addition, the typical cellulose I structure was maintained, with relatively high crystallinity. Mung bean hull nanocrystalline cellulose had good compatibility with the whey protein concentrate. When the content of mung bean hull nanocrystalline cellulose was 1%, the lowest water vapor permeability [2.67 × 10-13 g/(cm?s?Pa)] and the highest transmittance of the films were reached, and the surface of the whey protein concentrate film was smooth and homogeneous. When the content of mung bean hull nanocrystalline cellulose was 2%, the tensile strength was highest (1.41 MPa), the elongation at break was 139.8%, and the lowest oxygen permeability [1.8 × 10-5cm3/(m2?d?Pa)] was obtained. The addition of mung bean hull nanocrystalline cellulose can effectively improve the performance of whey protein concentrate films.
    8  In Vitro Antibacterial Activity and Mechanism of Sucrose Monocaprate Action against Salmonella Typhimurium
    ZHAO Lei ZHANG He-yan HAO Tian-yang LI Si-ran
    2016, 32(5):46-51. DOI: 10.13982/j.mfst.1673-9078.2016.5.08
    [Abstract](795) [HTML](0) [PDF 824.39 K](1851)
    Abstract:
    In this study, the in vitro antibacterial activity of sucrose monocaprate against Salmonella Typhimurium was investigated, along with its underlying mechanism. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of sucrose monocaprate against S. Typhimurium were evaluated under different pH conditions using a broth macrodilution assay. The possible antibacterial mechanism against S. Typhimurium was preliminarily determined by evaluation of the released cellular constituents, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopic observations, as well as a DNA-binding assay. The results showed that the MIC of sucrose monocaprate at pH 7.0 against S. Typhimurium was 20 mM, and the antibacterial activity was more significant under acidic conditions. Treating S. Typhimurium with sucrose monocaprate led to the leakage of nucleic acids, proteins, and reducing sugars, as well as damage to the integrity of cell membranes, but with a normal cell morphology. Sucrose monocaprate interfered with the synthesis and accumulation of bacterial proteins (especially for high-molecular-weight proteins). Moreover, the hydrophilic head group of sucrose monocaprate could bind to the phosphate group of DNA by hydrogen bonding, which increased the contraction of the DNA backbone. Therefore, sucrose monocaprate can serve as a safe multifunctional food additive with both emulsifying and antibacterial activities, and shows potential to be applied in the processing and storage of animal-derived foods.
    9  A Study on the Biological Characteristics of Brevibacillus laterosporus S62-9
    WANG Zhi-xin ZHANG Dan LI Xing-feng NING Ya-wei ZHANG Feng-jiao JIA Ying-min
    2016, 32(5):52-58. DOI: 10.13982/j.mfst.1673-9078.2016.5.09
    [Abstract](897) [HTML](0) [PDF 610.29 K](1452)
    Abstract:
    The thermal resistance, acid resistance, bile salt resistance, adhesion ability, antibiotic susceptibility, and other biological characteristics of Brevibacillus laterosporus strain S62-9 were studied in vitro. Strain S62-9 exhibited good thermal tolerance, with a survival rate of 86.20% after incubation in an 85 ℃ water bath for 5 min. It had the lowest survival rate (85.70%) after exposure to simulated gastric juices at pH 2.0 for 4 h, whereas the survival rates at pH 3.0 and 4.0 were both higher than 95.00%. The survival rates after 4-h treatments in 0.1%, 0.2%, and 0.3% bile-salt-stimulated intestinal fluids were 93.30%, 91.70%, and 88.30%, respectively. Strain S62-9 showed high tolerance to simulated gastrointestinal transit, where its survival rate was 96.00% after being treated with gastric juice at pH 2.0 for two hours followed by a three-hour treatment in intestinal fluid containing 0.3% bile salt. The bacterium in the trophozoite stage showed an adhesion ability of 20.70 CFU per Caco-2 cell, which was higher than that of the control strain (Bacillus subtilis K1). Strain S62-9 had no observable resistance to 10 types of antibiotics tested and was thus considered to be a biosafe strain. These excellent probiotic characteristics of B. laterosporus S62-9 meet the standards and requirements of a good probiotic, laying a theoretical basis for its development and application as a probiotic strain.
    10  Correlation Analysis of Lipoxygenase (LOX) Activity and Fatty Acids with Volatile Components in Fresh Corn
    NIU Li-ying MA Yu-ling WU Jian-ping LI Da-jing LIU Chun-quan CHEN Ji-luan
    2016, 32(5):59-64. DOI: 10.13982/j.mfst.1673-9078.2016.5.010
    [Abstract](863) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The lipoxygenase (LOX) activities and the compositions of fatty acids and volatiles as well as their changes in sweet corn (var. Jingtian 5) and waxy corn (var. Jingtianzihuanuo 2), harvested before, at, and after the favorable harvest time, were investigated. The LOX activities of the samples were in a range of 2.63~4.28 U/gFW, and the fatty acids in the highest and lowest amounts were linoleic acid (32.40%~46.68%) and linolenic acid (0.97%~2.40%), respectively. The volatiles in the highest amount were hexanol and hexanal. Jingtian 5 samples harvested before and at the favorable harvest time showed the highest hexanol content, whereas Jingtian 5 harvested after the favorable harvest time and Jingtianzihuanuo 2 harvested in all three periods had the highest hexanal content. With prolonging of the harvest time, the LOX activities and crude fat content in both cultivars increased, but the contents of linoleic acid and hexanal exhibited a downward trend. Correlation analysis indicated that the substrates linoleic acid and linolenic acid in the LOX pathway had significant positive correlation with the hexanal contents but no significant correlation with LOX activity. These findings indicate that the volatiles from the LOX pathway in these fresh corns may depend on the level of linoleic acid or linolenic acid, rather than the level of LOX activity. In addition, the differences in the volatile contents between the two cultivars, especially of hexanol and hexanal, might reflect the differences in the LOX pathway between the two samples.
    11  Accumulation of Soybean Glyceollins Induced by Solid-state Fermentation and Antioxidant Activity Evaluation
    CHEN Yan-qiong SU Hua-jia WANG Jin-mei YAN Zhe YANG Xiao-quan HU Wen-feng OUYANG Ying
    2016, 32(5):65-70. DOI: 10.13982/j.mfst.1673-9078.2016.5.011
    [Abstract](813) [HTML](0) [PDF 0.00 Byte](0)
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    Soybean glyceollin is a member of the phytoalexin family, and shows estrogen receptor modulator activity. Therefore, it has been used to control and prevent postmenopausal osteoporosis. In this study, using Nannong 99-6 soybean as the raw material, the conversion of soybean glucosidic isoflavones into aglycone and glyceollins, and the accumulation of aglycone and glyceollins were achieved by screening food-grade fungal strains and optimizing the solid-state fermentation process. Furthermore, the in vivo antioxidant activity of fermented soybean was evaluated. The results indicated that stimulation by microbial elicitors could result in the successful conversion of isoflavone to aglycone and glyceollins, and in the consequent accumulation of aglycone and glyceollins in soybeans. Moreover, the conversion efficiency was influenced by inoculation conditions (microorganism species, inoculation concentration, fermentation time, injury treatment, and germination pretreatment). The optimal solid-state fermentation process to obtain aglycone- and glyceollins-rich soybean-fermented products was to carry out the solid-state fermentation of soybeans with Aspergillus oryzae CICC2436 at a spore concentration of 107/g soybeans for three days. Moreover, the injury and germination pretreatments were also conducive to the conversion of soybean isoflavone, but the accumulation of glyceollins was mainly affected by the elicitor–injury treatment. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging rate and ferric-reducing power value confirmed the high in vitro antioxidant activity of fermented soybean.
    12  Release Model of Antimicrobial Agent from Polysaccharide-based Film into Food Stimulant
    YU Wen-xi HU Chang-ying WANG Zhi-wei
    2016, 32(5):71-78. DOI: 10.13982/j.mfst.1673-9078.2016.5.012
    [Abstract](1006) [HTML](0) [PDF 0.00 Byte](0)
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    Low methoxyl pectin–carboxymethyl cellulose (LMP-CMC) composite films carrying potassium sorbate (LCP films) were prepared to study the release kinetics of Psb into food stimulant (50% ethanol). The release of Psb from LCP ?lms with three ratios of LMP:CMC (8:2, 6:4, and 4:6) was studied at 4?C. The release of Psb from LCP films (4:6) with different contents of calcium chloride (1%, 2%, 4%, and 8%), MMT (1%, 4%, 8%, and 12%) and Psb (2%, 5%, 8%, 15%) at 4 ℃ was also investigated. The release kinetics of Psb was described using the Fickian second law of diffusion and a simple model. The diffusion coef?cient was determined by fitting the experimental data of Psb released to models to estimate diffusivity of Psb by nonlinear least square method. The results clearly demonstrated that the release of Psb from LCP films can be tailored by changing the composition of the initial casting solution, the content of calcium chloride and MMT. The increased LMP, calcium chloride, and MMT levels resulted in a reduction of diffusion coefficients of Psb. The Fickian model satisfactorily described the experimental data, suggesting that the release kinetic of Psb can be described through the model (R2 >0.98%), and the method of calculating diffusion coef?cient from Fickian second law was reliable. The simple model can be used to describe Psb released for short contact times, to shorten the testing time; the model was satisfactory to determine the diffusion coefficients of Psb. The results indicated that the LCP film has a good potential to achieve a controlled release in antimicrobial packaging.
    13  LF-NMR Relaxation Characteristics and Discriminant Analysis of Water-injected Ground Meat
    WANG Xin WANG Zhi-yong Chen Li-hua LIU Bao-lin
    2016, 32(5):79-84. DOI: 10.13982/j.mfst.1673-9078.2016.5.013
    [Abstract](1309) [HTML](0) [PDF 0.00 Byte](0)
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    The low-field nuclear magnetic resonance (LF-NMR) relaxation characteristics of ground meat samples injected with different proportions of water were systemically evaluated in this study, and the feasibility of qualitative and quantitative discrimination analysis for examining the extent of water injection was explored. The results showed that injecting water into meat significantly changed the relaxation properties. With an increasing proportion of injected water, the T2w value was increased linearly (R2 = 0.9118), while T22 and T22m showed a stepped increase with increasing proportion of injected water, in the ranges of 2~14%, 16~0%, and 32~40%, respectively. T22 and T22m showed significant differences in all ranges (p<0.05). The values of T22 and S22 were increased, while that of S23 was decreased. LF-NMR combined with discriminant analysis showed that the samples with the same proportion of injected water were clustered, and significant differences were found in the group centroids among the samples with different proportions of injected water (raw meat and meat with small, medium, and large proportions of injected water). The rates of correct grouping based on the extent of water injection, and the rates of cross-validation accuracy were 85.70~100% and 81.00~100%, respectively. The results indicate that the proportion of injected water can be effectively predicted using T2w in LF-NMR, as well as by discriminant analysis combined with the multicomponent LF-NMR relaxation properties of the samples.
    14  Analysis of the Diversity and Change in Dynamics of Bacterial Communities during Acetic Acid Fermentation of Tianjin Duliu Mature Vinegar
    ZHANG Rong-zhan NIU Ji-wei DU Hong-fu LUO Jian-mei WANG Min ZHENG Yu
    2016, 32(5):85-90. DOI: 10.13982/j.mfst.1673-9078.2016.5.014
    [Abstract](895) [HTML](0) [PDF 0.00 Byte](0)
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    The polymerase chain reaction/denaturing gradient gel electrophoresis (PCR-DGGE) was used to explore the diversity and change in dynamics of the bacterial communities during AAF of TDMV. In particular, the bacterial communities in the vinegar pei from the top and bottom layers were compared. Thirteen genera of bacteria were detected in the vinegar pei of the two layers. Although only the vinegar pei in the upper layer was stirred manually every day during the production process, the two layers of pei still belonged to the same system and the bacterial compositions were consistent, but there were differences in the diversity of the bacterial communities in the two layers. Using cluster analysis, the bacterial compositions were divided into two groups: the first stage and the second stage. According to the Shannon index, the diversity of bacteria from the first stage was higher than that of the second stage, and the diversity of bacteria in the upper layer was slightly higher than that of the bottom layer. The abundance of Acetobacter pasteurianus, the main microorganism converting ethanol to acetic acid in the AFF, increased gradually during the fermentation process and reached a peak value at the end of the fermentation. The abundance of some lactic acid bacteria (LAB), including Lactobacillus plantarum and Lactobacillus acetotolerans, increased gradually over the fermentation time, likely as a result of their high acid tolerance.
    15  Changes in Water and Gel Properties of Silver Carp (Hypophthalmichthys molitrix) Surimi during Gelation Process
    LI Rui-zhi WANG Wei YI Shu-min LI Jian-rong LI Xue-peng LI Yu-jin LI Chun XIONG Shan-bai HUANG Qi-lin
    2016, 32(5):91-97. DOI: 10.13982/j.mfst.1673-9078.2016.5.015
    [Abstract](862) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The pattern of changes in water and gel properties of silver carp surimi during gelation process was studied. Changes in water-holding capacity, T2 transverse relaxation time, T2 peak ratio at low field, gel properties, color, and microstructure of the gel during surimi gelation were investigated. Additionally, change in crystal water content of the surimi gel during two-step heating was analyzed by thermogravimetric-derivative thermogravimetry analysis (TG-DTGA). Surimi was chopped and mixed with starch, water, and salt, and gelation was performed by a two-step heating method. The results showed that the water-holding capacity of surimi increased significantly during the heating process, and reached the maximal value (96.96%) after 25 min of heating at the second step. T23 transverse relaxation time showed a downward trend; faster rate of the decline was observed during the second step, and the minimal value (30.51 ms) was reached after 30 min of heating at the second step. The peak ratio of T23 showed an upward trend; faster rate of the increase was observed during the first step, and the maximal value (93.97%) was reached after 10 min of heating at the second step. Elasticity, hardness, and other indices of gel properties all increased significantly; both brightness and whiteness showed an increasing trend; crystal water content increased first and then decreased and reached the maximal value (6.59%) after 30 min of heating at the first step.
    16  Changes of Fungal Flora during Processing of Shredded Squid and Isolation and Identification of the Predominant Fungus from the Product
    HUANG Peng-xiao WU Zu-fang SHEN Biao WENG Pei Fang LIU Qian
    2016, 32(5):98-103. DOI: 10.13982/j.mfst.1673-9078.2016.5.016
    [Abstract](875) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The purpose of this study was to reduce fungal contamination in the processing of shredded squid and improve product quality. A combination of traditional microbial identification techniques, sequence analysis of 5.8S rDNA-internal transcribed spacer (ITS), and phylogenetic tree analysis were used to examine changes in fungal flora as well as to identify the dominant fungal strains in shredded squid during production. The results showed that significant differences in fungal counts were seen at different stages of squid processing. The fungal population reached 2.61 log cfu/g at the end of processing (after drying and packaging), and the flavoring, drying, and packaging stages were the main stages for fungal contamination. Six types of yeast and four types of mold were isolated from shredded squid at the end of processing. After sequencing and comparing with sequences from the National Center for Biotechnology Information (NCBI) database, these fungi were identified as Candida sp., Cryptococcus sp., Dothideomycetes sp., Rhodotorula sp., Trichosporon sp., Phoma sp., Penicillium sp., Aspergillus sp., and Cladosporium sp.. Among them, Penicillium (M-04) and Candida (Y-06) were the predominant fungi found in the processing of shredded squid, and their corresponding counts at the end of the processing were 1.85 log cfu/g and 2.15 log cfu/g, respectively.
    17  Effect of Culture Media Containing Different Grape Seeds on Phenolic Compounds and the Antioxidant Activity of Pleurotus Ostreatus
    YANG Jiu-fang CHI Quan-bo LI Xiao-xue LI Jing-ming
    2016, 32(5):104-111. DOI: 10.13982/j.mfst.1673-9078.2016.5.017
    [Abstract](900) [HTML](0) [PDF 0.00 Byte](0)
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    Grape seeds are the major component of mushroom culture media. This study aimed to examine the effects of different grape seeds on the antioxidant activities of Pleurotus ostreatus polyphenols. Four different assays were employed to measure antioxidant activity, including the Folin–Ciocalteu assay, flavonoid content determination assay, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) scavenging activity assay, and the ferric reducing ability of plasma assay. Polyphenol content was assessed using high performance liquid chromatography-mass spectrometry (HPLC-MS). Comparison of grape seeds from Cabernet Sauvignon and Longyan species, and different mass fractions (39% and 78%), showed that 78% of Cabernet Sauvignon grape seeds had positive effects on the antioxidant ability of mushroom (69.4% as determined by the ABTS radical scavenging assay) and 10 kinds of polyphenols were identified. Grape seeds can be used for cultivation of mushrooms.
    18  Synthesis of Tenuazonic Acid Artificial Antigens and Preparation of an Anti-tenuazonic Acid Polyclonal Antibody
    MA Liang ZHANG Yu-hao WU Chun-sheng SU Min ZHONG Hong
    2016, 32(5):112-116. DOI: 10.13982/j.mfst.1673-9078.2016.5.018
    [Abstract](1040) [HTML](0) [PDF 0.00 Byte](0)
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    The oximation reaction was used to derivatize tenuazonic acid (TA), and a connecting arm was introduced to synthesize the hapten, TAO. The TAO-BSA immunogen and TAO-KLH coating antigen conjugates were prepared by the active ester method. After dialysis purification, UV spectrum scanning, Fourier transform infrared (FT-IR) spectroscopy, and animal immunization experiments were used to test and verify the synthesis products. The coupling ratios of the two conjugates were 18.3:1 and 38.7:1. Balb/c mice were immunized by TAO-BSA and a polyclonal TA antibody was obtained from the antiserum. The sensitivity of the mouse antiserum was measured by indirect competitive ELISA. The optimum concentrations of the coating antigen and antibody dilutions were determined by the chessboard method. The sensitivity, as measured by IC50, was 335.55 ng/mL. The detection limit (LOD) was 19.00 ng/mL, and the linearity range was 200.00~1563.00 ng/mL.
    19  Separation of Acetoin from Fermentation Broth Using Ethanol-dipotassium Hydrogen Phosphate Aqueous Two-phase System
    TIAN Yan-jun LIU Jian-jun ZHAO Xiang-ying FAN Yi-xiao CHEN Wei CHEN Yong-quan
    2016, 32(5):117-123. DOI: 10.13982/j.mfst.1673-9078.2016.5.019
    [Abstract](823) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The downstream separation process during acetoin production by microbial fermentation has long required investigation. Aqueous two-phase system (ATPS) is a highly efficient and mild separation technology, used extensively in the separation of organic substances. The application of ATPS in the separation of acetoin from fermentation broths was investigated, the effects of the types and compositions of ATPS on the extraction of acetoin were explored, and the ethanol/dipotassium hydrogen phosphate system was determined as the optimal ATPS. The highest partition coefficient (16.81) and recovery (98.2%) of acetoin were obtained, when the mass concentrations of dipotassium hydrogen phosphate and ethanol were 25% (m/m) and 26% (m/m), respectively. A pilot experiment indicated that the ATPS showed good stability, and changes in the scale of the system did not affect the partition coefficient and recovery for acetoin. This shows that the ethanol/dipotassium hydrogen phosphate ATPS can be applied to large-scale industrial production. Finally, acetoin dimers were produced using vacuum distillation and crystallization, further demonstrating the potential application of this ATPS process for acetoin separation from fermentation broth.
    20  Effects of Ultrasonic Treatment on the Physicochemical and Immunomodulatory Properties of Polysaccharides from Longan Pulp
    MIN Ting SUN Jie HUANG Fei YI Yang WANG Hong-xun WANG Li-mei
    2016, 32(5):124-131. DOI: 10.13982/j.mfst.1673-9078.2016.5.020
    [Abstract](838) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Ultrasonic treatment has been widely used to increase the yield during extraction of polysaccharides from longan pulp; however, its effect on the bioactivity of polysaccharides remains unclear. Polysaccharides from dried (LPD) and fresh longan pulp (LPF) were treated with ultrasonic waves at different power settings. Resulting molecular weight distribution as analyzed by gel chromatography indicated significant changes after ultrasonic treatment at 150~450 W for 15 min, partly due to degradation of their high molecular weight fractions. This degradation was confirmed by a decrease in intrinsic viscosity following an increase in the power of ultrasonic waves from 150 to 450 W. The effects of different power values on molecular weight distribution showed no obvious difference. Additionally, the ultrasonic treatment resulted in the cleavage of O-glycosidic bonds in LPD and the dissociation of non O-glycosidic bond-bound protein in the high-molecular weight fraction of LPF. In vitro immunomodulatory evaluation showed that LPD and LPF (50~400 μg/mL)-mediated stimulation of splenic lymphocyte proliferation, macrophage phagocytosis, and NO production were weakened to various degrees after ultrasonic treatment, which might be related to macromolecule degradation and dissociation of bound proteins. Moreover, ConA-induced lymphocyte proliferation by LPD at 400 μg/mL was significantly increased after ultrasonic treatment (p < 0.05), which might be due to the decrease in viscosity. The results suggest that the degradation of polysaccharides from longan pulp due to ultrasonic treatment leads to a significant reduction in immunomodulatory activity in vitro.
    21  Preparation of Soy Protein based Fluid Gel Particles and Their Functional Properties
    ZHOU Qian GUO Jian YANG Xiao-quan
    2016, 32(5):132-137. DOI: 10.13982/j.mfst.1673-9078.2016.5.021
    [Abstract](942) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The applications of fluid gel particles have been of widespread interest, but researchers have rarely focused on the large-scale production and the control of the particle morphology. In this study, soy protein isolate (SPI) was used as the main raw material, and different amounts of gum arabic (GA) and Tween 80 were added to prepare soy protein based fluid gel particles by heat treatment with continuous stirring and spray drying process. The functional properties of the obtained fluid gel particles, including average particle size, viscosity, morphology, moisture content, hygroscopicity, and dispersibility were characterized. The results showed that the surface of the particles prepared with GA was smooth and the number of collapses was reduced. Particles prepared with the addition of 1.6% GA were smaller than the other fluid gel particles. The addition of Tween 80 allowed the particles to become spherical and increased the roughness of the particle surface. The hygroscopicity of the particles increased rapidly with increasing amount of added Tween 80, but was not affected significantly with the addition of GA. The wettability of the particles could be improved by adding Tween 80. The hardness of the soy protein based heat-set gel could be enhanced when this type of particles were used to partially replace SPI. These fluid gel particles can modify the viscosity and textural properties of food systems, and can serve as a new generation of protein based ingredient in food processing.
    22  Removal of Deoxynivalenol from Dried Noodles by Using Different Cooking Methods
    CHANG Jing-hua HE Zhi-ming ZHAO Yue-ju XING Fu-guo ZHOU Lu WANG Yan LIU Yang
    2016, 32(5):138-143. DOI: 10.13982/j.mfst.1673-9078.2016.5.022
    [Abstract](960) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    This study investigated the removal of the contaminant deoxynivalenol (DON) from dried noodles by cooking them in alkalinized water. First, the effect of added sodium carbonate on the quality of cooked noodles was determined. Additionally, the effects of using a microwave oven and induction cooker on the removal of DON from cooked noodles were analyzed. The results showed that 0.25% sodium carbonate solution had no significant effect on noodle quality. However, it increased the efficiency of DON removal. Moreover, the efficiency of DON removal by cooking noodles by using a microwave oven was higher than that using an induction cooker, though the difference was not significant. Second, dried noodles with different levels of DON contamination were cooked in 0.25% sodium carbonate solution and a prediction curve for DON removal was obtained: y = 0.4546x - 0.0377, R2 = 0.9605. The results showed that addition of sodium carbonate reduced DON content from 2.30 mg/kg to 1000 mg/kg (the national upper limit for DON in China). This removal efficiency was significantly higher than that without adding sodium carbonate. Furthermore, the degradation products of DON standard in 0.20% sodium carbonate solution were analyzed using a quadrupole time-of-flight mass spectrometry (Q-TOF) system. The possible degradation products of DON were C15H20O6 (isoDON, lactone DON), C15H20O5 (norDON D), and C14H18O5 (norDON A, B, C). The toxicity of the products was significant reduced. Thus, cooking dried noodles in 0.25% sodium carbonate solution showed good DON removal efficiency.
    23  Preparation and Structural Analysis of Nata Aerogel
    XIONG Jian WANG Zi-rong YE Jun
    2016, 32(5):144-150. DOI: 10.13982/j.mfst.1673-9078.2016.5.023
    [Abstract](885) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    A three-dimensional porous Nata aerogel material with remarkable toughness and a density of 30 mg/cm3 was prepared by freeze-drying with Nata hydrogel as the raw material. The morphological structure, supra-molecular structure, crystal structure, and thermal properties of the prepared Nata aerogel were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and thermo-gravimetric analysis. The XRD pattern revealed that the supramolecular structure of cellulose in the Nata aerogels was cellulose I, and Nata aerogels showed a higher relative crystallinity and larger grain size than Nata and microcrystalline cellulose (MCC). FTIR spectra indicated that no new functional groups were generated, and the calculated infrared crystallinity index was greater than those of Nata and MCC, which was consistent with the XRD result. Peak separation and fitting were performed for FTIR characteristic peaks. The peaks sizes of 3100–3600 cm-1 were fitted for the changes in intra- and inter-molecular hydrogen bonds, which showed that the strength of intramolecular hydrogen bonds for O (2) H... O (6) was decreased, the strength of O (3) H... O (5) was increased, and the strength of intermolecular hydrogen bonds for O (6) H ... O (3 ') was increased. The peaks in the range of 660–760 cm-1 were fitted for the content of cellulose Iα, showing a result of 92.18%. Scanning electron microscopy indicated the presence of a large number of pores in the aerogels. Thermo-gravimetric analysis revealed a thermal decomposition temperature of 322.07?C, indicating that the thermal stability of Nata aerogels is better than those of Nata and MCC.
    24  Screening of an Antagonistic Endophytic Bacterium against Colletotrichum capsici and Its Fresh-keeping Effects on Postharvest Capsicum
    TIAN Jian ZHOU Hong-li YI You-jin ZHOU Jin-wei BO Lian-yang HU Xie-xin LUO Cheng-yin XIA Bo
    2016, 32(5):151-160. DOI: 10.13982/j.mfst.1673-9078.2016.5.024
    [Abstract](729) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    An antagonistic endophytic bacterium strain (P5) against Colletotrichum capsici was isolated from capsicum fruits, and identified as Bacillus subtilis based on observations of bacterial cell and colony morphologies, physiological and biochemical measurements, and 16S rDNA sequence analysis. The physical and chemical properties of the crude fermentation extract were determined with Colletotrichum capsici as the indicative bacterium. In addition, the fresh-keeping effects of the crude fermentation extract of P5 on postharvest capsicum were studied by measuring the weight loss rate, rate of decay, titratable acidity, and the contents of vitamin C, total carbohydrates, and chlorophyll, along with other quality indices of capsicum. The results indicated that the crude fermentation extract had good thermal stability, and the antibacterial activity was stable, showing no changes in an environment with a pH value <8.0 and a temperature range from 40~100 ℃. The antibacterial activity decreased to 85% of that of the control group after treatment at 121 ℃ for 30 min. No changes in the antibacterial activity were observed from pH 2.0 to pH 12.0 under room temperature, showing good stability to pH fluctuations. The crude fermentation extract was stable to ultraviolet (UV) light and could maintain 89.87% of the initial activities under UV irradiation for 12 h. The crude fermentation extract treatment group exhibited better fresh-keeping effect on postharvest capsicum compared with the sterile water treatment group, and the fermentation extract could effectively reduce the weight loss rate and rate of decay. The treatment inhibited the reductions in titratable acidity and the contents of vitamin C, total carbohydrates, and chlorophyll, showing an apparent fresh-keeping effect on capsicum.
    25  Effect of the Duration of Frozen Storage on the Structure and Thermodynamic Properties of Gluten Protein
    ZHAO Lei YU Ya-nan HU Zhuo-yan LI Bing LI Lin
    2016, 32(5):161-166. DOI: 10.13982/j.mfst.1673-9078.2016.5.025
    [Abstract](787) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The effects of frozen storage (-18 ℃) on the molecular weight, the distribution of molecular weight, microstructure and thermodynamic properties of wheat gluten protein were studied by size-exclusion chromatography in conjunction with multi-angle laser light scattering (SEC-MALLS), scanning electron microscope (SEM) and thermogravimetric analyzer (TGA). With increasing storage time, free thiol content increased due to the cleavage of disulfide bonds. Depolymerisation of the gluten proteins occurred, and low molecular weight proteins were produced. The molecular weight of the gluten proteins with relatively high molecular weight (106 u ~ 4 ? 108 u) was decreased after 120 days of storage, and that of the relatively low molecular weight (105 u ~ 106 u) gluten proteins exhibited a significant decline after 60 days of storage. The mesh like structure of gluten proteins became significantly loose, and unevenly distributed pores with a diameter over 100 μm could be seen after 120 days of storage. Thermal analysis indicated that the degradation temperatures of the gluten and glutenin showed a downward trend with increasing storage time and their thermal stability decreased. To summarize, during frozen storage, moisture migration and recrystallization led to the depolymerization of the gluten polymers, and the disulfide bonds between gluten protein molecules were broken, so that the mesh like structure became loose and the thermal stability of the gluten and glutenin decreased.
    26  Effect of Hsian-tsao Gum/Casein Composite Film on the Quality of Chilled Pork During Storage
    YANG Hui SU Ze-ping GUO Shan-guang WAN Jun ZHANG Da-lei CHEN Wei-wei JIANG Ai-min
    2016, 32(5):167-172. DOI: 10.13982/j.mfst.1673-9078.2016.5.026
    [Abstract](838) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The effect of casein/hsian-tsao composite film on the quality of fresh pork during cold storage was investigated in this study. Changes in the content of total volatile basic nitrogen (TVB-N), thiobarbituric acid-reactive substances (TBARS) value, color (L*, a*, b*, and ΔE values), toughness, and the total number of colonies during storage at (4 ± 1) ℃ were measured for all samples subjected to different treatments (no film, casein film, and hsian-tsao gum/casein composite film) for preservation. The results indicated that the quality of pork packaged with hsian-tsao gum/casein composite films was better than that packaged in the other two groups. The values of TVB-N and TBARS as well as the number of bacterial colonies on the pork treated with hsian-tsao gum/casein composite films and stored for ten days at 4 ℃ still met the standards for fresh pork. The preservation times of pork treated with composite films were extended by 2 and 4 days, compared to those in the casein film and control groups, respectively. These results indicate that the addition of hsian-tsao gum can effectively increase the antimicrobial and antioxidant capacities of casein edible films. The use of hsian-tsao gum/casein composite films for packaging pork can effectively control the changes in TVB-N and TBARS values, color, and toughness, slow the fat oxidation process, increase the total number of bacterial colonies on the pork during storage, enhance pork quality during cold storage, and extend the shelf-life of pork.
    27  Isolation and Identification of Yeast from Acidic Tofu Whey and its Application to Soy Yogurt
    LI Li FENG Jing-wen LIU Li FEI Yong-tao LIU Dong-mei
    2016, 32(5):173-179. DOI: 10.13982/j.mfst.1673-9078.2016.5.027
    [Abstract](784) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The yeast strain Y isolated from acidic tofu whey was identified as Pichia amenthionina Y by morphological examination, 26S ribosomal DNA sequence analysis, and by means of the Biolog microbial identification system. Further analyses indicated that this strain can grow in a wide temperature range (26 ℃~42 ℃), and that its optimal temperature is 36 ℃. Strain Y and lactic acid bacteria XPL-1 were used as combined starter culture to prepare soy yogurt,, and headspace solid phase microextraction with gas chromatography and tandem mass spectrometry (SPME-GC-MS) was employed to analyze the volatile components in the soy yogurt samples. The data were normalized and then analyzed by principal component analysis (PCA). The results indicated that the characteristic beany flavor of the soy yogurt generally disappeared, and abundant alcohol and ester aroma components were generated, including ethyl acetate, octyl acetate, isoamyl acetate, phenylethanol, and 2,3-butanediol. A higher concentration of ethyl acetate was found in the soy yogurt after fermentation at 36 ℃, in the presence of 2-ethyl hexanol and other aroma components, indicating that P. amenthionina Y is a thermophilic yeast that can produce aroma and remove the beany flavor, and has good prospects for development and practical applications.
    28  Changes in Edible Quality of Crusts from Battered and Deep-fat-fried Pork Slices during Frying Process
    ZHANG Ling-wen JI Hong-fang MA Han-jun YANG Ming-duo ZHANG Yao-yao
    2016, 32(5):180-185. DOI: 10.13982/j.mfst.1673-9078.2016.5.028
    [Abstract](1049) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Changes in color, moisture, oil-content, hardness, and crispness of crusts of battered and deep-fat-fried pork slices during the frying process were studied using a colorimeter, fat analyzer, and texture analyzer. The results showed that with an increased frying temperature and prolonged frying time, L* value of the crusts decreased, and both, a* and b* values increased. L* value was relatively high and b* value was relatively low when the second-frying time was shortened. On the other hand, a* value was relatively high when the second-frying time was prolonged. Texture analysis indicated that the hardness of the crusts increased and the crispness improved with increased second-frying time. Additionally, a strong negative correlation was observed between the oil and moisture contents of crusts (R2 = 0.981). Based on color, oil content, and texture, the crusts fried at 180 ℃ for 100 s and refried at 200 ℃ for 40~60 s achieved a relatively higher edible quality.
    29  Quality of Dezhou Braised Chicken Prepared from Frozen Distinguished Chicken and Ordinary Chicken
    LIU Deng-yong TAN Yang DONG Li ZHANG Qing-yong WANG Sai-sai XU Xing-Lian SONG Ai-yi
    2016, 32(5):186-191. DOI: 10.13982/j.mfst.1673-9078.2016.5.029
    [Abstract](803) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Moisture content and edible quality (water-holding capacity and tenderness), sensory evaluation, and microstructure analysis were mesured on Dezhou braised chicken prepared from distinguished chicken and ordinary chicken after frozen storage. The effects of different breeds of chicken and frozen storage on the quality of Dezhou braised chicken were studied, to determine references for the selection and the processing of raw chicken for preparation of Dezhou braised chicken. The results revealed that the quality of products from the two types of chilled chicken meats analyzed in this study showed no significant difference; however, the overall sensory quality of taste in ordinary chicken was better than that in distinguished chicken. The frozen storage of raw meat reduced the quality of Dezhou braised chicken to some extent, with greater impact on ordinary chicken than the distinguished chicken, reflected mainly by the considerably damaged microstructure. The muscle fiber diameters in the leg and chest meat from ordinary chicken had significantly decreased from 31.29 to 18.91 μm (p < 0.05) and from 39.07 to 27.62 μm (p < 0.05), respectively, while shear force was significantly reduced (chilled treatment: 2.88 kg; frozen storage treatment: 1.46 kg) (p < 0.05). Meanwhile, water-holding capacity and shear force of distinguished chicks were better than in regular chicks after frozen storage.
    30  Effects of Freeze-thaw Cycles on the Quality of Cantonese-style Egg Custard Bun
    RUAN Zheng ZHANG Ting-ting QIU Xiao-bin LI Bian-sheng HUANG Jia-rong LIANG Lan-lan
    2016, 32(5):192-198. DOI: 10.13982/j.mfst.1673-9078.2016.5.030
    [Abstract](955) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The objective of this study was to investigate the changes in the moisture content, color, specific volume, textural properties of each layer, and the pore structure of the skin and crumb of Cantonese-style egg custard bun after consecutive freeze-thaw cycles. The results demonstrated that the rates of temperature drop during the freezing and the rates of temperature rise during the thawing of each layer decreased in the following order: skin > crumb > filling. Compared with the egg custard buns that were not subjected to freeze-thaw cycles (control group), after the first freeze-thaw cycle, the chewiness of the samples increased significantly (p < 0.05), while the springiness and resilience decreased. The skin moisture content, lightness (L*), and specific volume of egg custard bun decreased significantly after two freeze-thaw cycles, while redness–greenness (a*) and yellowness-blueness (b*) increased significantly. Hardness and adhesiveness did not change significantly after four freeze-thaw cycles. The pore density (CD) value of the egg custard buns showed a downward trend after four consecutive freeze-thaw cycles, but the value of the percentage area fraction (AF) of the pores increased. In addition, the freeze-crack rate of the buns increased to 36% after four freeze-thaw cycles, and the crack became more severe. Therefore, reducing temperature fluctuations in the storage process and avoiding freeze-thaw cycles are helpful strategies for maintaining the quality of Cantonese-style egg custard bun.
    31  Effects of Different Sugar Treatments on the Activity of In Vitro Antioxidant Enzymes and Quality of Broccoli
    DONG Shuan-quan XU Feng WANG Chun-xing XIONG Qian WANG Hong-fei SHAO Xin-feng LI He-sheng
    2016, 32(5):199-204. DOI: 10.13982/j.mfst.1673-9078.2016.5.031
    [Abstract](761) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    In vitro culturing of broccoli florets was carried out in a medium containing 150 mM glucose, fructose, or sucrose, to study the effects of various exogenous sugars on the antioxidant enzyme activities and the quality of broccoli. All three sugar treatments could effectively delay the de-greening of detached broccoli florets and inhibit the degradation of chlorophyll, whereas the florets of non-treated broccoli turned completely yellow. The highest chlorophyll content was found in the fructose treatment group and was 1.83 times higher than that of the non-treated control group. The activities of antioxidant enzymes, including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX), were effectively enhanced under these exogenous sugar treatments, albeit the effect of each sugar was different. The fructose-treated florets had the highest CAT and APX activities, whereas the sucrose-treated florets had the highest POD and SOD activities. The sugar treatments did not enhance the total phenolic content in the detached broccoli, but resulted in relatively high levels of total sugars and total flavonoids, as well as enhanced 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, and maintained a relatively good quality of the broccoli.
    32  Comparison of Different Deodorization Methods for Deodorizing Rabbit Meat
    WANG Xiao-jun XIA Yang-yi ZAHNG Dan SHANG Yong-biao LI Hong-jun
    2016, 32(5):205-212. DOI: 10.13982/j.mfst.1673-9078.2016.5.032
    [Abstract](1054) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Rabbit leg muscle, which accounts for a large weight proportion of the whole animal and has a heavy off-odor, was selected to test the effectiveness of deodorization by the acid method, alkali method, and yeast method. Sensory scores and thiobarbituric acid reactive substance (TBARS) values were used as the assessment indicators to evaluate the optimal method and conditions for deodorization, and the results were verified by gas chromatography-mass spectrometry (GC-MS). The best deodorizing effect of the acid method (at 4 ℃ and 25 ℃) was found at pH 4.5, and at a temperature of 4 ℃ instead of 25 ℃. In the alkali method (at 4 ℃ and 25 ℃), pH 11.5 was the optimal pH and there was no significant difference between incubation at 25 ℃ and 4 ℃ (p > 0.05). Among the yeast methods tested, the brewer’s yeast method produced a relatively good deodorizing effect, with the following optimal conditions: 0.1% initial yeast, 30 min fermentation time, and 30℃ fermentation temperature. A comprehensive comparison showed that the deodorization capabilities of the deodorizing methods tested were in the descending order of brewer’s yeast method > alkali method (25 ℃, pH 11.5) > acid method (25 ℃, pH 4.5) > alkali method (4 ℃, pH 11.5) > acid method (4 ℃, pH 4.5).
    33  Effect of Storage Temperature on Chilling Injury and Antioxidant System of Papaya Fruit
    YUAN Meng-qi PAN Yong-gui
    2016, 32(5):213-218. DOI: 10.13982/j.mfst.1673-9078.2016.5.033
    [Abstract](847) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    In order to investigate the effect of storage temperature on the extent of chilling injury and antioxidant system of papaya, papaya fruits were stored at 1 ℃, 6 ℃, 11 ℃, and 16 ℃ and the extent of chilling injury and changes in the antioxidant system of the fruit were measured at regular intervals. The results suggested that the susceptibility of papaya to chilling injury was different at the different storage temperatures studied. Chilling injury happened when the storage temperature was less than 11 ℃ and the most severe chilling injury was found in the fruits stored at 6 ℃. Chilling injury was characterized by rapid increases in the relative membrane permeability, malondialdehyde (MDA), O2-? and H2O2 contents and significant decrease in the activities of peroxidases (POD), superoxide dismutases (SOD), and catalases (CAT). Chilling injury symptoms of the fruit were more pronounced in late stages of chilling, followed by decay. However, during storage at 11°C, relative membrane permeability, MDA content, rate of O2-? production and H2O2 content of the papaya fruit were very low and slight decreases in the activities of POD, SOD, and CAT were found.Therefore, the fruits were less prone to chilling injury.
    34  Effects of Washing Treatments with Different Salt Solutions on Gel Strength and Flavor of Hairtail Surimi
    ZHANG Wen YANG Wen-ge CHEN Xia-xia XU Da-lun LOU Qiao-ming ZHANG Jin-jie YAN Xiao-jun LOU Yong-jiang
    2016, 32(5):219-226. DOI: 10.13982/j.mfst.1673-9078.2016.5.034
    [Abstract](874) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Hairtail meat was rinsed with various concentrations of four salt solutions, and the effects on its gel strength and flavor were studied by electronic nose and gas chromatography mass spectrometry (GC-MS), using the relative amount of salt-soluble proteins, gel strength, and rate of loss of fish meat during rinsing as indices. The different salinity levels of the salt solutions were found to influence the fish meat to different degrees, and the appropriate concentrations of four salt solutions were determined to be 0.3% sodium chloride, 0.06% calcium chloride, 0.5% sodium bicarbonate, and 0.5% sodium citrate. The electronic nose analysis revealed that there were significant differences in the principal component analysis (PCA) plot for the surimi flavor between the control and experimental groups involving four salt solutions, without an overlap. Relatively more overlaps were found in the PCA plots for the surimi samples treated with calcium chloride, sodium chloride, and sodium citrate solutions. According to the GC-MS analysis, there were 51, 36, 40, 38, and 56 different volatile compounds in the surimi samples from the control, sodium chloride-, calcium chloride-, sodium bicarbonate-, and sodium citrate-treated groups, respectively. These compounds were mainly aldehydes, ketones, and alcohols. Compared with the control group, the experimental groups showed an increase in the concentration of esters upon removal of volatile acids. The concentrations of alkanes and alkenes noticeably increased in the calcium chloride-treated group, while the concentrations of ketones, alcohols, and aldehydes significantly increased in the sodium chloride-, sodium bicarbonate-, and sodium citrate-treated groups.
    35  Effect of High-pressure Homogenization on the Properties and Digestibility of Dioscorea opposita Starch
    HE Yong-zhao WU Xiao-qi SONG Hong-bo HUANG Qun WANG Yi-wei TENG Hui
    2016, 32(5):227-233. DOI: 10.13982/j.mfst.1673-9078.2016.5.035
    [Abstract](1067) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The effect of the pressure from high-pressure homogenization on granule morphology, polarization cross, grain diameter, crystal property and in vitro digestibility of Dioscorea opposita starch were investigated in this study. The results showed that the surface of Dioscorea opposita starch granule was damaged and the intensity of polarization cross was reduced by high-pressure homogenization. The particle size decreased initially and increased subsequently with increasing homogenization pressure. The minimum (25.16 μm) and maximum sizes (27.81 μm) were found at pressures of 40 MPa and 100 MPa, respectively. The C-type crystal structure was not changed, while the degree of crystallinity decreased from 26.45% to 21.00%. The widths and intensities of the infrared (IR) absorption peaks at 3233.42, 1164.01, 1081.90, 1050.27, and 1015.81 cm-1 decreased. The degree of order in the starch was also reduced to some extent. The contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) in the native starch were 11.32%, 7.00%, and 81.68%, respectively. After the homogenization treatment at 100 MPa, the contents of RDS and SDS were increased to 20.63% and 10.41%, respectively, while the RS content was reduced to 68.96%. The results suggested that high-pressure homogenization reduced the degree of crystallinity in the starch, which results in reduced resistance to enzymatic digestion and enhanced digestibility. This trend was more apparent at higher pressure.
    36  Effect of Different Harvest Dates on the Quality of Pinot Noir Grape and the Resulting Wine
    SU Peng-fei YUAN Chun-long YANG Li ZHOU Ya-li YAN Xiao-yu
    2016, 32(5):234-240. DOI: 10.13982/j.mfst.1673-9078.2016.5.036
    [Abstract](874) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The quality of Pinot Noir grapes and the resulting wines was evaluated according to different harvest dates in this study. The grape samples were collected once every seven days after veraison to monitor the changes of physicochemical indices and polyphenol contents. In addition, quantitative descriptive analysis (QDA) was performed on the sensory indices of the wines prepared from the grapes collected at different harvest dates, to determine the optimum harvest date of Pinot Noir grape from Qingtongxia City in Ningxia. Principal components analysis (PCA) was performed on the polyphenol indices of the grapes collected at different harvest dates and the resulting wines, and the indices that had the most significant impact on their quality were screened out, which proved to be a simplified and practical approach. The results showed that the reducing sugar contents and the sugar-acid ratios increased and the total acid contents decreased continuously during the grape ripening. The polyphenol contents of both the skins and seeds showed an upward trend after the initial decrease. The results of QDA indicated that the sensory quality of the wines increased with a prolonged harvest date. The results of PCA showed that the total flavonoids of the seeds, total flavonoids of the skins, and total anthocyanins of the skins had the most significant impact on the quality of the grapes and wines. Moreover, when their contents were 52.02 ± 0.13 mg/g, 29.95 ± 0.28 mg/g, and 7.09 ± 0.02 mg/g, respectively, the polyphenolic maturity of the grapes and the quality of the wines were relatively good. This study can provide guidance for determination of the most suitable harvest date of Pinot Noir grapes in this region.
    37  Effect of Smoking Materials on Quality of Xiang-xi Bacon
    ZHONG Yi-ru CHEN Xin-xin ZHOU Hui LOU Ai-hua LUO Feng-lian LIU Cheng-guo
    2016, 32(5):241-252. DOI: 10.13982/j.mfst.1673-9078.2016.5.037
    [Abstract](912) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Changes in physicochemical indices, microbial populations, and volatile compounds in Xiang-xi traditional Chinese bacon, caused by five smoking materials (orange branches, sawdust, rice husk, wood grains, and miscellaneous wood), were compared, with Hunan Xiang-xi bacon as the study object. The results revealed that with extended smoking time, moisture content of Xiang-xi bacon samples, prepared with one of the five smoking materials, decreased; salt content increased; and benzopyrene content gradually increased. None of these concentrations exceeded the national standard values. The predominant microorganisms in all the smoked Xiang-xi bacon products (prepared with each of the five smoking materials) were Staphylococcus and Micrococcus. A total of 40, 29, 39, 19, and 35 volatile compounds were identified in the smoked bacon products prepared using orange branches, sawdust, rice husk, wood grains, and miscellaneous wood, respectively. The bacon product prepared using sawdust had the highest counts of Staphylococcus, Micrococcus, lactic acid bacteria, and yeast, and the lowest benzopyrene content. Thus, sawdust is an ideal smoking material.
    38  Optimization of a Quantitative Model of Fatty Acids in Edible Oil Based on Characteristic Raman and NIR Spectra
    WU Jing-zhu DONG Wen-fei LEI Qian CHEN Yan LIU Cui-ling
    2016, 32(5):253-257. DOI: 10.13982/j.mfst.1673-9078.2016.5.038
    [Abstract](856) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Rapid Raman quantitative analysis models were constructed for four fatty acids (oleic acid, linoleic acid, stearic acid, and palmitic acid) from edible vegetable oil. The regions corresponding to the Raman active groups in the molecular structure of the fatty acids were selected as multiple characteristic regions in the measured spectra, and 46 edible vegetable oil samples were collected as experimental materials to construct the model for these four fatty acids via the partial least squares method. The experimental results indicated that compared with the model built according to the full spectrum, use of the characteristic spectral region reduced the number of variables required for effective modeling and significantly improved the prediction performance of the models. In the experiment, variation in the degree of fluorescence interference was caused by the different colors of edible oils. Therefore, the selected characteristic spectral regions were combined with the spectral bands that showed significant interference (ranging from 295 to 325 cm-1) for joint modeling, thus significantly enhancing the performance of the Raman quantitative models. Furthermore, a mathematical-statistical method was employed to optimize the characteristic spectral regions for the construction of near infrared (NIR) models, which were compared with the established Raman models. The results indicated that the two kinds of models had similar performance and both can be applied for the rapid and accurate detection of the fatty acids in edible oils. However, the Raman-based model has more advantages due to the smaller sample size required and the explicit mechanism.
    39  Development of a Chromatographic Fingerprint for Fresh Flat Peach by GC-MS Combined with Chemometric Methods
    WANG Peng TIAN Hong-lei ZHANG Hai-lun ZHAN Ping Tan Si-wei ZHANG Hong-an
    2016, 32(5):258-263. DOI: 10.13982/j.mfst.1673-9078.2016.5.039
    [Abstract](857) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The volatile components of fresh flat peach (FP) samples were analyzed by solid-phase micro-extraction/gas chromatography–mass spectroscopy (SPME/GC-MS). Nine batches of samples were selected using clustering analysis (CA) and 15 “common volatiles” were selected as characteristic FP components to construct the fingerprint. The established method for constructing an FP fingerprint was validated using precision, repeatability, stability tests, and similarity analysis. The results showed that the FP samples selected from different batches based on CA were relatively consistent, and the method met the requirements for the establishment of a chromatographic fingerprint. Subsequently, based on fingerprint data, principal component analysis (PCA), and partial least squares-discriminant analysis, (PLS)], fresh FP samples and samples from different brands of peach juice were identified and differentiated. The results indicated that PCA and PLS could generally differentiate between fresh FP and different brands of peach juice. The tests showed that phenethyl ethanol, acetaldehyde, E-2-hexene-1-alcohol, hexanol, methyl acetate, and propyl acetate are possibly significant contributors to differences in the flavors of FP and commercially available peach juices. The results of this study provide scientific basis for quality control testing of FP during development of FP flavor products.
    40  Identification of Aroma-active Compounds from Yang jiang Douchi by SDE and HS-SPME Combined with GC-MS/O
    ZHAO Mou-ming CAO Yong CAI Yu SU Guo-wan FENG Yun-zi
    2016, 32(5):264-275. DOI: 10.13982/j.mfst.1673-9078.2016.5.040
    [Abstract](967) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The aroma profiles of Yang jiang douchi were studied by simultaneous distillation extraction (SDE) and head space-solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry/olfactometry, and a total of 174 volatile compounds were identified. SDE is suitable for extraction of high-molecular weight and low-volatile substances such as furanones and pyrones, while SPME is effective for extracting high-volatile compounds such as small-molecule acids and esters. Using gas chromatography-olfactometry, 46 aroma-active regions were detected in the extracts by SDE and SPME. Among them, nine compounds [2/3-methylbutanal, 2/3-methylbutanoic acid, 3-(methylthio)propanal, phenylacetaldehyde, 2-methoxyphenol, 3-hydroxy-2-methyl-4H-pyran-4-one, and phenethyl alcohol] were identified in the extracts by both methods. Four compounds [sotolone, 2-acetyl-1-pyrroline, 2-allyl-3-methylpyrazine, and 4-hydroxy- 2,5-dimethyl-3(2H)-furanone] and one compound (1-octen-3-ol) with high aroma intensity were identified only by SDE and SPME, respectively. These compounds are key aroma-active substances that contribute to the malty, cheese-like, cooked potato-like, floral, smoky, caramel-like, and roasted-like smells of Yang jiang douchi.
    41  Nucleosides from the Fruiting Body of Cultured Ophiocordyceps lanpingensis
    DU Ya-xi YU Hong GE Feng ZHANG Yan-yan ZENG Wen-bo YANG Yan
    2016, 32(5):276-282. DOI: 10.13982/j.mfst.1673-9078.2016.5.041
    [Abstract](992) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Ophiocordyceps lanpingensis, an entomogenous fungus found in Northwestern Yunnan, China, is a parasite of Hepialidae larvae. A rapid high-performance liquid chromatography (HPLC) method was developed to simultaneously determine the content of ten nucleosides (uracil, inosine, 2'-deoxyuridine, uridine, guanosine, adenosine, adenine, thymidine, 2'-deoxyadenosine, and cordycepin) in the Ophiocordyceps lanpingensis fruiting body, cultured in four different media. To conduct a preliminary quality evaluation of the cultured Ophiocordyceps lanpingensis fruiting body, it was compared with wild Ophiocordyceps sinensis. Ophiocordyceps lanpingensis cultured in a medium with rice and silkworm chrysalis powder as the major ingredients had an average growth period of 40 days, which was shorter than that observed with three other culture media. Additionally, adenosine and total nucleoside contents in the cultured Ophiocordyceps lanpingensis fruiting body were 2744 and 8015 μg/g, respectively, which were considerably higher than those in wild Ophiocordyceps sinensis and Ophiocordyceps lanpingensis. Thus, the fruiting body of cultured Ophiocordyceps lanpingensis has significant research value and application potential.
    42  Sensor Fusion of Electronic Nose and Tongue for Identification of Chinese Liquors
    MEN Hong ZHANG Xiao-ting DING Li-chao CHEN Dong-lin LIU Jing-jing
    2016, 32(5):283-288. DOI: 10.13982/j.mfst.1673-9078.2016.5.042
    [Abstract](1030) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Two different fusion systems of electronic nose and tongue were used to collect data on aroma and taste of Chinese liquors of different brands: (A) a fusion system of electronic tongue and nose, based on Taguchi gas sensors (TGS); (B) a fusion system of electronic tongue and nose, based on MQ-MP-type gas sensors. Clustering analysis of the aroma and taste was performed using principal component analysis (PCA) and the k-means algorithm. Next, prediction and classification of the different brands of Chinese liquors were performed using a support vector machine (SVM). After clustering analysis by PCA, fusion system A could distinguish three brands of Chinese liquors, while the rest of the brands showed overlapping results. Fusion system B could distinguish eight brands of Chinese liquors. The k-means algorithm was applied to the two fusion systems, and the wrong classification rates of fusion systems A and B were found to be 33.3% and 23.75%, respectively. The accuracy of prediction and classification of the Chinese liquors by the fusion systems A and B for was 93.75% and 98.75%, respectively. The study showed that the combination of information on aroma and taste could be used for identification of different brands of Chinese liquors. Additionally, identification by the fusion system B was better than that by the fusion system A.
    43  Determination of Glycidyl Esters in Edible Oils by GC-MS
    LIU Guo-qin YIN Shi-qin WANG Xue-de
    2016, 32(5):289-294. DOI: 10.13982/j.mfst.1673-9078.2016.5.043
    [Abstract](1242) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    An improved method for the determination of glycidyl esters (GEs) in edible oils is described here. Gas Chromatography-Mass Spectrometry (GC-MS) reveled that, after being derivatized with phenylboronic acid, 3-MCPD was successfully released by transesterification with sodium methoxide. For GC-MS analysis, a TG-5MS capillary column (0.25 mm × 30 m × 0.25 μm) was used with a gradient temperature program. The injection and transfer line temperature was 280 ℃ using pulsed splitless mode,and ultrapure grade helium with a flow of 1.18 mL/min as the carrier gas. Electron impact ionization mode was used with an ionization energy of 70 eV. The interface temperature was 280 ℃, with an 8 min solvent delay. The MS was operated in elected ion mode. The limit of detection was 0.010 mg/kg and the recovery rate was 87.64-98.99% with a relative standard deviation of 2.16-5.87%. The content of GEs in several edible vegetable oils was detected to verify this method. Additionally, the effects of oil and fat refining processes on GEs have been studied. The results showed that this method of analysis is both qualitatively and quantitatively accurate,with high sensitivity and good reproducibility. Therefore, this method can meet the demands of the detection and analysis of GEs in edible oils. Among edible vegetable oils, palm oil had a relative high content of GEs. Additionally, analysis of the oil refining process revealed that deodorization was the key process in which GEs were generated.
    44  Nondestructive Measurement of Sugar Content and Firmness in Korla Fragrant Pears by Using Their Dielectric Spectra
    FANG Li-jie GUO Wen-chuan
    2016, 32(5):295-301. DOI: 10.13982/j.mfst.1673-9078.2016.5.044
    [Abstract](1032) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Dielectric spectra of Korla fragrant pears were used for nondestructive measurement of their sugar content and firmness. For this purpose, the dielectric constant and dielectric loss factor at 201 discrete frequencies across the frequency range of 10 to 4500 MHz were measured in 168 Korla fragrant pears from different areas, by means of an open-ended coaxial-line probe and vector network analyzer. Patterns of changes in the dielectric properties were analyzed. Sample-set partitioning based on the method of joint x-y distances was used to group 112 samples as a calibration set and 56 samples as a prediction set. To the full dielectric spectra (FS), uninformative-variable elimination and successive projection algorithm (SPA) were applied in order to extract 144 and 20 characteristic variables (CVs) for prediction of sugar content, and to extract 52 and 9 CVs for firmness prediction, respectively. The FS and extracted CVs were subjected to partial least squares, back propagation network, least square support vector machine, and extreme learning machine (ELM) analyses to establish sugar content and firmness measurement models for Korla fragrant pears. The results revealed that the SPA-ELM model showed the best prediction for sugar content of the Korla fragrant pears: correlation coefficients of the calibration and prediction sets were 0.943 and 0.876, respectively, and the root-mean-squared errors of the calibration and prediction sets were 0.298°Brix and 0.330°Brix, respectively. The correlation coefficients of the calibration and prediction sets of all predicted models for firmness were less than 0.6. The study indicates that dielectric spectra can be used to nondestructively measure sugar content of Korla fragrant pears. However, this approach shows poor predication performance on firmness. Further studies should be conducted to evaluate feasibility of the use of dielectric spectra to nondestructively measure the firmness of Korla fragrant pears.
    45  New Method Based on Animal Genetic Information for Identification and Detection of Edible Oil
    SHI Ya-xin GE Wu-peng ZHANG Xiao-xu FANG Ruo-yu WANG Yu-xin YANG Jing GENG Wei
    2016, 32(5):302-308. DOI: 10.13982/j.mfst.1673-9078.2016.5.045
    [Abstract](785) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    The detection limit and detection conditions of edible oil combined with one or more animal oils were explored by using four pairs of species-specific primers for polymerase chain reaction to identify and detect edible oil combined with animal oils. The specificities of the four pairs of species-specific primers were verified using DNA extracted from pig, bovine, sheep, and chicken. Oil from a single animal (pig, bovine, sheep, or chicken oil) was mixed with edible oils in different proportions, the DNA in the oil was extracted using a silica spin column, and a detection level of 0.1% (m/m) single animal-derived component mixed in edible oil was used. Next, the edible oil was combined with two, three, or four types of animal oils and PCR amplification was performed after DNA extraction. The genetic information of each animal was analyzed. Finally, pig-, bovine-, sheep-, and chicken-derived components were identified and detected in the edible oil combined with one or more animal samples, using selected species-specific primers. This method can detect edible oil combined with animal-derived components at a level of 0.1% (m/m) and its provides a new reference method for detected edible oil combinations.
    46  Preliminary Analysis, Separation, and Purification of the Chemical Components of Minnan Preserved Radish Produced in Different Years
    XIONG LI-xia SU GUO-cheng JIANG FENG LIU JING-wen ZHOU CHANG-yi CHEN JUN-de LI JIAN
    2016, 32(5):309-314. DOI: 10.13982/j.mfst.1673-9078.2016.5.046
    [Abstract](1214) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    High performance liquid chromatography-diode array detection (HPLC-DAD) was used to establish the HPLC fingerprints. The similarity evaluation system for traditional Chinese medicine (TCM) chromatographic fingerprint (version A) was applied to analyze and evaluate the similarities of the HPLC fingerprints. The components of five-year preserved radish were separated and purified by using SephadexLH-20 resin, positive phase silica gel column chromatography, and reversed phase C18 (RP-C18) silica gel column chromatography. The structures were identified using thin layer chromatography (TLC), ultraviolet (UV) detection, electrospray ionization mass spectrometry (ESI-MS), and nuclear magnetic resonance spectroscopy (NMR). The liquid chromatograms of the methanol extracts of Minnan preserved radish produced in different years and those of fresh radish were obtained, and the results showed that the similarities between the chemical components of the Minnan preserved radish produced in different years and those of fresh radish were less than 40%. Additionally, two compounds–pinoresinol and linoleic acid methyl ester–were isolated and purified from five-year preserved radish, and both were first found in preserved radish, which provided a basis for the edible and therapeutic value.
    47  Colorimetric Aptasensor for the Determination of Chloramphenicol in Fish and Goose Meat
    GAO Hui-ju PAN Dao-dong SUN Yang-ying CAO Jin-xuan ZENG Xiao-qun WU zhen
    2016, 32(5):315-321. DOI: 10.13982/j.mfst.1673-9078.2016.5.047
    [Abstract](909) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    A novel colorimetric aptasensor was developed for rapid identification of chloramphenicol (CAP) in fish and goose samples. The assay is based on a highly selective aptamer binding to its targets followed by a dual-amplification effect from large amounts of palladium oxide (PdO) nanoparticle labeled EnVision (EV). This method could detect ultra-trace amounts of CAP specifically, sensitively, and rapidly. EV has approximately 100 horseradish peroxidase (HRP) molecules and can effectively catalyze the substrate 3,3’,5,5’-tetramethylbenzidine (TMB) for color development. In addition, PdO can catalyze TMB to produce a blue-green color. Thus, a dual-amplification effect can be achieved by using the proposed method. The amount of CAP in samples can be calculated by measuring the change in the absorbance of TMB. The results indicate that, under optimal conditions, this method displays relatively high sensitivity and a good linear correlation with CAP concentration, within the range of 0.02~150 ng/mL. The lower detection limit was identified as 0.01 ng/mL. In addition, this assay was successfully used to analyze CAP concentrations in fish and goose samples, and the results were consistent with those obtained by the conventional ELISA method.
    48  HS-SPME-GC-MS Study on the Relationship between the Freshness of Tomato and Its Volatile Components
    NIU Yuan-yang LUO An-wei LIU Huan-jun YAO Jie LI Chen LI Zhi-cheng YUE Tian-li BAI Lian-she
    2016, 32(5):322-331. DOI: 10.13982/j.mfst.1673-9078.2016.5.048
    [Abstract](746) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Changes in the volatile components of tomatoes and the characteristic odor components arising from high-temperature (38°C ± 1 ℃, reduces freshness) and low-temperature (4 ℃± 1 ℃, preserves freshness) storage were analyzed by headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS). Additionally, the indexes of tomato freshness degree were analyzed. Tomatoes in the high-temperature environment lost their freshness on the 6th day, with ethyl acetate, ethanol, trans-2-hexenal, 1-octen-3-ol, 1-heptanol, and acetic acid being the resultant characteristic odor components. Tomatoes in the low-temperature environment started losing freshness on the 14th day, where ethanol, 2-hexen-1-ol, α-farnesene, acetic acid, 1,1-diethoxy-octane, octanol, and octanoic acid were the characteristic odor components. After loss of freshness, the content of soluble solids and the hardness of the tomato fruits decreased, while the pH value and the rate of weight loss increased. Ethanol was the characteristic odor for tomatoes with reduced freshness, with a threshold value of 234.48 μg/L. This study provides a theoretical basis for judging the freshness of tomatoes by measuring their volatile components. Meanwhile, the results can be used to develop a smart refrigerator to determine the freshness of tomatoes via detection of their volatile components. However, the set of threshold values of the probe needs further exploration.
    49  A Review of the Bioactive Components and Biological Activities of Zizyphus jujuba Mill. (Jujube) Fruits
    DING Sheng-hua WANG Rong-rong WU Ji-hong DAN Yang HU Xiao-song
    2016, 32(5):332-348. DOI: 10.13982/j.mfst.1673-9078.2016.5.049
    [Abstract](1115) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Jujube (Ziziphus jujuba Mill.) fruit belonging to the Ramnaceous family ranked first in dried fruit production and seventh in fresh fruit production. Its fruit is consumed as the homology of medicine and food. Medical studies show various biological activities, including anticancer, antioxidant, anti-inflammatory, hepatoprotective, gastrointestinal protective, immunostimulating, anti-anxiety, anti-obesity, and anti-bacteria properties. Current studies of Ziziphus jujuba Mill. have focused on the separation of its chemical components, as well as their structural identification, content determination, and biological activities. The analysis of chemical components have revealed that jujube fruits contain polysaccharides, phenolic acid, terpenoids, flavonoids, alkaloids, nucleosides, nucleobases, carotenes, α-tocopherol, ascorbic acid, and volatile oils. Among them, polysaccharides, phenolic acids, flavonoids, terpenoids, and cyclic nucleotides are the main biologically active components of jujube fruits. Ziziphus jujuba Mill. polysaccharides exhibit hepatoprotective and immunostimulating effects; ascorbic and phenolic acids, and flavonoids are the main antioxidant components; and triterpenoids are the main anticancer components of jujube fruits.

    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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