Volume 35,Issue 4,2019 Table of Contents

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  • 1  Effects of Camel Colostrum on Cyclophosphamide-induced Immunodeficiency in Mice
    ZHANG Zhao-xiao ZHENG Zheng YANG Li FENG Xin-huan MIAO Jing FU Ying-hua SHEN Tong YUE Hai-tao YANG Jie
    2019, 35(4):1-8. DOI: 10.13982/j.mfst.1673-9078.2019.4.001
    [Abstract](607) [HTML](214) [PDF 14.06 M](771)
    Abstract:
    In this paper, the effect of camel colostrum on immune function in immunocompromised mice was investigated. A 30-day gavage experiment using Kunming mice was performed to explore the immune regulation of camel colostrum on cyclophosphamide (CY)-induced immunodeficiency and immune injury by immunological parameters. The mice were fed with camel colostrum and casein to calculate the food conversion rate and protein efficacy ratio of camel colostrum. The percentage of positive lymphocyte and the count of white blood cells in the high dose group of colostrum were 2.2 times and 1.4 times higher than those in the immunocompromised group, respectively (p<0.05). Medium and high dose of camel colostrum can significantly increase CD4+/CD8+ ratio, IgG level (p<0.05), phagocytic capacity and immune organ index of macrophage in immunocompromised mice. Moreover, camel colostrum can effectively repair the damage of immune organs in mice. The protein utilization rate of camel colostrum is 85.05%, and the corrected protein efficacy ratio is 3.17. In conclusion, camel colostrum has the effect of enhancing immune function in immunocompromised mice. Camel colostrum protein is a high-quality protein that is more easily absorbed to exert immunoregulatory functions. In addition, camel colostrum could be a promising, potent immunomodulatory therapeutic agent for various immune disorders.
    2  Effect of Green Tea Extract on the Nonalcoholic Steatohepatitis Induced by MCD Diet
    HUANG Tian-yang LI Hui-min FENG Yu LEE Ming-yuan CUI Guo-zhen
    2019, 35(4):9-15. DOI: 10.13982/j.mfst.1673-9078.2019.4.002
    [Abstract](607) [HTML](209) [PDF 44.82 M](817)
    Abstract:
    To evaluate the effect of green tea extract on the NASH mice -induced by MCD diet and its possible mechanism, forty C57BL/6 mice were randomly divided into four groups: control group (MCS diet), MCD group (MCD diet), MCD diet supplemented with green tea extract (0.15 g/kg/day or 0.30 g/kg/day). After 8-weeks administration, blood and liver were harvested. The levels of serum ALT, AST, IL-6 and TNF-α were measured. The levels of hepatic TG and TC were also measured. The oil red stained was used to evaluate the lipid accumulation area in liver. Additionally, the liver tissues were stained with hematoxylin-eosin to evaluate the hepatic steatosis, inflammation and the ballooning according to the non-alcoholic fatty liver disease activity score. Western blot was used to analyze the protein expression levels of GRP78 and LC3. Results showed that, compared to MCD model, administration of green tea extract could significantly decrease the levels of serum ALT、AST、IL-6 and TNF-α, with the largest decrease rate of 38%, 45%, 46% and 74%, respectively. In addition, result of oil red O staining indicated that the extract also could obviously attenuate the accumulated fat in the liver. The extract could decrease the levels of hepatic TG and TC, with the largest decrease rate of 44% and 37%, when compared to MCD group. Result of H&E staining showed that the score of steatosis, lobular inflammation, hepatic ballooning was significantly reduced by green tea extract in C57/BL6 mice subjected to MCD diet. The expression level of GRP78 was markedly restrained while that of LC3-II was increased by administration of green tea extract. Green tea extract has beneficial effects against NASH-induced by MCD diet. The regulations of GRP78 and LC3-II might be involved in the mechanisms of action of green tea extract.
    3  Isolation and Purification of 7-deoxynarciclasine and Its Antitumor Activity in Vitro
    WAN Lin XU Xi-lin YANG Lin-jiang JIANG Jian-guo
    2019, 35(4):16-21. DOI: 10.13982/j.mfst.1673-9078.2019.4.003
    [Abstract](544) [HTML](196) [PDF 26.97 M](699)
    Abstract:
    In this study, a compound was obtained from the n-butanol fraction of the active part of Lycoris radiate Herb. The compound was identified as 7-deoxynarciclasine by mass spectrometry and Nuclear Magnetic Resonance spectroscopy. To study the cytotoxicity of 7-deoxynarciclasine against normal human cells (LO2 cells and HFF-1 cells), and its effect on the cell viability of human cervical cancer cells (Hela cells) and human colon cancer cells (HT-29 cells) were examined. The results showed that human foreskin fibroblasts (HFF-1 cells) were more tolerant to 7-deoxynarciclasine than normal human hepatocytes (LO2 cells). The concentration of 7-deoxycycline, which led to a LO2 cell survival rate higher than 80%, was applied to HT-29 and Hela cells. As a result, the median lethal concentration (IC50) of 7-deoxynarciclasine to HT-29 or Hela cells was 17.04 μM and 6.39 μM respectively. These values were lower than those of 5- fluorouracil against HT-29 (22.45 μM) or Hela cells (37.05 μM), and that against LO2 (40.11 μM). These findings indicate that 7-deoxynarciclasine may significantly inhibit the proliferation of tumor cells without affecting significantly the normal cells.
    4  Lipid-Modulating Effects of Visceral Lipids from Haliotis discus hannai on HepG2 Cells
    CHEN Bei ZHANG Bo-chao WU Yu-min QIAO Kun QU Hai-dong XU min PAN Nan LIU Zhi-yu
    2019, 35(4):22-29. DOI: 10.13982/j.mfst.1673-9078.2019.4.004
    [Abstract](461) [HTML](189) [PDF 18.33 M](625)
    Abstract:
    In this study, the effects of the visceral lipids from Haliotis discus hannai (HDHL) on lipid metabolism of human hepatoma cell line, HepG2 cells, were investigated. The HDHL fatty acid composition, HepG2 cell activity, and the content of intracellular cholesterol and triglycerides as well as the mRNA expression of fatty acids metabolism-related genes were examined. It was found that the unsaturated fatty acids in HDHL accounted for 59.50% of the total fatty acids, of which polyunsaturated fatty acids accounted for 29.71%. After an incubation of HDHL and HepG2 cells for 24 h and 48 h, respectively, HDHL at 0~240 μg/mL had no toxic effect on HepG2 cells, whereas, HDHL at 30~240 μg/mL could significantly reduce the total cholesterol content of HepG2, with HDHL at 30~120 μg/mL causing a significant decrease in the content of intracellular triglycerides. The qPCR results revealed that in HepG2 cells, HDHL could significantly reduce the mRNA expression of fatty acid synthesis-related genes SREBP1c, ACC1 and FAS as well as fatty acid transport and absorption-related gene CD36, while increasing the expression of mitochondrial fatty acid oxidation gene CPT1. Therefore, HDHL might regulate cell lipid metabolism through inhibiting the synthesis and transportation of fatty acids while enhancing the oxidation of fatty acids in mitochondria. This study provides a theoretical basis for the development of lipid-regulating functional foods.
    5  Tetracycline-resistant Bacteria on Food Contact Surfaces in a Raw Pork Processing Plant and Distributions of Their Tetracycline Resistance Genes
    MENG He-cheng WEI Si-yu LI Li-li
    2019, 35(4):30-35. DOI: 10.13982/j.mfst.1673-9078.2019.4.005
    [Abstract](500) [HTML](341) [PDF 4.18 M](858)
    Abstract:
    The spread of drug-resistant bacteria poses a serious threat to food safety and human health. In this study, the tetracycline resistance of the contaminated microorganisms on the food-contact surfaces in a large raw pork processing plant was analyzed, and the potential quality and safety hazards in raw pork products. A total of 168 strains were isolated in the 100 samples collected .from the food contact surfaces in the plant. Drug sensitivity tests revealed that 60.7% of the contaminating bacteria were resistant to tetracycline, including Pseudomonas sp., 85.7%; Staphylococcus sp., 85.7%; Serratia sp., 86.7%; Lactococcus sp., 80%; Escherichia coli, 80%; Acinetobacter sp., 60.0%; Aeromonas sp., 55.0%. Through screening 15 tetracycline resistance genes in the isolated strains, nine tetracycline resistance genes with different detection rates were found (including tetL, 7.7%; tetA, 6.0%; tetB, 4.8%; tetC, 4.8%; tetE, 3.6%; tetM, 3.6%; tetS, 3.6%; tetK, 1.2%; tetX, 0.6%). These results indicated the high prevalence and cross contamination of tetracycline-resistant bacteria on food-contact surfaces in the plant and in raw pork products, and the possible spread of tetracycline resistance genes among different bacterial species and along the food chain to humans, which will pose a potential threat to human health.
    6  Blueberry Anthocyanin Extracts Regulate Glucose Consumption in HepG2 Cells
    ZHANG Sen WU Ying ZHANG Jiu-liang
    2019, 35(4):36-43. DOI: 10.13982/j.mfst.1673-9078.2019.4.006
    [Abstract](562) [HTML](231) [PDF 46.47 M](709)
    Abstract:
    The regulation of glucose consumption in insulin-resistant hepatoma cell line HepG2 with blueberry anthocyanin extracts was investigated. The optimum concentration of blueberry anthocyanin extracts was screened by MTT assay. Different concentrations of insulin and glucose were performed to induce insulin resistance in HepG2 cells. The number of cells was corrected by MTT, and contents of glucose in medium were detected by glucose oxidase method. Changes in glucose in the medium reflected the intervention of the blueberry anthocyanin extract on cellular insulin resistance. MTT results showed that and there was no significant effect on the activity of HepG2 cells at concentrations below 200 μg/mL of the extracts of NL BAEs and that below 100 μg/mL of the extracts of BW BAEs and GB BAEs. With the inducing agent insulin concentration of 1×10-8 mol/L and incubation for 24 h as the induction condition, the model was effective, while the cell viability had no significant change and the stability was good. It could promote glucose consumption in normal HepG2 cells and insulin-resistant HepG2 cells at the concentration of 7.8125~31.25 μg/mL of three varieties of blueberry anthocyanin extracts and showed a dose-effect relationship. It had a maximum at 31.25 μg/mL. Compared to the model group, sugar consumptions of extracts of NL BAEs, BW BAEs and GB BAEs had increased by 60%, 65% and 88%, respectively. Three varieties of blueberry anthocyanin extract could prevent and improve the utilization of glucose by insulin-resistant HepG2 cells.
    7  Study on the Hypolipidemic Effect of Zhi Qing Shuang Healthy Tea
    YANG Jia-ying JIANG Li-juan ZHANG Yu LI Cai-xia JIANG Yan-yan LIU Bin
    2019, 35(4):44-49. DOI: 10.13982/j.mfst.1673-9078.2019.4.007
    [Abstract](553) [HTML](264) [PDF 11.10 M](734)
    Abstract:
    This paper was to study the hypolipidemic effect of Zhi Qing Shuang (ZQS) in rats and cells, which provided a reference for the development of health food with hypolipidemic effect. The animal experiment was carried out according to evaluation method of auxiliary hypolipidemic function. During the experiment, 60 rats were used in this study, of which 10 rats as the normal group were given normal feed. The remaining rats were given high-fat feed, according to the TC level, which were randomly divided into model group, positive control group and ZQS (high, middle and low dose) group. Each group was normally fed for 4 weeks, the groups were given ZQS (high, middle and low dose) and positive drug, the levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were determined after the last gavage administration by collecting the blood of orbit. For in vitro cell experiment, the hyperlipidemia model was established in hepG2 cells which was induced by sodium oleate. The hypolipidemic effect was evaluated by comparing the content of TC, TG between model group and drug group. Compared with the model group, the results showed that ZQS induced a significant reduction in TC, TG and LDL-C levels, with the largest reduce rates of 34.52%, 43.22% and 44.89%, respectively. The content of HDL-C was significant increased up to 50.62% in high dose of ZQS group. The in vitro cell experiment results demonstrated that ZQS induced a significant reduction in TC, TG, with the largest reduce rates of 27.54%, 27.98%. In conclusion, ZQS has the function of reducing blood lipid. The study lays a foundation for the development and application of ZQS health food.
    8  High-throughput Sequencing Analysis of Probiotics Intervention in Intestinal Flora of Cold-fed Mice
    LYU Ge ZHANG Zhi YANG Ke-xin WEI Gang WANG Jia-fu
    2019, 35(4):50-55. DOI: 10.13982/j.mfst.1673-9078.2019.4.008
    [Abstract](824) [HTML](262) [PDF 32.34 M](791)
    Abstract:
    High-throughput sequencing was used to analyze the effects of probiotics on the intestinal flora of cold-fed mice. The experimental mice were randomly divided into a model group, a control group, and a low, medium, and high dose group, and an equal amount of ordinary ice cream, 107 cfu/mL probiotic liquid, and 107, 108, 109 cfu/mL probiotic ice cream, respectively. The rats were continuously fed for 15 days, and the stool rate and diarrhea index of mice were recorded and calculated. After 15 days, the feces of each group were collected for high-throughput sequencing analysis. It was found that cold food could cause diarrhea in some mice. In the dose range, probiotics could alleviate the symptoms of diarrhea in cold-sensitive mice. The high-dose group decreased the stool rate by 3.11% and the diarrhea index (10-1) by 0.33. The inhibition effect was significant, compared to the other groups. The fecal flora of mice with probiotics was highly diverse (the high-dose group had an ACE value of 69987.29 and the Chao1 value was 27098.77), and the proportion of genus Lactobacillus, Ekmenia, and Blautia increased and their structure changed. Therefore, probiotics could improve the acceptance of cold food in cold-sensitive diarrhea-sensitive mice. The probiotics under the frozen carrier could be colonized in the intestine of mice and regulate the intestinal tract of mice.
    9  Interaction between Wheat Gliadin and Tea Saponin and Its Effect on the Properties of Glycerol-based Foam
    LIU Yu-yang YANG Xiao-quan
    2019, 35(4):56-60. DOI: 10.13982/j.mfst.1673-9078.2019.4.009
    [Abstract](464) [HTML](220) [PDF 56.92 M](780)
    Abstract:
    In this study, we prepared an interface-dominated food foam system via regulating the interactions between macromolecules and small molecules. For the first time, food-grade glycerol was used as a green co-solvent to dissolve the hydrophobic gliadin and amphiphilic small-molecule tea saponins (TS). The interaction between gliadin and tea saponin as well as its foam-forming ability and stability were further evaluated. Intrinsic fluorescence spectroscopy measurements revealed that the fluorescence quenching parameter was 1.345×109 M-1 S-1, which was much smaller than the maximum dynamic quenching constant (2×1010 M-1 S-1). These findings indicated that TS-mediated dynamic quenching enabled the formation of a complex system via the non-specific hydrophobic interactions prior to the formation of foam. The results of dynamic adsorption at the interface showed that at a suitable TS concentration (0.5%~0.75%), the gliadin-TS interaction could increase the interfacial activity and coverage area, compared with gliadin or tea saponin. Confocal laser scanning microscopy showed that at the above-mentioned TS concentrations, gliadin was accumulated on the foam surface, leading to a foam containing small-sized air bubbles, and eventually a gliadin-TS system with foam-forming ability and stability.
    10  Effects of Different Concentrations of NaCl Treatment on Carotenoid Enrichment in Germinated Corn
    WANG Yu-xi HE Wei-wei LI Da-jing BAO Yi-hong LIU Chun-quan SONG Jiang-feng
    2019, 35(4):61-69. DOI: 10.13982/j.mfst.1673-9078.2019.4.010
    [Abstract](401) [HTML](299) [PDF 33.33 M](724)
    Abstract:
    In the present study, the effects of different concentrations of NaCl on the carotenoid content, antioxidant capacity and relative expression levels of key enzyme genes in germinated corn kernels were investigated. The results showed that NaCl stress significantly reduced the germination rate and sprout length of corn kernels and increased the respiratory intensity after 3 days of germination. With the increasing concentration of NaCl, the carotenoid content and the expression levels of key enzyme genes in the germinated corn kernels increased first, then decreased. The lutein and zeaxanthin contents reached maximum values in 300 mmol/L of NaCl treatment, which were 1.19 and 1.30 times of the control, respectively. Meanwhile, NaCl stress led to a significant increase in SOD, POD activities and total antioxidant capacity. However, the expression levels of key enzyme genes decreased and the synthesis of carotenoids were inhibited when NaCl concentration is greater than 300 mmol/L. The results suggest that NaCl treatment could increase the expression levels of related genes in germinated corn kernels and promote the enrichment of carotenoids such as lutein and zeaxanthin. Moreover, the antioxidant capacity also increased. The present study provides new methods for enriching carotenoids in yellow corn kernels, and provides theoretical basis and technical support for the development of health functional foods with germinated corn kernels.
    11  Activities of Active Oxygen Metabolism Enzymes and Isoenzymes in Apricot Fruit Treated with 1-MCP and Ethephon
    ZHU Wan-tong BAI Yu-jia FENG Zuo-shan ZHANG Yue GONG Xuan-yun WANG Jin
    2019, 35(4):70-76. DOI: 10.13982/j.mfst.1673-9078.2019.4.011
    [Abstract](417) [HTML](244) [PDF 43.64 M](704)
    Abstract:
    Using Luntai Baixing as test material, 1 μL/L of 1-methylcyclopropene (1-MCP) and 30 mg/kg of ethephon were used to treat apricot fruit, the aim is to study the changes in the activities of superoxide dismutase (SOD), polyphenol oxidase (PPO), peroxidase (POD) and lipoxygenase (LOX) in apricot pulp stored at 25 ℃, and their isoenzyme expression changes. The results showed that the 1-MCP treatment group significantly delayed the aging and softening of apricot fruit, and the ethephon treatment accelerated the senescence and softening of apricot fruit. The enzyme activities of SOD, PPO and POD in the apricot fruit treated by 1-MCP were higher than those in the control and ethephon treatment groups. The activity of SOD was 25.21% higher than that of the control group (p<0.05), the activity of PPO was 12.93% higher than that of the control group (p<0.05), the activity of POD was 9.96% higher than that of the control group (p<0.05), and the activity of LOX was significantly lower than that of the control group, and the ethephon treatment group was 46% lower than the control group (p≥0.05). The expression of SOD, PPO and POD isoenzymes in the 1-MCP treatment group and the control group were enhanced, and the expression of LOX isoenzyme was reduced. As the storage time increased, the isozyme bands changed from clear to diffuse band, and isozyme expression decreased with time. 1-MCP reduced the activity of active oxygen metabolism and the production of reactive oxygen species, slowed down the process of cell aging, delayed softening, and improved the storage quality of apricot fruit.
    12  Effect of Slurry Ice Precooling Treatment on Quality of Broccoli
    LIU Yao ZUO Jin-hua GAO Li-pu SHI Jun-yan SUN Wen YAN Zhi-cheng WANG Qing SUI Yuan
    2019, 35(4):77-86. DOI: 10.13982/j.mfst.1673-9078.2019.4.012
    [Abstract](545) [HTML](316) [PDF 51.58 M](808)
    Abstract:
    To study the effect of slurry ice precooling treatment on broccoli, slurry ice were used to treat broccoli, then stored at 20±1 ℃ after cooled to 0±1 ℃. Sensory index, yellow index, chlorophyll, glucosinolate and antioxidant enzyme activities were periodically measured to evaluate the storage quality. The experimental results showed that slurry ice precooling technology can quickly reduce the temperature of broccoli to 0.4 ℃ and reduce the cooling time to 4 h. On the third day, the contents of chlorophyll and vitamin C (Vc) in broccoli treated with flowing ice were 2 times higher than those in CK group, and the content of MDA was 1 times higher than that in CK group; the contents of soluble solids (TSS) and glucothioside were both in high level, maintaining the nutritional quality of broccoli; and the activity of CAT, POD, APX increased by 32%, 23% and 64%, respectively. Thus, slurry ice precolling treatment could maintain the storage quality and prolonging the shelf life of broccoli.
    13  Comparison of the Edible Characteristics and Nutrient Quality of Rice Flour Prepared with Different Processing Degrees
    ZHAO Yue LI Jia-shuang TAN Yao-yao LIU Hui ZHANG Cui-cui WANG Jing ZHANG Hong
    2019, 35(4):87-95. DOI: 10.13982/j.mfst.1673-9078.2019.4.013
    [Abstract](557) [HTML](364) [PDF 15.01 M](638)
    Abstract:
    In this study, rice flour was prepared from fresh brown rice with different degrees of processing, and the basic nutritional quality, vitamins, microelements, amylose, thermal characteristics, rheological characteristics and sensory quality of rice flour with different grades of fresh brown rice were compared. It was found that, in addition to carbohydrate and microelement Cr, with the improvement of processing degree, the embryo retention rate decreased and the basic nutritional value of brown rice was seriously lost. The fat content and ash content of rice flour prepared by brown rice were nearly 3 times those of white rice flour, and the protein content of wheat flour was up to 8.13 g/100 DM, and the contents of vitamin B1 and B3 were 133.74 μg/100 DM and 3.39 mg/100 DM, respectively, which were 7.5 times and 10.6 times those of white rice flour, respectively. The over processed white rice flour and white rice flour had better thermal characteristics and sensory evaluation due to their high amylose content (24.35% and 23.50%, respectively). A comprehensive comparison showed that the edible and nutritional characteristics of 5-cent white rice flour were best, and the content of Zn was the highest, which was 18.65 mg/kg (DM). The apparent viscosity of 5-cent white rice flour was similar to that of white rice flour, and the rice paste state was better, which was suitable for the development of supplementary rice flour products.
    14  Antimicrobial Activity of the Litchi Juice Fermented by Lactobacillus casei and the Strain’s Tolerance in Simulated Gastrointestinal Tract
    GUAN Xiao-ying WEN Jing XIAO Geng-sheng XU Yu-juan WU Ji-jun YU Yuan-shan ZOU Bo
    2019, 35(4):96-102. DOI: 10.13982/j.mfst.1673-9078.2019.4.014
    [Abstract](510) [HTML](218) [PDF 13.82 M](724)
    Abstract:
    The survival of Lactobacillus casei in its fermented lychee juice was investigated in an artificial gastric juice and artificial intestinal juice model. At the same time, the antimicrobial activities of the fermented juice against six common foodborne pathogens (Salmonella, Shigella sonnei, Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus and Enterobacter sakazakii) were examined using the agar diffusion method, considering the effects of acids and enzymes. The results showed that in the simulated gastrointestinal digestion model, the viable counts of Lactobacillus casei were 260, 8.63×107, 9.57×107 and 1.15×108 CFU/mL, respectively, after a 4-h incubation in an artificial gastric juice at pH 1.5, 2.0, 3.0 or 4.0, while above 107 CFU/mL after a 12-h digestion in the artificial intestinal juice. In terms of antimicrobial activity, the fermentation broths subjected to different treatments such as deacidification, hydrogen peroxide removal and enzymatic hydrolysis exhibited significant inhibitory effects on five common foodborne pathogenic bacteria including Salmonella enteritidis, except for Enterobacter sakazakii. Exopolysaccharide, H2O2 and protein peptides were the main antimicrobial substances against five common pathogenic bacteria. These results will lay a theoretical foundation for in vitro experiments on whether Lactobacillus casei fermented lychee juice could offer beneficial effects in the gastrointestinal tract and provides a scientific basis for local food industrial development and application.
    15  Effect of Different Atmosphere Packaging on the Preservation of Bracken
    ZHENG Quan DING Yun-shan CUI Lin-lin MA Rui-bo QIN Yi-qin ZHANG Jia-li HE Mei-shan CHEN Jun-pu ZHANG Qun-li
    2019, 35(4):103-108. DOI: 10.13982/j.mfst.1673-9078.2019.4.015
    [Abstract](560) [HTML](218) [PDF 19.38 M](762)
    Abstract:
    The effect of controlled atmosphere treatment on the fresh-keeping of Pteridophyte was studied in this paper. The effects of controlled atmosphere on the fresh-keeping of Pteridophyte were studied by using natural fern as blank control group and the modified atmosphere packaging of carbon dioxide and oxygen-mixed gases with different proportions of 6% CO2+2% O2, 6% CO2+6% O2 and 6% CO2+10% O2 as experimental groups. By testing the weight loss, soluble solids, Vc content, titratable acid content, hardness and chlorophyll content of fresh-keeping ferns, the effects of different gas ratios on fresh-keeping of ferns were analyzed, and the gas ratio with best fresh-keeping effect was selected. The experimental results showed that the modified atmosphere storage slowed down the decline rate of bracken quality. Modified atmosphere preservation prolong the time to reach the peak of soluble solids and chlorophyll a from the 4th day to the 8th day, and the peak of soluble solids in the experimental group was 1.56 times that of the control group. On the 14th day, the soluble solid content of 6% CO2+10% O2 was 1.31 times that of the control group, and the chlorophyll a content was 1.55 times that of the control group. Modified atmosphere preservation slowed down the decomposition of Vc by 5%, 5% and 10% respectively, and the slow-down effect for 6% CO2+10% O2 gas ratio was more obvious. The results showed that the fresh-keeping effect of Pteridium aquilinum was the best when the contents of CO2 and O2 were 6% and 10%, respectively.
    16  Effects of Drying Temperature on the Dissolving-out Properties of Polysaccharides in Dendrobium officinale Particles
    MA Hou-yu XING Li MIAO Ye-lian
    2019, 35(4):109-115. DOI: 10.13982/j.mfst.1673-9078.2019.4.016
    [Abstract](545) [HTML](207) [PDF 20.74 M](838)
    Abstract:
    The objective of this work was to evaluate the effect of drying temperature on the dissolving-out ratio and the dissolving-out velocity of polysaccharides in D. officinal particles. The fresh D. officinal particles (5 mm in diameter×5 mm in length) as the raw material was used to prepare the dried D. officinal particles by hot-air-drying at different temperatures with the range of 60 to 140 ℃.Polysaccharides in the dried D. officinal particles were extracted by hot-water soaking at 60 ℃.The tissue structures of fresh and dried D. officinal particles were compared. The polysaccharide dissolving-out ratio and diffusion coefficient of fresh D. officinale particles were (46.65±0.86)% and 1.02×10-2 mm2/h, respectively. In the drying temperature range of 60 to 100 ℃, the dissolving-out of polysaccharides in dried D. officinale particles was promoted by drying. Low temperature is beneficial to the dissolving-out of polysaccharides. The polysaccharide dissolving-out ratio and diffusion coefficient of dried D. officinale particles prepared at 60 ℃ reached (64.54±1.27)% and 1.94×10-2 mm2/h, respectively. The low drying temperature was beneficial for D. officinale particles to maintaining the tissue structure, reducing shrinkage, mitigating Maillard reaction and caramelizing reaction, and producing certain internal voids, which promoted the dissolving-out of polysaccharides. This work provided technical data and theoretical basis for the drying and utilization of D. officinale.
    17  Accumulation Characteristics of Non-anthocyanin Phenolic from Five Different Red Wine Grape Varieties in the Northern Foothills of Tianshan Mountains
    ZHANG Ke YUAN Lin YANG Xing-yuan LI Qian WANG Rui YAN Xue WANG Jing WANG Wen-xuan ZHANG Zhen-zhen
    2019, 35(4):116-123. DOI: 10.13982/j.mfst.1673-9078.2019.4.017
    [Abstract](477) [HTML](185) [PDF 29.23 M](811)
    Abstract:
    In order to investigate the non-anthocyanin of five different red wine grape varieties in the northern foothills of Tianshan accumulation characteristics, five red wine grape varieties from Wujiaqu production area were selected to detect the content and composition of flavonol and flavan-3-ol during growth and development. Three major categories of flavonols were quercetin, kaempferol and myricetin. The results showed that the content of quercetin, kaempferol and myricetin in 'Cabernet Sauvignon' reached the maximum at 12 weeks after flowering, which were 0.122 mg/g, 0.015 mg/g, 0.065 mg/g, respectively. At 12 weeks after flowering, the content of quercetin substance in 'Cabernet Franc' reached a maximum of 0.500 mg/g. At 16 weeks, the contents of kaempferol and myricetin in 'Cabernet Franc' reached a maximum of 0.092 mg/g, 0.068 mg/g, respectively. The content of kaempferol of 'Syrah' reached a maximum of 0.043 mg/g at 14 weeks after flowering, but the content of myricetin substance in 'Syrah' reached a maximum of 0.042 mg/g at 16 weeks. At 16 weeks, the contents of myricetin and the kaempferol in 'Petit Verdot' reached a maximum of 0.050 mg/g and 0.035 mg/g, respectively. At 12 weeks, the content of kaempferol in 'Marselan' reached a maximum of 0.013 mg/g, and at 14 weeks, the content of myricetin in 'Marselan' reached a maximum of 0.077 mg/g. Principal component analysis of five varieties of flavonol and flavan-3-ol showed that the relative content of flavan-3-ols in 'Syrah', kaempferol in 'Petit Verdot', quercetin in 'Cabernet Sauvignon' and 'Marselan' were relatively high. The accumulation characteristics of the five varieties in the production area were different, which directly reflected the performance of the varieties in the production area. It will be helpful to grape cultivation and brewing in the northern foothills of Tianshan.
    18  Effect of β-glucanase on the Physical Characteristics and Sensory Quality of Noodles Made with Barley-wheat Mixed Flour
    LI Zhen GAO Wen-qian JI Sheng-xin SUO Biao AI Zhi-lu
    2019, 35(4):124-129. DOI: 10.13982/j.mfst.1673-9078.2019.4.018
    [Abstract](446) [HTML](186) [PDF 740.00 K](671)
    Abstract:
    In this study, noodles were prepared through using barley-wheat mixed flour (with a mass ratio of 4:6). The effects of adding β-glucanase at 0, 300, 500, 700, 900 or 1100 mg/kg on the physical characteristics and sensory quality of noodles were investigated through measuring the pasting properties of mixed flour, and texture, color and cooking characteristics of noodles. The results showed that adding β-glucanase at 300 mg/kg caused the greatest decrease in the peak viscosity, trough viscosity, breakdown, final viscosity, setback and peak time of mixed flour, with the decreases being 313.33 cP, 211.67 cP, 101.66 cP, 341.7 cP, 129.34 cP and 0.24 min, respectively. The addition of β-glucanase could improve the texture properties of raw noodles, with the hardness, chewiness and resilience being reduced by 29.17%, 33.10% and 12.44%, respectively, and the score of sensory evaluation exhibiting an upward trend. When the amount of added β-glucanase was more than 300 mg/kg, the brightness of dough decreased significantly. When the amount of β-glucanase reached 1100 mg/kg, the cooking loss of noodles decreased significantly from 7.97% (the control group) to 7.10%, and the score for overall acceptability was 5.7. Accordingly, the addition of an appropriate amount of β-glucanase can improve the quality of the noodle made with barley-wheat mixed flour, thus, β-glucanase may be considered as a modifier for this kind of noodle.
    19  Optimization of the Extraction of the Polysaccharides from Caulis Lonicerae and Their Abilities of Scavenging Nitrite and Blocking Nitrosamine Synthesis
    LI Zhen LI Ping
    2019, 35(4):130-139. DOI: 10.13982/j.mfst.1673-9078.2019.4.019
    [Abstract](548) [HTML](275) [PDF 91.77 M](715)
    Abstract:
    In this research, the extraction, isolation and purification of the polysaccharides from Caulis Lonicerae were performed, and their functions to removing nitrite and block the synthesis of nitrosamine were determined. The ultrasound-assisted polysaccharide extraction was optimized using the yield of polysaccharides from Caulis Lonicerae as the index, and the response surface method. The extracted polysaccharides was deproteinized using the Sevag method, precipitated using alcohol, and vacuum dried, before the examinations on their abilities of scavenging nitrite and blocking nitrosamine synthesis under simulated gastric acid conditions. The results indicated the optimal extraction conditions: the ratio of liquid to material, 30:1; extraction time, 40 min; ultrasonic power, 210 W; extraction temperature, 70 ℃. Under the optimal conditions, the theoretical yield of polysaccharides was 8.53%, while the experimental value was 8.46%; at a concentration of 500 μg/mL, the polysaccharide extract had a nitrite-scavenging rate of 90.44% and a blocking rate of 71.24% for nitrosamine synthesis. Therefore, the response surface method, which was used to optimize the ultrasound-assisted extraction of polysaccharides from Caulis Lonicerae, provided good quality predictions. The obtained polysaccharides were capable of removing nitrite and blocking the synthesis of nitrosamines. This research provides a theoretical basis for further utilization of Caulis Lonicerae and development of derived bioactive polysaccharide products.
    20  Preparation and Characterization of Edible Antibacterial Peptide-gelatin Composite Films
    DUAN Xing-xing DUAN Shan LUO Hui-fen LIN Ye-ping CAO Yong MIAO Jian-yin
    2019, 35(4):140-147. DOI: 10.13982/j.mfst.1673-9078.2019.4.020
    [Abstract](715) [HTML](227) [PDF 28.88 M](1198)
    Abstract:
    In order to study novel edible antibacterial packaging materials, antibacterial peptide-gelatin composite films were prepared using gelatin, glycerol, and different concentrations of antibacterial peptides as antibacterial agents. The properties of the composite films were characterized based on optical properties and by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and differential scanning calorimeter (DSC). The results showed that the addition of the antibacterial peptide to the gelatin-based composite films increased the absorption in the wavelength range of 250~300 nm, made the film color slightly turn yellow, and improved film’s mechanical properties. Adding 50 mg/mL of antibacterial peptide reduced the water vapor permeability to a certain extent (17.30% reduction compared to the film made with gelatin alone), increased film tensile strength (TS) and elongation at break (EAB) by 11.40% and 42.90%, respectively (compared to the film made with gelatin alone), and enabled the highest film antibacterial activity (the diameters of the inhibition zones against Escherichia coli and Staphylococcus aureus were 14.60 mm and 12.30 mm, respectively). The FT-IR and SEM examinations revealed the good compatibility of the composite films. DSC results showed that antimicrobial peptides might reduce the thermal stability of the composite films to some extent.
    21  Effects of Straw Ash Aqueous Extracts on Physicochemical Characteristics of Salted Egg Yolk
    LYU Hui MA Mei-hu LIU Yuan-yuan
    2019, 35(4):148-156. DOI: 10.13982/j.mfst.1673-9078.2019.4.021
    [Abstract](526) [HTML](264) [PDF 22.19 M](797)
    Abstract:
    In this work, straw ash aqueous extracts were mixed with salt to prepare salted egg. Effects of saline salting and straw ash aqueous extracts salting on salt content, water content, oil exudation, rheological properties, texture characteristics and protein structure of salted egg yolk were evaluated. Results showed that the texture characteristics of egg yolk, such as hardness, gumminess and chewiness, increased firstly and then decreased due to the penetration of salt and exudation of oil (p<0.05). The hardness of the aqueous extracts group increased from 272.89 g to a maximum of 458.65 g and then gradually decreased to 228.87 g. The rheological results indicated that the elastic modulus and viscous modulus of egg yolk increased significantly. The α-helix of the egg yolk protein of the aqueous extracts group significantly reduced to 12.36% at 25 days (p<0.05), while β-sheet significantly increased to 41.71% (p<0.05). SDS-PAGE showed that the aqueous extracts did not affect the structure of peptide chain of the egg yolk protein. The oil exudation of salted egg yolk in the aqueous extracts group reached 20.12%, which was higher than that of saline salting group. The oil exudation was an important indicator to evaluate the quality of salted egg. The condition of traditional plant ash salting process was optimized to obtain the excellent quality of salted egg, providing a new idea to produce salted egg.
    22  Extraction and Antioxidant Activity of Polyphenols from Artichoke Leaves
    YANG Mei-lian CHENG Gui-guang CAI Sheng-bao CAO Jian-xin HU Xiao-song YI Jun-jie
    2019, 35(4):157-165. DOI: 10.13982/j.mfst.1673-9078.2019.4.022
    [Abstract](582) [HTML](235) [PDF 21.60 M](824)
    Abstract:
    In this study, the optimal conditions for extracting polyphenols from artichoke leaves were investigated using single factor and orthogonal tests. The antioxidant and antibacterial activities of the polyphenol extracts from artichoke leaves before and after the purification by macroporous resins were compared. The results showed the optimal extraction conditions were: extraction solvent, 70% ethanol; sample/solvent ratio, 1:20 (g/mL); ultrasonic time, 40 min. Under these conditions, the total phenol content of the extract from artichoke leaves was 88.36 mg/g. Based on the comparison of static adsorption and desorption of nine macroporous resins, NKA-2 resin was found to be the best option for purification of the polyphenol extract. After such purification, the antioxidant activity of the purified polyphenol extract from artichoke leaves was significantly increased e.g. the IC50 values of 1-diphenyl- 2-trinitrobenzene hydrazine (DPPH) and 2, 2'-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS) radical scavenging decreased to 32.30±0.25 μg/mL and 107.98 ± 0.42 μg/mL from 82.79 μg/mL and 251.30 μg/mL, respectively. In addition, the purification process significantly improved the antibacterial effect of the extract from artichoke leaves, including the inhibition of Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Monilia albican, Pseudomonas aeruginosa and Lactobacillus. In summary, this work provides a scientific basis and theoretical foundation for the extraction, purification and application of the polyphenols from artichoke leaf.
    23  Preparation of Micro-sized Sulfonated Polystyrene Microspheres and Rapid Adsorption of Pb2+
    YANG Xiao-cui GONG Bin PENG Yao-tian XIAO Kai-jun
    2019, 35(4):166-173. DOI: 10.13982/j.mfst.1673-9078.2019.4.023
    [Abstract](541) [HTML](339) [PDF 108.41 M](867)
    Abstract:
    Micron-sized polystyrene (PS) microspheres were prepared via dispersion polymerization using styrene as the monomer. Micron-sized sulfonated polystyrene (SPS) microspheres were produced via modification with concentrated sulfuric acid before being applied to adsorb heavy metal Pb2+. The structural characterization of PS and SPS microspheres were performed by SEM, FIRT, TG, XRD, XPS and elemental analysis. In the meantime, the effect of the ratio of PS microspheres to concentrated sulfuric acid (g : mL), and the sulfonation degree of microspheres as a function of sulfonation time, were also studied. Moreover, the effects of adsorption time, solution pH and initial substrate concentration on the adsorption of Pb2+ on SPS microspheres were investigated, along with the adsorption stability and desorption properties of SPS microspheres. The results showed that the prepared PS microspheres had uniform particle size and an average particle size of 1.2 μm. The sulfonation modification performed at 40 ℃ for 48 h and a solid-to-liquid ratio of 1:40 (g : mL yielded SPS microspheres with good water solubility, monodispersity and uniform particle size, along with an average particle size of 1.4 μm and degree of sulfonation of 0.560±0.01 mmol/g. The adsorption and desorption equilibrium times for Pb2+-SPS microspheres were 5 min and 1 min, respectively, with a desorption rate of 99.81% and unchanged adsorption performance after four cycles.
    24  Optimization and Characterization of Crab Oil Nanoemulsion
    WANG Feng-ya LIN Lin LU Jian-feng JIANG Shao-tong
    2019, 35(4):174-181. DOI: 10.13982/j.mfst.1673-9078.2019.4.024
    [Abstract](586) [HTML](252) [PDF 26.54 M](883)
    Abstract:
    In order to improve the stability of crab oil, the nanoemulsion of crab oil was prepared by ultrasonic emulsification. The effects of emulsifier types, emulsifier concentration, crab oil and water on the particle size of crude emulsion were investagated by single factor experiments. Furthermore, the Box-Behnken experimental design combined with response surface methodology was employed to optimize the composition of crude crab oil emulsion. The results showed that the optimal composition of crude emulsion was 1.84 g (6.9%) of emulsifer (soybean phosphatides), 1.94 g (7.2%) of crab oil and 23 mL (85.9%) of water. Then the crude emulsion was ultrasonically dispersed to obtain a nanoemulsion with an average particle diameter of 68 nm. Compared with the crude emulsion, the nanoemulsion showed good physical stability at different temperatures (20~100 ℃), pH (3~9) and calcium ion concentration (100~500 mM CaCl2). In the digestion experiment in vitro, the released fatty acids and the bioavailability of β-carotene of nanoemulsion were better than those of the crude emulsion. The crab oil nanoemulsion prepared by ultrasonic dispersion method could improve the stability of crab oil as an additive in food system, and may have wider application prospects.
    25  Research on Powder Characteristics and Active Components of Prunus mira Koehne Powder Prepared by Superfine Grinding Technology
    ZUO Li-xu LYU Jian BI Jin-feng CHEN Qin-qin JIN Xin LI Xuan
    2019, 35(4):182-189. DOI: 10.13982/j.mfst.1673-9078.2019.4.025
    [Abstract](681) [HTML](186) [PDF 19.97 M](1023)
    Abstract:
    To investigate the effect of superfine grinding on powder characteristics and active components of Prunus mira Koehne, freeze-drying combined with coarse grinding (3 min) and superfine grinding (5, 10 and 15 min, respectively) were employed to prepare the powder of Prunus mira Koehne. The powder characteristics (including particle size, microstructure, flowability and hygroscopicity) and the contents and antioxidant capacity of active components (including polyphenol, polysaccharide and water soluble pectin) of Prunus mira Koehne powder were determined. Results showed that with increasing superfine grinding time, the particle size of Prunus mira Koehne powder became smaller than coarse powder, and the size distribution span decreased from 6.58±0.54 to 2.86±0.09. A significant decline in the compressibility was observed, while both bulk density and basic fluidity energy increased. Superfine grinding technology could improve hydration characteristics of the powder. When relative humidity was less than 50%, the powder hygroscopicity had no significant change. The antioxidant activity of polyphenol and polysaccharide extracted from Prunus mira Koehne powder prepared by superfine grinding technology show no significant difference. Content of water soluble pectin extracted from Prunus mira Koehne powder was decreased, however, its antioxidant activity was significantly increased (p<0.05). Therefore, the superfine grinding technology could be a deep processing method to improve the quality of Prunus mira Koehne powder and preserve its active components.
    26  Effects of Constant Temperature and Room Temperature on Fermentation Metabolites and Lactic acid bacteria of Fern Kimchi
    SHU Hong-yang WANG Ping
    2019, 35(4):190-197. DOI: 10.13982/j.mfst.1673-9078.2019.4.026
    [Abstract](540) [HTML](286) [PDF 26.84 M](871)
    Abstract:
    In this paper, 16S rDNA sequencing and high performance liquid chromatography (HPLC) were used to analyze the effects of constant temperature and room temperature fermentation on the physicochemical properties, lactic acid bacteria and organic acids of fern kimchi. The results showed that room temperature fermentation had little effect on the pH and titratable acid of kimchi juice and sample within 7 days. The pH of both constant temperature and room temperature fermentation were decreased to 4.2 (p< 0.05), and the titratable acid increased to 0.68% and 0.65% (p<0.05), respectively. The peak value of nitrite in the kimchi under constant temperature appeared 1 d earlier than the kimchi under room temperature, and decreased to 0.68 mg/L and 0.65 mg/L on the 7 th day. The overall acceptability of sensory score showed that the room temperature-fermented kimchi (7.5) was better than the constant temperature-fermented kimchi (7.2). Leuconostoc species in the room temperature-fermented kimchi decreased the Lactobacillus / Leuconostoc ratio; the content of the lactic acidinthe constant temperature-fermented kimchi was 122.58 mg/L, while the room temperature-fermented kimchi was103.09 mg/L; their contents of acetic acid finally was 16.25 mg/Land 18.90 mg/L, respectively. The difference of lactic acid/acetic acid was also the main reason why the sensory score of room temperature-fermented kimchi was better than that of constant temperature-fermented kimchi. Lactobacillus plantarum was identified as the dominant bacteria in fern kimchi.
    27  Extraction Optimization and Antioxidant Activity of Phenolic Compounds from Lotus Seed Epicarp Residue
    JIANG Lei Jarukitt Limwachiranon RU Qiao-mei WANG Shu-ping HUANG Hao LUO Zi-sheng
    2019, 35(4):198-208. DOI: 10.13982/j.mfst.1673-9078.2019.4.027
    [Abstract](596) [HTML](248) [PDF 84.28 M](787)
    Abstract:
    Lotus seed processing by-product-lotus seed epicarp residue was collected as experimental materials. Based on the results of single factor experiment, response surface methodology (RSM) was used to optimize the ultrasonic-assisted extraction of bioactive compounds from lotus seed epicarp residue, and total phenolic content (TPC), total proanthocyanidin content and DPPH·+ scavenging capacity were set as response values. Experimental data were fitted to three quadratic polynomial models and the regression equations were significant with good fitting degree. The optimal extraction conditions were as follows: Acetone concentration of 70%, liquid to solid ratio of 1:25.5 g/ mL, extraction temperature as 50 ℃ and sonication time as1.6 hour. Under these conditions, the practical values of responses were 194.54±3.63 mg GAE/g DW, 243.15±2.88 mg CE/g DW, 238.53±3.07 mg AAE/g DW, respectively, which were consistent with the predicted values. So the established models could accurately predict the results of total phenolic content, total proanthocyanidin content and DPPH·+ scavenging capacity in lotus seed epicarp residue. We determined the phytochemical content and in vitro antioxidant activities of diverse lotus seed epicarp residue and found that they are rich in bioactive compounds including polyphenols, flavonoids, proanthocyanidins, triterpenes, and with high antioxidant activity. The study suggested that lotus seed epicarp residue contains high amount of bioactive chemicals and is of great potential for research and development.
    28  Optimization of Quinoa and Pumpkin Compound Powder Formula
    HE Xing-fen YANG Fu-min ZHANG Ming-xia YANG Fa-rong WEI Yu-ming HUANG Jie
    2019, 35(4):209-216. DOI: 10.13982/j.mfst.1673-9078.2019.4.028
    [Abstract](638) [HTML](179) [PDF 30.72 M](825)
    Abstract:
    In order to develop ready-to-eat new products of quinoa, the research on the preparation of quinoa powder under different milling methods of frying, steaming and spray drying was carried out. By comparing the water solubility, water absorption, solubility, wetting subsidence and stability index of quinoa flour, the quinoa flour with good solubility was selected to be compounded with pumpkin flour, xylitol, milk powder, modified cassava starch and maltodextrin. On the basis of the single factor experiment, the response surface design was used, and the sensory score was used as the response value, and the nutrients and fluidity of the finished product were determined. The results showed that the water-soluble, water-absorbing, soluble, wet-sinking and stable indexes of the quinoa flour made by spray drying were 50.31%±0.56%, 3.75%±0.19%, 62.20%±2.71%, 120.00±7.16 s, and 40.98%±4.41%, respectively, which was better than the frying and steaming. The best formula for quinoa pumpkin compound powder is quinoa flour 46.0%, pumpkin powder 22.0%, xylitol 22.0%, milk powder 3.0%, modified cassava starch 2.5%, maltodextrin 4.5%.The energy, fat, protein, carbohydrate and sodium in the finished product were 1595 kJ/100 g, 3.8 g/100 g, 9.14 g/100 g, 75.6 g/100 g, 111 mg/100 g, respectively, the angle of repose was 24°, and the fluidity was good. The research results enrich the variety of quinoa products and provide a basis for industrial production.
    29  Effects of Different Cooking Methods on the Retention of Bone Dietary Nutrients
    WANG Jing-xing
    2019, 35(4):217-221. DOI: 10.13982/j.mfst.1673-9078.2019.4.029
    [Abstract](667) [HTML](528) [PDF 18.84 M](640)
    Abstract:
    In order to analyze the influence of different cooking methods on the retention of bone dietary nutrients, the beef bones purchased from a large fresh supermarket was selected as the research object. Three different cooking methods (frying, low-temperature cooking and boiling) were selected. The weight loss rate, protein loss rate, fat loss rate, lecithin loss rate, calcium loss rate and sensory quality score of beef cooked by different cooking methods were investigated. The results of comparative analysis showed that the beef weight loss rate was the lowest after low temperature cooking, which value was 32.74%, while the protein loss rate, fat loss rate in beef was 9.78%, 47.82%, respectively. The lowest rate of calcium loss was obtained by low temperature cooking with the higher retention of lecithin. Compared to frying and boiled method, the color value, the sensory quality scores such as taste and odor of beef prepared by the low-temperature cooking method are higher, indicating that low-temperature cooking could effectively improve the retention of nutrients in bone diet and sensory quality.
    30  Analysis of Taste Compounds in Adult Stage of the Cultured Large Yellow Croaker (Larimichthys crocea)
    GUO Quan-you ZHANG Xiu-jie JIANG Chao-jun
    2019, 35(4):222-229. DOI: 10.13982/j.mfst.1673-9078.2019.4.030
    [Abstract](641) [HTML](288) [PDF 10.72 M](872)
    Abstract:
    To explore the enhancement of flavor of the large yellow croaker cultured in deep-water cage, the differences of free amino acids, flavor nucleotides and electronic tongue potential in back muscle of the large yellow croaker cultured in deep-water cages at three stages (July 2016, October 2016 and January 2017) were compared. The results showed that the differences in the taste profile of the cultured large yellow croaker in different stages could be effectively distinguished by electronic tongue. The maximum potential variation of umami and richness was observed in January. The contents of umami amino acids (UAA) and bitter amino acids (BAA) in the cultured large yellow croaker reached the highest in October, and the contents of sweet amino acids (SAA) showed an upward trend during the three stages of cultivation. The content of taste nucleotide of the cultured large yellow croaker was greatly affected by the culture time. The contents of IMP, AMP and GMP all reached the highest in January. The TAV value of IMP in January was higher than 1, which contributed to the taste of the cultured large yellow croaker. Results of EUC showed that the cultured large yellow croaker had the highest EUC value in January with strong umami taste and therefore flavor quality of fish was improved. In conclusion, the culture model of deep-water cages could improve the taste quality of the large yellow croaker, and the best taste was obtained when the fish was transferred to the deep-water cage to January of the next year, which could provide a certain foundation for the improvement of quality and taste of the culture large yellow croaker.
    31  Rapid Determination of Potato Powder Composition of Noodles by NIR Spectroscopy and Stoichiometry
    LYU Du DONG Nan CHEN Zhong-ai WANG Hui LI Jun LIU Jia
    2019, 35(4):230-236. DOI: 10.13982/j.mfst.1673-9078.2019.4.031
    [Abstract](507) [HTML](233) [PDF 15.29 M](696)
    Abstract:
    It was difficult to determined the content of whole potato powder and flour in potato noodles by chemical method. The objective of the study was to establish prediction model for rapid determination of potato powder composition in noodles by NIR spectroscopy and stoichiometry. The method was that 236 potato noodles studied by near infrared spectroscopy and stoichiometry were used to establish prediction model. The result indicated that the prediction model based on wave number of 9403.6~5446.2 cm-1 and spectral pretreatment by minimum-maximum normalization showed an excellent prediction accuracy. The external validation determinant (R2val) was 0.9775, the root mean square error of prediction (RMSEP) was 1.28%, the slope was 0.95, and the relative prediction deviation (RPD) was 4.74. The results indicated that near infrared spectroscopy can be used as an efficient way to detect the potato powder content in potato noodles.
    32  Study on Crispness Evaluation for Korla Pear Flesh by Puncture Test
    YU Li-juan WU Jie WANG Qian-qian MA Hong-qiang WANG Jia-ping
    2019, 35(4):237-243. DOI: 10.13982/j.mfst.1673-9078.2019.4.032
    [Abstract](508) [HTML](210) [PDF 59.04 M](718)
    Abstract:
    In this study, the second order differential (SOD) method and peak method were used to measure the jaggedness of the puncturing force-deformation curves of Korla pear flesh at different maturity stages. The jaggedness index CI, the average puncturing force Fcr, the spatial frequency of structural ruptures Nsr, the average specific force of structural ruptures fsr and the crispness work Wc with storage time of Korla pear were calculated. The changes of these five parameters during storage time of pear fruit were then analyzed combining with the microstructure observation of flesh tissue of Korla pear. Furthermore, the correlation of the five parameters with jaggedness, soluble solid content and moisture content of Korla pear was analyzed and the sensitivity of these parameters to the crispness change of Korla pear flesh was compared. There were notable differences in observed jaggedness for the puncturing force-deformation curves of Korla pear flesh at different maturity stages. Four parameters including CI, Fcr, fsr Wc, decreased gradually with the decreasing crispness of pear, while the parameter Nsr showed a rising trend. The five parameters related to jaggedness were significantly correlated with the content of soluble solids and the moisture content. The average specific force of structural ruptures fsr by peak method had the highest correlation coefficient with the soluble solid content and moisture content. Moreover, it had the highest sensitivity to the crispness changes of Korla pear. Therefore, this parameter is most suitable for evaluating the crispness of Korla pear.
    33  Comparative Analysis of the Quality of Different Varieties of Fat Buttocks
    LIU Dan HE Xin LI Tao LI Jin-yu DU Ting-ting CHENG Yang-yang CHEN Wei-lin WANG Zi-rong
    2019, 35(4):244-249. DOI: 10.13982/j.mfst.1673-9078.2019.4.033
    [Abstract](543) [HTML](324) [PDF 764.14 K](841)
    Abstract:
    In order to valuate the qualities of different varieties of fat-hip sheep fat, the sheep tail fat from Altay sheep, Bayinbulak and Kazakh sheep were selected as raw materials. The vacuum-heat extraction was used to prepare the sheep tail fat. Physicochemical indicators were determined. The fatty acid composition of various varieties of fat-hip sheep tail fat was analyzed by gas chromatography/mass spectrometry. The results showed that the physicochemical properties of different varieties of fat-hip sheep tail fat were different. The saponification value, acid value and melting point of Altay sheep tail fat were the highest, which were 196.87 mg/g, 0.80 mg/g, 39.2 ℃, respectively. For Bayinbulak sheep, the iodine value and water content of tail fat were 50.29 g/100 g and 9.36%, respectively. The fatty acids of different varieties of fat-hip sheep tail fat were different. There were significant differences in the ratios of the saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acids and n-6/n-3. Pentadecanoic acid (C15:0), heptadecanoic acid (C17:0), stearic acid (C18:0), the ratio of palmitic acid (C16:0) to palmitic acid (cis-9 C16:1), the ratio of oleic acid (cis-9 C18:1) and stearic acid (C18:0) is strongly correlated with the variety. In conclusion, from the review of the relationship between saturated fatty acids and human health, the beneficial effects of polyunsaturated fatty acids on the human body and the ideal ratio of n-6/n-3, the three varieties of sheep fat are benifit to health.
    34  Monitoring and Risk Assessment of 30 Kinds of Pesticide Residues inTea Samples
    YI Jun YANG Ming NIE Yi TU Feng-qin KANG Cui-xin ZHOU Zhou ZHU Jing-xuan HE Rong HU Xiao-jing
    2019, 35(4):250-257. DOI: 10.13982/j.mfst.1673-9078.2019.4.034
    [Abstract](638) [HTML](298) [PDF 24.56 M](838)
    Abstract:
    To monitor the pollution level of pesticide residues in commercial tea and evaluate the health risk of dietary exposure, 390 tea samples were collected randomly. According to GB 2763-2016, 30 kinds of pesticide residues were detected. The risk of dietary exposure was assessed by point evaluation and @Risk v7.6 software. Health risk existed in the process of tea planting, such as overuse of pesticides and combined use of multiple pesticides. Among 390 samples, bifenthrin was the highest frequency of detection, reached to 39.2%. There were no pesticide residues detected in 48% tea samples. More than 203 samples contaminated by pesticide residues which include 114 samples contained more than 2 kinds of pesticide simultaneously. Fitting value near 95% site of all pesticide residues was lower than maximum residue limits of GB 2763-2016, but three of them were higher than maximum residue limits of European Union. Only glyphosate maximum residue value of a sample was higher than the limit value of GB 2763-2016.The health risk was at an acceptable level of safety, but except the acute hazard quotient fenpropathrin.
    35  Nutritional and Lipid Components of Substrate from Isaria cicadae
    KUNDUZI•Sikan-daer RENAGULI•Mu-sha SUN Chang-sheng YAN Wen-juan AIBIBULA•Yima-mu
    2019, 35(4):258-263. DOI: 10.13982/j.mfst.1673-9078.2019.4.035
    [Abstract](810) [HTML](208) [PDF 9.78 M](849)
    Abstract:
    In this research, the waste substrate matrix of Isaria cicadae was used as the test material, and its common nutrients were determined using the routine analysis methods. The total lipid content was extracted using an improved chloroform-methanol method, while the polar and neutral lipids in the total fat were separated by silica gel column chromatography. The functional lipid components and fatty acid composition were determined by TLC and gas chromatography. The results showed that the crude protein, total lipid, ash and crude fiber content in the waste substrate matrix of I. cicadae were 15.22, 1.47, 1.33 and 5.54% (on dry mass basis), respectively. The contents of calcium, phosphorus, vitamin A and vitamin E were 0.27%, 0.13% and 266.59 mg/100 g, 62.98 mg/100 g, respectively. TLC analysis revealed that the lipid component contained functional lipids such as sphingomyelin (SM), phosphatidylcholine (PC), phosphatidyl ethanolamine (PE) and triglycerides (TG). The waste substrate matrix of I. cicadae was rich in polyunsaturated fatty acids (accounting for 48.06% of the total fatty acids), with the content of linoleic acid as high as 47.94%. I. cicadae contained 17 types of amino acids with the total amount being 88.27 mg/g (out of which essential amino acids accounting for 53.11%). In summary, the waste substrate matrix of I. cicadae is rich in various nutrients and can be used for food or animal feed applications.
    36  Analysis of the Composition of Essential Oils from Four Citrus Peels
    LI Yong-hui GENG Hui-min LI Shuang-shuang
    2019, 35(4):264-272. DOI: 10.13982/j.mfst.1673-9078.2019.4.036
    [Abstract](560) [HTML](452) [PDF 9.20 M](1165)
    Abstract:
    This study provides a theoretical basis for comprehensive development and utilization of citrus volatile oils through examining the volatile oil composition. The volatile oils were extracted via Supercritical Fluid Extraction (SFE)-CO2 from satsuma, lemon, navel orange, ponkan for the analysis by GC-MS. The final oil yields for citrus, lemon, navel orange and ponkan were 0.620%, 0.556%, 0.593% and 0.742%, respectively. The results showed that 39, 33, 37 and 31 volatile compounds, respectively, were found in four types of volatile oils, and they were mainly terpenes, alcohols, aldehydes, esters, ketones, and phenolics (among which terpenes, alcohols, aldehydes had higher contents). While the volatile oils of four citrus peels had their own distinct components, they all contained D-limonene, β-elemene, citronellol, elemol, sunflower aldehyde, (E,E,E)-2,6,10-trimethyl-2,6,9,11-dodecatetraenal, etc. It was concluded that these common compound and unique components represent one of the factors influencing the quality of citrus. The use of retention indices to distinguish the isomers could improve the accuracy of a qualitative compositional analysis for natural fragrance materials.
    37  Study on the Detection Method of Cloxacillin Visualized Immunoaffinity Gel Column
    ZHANG Dong-hao ZHAO Tong-tong WEI Dong XING Yan-zhi HE Kuo
    2019, 35(4):273-278. DOI: 10.13982/j.mfst.1673-9078.2019.4.037
    [Abstract](616) [HTML](261) [PDF 21.14 M](776)
    Abstract:
    In order to establish a method for the detection of cloxacillin visualized immunoaffinity gel column, the activated ester method was used to combine horseradish peroxidase (HRP) with cloxacillin to obtain the cloxacillin enzyme standard antigen. Results of the UV spectrum scanning showed that the CLOX enzyme standard antigen was successfully synthesized. The agarose gel activated by hydrogen bromide was combined with cloxacillin antibody and HRP antibody, respectively, which was used as the detection layer and the quality control layer of the affinity gel column, respectively. A visual immunoaffinity gel column analysis method for cloxacillin was established. The optimum condition of this method was the dilution ratio of enzyme-labeled antigen of 4000, dilution ratio of antibody gel of 10, dilution ratio of HRP gel of 20, sample dilution pH of 5.7 and sample addition time of 60 s. The detection limit of this method was 25 μg/L. Its specificity was strong. There was no cross-reaction with piperacillin, amoxicillin, ampicillin, tetracycline, furantanone, thiamphenicol and streptomycin. The detection limit of cloxacillin in animal-derived foods was 25 μg/kg. This method is convenient, rapid and visual. It is suitable for high-throughput screening of cloxacillin.
    38  Detection of Cocaine in Sports Nutritional Food
    SHU Jun-hong
    2019, 35(4):279-284. DOI: 10.13982/j.mfst.1673-9078.2019.4.038
    [Abstract](485) [HTML](314) [PDF 17.32 M](642)
    Abstract:
    Cocaine in food is hard to detect. In order to evaluate the safety of sports nutritional food, the method of liquid-liquid extraction-gas chromatography was used to detect cocaine in urine and blood. The human urine and blood biological samples to be detected were pretreated. After optimizing the conditions of liquid-liquid extraction, the chromatograms of urine and blood under different conditions were obtained by GC-FID. The results showed that the separation effect of COC in urine and COC, EME and matrix interference in blood were obvious. With the increase of the concentration of standard solution of cocaine, the average recovery rate of cocaine in urine and blood increased. The highest average recovery rate was 96.73% and 98.43%, respectively. The average minimum relative standard deviation was 1.39%. The average relative standard deviation of EME and COD in the blood of daytime and daytime after eating sports nutritional food was less than 2.3%. It shows that this method could accurately detect the cocaine in human urine and blood after eating sports nutritional food. It could evaluate the safety of sports nutritional food.
    39  Analysis of Potential Risk Factors for Cassia tora Seed Extract
    LIU Feng-song YANG Yu-qi LU Zhi DUAN Liang-jie XIA Xiao-le
    2019, 35(4):285-292. DOI: 10.13982/j.mfst.1673-9078.2019.4.039
    [Abstract](597) [HTML](710) [PDF 7.25 M](882)
    Abstract:
    This paper mainly reviews the efficacy and adverse reactions of Cassia tora seed consumption found in recent years, and analyzes the major components and their contents in Cassia tora seed. The main potential risk factors screened included anthraquinones, phytosterols and their oxides, and alkaloids. Emphasis was placed on the analysis of these potential risk factors, including their properties, structure and safety. Anthraquinones such as emodin have a planar, rigid structure and can significantly inhibit the activity of L-02 cells. Phytosterols have similar structure to cholesterol, are easily oxidized to produce persistent organic pollutants (POPs) that are similar to harmful COPs., which can significantly inhibit the activity of HepG2 cells. Oral administration of adenine also caused significant acute toxicity in rats. Finally, prospects of the toxicological research on Cassia tora seed extract were presented, along with the need to set up in vitro toxicological evaluation model, dose-response model and structure-toxicity model for developing a basic toxicological database and an early warning system to assess the safety of health food products and safety limits.
    40  Research Progress on Methods to Increase the Bacteriocin Synthesis in Lactic acid bacteria
    MAN Li-li XIANG Dian-jun BU Ri-e WANG Si-zhen ZHANG Chun-lan GONG Xiao-xu
    2019, 35(4):293-300. DOI: 10.13982/j.mfst.1673-9078.2019.4.040
    [Abstract](693) [HTML](241) [PDF 729.42 K](678)
    Abstract:
    Bacteriocins are antibacterial protein or polypeptide produced by ribosomal synthesis in some bacteria that are active against the microorganisms with common or similar genetic relationship. Some bacteriocins can inhibit the pathogenic bacteria and spoilage bacteria during food processing and food fermentation. Lactic acid bacteria are generally considered to be safe, more attention has been paid to bacteriocins produced by lactic acid bacteria (LAB) due to their potential use as a new food bio-preservatives with high safety, good stability and broad antibacterial spectrum. However, commercialized bacteriocins are limited in number, e.g. Nisin and pediocin PA-1, low synthetic amount is one of the main reasons for the limited application of bacteriocin in food. Increasing methods of bacteriocin synthesis in lactic acid bacteria were summarized from six aspects including screening of high yield strains from different materials, optimization of fermentation medium and fermentation conditions, mutation breeding, protoplast fusion, genetic engineering method, and regulation of quorum sensing system. It will provide some reference for realizing the industrial production of bacteriocin.

    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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