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Volume 35,Issue 8,2019 Table of Contents

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    • 1  The Effect of Procyanidin B2 on Alleviating Cellular Senescence Through GATA4/P53 Pathway in BNL.CL2 Cells
    DAN Li ,  LI Cong ,  LUO Yue ,  ZHOU Yong-qin ,  ZHANG Chang-cheng ,  YUAN Ding ,  LIU Chao-qi
    2019, 35(8):1-5. DOI: 10.13982/j.mfst.1673-9078.2019.8.001
    [Abstract](434) [HTML](253) [PDF 7.23 M](660)
    Abstract:
    The alleviation of BNL.CL2 hepatocyte senescence by procyanidin B2 was investigated. Palmitic acid (PA) was used to induce hepatocyte senescence. The MTT assay was used to identify the cell viability treated by PA and PCB2. The effect of PCB2 on cell senescence-specific β-galactosidase (SA-β-Gal) expression was detected by senescence-specific β-galactosidase assay kit. The effect of PCB2 on the expression of cell cycle-related genes CDK6 and p53 mRNA was examined by real-time quantitative PCR. The effect of PCB2 on P53 and GATA4 protein expression and nuclear size was detected by immunofluorescence staining. The results showed that the 100 μM PA inhibited cell proliferation (control: 1.289 vs PA: 0.655, p<0.001), 12.5 μg/mL PCB2 improved the cell proliferation (0.766, p<0.01) which was inhibited by PA. Compared with PA group, the number of positive cells expressing β-galactosidase in PCB2 group is significantly decreased. The nucleus size was increased after PA treatment (PA: 7995.1, p <0.05), while PCB2 reversed the effect (3848.8, p <0.05). Senescence associated gene p53 expression was raised (3.36, p <0.05), CDK6 gene expression decreased (0.49, p <0.05) in the PA group; PCB2 could effectively improve the senescence of pa induced liver cells (p53: 1.11; CDK6: 1.01, p <0.05). Immunofluorescence staining showed that p53 and GATA4 were co-localized in the nucleus of the PA-induced senescent cells. After the PCB2 treatment, expression of p53 and GATA4 proteins in nucleus decreased, and p53 and GATA4 proteins co-occurred in the cytoplasm. Therefore, we believe that PCB2 can alleviate hepatocyte senescence, which may be through the GATA4/p53 signaling pathway.
    2  Anti-oxidative Stress of Yunnan Bitter Tea Extract Protects Mice in High Fat-cadmium Induced Diabetic Nephropathy
    GONG Pin ,  SHI Fu-xiong ,  CHEN Fu-xin ,  HE Rong-rong
    2019, 35(8):6-12. DOI: 10.13982/j.mfst.1673-9078.2019.8.002
    [Abstract](435) [HTML](184) [PDF 37.97 M](719)
    Abstract:
    This wok was designed to assess the regulatory potential of Yunnan, a bitter tea extract 1, 3, 4, 9-tetramethyl uric acid (TC) for oxidative stress in diabetic nephropathy mice. The mices were feed by high-fat and high-sugar diet, intraperitoneal injection of cadmium chloride (CdCl2) for 12 weeks to establish an animal model of diabetic nephropathy, and TC for 28 days, to evaluate the changes of serum biochemical indicators. The kidney malondialdehyde (MDA), lipid Oxidation of plasma peroxidation products (LOOH), protein carboxylation (PCO), non-enzymatic antioxidant activities such as superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) were analyzed to study the effect of cadmium on the degree of oxidative damage in the kidney and tetraethyl uric acid. The results showed that the levels of TG, ALT and LDL-C in the serum of the injury group were significantly up-regulated, 1.88 times, 2.39 times, and 2.86 times, respectively, compared with the blank group. The oxidative indexes MDA, PCO and NO in the tissue were significantly increased by 1.51, 3.88 and 2.03 times, respectively. The antioxidant indexes CAT, SOD and GSH were significantly down-regulated in the injury group, only 68.75%, 77.59%, and 80.95%, respectively. After given TC protective drug, the serum index level was only 68.09%, 49.09%, and 45.65% of that of the injury group; the oxidation index content was decreased to 82.14%, 74.19%, and 64.94% of that of the injury group, which was only; the antioxidant level decreased to 1.41, 1.20 and 1.12 times of that of the injury group. The balance between oxidation and anti-oxidation in cadmium-induced diabetic nephropathy (DN) mice, which leads to an increase in oxidative stress; TC enhanced the antioxidant capacity of antioxidant systems by increasing the activity of antioxidant enzymes. The kidneys were protected together by anti-oxidative stress and anti-inflammatory effects.
    3  Hypoglycemic Effect of Rosa roxburghii Juice on Type I Diabetic Mice
    CHEN Xiao-min ,  TAN Shu-ming ,  HUANG Ying ,  CHEN Ping ,  SONG Zhang-jun
    2019, 35(8):13-20. DOI: 10.13982/j.mfst.1673-9078.2019.8.003
    [Abstract](612) [HTML](294) [PDF 28.59 M](746)
    Abstract:
    The hypoglycemic effect of Roxburghii juice in high, middle and low dose groups on streptozotocin (STZ) -induced type I diabetic mice was studied. The mice were randomly divided into blank group, model group, positive group, high, middle and low dose groups administration by gavage for 4 weeks. Changes in diet and water intake, body weight, fasting blood glucose (FBG), glucose tolerance, glycosylated serum protein (GSP), glycosylated hemoglobin (GHb), serum insulin (INS), liver glycogen and organ index were measured during the study. After continuous gavage for 28 days, the symptoms of polydipsia and polyphagia were significantly improved and weight loss was inhibited. Compared with the model group, FBG in the high, medium and low dose groups of Rosa roxburghii juice decreased by 39.80%, 18.18% and 7.18%, respectively. GHb decreased by 29.85%, 16.04% and 10.52%. GSP decreased by 18.52%, 9.80% and 6.32%. INS increased by 26.13%, 20.60% and 14.21% respectively, the areas under the blood glucose time curve (AUC) were reduced by 44.43%, 22.62% and 14.07%, respectively, liver glycogen levels were increased by 1.39, 1.10 and 1.02 times, respectively, show that thorn pear juice have auxiliary therapy effect on theⅠdiabetes mice.
    4  Effects of Ginkgo biloba Extract on Proliferation and Apoptosis of Thyroid Cancer Cells
    GUO Wei ,  ZHANG Qiu-yu ,  LIU Ming-qing ,  XU Zhi-guang
    2019, 35(8):21-26. DOI: 10.13982/j.mfst.1673-9078.2019.8.004
    [Abstract](575) [HTML](273) [PDF 17.26 M](804)
    Abstract:
    To investigate the effects of Ginkgo biloba extract on proliferation and apoptosis of thyroid cancer cells. The cultured cells were divided into blank group, low concentration ginkgo leaf group, medium concentration ginkgo leaf group and high concentration ginkgo leaf group. The proliferation, apoptosis, invasion, migration and adhesion ability of the four groups were analyzed, and the expression of apoptosis-related protein p53, B lymphoma-2 gene (Bcl-2) and Bax were detected. The results showed that the cell proliferation rate and apoptotic rate of high concentration Ginkgo biloba leaves group at 72 h were 14.25%, lower than that of the other three groups, and 81.64%, higher than those of the other three groups, respectively. The number of migration, invasion and adhesion of thyroid cancer cells in the high concentration Ginkgo biloba group were 25.66, 24.19, 13.02, respectively, lower than that of the other three groups (p<0.05). The relative expression of p53 and Bcl-2 in thyroid cancer cells of high concentration Ginkgo biloba leaves group were 0.36 and 0.26, respectively, lower than that of the other three groups. The relative expression of Bax in high concentration Ginkgo biloba leaves group was 1.79, higher than that of the other three groups (p<0.05). Ginkgo biloba extract can inhibit the proliferation, invasion, migration and adhesion of thyroid cancer cells, and promote cell apoptosis by regulating the expression of apoptosis-related proteins p53, Bcl-2 and Bax in a concentration-dependent manner.
    5  Evolution of Microbial Community Structure in Different Fermentation Periods in Kefir
    MA Long ,  XING Jun ,  LI An ,  ZHANG Rui
    2019, 35(8):27-34. DOI: 10.13982/j.mfst.1673-9078.2019.8.005
    [Abstract](508) [HTML](418) [PDF 5.44 M](882)
    Abstract:
    To investigate the changes in microbial flora structure in Kefir during different fermentation periods. In this work, high-throughput sequencing technology was used to sequence the Kefir samples obtained in different fermentation time in the laboratory, and the dynamic evolution of microbial community structure during the whole fermentation process was analyzed. The results showed that a total of 12 door bacteria and 4 door fungi were identified during the Kefir fermentation process., and it was confirmed that the Firmicutes accounted for the abundance of the largest bacteria. A total of 117 genera of bacteria participate in the fermentation process, in which Lactobacillus increased firstly, and then decreased, and increased during the final phase of process. Streptococcus increased first and then decreased during the fermentation process. Bacillus gradually decreased throughout the fermentation process. Some unclassified fungi needed to be further investigated. In this wok, the yeast was not found. The abundance of fungi in the fungus is Ascomycota. It was found that there were mainly Alternaria, Mortierella, Cladosporium, Aspergillus.etc. However, the proportion of fungi in the fermentation process gradually decreased.
    6  Effects of Dry Heat Treatment on Starch Crystalline Structure and Oil-binding Ability in Whole Pinto Bean Cells
    LIN Xiao-ying ,  SONG Jing-jing ,  HE Xiao-wei ,  WANG Zhi-gang ,  HUANG Qiang ,  ZHANG Bin
    2019, 35(8):35-41. DOI: 10.13982/j.mfst.1673-9078.2019.8.006
    [Abstract](504) [HTML](291) [PDF 69.07 M](795)
    Abstract:
    In this study, intact pinto bean cells were isolated as a research model of whole pinto bean flour, and subjected to dry-heat treatments. The effects of dry-heat temperature (80~160 ℃) on the crystalline structure and oil-binding ability of the starch were investigated. The results showed that pinto bean cells still remained intact with surface becoming wrinkled after the dry heat treatment. At lower dry heat temperatures (80~120 ℃), the relative crystallinity of the starch in the cells decreased slightly (ca. 3%) with increasing temperature. The thermodynamic analysis revealed the occurrence of two endothermic peaks: The first peak belonged to starch gelatinization, and the second one was the denaturation peak of pinto bean protein. The enthalpy values for both peaks decreased with increasing dry heat temperature. At higher dry heat temperatures (140~160 ℃), no change in the relative crystallinity of the starch in the cells was observed along with the disappearance of the protein denaturation peak, as compared with the cells treated at lower temperatures (80~120 ℃). It was found that as the dry-heat temperature rose, the oil-binding ability of the starch and the three-phase contact angle of pinto bean cells (122.0°~145.4°) increased gradually, but the volume of free oleic acid decreased (0.60~0.05 mL). The oil-binding stability was poor at higher dry heat temperatures (140~160 ℃). The results obtained in this research provided a theoretical basis for the utilization of the oil-binding properties of whole pinto bean flour in food formulations.
    7  Study on the Emulsifying Performance of the Maillard Reaction Products between Chitosan and Xylose
    ZHANG Hui-hui ,  XIAO Jun-xia ,  CHEN Guan-qun ,  WANG Bao-wei ,  SUN Jing-xin ,  HUANG Guo-qing
    2019, 35(8):42-47. DOI: 10.13982/j.mfst.1673-9078.2019.8.007
    [Abstract](438) [HTML](209) [PDF 1.18 M](850)
    Abstract:
    In this study, the Maillard reaction products (MRPs) were prepared by using chitosan and xylose as the raw materials, and their particle size, zeta potential and emulsifying properties of MRPs were measured. Soybean oil emulsions were prepared by using MRPs as the emulsifier, and the emulsion stability was used as the index for evaluating the emulsions made with MRPs. The effects of the chitosan: xylose mass ratio, soybean oil: MRPs volume ratio, emulsification speed, emulsification time and emulsification temperature on the emulsification were studied. The results showed that the MRPs obtained via the reaction at pH=4, chitosan-xylose mass ratio of 1:1 and 100 ℃ for 3 h significantly improved the solubility and emulsifying properties of chitosan (p<0.05). The obtained MRPs were mixed and emulsified with soybean oil. When the oil and MRPs were mixed at a volume ratio of 1:5, 20 ℃, 10000 r/min, and dispersed at a high speed for 20 min, the stability of the obtained emulsion was the highest. This study is expected to provide a reference for expanding the application of chitosan-xylose MRPs in the development of new emulsifiers and in the food field.
    8  Effects of Konjac Glucomannan with a High Degree of Deacetylation on the Gelling Properties of Silver Carp Surimi
    YU Jia-mei ,  GAO Rui-chang ,  SHI Tong ,  ZHENG Zhi-ying ,  YUAN Li
    2019, 35(8):48-54. DOI: 10.13982/j.mfst.1673-9078.2019.8.008
    [Abstract](385) [HTML](199) [PDF 4.83 M](624)
    Abstract:
    In this study, the effects of Konjac glucomannan (KGM) with a high degree of deacetylation on the gelling propertiesof silver carp surimi were investigated. After different amounts (0.5 wt%, 1.0 wt% and 1.5 wt%) of the deacetylated KGM were added to silver carp surimi, the rheological and textural characteristics, water-holding capacity, relaxation time T2 and microstructural changes of the silver carp surimi were measured. It was found that the elastic modulus G' and loss modulus G" of the composite surimi were higher than those of pure surimi, showing an upward trend with an increase of the amount for addition, and the greatest increase of 27.98% and 49.24% respectively, in G' and G" as compared with the pure surimi gel. The hardness, viscosity and chewiness of the composite surimi gels were significantly higher than those of the pure surimi gel, with the greatest increase as 10.70%, 10.53% and 9.52% respectively, although the elasticity decreased. The results of the low field NMR analysis showed that the peak height of T22 decreased with the peak ratio of T23 increasing for the composite surimi gels, compared to the pure surimi gel. The water-holding capacity showed a downward trend, and reached the lowest value at 0.5 wt% of KGM. The analysis by scanning electron microscopy revealed that the network structure of the composite surimi gels became more complete and orderly. KGM with a high degree of deacetylation affected the thermal aggregation behavior of proteins, promoted the cross-linking of protein molecules and improved the gel network structure, thus, changed the gelling properties of surimi.
    9  Fabrication and Characterization of High Internal Phase Emulsions Stabilized by Natural Soy Protein Isolates
    JIN Yin-shuang
    2019, 35(8):55-61. DOI: 10.13982/j.mfst.1673-9078.2019.8.009
    [Abstract](579) [HTML](288) [PDF 69.48 M](777)
    Abstract:
    In this study, natural soy protein isolate (SPI) was used as the raw material to explore the basic properties of SPI-stabilized high internal phase emulsions (HIPEs). Through SDS-PAGE, average particle size and zeta potential analyses of SPI, the effects of protein concentration on the microstructure, oil droplet size and rheological properties of stable HIPEs were examined. The results indicated that the SPI particles prepared in the laboratory were of high quality and belonged to those with low denaturation rates. The freshly prepared HIPEs were in the gel state, and remained stable after a 6-month storage at room temperature, with its stability better than those of bovine serum albumin (BSA)- and sodium caseinate (SC)-stabilized HIPEs. The micrographs revealed a tightly packed internal network structure. At a protein concentration of 1.0 wt%, the highest oil phase volume fraction of SPI-stabilized HIPEs was 0.87. At an oil phase volume fraction of 0.8, the minimum protein concentration of SPI-stabilized HIPEs was 0.6 wt%. The rheological analysis showed that there was an elasticity-dominated gel network structure inside HIPEs. With an increase of protein concentration, the particle size of oil droplets decreased and the viscoelasticity of HIPEs increased gradually with oil droplets evenly distributed. This study provides new ways to develop novel healthy foods high in fat.
    10  Comparison of the Prevention and Treatment of Alcoholic Liver Injury in Mice from 8 Kinds of Chinese Medicine Decoctions
    ZHU Lei-lei ,  XU Li-ping ,  WANG Ya-juan ,  WU Qing-qing ,  WANG Bao-ying ,  LI Yu-cheng
    2019, 35(8):62-66. DOI: 10.13982/j.mfst.1673-9078.2019.8.010
    [Abstract](529) [HTML](362) [PDF 42.14 M](621)
    Abstract:
    In this article, Chinese medicines herbs with best protective effect on alcoholic liver injury were screened from eight kinds of Chinese medicines. Alcoholic liver injury model was established by intragastric administration of 56° red star Erguotou wine (12 mL/kg·bw) for 10 days. The drunken time and sobering time of mice, serum aspartate aminotransferase (AST) and Glutamic-oxalacetic transaminase (ALT) levels were determined. Meanwhile, HE staining were performed to observe pathological changes in liver tissue. Compared with pre-administration, the drunken times of Chuanxiong rhizoma, Schisandrae chinensis fructus and glycyrrhizae groups were respectively prolonged by 75.64% (p<0.05), 73.87% (p<0.05) and 153.58% (p<0.001). The sobering times of the Chuanxiong rhizoma, Schisandrae chinensis fructus, Puerariae lobatae radix, fios puerariae, Hovenia acerba，glycyrrhizae and Scutellariae radix groups were respectively shortened by 75.04% (p<0.001), 67.95% (p<0.001), 71.39% (p<0.01), 60.84% (p<0.001) and 75.26% (p<0.01), 80.48% (p<0.001),and 54.83% (p<0.05). Compared with the model group, the ALT levels of Chuanxiong rhizoma, Paeoniae radix alba, Puerariae lobatae radix, fios puerariae, glycyrrhizae and Scutellariae radix group were respectively decreased by 22.78% (p<0.001), 27.84% (p<0.001), 14.31% (p<0.01), 20.68% (p<0.01), 12.14% (p<0.05), 20.81% (p<0.01), and AST levels in paeoniae radix alba, and Puerariae lobatae radix were respectively decreased by 14.71% (p<0.05) and 12.69% (p<0.05). The pathological results showed that the hepatocyte edema and necrosis of Chuanxiong rhizoma, paeoniae radix alba, Puerariae lobatae radix, fios puerariae, glycyrrhizae and scutellariae radix were significantly reduced, and the degree of hepatocyte lesions was alleviated. The present study showed that among the eight Chinese medicines, Chuanxiong, radix paeoniae alba and radix puerariae had a better protective effect against alcoholic-induced liver injury. Moreover, Chuanxiong rhizoma also had effect for treating hangover and preventing drunkenness.
    11  Effect of Fuzhuan Milk Tea on Blood Lipid Level in High-fat Mice
    TANG Shu-fen ,  LI Zong-jun ,  SHAO Shuai
    2019, 35(8):67-72. DOI: 10.13982/j.mfst.1673-9078.2019.8.011
    [Abstract](469) [HTML](316) [PDF 1.21 M](704)
    Abstract:
    To investigate the effect of Fuzhuan Milk Tea on blood lipid level of mice fed with high fat diet. In this wok, 126 male kunming mice according to their body weight were selected, which were randomly divided into seven groups: blank group, control group, tea soup group, milk group, low (167 mg/kg), middle (834 mg/kg), high (1667 mg/kg) milk tea group. The mice model with hyperlipidemia was established by feeding a high-fat diet. At 28 th, 35 th, 42 th day of continuous gavage, serum total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol(HDL-C), low density lipoprotein cholesterol (LDL-C) of mice content were detected. The results showed that the contents of TC, TG and LDL-C in high-fat mice decreased significantly by intragastric administration of medium dose milk tea compared with the control group, which deceased by 16.38%, 66.67% and 34.34% respectively. Under the condition of continuous gavage for 28 days, 35 days and 42 days, the effect of reducing blood lipid in tea group was remarkable at 35 days, while the milk group was no significant difference. The lowest blood lipid level was observed at 28 days after gavage of high-fat mice with medium dosage of milk tea. In conclusion, Fuzhuan milk tea had a significant effect on reducing blood lipid, which could provide a theoretical basis for further development of products with Fuzhuan tea as raw material.
    12  Comparison of Antioxidation Activities in a Mouse Model for Enteromorpha Processed with Different Methods
    DONG Xiao-jing ,  WANG Peng ,  WU Bin
    2019, 35(8):73-77. DOI: 10.13982/j.mfst.1673-9078.2019.8.012
    [Abstract](378) [HTML](209) [PDF 1.53 M](587)
    Abstract:
    This study compared the antioxidant effects of three Enteromorpha products processed with different processing methods in a mouse model. Aged mice were administrated by gavage with enteromorpha original (EO, 300 mg/kg·d), enteromorpha polysaccharide (EP, 100 mg/kg·d), low dose of enteromorpha ultrasound (EU-L, 300 mg/kg·d) or high dose of enteromorpha ultrasound (EU-H, 350 mg/kg·d). The contents of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), catalase (CAT) in serum, liver and brain tissues of mice were analyzed after 7 weeks. The results showed that all these enteromorpha products had no effect on the weight gain of the mice. The serum CAT content in model group was 6.90 U/mL, which was significantly (p<0.01) lower than to those for the EP group (8.79 U/mL), EU-L group (8.31 U/mL) and EU-H group (9.43 U/mL). The contents of SOD, GSH-Px and CAT in serum, liver and brain tissues of the EU-H were significantly (p<0.01) higher than the model group. The MDA contents of the four groups fed with enteromorpha products were lower (p<0.05) than that of the model group：9.94 U/mL, 7.88 U/mg prot, 6.63 U/mg prot (p<0.05).These results indicate that EU-H effectively improved the activities of antioxidant enzymes in the aged mouse model with the rate of reversing aging over 90%，showing advantages over EP; According to the comparison on dose, EU could increase the antioxidant effect on aged mice in a dose-dependent manner.
    13  Study on Hypolipidemic Activity of Rosa roxburghii Tratt, Propolis and Crataegus Oral Liquid
    CHEN Ping ,  TAN Shu-ming ,  CHEN Xiao-min ,  HUANG Ying ,  SONG Zhang-jun
    2019, 35(8):78-83. DOI: 10.13982/j.mfst.1673-9078.2019.8.013
    [Abstract](555) [HTML](206) [PDF 537.43 K](744)
    Abstract:
    The aim of this work was to investigate the effect of oral liquid with Rosa roxburghii Tratt, propolis and Crataegus as main raw materials on hypolipidemic activity induced by diet-induced hyperlipidemia, the hyperlipidemic model mice were established by feeding high fat diet. The hyperlipidemia mice were divided into high-fat model group, Rosa roxburghii Tratt juice group, Rosa roxburghii Tratt propolis group, Rosa roxburghii Tratt Crataegus group, and Rosa roxburghii Tratt propolis Crataegus group, and each group received different Rosa roxburghii Tratt oral liquid for 28 days. The body weight and feed intake of the mice were measured during the gavage. Total cholesterol (TC), Triglyceride (TG), High-density Lipoprotein (HDL-C), Malondialdehyde (MDA) in serum and liver of mice were measured after 28 days feed. Results showed that the Rosa roxburghii Tratt oral liquid could effectively alleviate hyperlipidemia symptoms. The total cholesterol (TC) in the serum of the mice administrated with the Rosa roxburghii Tratt propolis Crataegus oral liquid was significantly reduced by 23.94% (p<0.05), serum triglyceride (TG) was significantly reduced by 46.41%(p<0.05), and the MDA content in serum was significantly reduced by 73.83% (p<0.05). These indicated that the Rosa roxburghii Tratt propolis Crataegus oral liquid had good hypolipidemic effect and could effectively delay the rate of lipid peroxidation.
    14  Effect of Vacuum Cooling Treatments on the Filtration of E. coli O157:H7 into Fresh Lettuce
    WEI Shen-jian ,  XIE Si-yun ,  SONG Yan-qing ,  LI Yi-fei ,  LIAO Cai-hu
    2019, 35(8):84-90. DOI: 10.13982/j.mfst.1673-9078.2019.8.014
    [Abstract](340) [HTML](194) [PDF 55.62 M](638)
    Abstract:
    The technology of air cooling, vacuum cooling with different evacuation rate, final pressure value and repressuring time utilized to lower the temperature of iceberg lettuce were investigated in this work. All of samples were stored at the temperature of 5±2 ℃ after cooling. the indice including the total and internal Escherichia coli O157:H7 cell counts were detected to evaluate the effects of different evacuation rates, final pressure values and repressuring times on the iceberg lettuce. Effects of different evacuation rates, final pressure values and repressuring times on the variation of the total and internal Escherichia coli cell counts during cold storage were also evacuated. The results showed that all vacuum cooling methods had a more internal cell conts of Escherichia coli of 4.5×103 cfu/g and less total cell counts of Escherichia coli of 1×106 cfu/g compared to the internal and total cell conts of Escherichia coli of 1.9×103 cfu/g and 2.3×106 cfu/g subjected to air cooling. It was found that higher evacuation rates, lower final pressure value and quicker repressuring time led to a more infiltration of Escherichia coli into the inner of iceberg lettuce. Compared to air cooling, vacuum cooling was more effective to decrease the cell counts of total Escherichia coli. Compared to the reduction rate of 69.57% of the total cell conts of Escherichia coli after 3 d cold storage, all vacuum cooling methods had a more reduction rate of 90%. All vacuum cooling methods had a higher internal Escherichia coli cell counts of 1.5×102 cfu/g after 3 d cold storage than 1.1×102 cfu/g subjected to air cooling. It was reasonable to assumed that controlling the cell counts of Escherichia coli before vacuum cooling and adjusting properly the evacuation rate of 0.229 min-1, final pressure value of 1500 Pa and repressuring time of 9min might be a effective method to assure the quality and safety of leaf vegetable. These above-mentioned conclusions could provide a reference for the mechanism of filtration of Escherichia coli into the inner of iceberg lettuce.
    15  Anti-radiation Effect and Physicochemical Properties of Tilapia Scale Collagen Composite Gel
    LIU Lei ,  SUN Wei-dong ,  ZHANG Ye-hui ,  LI Si-jia ,  ZHANG You-sheng ,  RUAN Qi-jun ,  WANG Jing-yu ,  HUANG Li-hua
    2019, 35(8):91-97. DOI: 10.13982/j.mfst.1673-9078.2019.8.015
    [Abstract](533) [HTML](334) [PDF 29.85 M](854)
    Abstract:
    In order to study the anti-ultraviolet radiation effect and physicochemical properties of tilapia fish scale collagen composite gel. In this paper, three coagulants were used to form a composite gel with fish scale collagen, and the effects of coagulant on its anti-ultraviolet radiation and physical and chemical properties were studied. The results show that the absorbance of the gel decreases with the increase of the quality of the curdlan. After exposure to UV light for 300 s, the survival rates of Escherichia coli under the protection of collagen and gelatin, agar and curdlan gel were 0, 46.43%± 0.75%, 33.28%± 0.75%, 62.06%± 0.75%, respectively. Therefore, it is best to obtain the anti-ultraviolet radiation effect of the curdlan composite gel. The type and quality of the coagulant have a significant effect on the hardness, gumminess and resilience of collagen. Scanning electron microscopy showed that the Therefore, it is best to obtain the anti-ultraviolet radiation effect of the curdlan can be effectively combined with collagen to form a stable structure. By determining the viscoelasticity of the collagen gel by the rheological method, it is found that the gel elastic modulus G' and the viscous modulus G" formed by the curdlan are larger, and the influence of time and temperature changes is small. The research results provide a scientific basis for the study of the anti-radiation effect of tilapia fish scale collagen composite gel material.
    16  The Preservation Effect of Eugenol Sustained-release Diatomite on Strawberry
    ZHANG Li-hui ,  QIAO Yu ,  ZHOU Ying ,  CHEN Xue-ling ,  WANG Chao ,  WANG Jun ,  WANG Lan ,  LIAO Li
    2019, 35(8):98-106. DOI: 10.13982/j.mfst.1673-9078.2019.8.016
    [Abstract](376) [HTML](224) [PDF 2.97 M](621)
    Abstract:
    Different diatomite containing eugenol with different quality was used to preserve strawberries. The quality of strawberries was studied during storage at 4 ℃. The results showed that 1 g~7 g of eugenol/diatomite could keep fresh under 4 ℃ of storage condition, but 3 g eugenol/diatomite had the best effect. It could significantly inhibit the decay and mass loss of strawberry, reduce the decline rate of soluble solids, titratable acids and Vc contents of strawberry, delay the decline of hardness of fruit surface and pulp, and inhibit the activity of antioxidant enzymes. The decay rate of strawberries treated with Eugenol/Diatomite of 3 g was only 42.51% after 15 days of storage, which could prolong the storage period for 5 days. At this time, the weight loss rate of strawberries was 1.25%, the content of soluble solids was 4.45%, and titratable acid could be obtained. The contents of Vc, MDA, SOD and POD were 0.91% and 34.56 mg/100 g, 29.21 nmol/g, 334.15 U/mL and 0.67 U/mg, respectively. The surface hardness and pulp hardness of strawberry were 69.20% and 67.17 g, respectively. It can be seen that the sustained-release treatment of diatomite with eugenol has a certain fresh-keeping effect on strawberries, of which 3 g eugenol/diatomite was the best.
    17  Inhibitory Effect of Phlorizin and Young Apple Polyphenols on Tyrosinase Activity
    LIU Dong-ru ,  REN Ya-mei ,  BO Ji-fang ,  HU Xin-mu ,  REN Xiao-lin
    2019, 35(8):107-113. DOI: 10.13982/j.mfst.1673-9078.2019.8.017
    [Abstract](574) [HTML](220) [PDF 25.75 M](905)
    Abstract:
    To compare the potential of young apple polyphenols and phlorizin as tyrosinase inhibitors, the inhibitory effect and kinetics of phlorizin, young apple polyphenols and kojic acid on tyrosinase activity were analyzed and compared by spectrophotometry, in which kojic acid was used as a positive control. Results: phlorizin, young apple polyphenols and kojic acid could effectively inhibit tyrosinase activity. The order of their inhibitory effects was kojic acid>young apple polyphenols>phloridin, and their IC50 for monophenolase activity was 55.80, 54.30 and 23.81 μg/mL, respectively, and their IC50 for diphenolase activity was 75.30, 56.15 and 23.45 μg/mL, respectively. The phlorizin showed mixed inhibition at a concentration lower than 200 μg/mL and competitive inhibition at a concentration of 200 μg/mL, the young apple polyphenols showed non-competitive inhibition and the kojic acid showed mixed inhibition. In summary, the inhibitory effect and inhibitory mechanism of the inhibitor is not only related to its composition, but also related to its concentration. All three inhibitors can reduce the synthesis of melanin by inhibiting the hydroxylation of tyrosine to dopa and the oxidation of dopa to dopaquinone and dopachrome. Compared with phlorizin, young apple polyphenols is more suitable as tyrosinase inhibitors and has great potential for application in whitening products because of its better inhibitory effect, cheaper price and richer content.
    18  Effect of Different Preservatives on Quality of Embryo of Dictyophora
    WEI An ,  XU Yan-jun ,  XU Li ,  HE Fa-mei ,  PAN Ruo-ping
    2019, 35(8):114-120. DOI: 10.13982/j.mfst.1673-9078.2019.8.018
    [Abstract](390) [HTML](267) [PDF 1.00 M](653)
    Abstract:
    In this wok, the effects of different preservative treatments on the preservation of fresh embryo of Dictyophora during storage were studied. The embryo of Dictyophora were coated with different concentrations of chitosan, carrageenan and ascorbic acid as coating agents. The distilled water was used as a control. After packaging with PE fresh-keeping bags, they were stored at 4 ℃ to study the storage of embryo of Dictyophora. The weight loss rate, color difference, soluble protein content, free amino acid content, and polyphenol oxidase activity were analyzed. The results showed that the optimal treatment concentration of each preservative was as follows: 1.2% chitosan, 0.1% carrageenan and 0.1% ascorbic acid. All three preservatives could reduce the weight loss rate, PPO activity and PPO activity peak. Delayed appearance of 4 d, chitosan and carrageenan treatment had a certain effect on inhibiting protein decomposition into free amino acids. Ascorbic acid treatment could better maintain the color of embryo of Dictyophora and maintain soluble protein content. The preservation effects of three kinds of preservatives on embryo of Dictyophora were evaluated. The 0.1% concentration ascorbic acid had the best preservation effect. After the storage, the weight loss rate was 0.64%, the whiteness value was 50.73, the soluble protein content was 3.05 mg/g, and the free amino acid content was 327.73 mg/100 g. The PPO activity was 1.86 ΔOD420/min·g, which was superior to the control group.
    19  Effect of Carbonic Maceration Treatment on Vacuum-microwave Drying Characteristics and Microstructure of Ginger
    WEI Lai ,  WANG Zhi-tong ,  YU Yuan-shan ,  XU Yu-juan ,  AN Ke-jing
    2019, 35(8):121-129. DOI: 10.13982/j.mfst.1673-9078.2019.8.019
    [Abstract](475) [HTML](305) [PDF 11.07 M](621)
    Abstract:
    In order to study the effects of carbon dioxide impregnation (CDI) on the microwave-vacuum drying characteristics and microstructure of ginger, different temperatures (35, 40, 45 ℃), pressures (1, 2, 3 MPa) and treatment times (3, 5, 7 h) were selected for CDI to pretreat ginger. The changes in moisture ratio, drying rate, effective diffusion coefficient of ginger during drying were measured, and the mathematical model for thin layer drying was fitted. In addition, the microstructures of ginger under different CDI conditions were also studied. The results showed that after CDI, the rate of drying ginger significantly increased, especially in the late drying stage. When the ginger was pretreated at 2 MPa and 45 ℃ for 7 h, the moisture diffusion was the fastest, and the drying time was shortened by 47% compared to that for the sample dried directly. Among the five thin layer drying models, the Modified Page model exhibited the best fit to the changes in ginger’s moisture content during drying, based on the coefficient of determination (R2), chi-square (χ2) and root mean square error (RMSE). Scanning electron microscopy revealed that CDI increased the cell area and porosity of ginger tissues, and enhanced the mass and heat transfer of the material. Therefore, CDI had a positive effect on improving the internal structure and drying efficiency of ginger. The results obtained in this study provide the theoretical basis for the development of new drying technologies for ginger.
    20  Effect of High Gluten Powder Content on Gelatinization and Rheological Properties
    CHEN Shu-chang ,  SHEN A-qian ,  FENG Zuo-shan ,  BAI Yu-jia ,  REN Gui-ping ,  HUANG Wen-shu
    2019, 35(8):130-135. DOI: 10.13982/j.mfst.1673-9078.2019.8.020
    [Abstract](473) [HTML](235) [PDF 709.84 K](869)
    Abstract:
    In order to improve the dough characteristics of the Oil Tower made from commercially available wheat flour (10.3% protein), the commercial wheat flour (hereinafter referred to as wheat flour) was added to different proportion of high-gluten flour(12% protein). The basic properties, gelatinization characteristics and dough rheological characteristics of the mixed flour were determined. The results showed that with the increase of the amount of high-gluten powder, the whiteness of the composite powder increased significantly (p<0.05), and the content and moisture of protein dry base and wet gluten showed an upward trend, while the ash content changed slightly (p<0.05). The peak viscosity, minimum viscosity, and final viscosity of the composite powder decreased with the increase of the amount of high-gluten powder added. When the addition of high-gluten powder was 40%, the attenuation value and reappreciation reached the minimum values, which were 850.50 cp and 1035.50 cp, respectively. With the addition of high-gluten flour, the time of dough formation and wheat flour stabilization were reduced, but the weakening degree increased. when the addition of high-gluten powder was 40%, the tensile area, tensile resistance and elongation of the composite powder increased to 122.05 cm2, 341.75 BU ,179.30 mm, respectively. The results showed that high gluten powder had influence on the quality, gelatinization and dough stretching properties of flour sold in the market. The addition of 40% high gluten flour was appropriate condition to make oil tower dough.
    21  Effects of Two Drying Methods on Maillard Reaction of Camellia oleifera
    YANG Nan ,  LUO Fan ,  FEI Xue-qian ,  ZHONG Hai-yan
    2019, 35(8):136-141. DOI: 10.13982/j.mfst.1673-9078.2019.8.021
    [Abstract](464) [HTML](305) [PDF 21.55 M](709)
    Abstract:
    In this paper, the effects of two drying methods, hot air and microwave radiation, on the antioxidant properties of Camellia oleracea products were investigated. The changes of oxidative stability of Camellia oleifera seeds using different drying methods were investigated by measuring the contents of Maillard products such as pyruvic aldehyde, glyoxal and 3-deoxyositol in Camellia oleifera seeds. The results showed that with the prolongation of microwave heating time, Camellia oleifera seeds under all firepower had the ability to scavenge DPPH free radicals. When the microwave was heated at 700 w for 20 min, the DPPH free radical scavenging ability was the strongest (93.11%). When heated at 150 ℃ for 90 min, the DPPH free radical scavenging ability was 92.03%. When microwave heating for 0~10 min, the main substance affecting the antioxidant activity of Camellia oleifera seeds was 5-hydroxyfurfural; after 15 min of heating in microwave, the main substances affecting the antioxidant activity of Camellia oleifera seeds were pyruvic aldehyde and 3-deoxyosurose. The substances mainly affecting the antioxidant activity of Camellia oleiferain the oven heating mode were pyruvic aldehyde, 3-deoxyositol and 5-hydroxyfurfural. The content of glyoxal in Camellia oleifera seedshad little effect on its antioxidant activity. The results of this study provide a theoretical basis for exploring the antioxidant mechanism of maillard reaction of Camellia oleifera seed oil and optimizing the processing technology of Camellia oleifera seed.
    22  Preparation and Digestive Characteristics of Artificial Rice Supplemented by Selenium-rich Taro
    WANG Xia ,  GUO Shi-long ,  LU Bao-xin ,  QIU Dan ,  YANG Qing-yu ,  YANG Guo-qiang ,  DAI Lan ,  XIAO Zhi-gang
    2019, 35(8):142-152. DOI: 10.13982/j.mfst.1673-9078.2019.8.022
    [Abstract](454) [HTML](371) [PDF 1.30 M](592)
    Abstract:
    In this study, japonica broken rice and taro head powder were used as the main raw materials, supplemented by selenium nutrient, L-α-phosphatidylcholine and monoglyceride as the composite texture regulator. Selenium-rich taro was prepared by extrusion method, through the orthogonal experiment for process optimization, the best technological parameters were obtained: extrusion temperature of 140 ℃, the screw rotation speed of 180 r/min, moisture content of 25% and feed speed of 20 kg/h. Under the optimal processing conditions, the hardness, cohesion, elasticity, gluttony, chewing and loss rate of se-rich taro head reconstituted rice were 401.17 g, 0.75 mJ, 1.63 mm, 396.23 g, 4.05 mJ and 4.12%, respectively. The results were similar to those of japonica rice in texture and loss rate of cooking. The overall quality was better than japonica rice. Selenium-rich taro head recombinant rice had lower crystallinity, amylose - lipid complex, and the improved rough surface, irregular shape, incomplete particles, reduced viscosity, thermal stability and aging resistance. The contents of fast digestible starch, slow digestible starch and resistant starch in recombinant rice of se-rich taro head were decreased, and the contents of resistant starch and slowly digestible starch were increased. Starch and resistant starch in the recombinant rice of se-rich taro head were decreased, and the contents of resistant starch and slowly digestible starch were increased by extrusion. The results provide basis for developing starch food with low digestibility containing se and taro products.
    23  Effects of Low-intensity Alternating Magnetic Field on Liquid Fermentation of Antrodia camphorata
    ZHU Li-ping ,  MA Hai-le ,  LU Min ,  WU Ping
    2019, 35(8):153-159. DOI: 10.13982/j.mfst.1673-9078.2019.8.023
    [Abstract](497) [HTML](241) [PDF 1.89 M](526)
    Abstract:
    The effects of low-frequency alternating magnetic field on the liquid fermentation of Antrodia camphorata were studied using the self-developed equipment, and single factor and orthogonal optimization experiments were conducted to determine the optimal magnetic field parameters based on the index of the growth rate for mycelial biomass. Scanning electron microscopy (SEM) was used to compare the differences in the morphology of mycelia obtained by the traditional liquid fermentation and the magnetic field-assisted liquid fermentation. The results showed that when the magnetic induction intensity was 80 Gs, initial magnetic treatment was 3 d after inoculation followed by daily treatment for 4 h, the magnetic field stimulated the greatest growth of Antrodia camphorata. Under these conditions, the growth rate for the mycelial biomass of Antrodia camphorata, increasing rate of polysaccharides, and increasing rate of triterpenoid were 15.87%, 24.26% and 26.85%, respectively. The SEM results revealed that the mycelia of the Antrodia camphorata treated by the magnetic field had rougher surface with more wrinkles and looser structures than those obtained by traditional liquid fermentation. The experimental results showed that the liquid fermentation of Antrodia camphorata assisted by low-frequency alternating magnetic field can increase the yields of mycelial biomass, polysaccharides and triterpenoids.
    24  Studies on Characteristics and Model of Solar Low-temperature Adsorption Drying for Fresh Apple Slices
    ZHANG Fang ,  HUANG Yu-long ,  TANG Ying ,  LI Ming-ze ,  PANG Zhong-cun ,  KANG San-jiang
    2019, 35(8):160-167. DOI: 10.13982/j.mfst.1673-9078.2019.8.024
    [Abstract](411) [HTML](258) [PDF 38.20 M](646)
    Abstract:
    Using fresh apple slices as the research object and the low-temperature solar adsorption drying (LSAD) system developed in our company as the experimental facility, the effects of drying temperature, relative humidity, drying medium flow rate, sample loading amount and slice thickness on the LSAD characteristics of apple slices were investigated. The results showed that the LSAD process could be divided into three stages: Adjustment, constant speed, and decelerating drying stages. The drying temperature had the most significant effect on the drying rate of fresh apple slices e.g. drying at 50 ℃ reduced the drying time by 65.9% than at 10 ℃. The primary and secondary influences of the variables on the drying of apple slices were drying temperature > relative humidity > flow rate of drying medium > slice thickness> sample loading amount. The optimum process conditions for LSAD of apple slices were: drying temperature 50 ℃, relative humidity 20%, flow rate of drying medium 0.9 m/s, sample loading amount 7.5 kg/m2, slice thickness 3 mm. The mathematical software was used to select and fit the experimental data by three models, and the mathematical model of apple slice drying had the highest fitting degree with Page model. The mathematical equation for LSAD of fresh apple slices was MR = exp (-0.00557*t^1.76669). The establishment of such a model provides the theoretical support for the application of LSAD to the production of dehydrated apple slices.
    25  Effect of Enzymatic Hydrolysis of Chicken Protein on Calcium Chelation Ability of Their Hydrolysates
    WEI Xin-yan ,  SU Guo-wan ,  SUN Wei-zheng
    2019, 35(8):168-173. DOI: 10.13982/j.mfst.1673-9078.2019.8.025
    [Abstract](395) [HTML](271) [PDF 11.07 M](849)
    Abstract:
    In this work, the effects of enzymatic hydrolysis conditions on the calcium chelation of their hydrolysates were investigated. Results showed that the maximum chelation force was obtained at the enzymatic hydrolysis time of 3 h with papain. The chelation forces of hydrolysates prepared by one-step and two-step enzymatic hydrolysis with papain and flavor enzyme were compared. Results showed that addition of flavor enzyme could improve the calcium chelation of hydrolysates and two-step enzymatic hydrolysis was better than one-step enzymatic hydrolysis. For two-step enzymatic hydrolysis, the effects of the hydrolysis time and enzyme amount on the chelation force were evaluated. The papain enzymatic hydrolysis time, the amounts of papain and flavor enzyme were selected as independent variables, and the calcium chelation force was selected as the response value. The three-factor and three-level response surface experiments were designed. The optimal enzymatic hydrolysis conditions were as follows: the papain enzymatic hydrolysis time of 3.5 h, the flavor enzyme hydrolysis time of 2.84 h, flavor enzyme amount was 0.18%. The amino acid analysis of the hydrolysate obtained by the optimized conditions showed that there were more acidic amino acids and basic amino acids, which was helpful to the chelation reaction.
    26  Optimizition of Linoleic Acid Isomerase Producing Conditions from Recombinant E.coli by Response Surface Method
    ZHANG Si-xuan ,  LIU Ying ,  SHI Xu ,  SHI Hai-su ,  DU A-nan ,  WU Jun-rui ,  YUE Xi-qing ,  WU Ri-na ,  LUO Xue
    2019, 35(8):174-179. DOI: 10.13982/j.mfst.1673-9078.2019.8.026
    [Abstract](569) [HTML](217) [PDF 16.36 M](647)
    Abstract:
    Conjugated linoleic acid (CLA) is widely found in a variety of foods. In order to obtain high yield of active CLA, the mutant linoleic acid isomerase was cloned and expressed in escherichia coli in this work. The single factor test determined that the optimal conditions for enzyme production were as follows: fermentation time 18 h, IPTG induced concentration 0.2 mmol/L, 20% liquid loading, initial pH7 of the medium, pre-induction bacterial biomass OD600=0.4, LA concentration 0.5 mg/mL, and ion concentration 0.02%. The response surface method was used to optimize the culture conditions of recombinant escherichia coli to improve the capacity of producing linoleic acid isomerase. According to the response surface method analysis results, the fermentation time, pre-induction biomass and LA concentration had significant effects on the expression of recombinant linoleic acid isomerase, and all of them were positive effects. The optimal combination of the three influencing factors was as follows: 19.5 h fermentation time, pre-induction biomass OD600=0.47, and LA concentration 0.57 mg/mL. Unde this condition, the maximum amount of LA to CLA catalyzed by linoleic acid isomerase was predicted to be 143.33 μg/mL. The results showed that the yield of CLA was 141.75±0.14 μg/mL, which increased by 107.5%.
    27  Preparation and Properties Study of Carboxymethyl Starch-graft-acrylamide Copolymer
    LIANG Yi-chao ,  ZHANG Ben-shan
    2019, 35(8):180-189. DOI: 10.13982/j.mfst.1673-9078.2019.8.027
    [Abstract](554) [HTML](359) [PDF 8.82 M](895)
    Abstract:
    Carboxymethyl starch-graft-acrylamide copolymer (CMSGAM) was prepared by using carboxymethyl starch (CMS) as the raw material and acrylamide (AM) as the monomer for grafting. The preparation process was optimized through single factor and orthogonal experiments by using the viscosity of the CMSGAM paste as the index. Characterization of the CMSGAM was performed using fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analyzer (TG). The physical and chemical properties of CMSGAM such as viscosity, transparency, salt resistance, coagulation and water retention were determined. The results showed that the optimum conditions for the preparation were: pH 7.5, reaction temperature 50 ℃, and reaction time 3 h. Under such conditions, the viscosity of CMSGAM paste was the highest (26000 MPa·s). In the FT-IR spectra, a absorption peak near 1667 cm-1 was found (which reflected the characteristic stretching vibration of carbonyl residue in the amide group), along with the absorption peak near 1455 cm-1 (which corresponded to the characteristic vibration of C-N bond in the amide group). The thermalgravimetric analysis revealed the thermal decomposition of the acrylamide group from 350 ℃ to 450 ℃, which proved the success of grafting the acrylamide group into the carboxymethyl starch. The SEM images showed a large number of pores and fractures on the CMS particles, indicating that the graft copolymerization reaction was severe and the structure of starch granule was destroyed. The viscosity and transparency of the CMSGAM paste increased more than 4 times, along with higher anticoagulation effect and thermal stability and minimally improved salt resistance, compared to the CMS paste.
    28  Development of Kiwi & Medlar Fruit Wine
    WEI Li-na ,  ZHAO Jing ,  YU Si ,  LUO Cang-xue ,  SHI Chang-zheng
    2019, 35(8):190-197. DOI: 10.13982/j.mfst.1673-9078.2019.8.028
    [Abstract](603) [HTML](259) [PDF 45.70 M](808)
    Abstract:
    Kiwi was rich in nutrients, kiwifruit flavor unique, rich in a large number of volatile aroma components, was one of the best raw materials for fruit wine brewing. Medlar was rich in Lycium barbarum polysaccharide, betaine and other active substances, was a traditional “medicine and edible” raw materials, especially the rich β-carotene was given its products unique color. In order to further improve the color of kiwi fruit wine and enrich its nutritional value, the compound fruit wine of kiwi and medlar was developed. The kiwi and medlar were used as raw materials to develop the compound fruit wine. Based on the single factor experiment, the fermentation process of the compound fruit wine was optimized by the response surface method to obtain the best fermentation conditions. The optimum technical parameters were summed up as follows: The ratio of kiwi and medlar was 8.50:1, yeast inoculum was 1.22 g/L, fermenting temperature at 21.40 ℃, sugar content was 20 g/100 mL, fermentation time was 7 days. Under this optimal parameter, the compound fruit wine with orange red color, clear and transparent, refreshing taste, fruit aroma of kiwi and medlar, physicochemical indexes reaching relevant standards and the alcohol content of 12.10% can be obtained. This study provides a theoretical basis for the further processing of kiwi and medlar, and also broadens the ideas for the development of compound fruit wine.
    29  Screening of Cholesterol-reducing Probiotics and Its Acid and Bile Salt Tolerance
    HE Shan-shan ,  BAO Zhi-ning ,  LIN Wei-feng ,  XIA Feng-geng
    2019, 35(8):198-206. DOI: 10.13982/j.mfst.1673-9078.2019.8.029
    [Abstract](699) [HTML](366) [PDF 13.17 M](681)
    Abstract:
    In this study, probiotics with strong cholesterol-lowering ability were screened from five probiotics by using MRS-cholesterol liquid medium containing cholesterol micelles, and the selected probiotics were tested for their acid and bile tolerance. The results demonstrated that all the five strains exhibited cholesterol-lowering function, with the Lactobacillus casei (LCA-1), Lactobacillus rhamnosus (LR-D) and Lactobacillus plantarum (LP-C) having higher cholesterol degradation rates (as 25.26%, 22.18% and 20.03% respectively). LR-D could tolerate a low pH environment for a short time period but exhibited poor bile salt tolerance, with a survival rate of 14.39% after a 2 h culture in the fermentation broth at pH 2.5. LP-C could tolerate a low acid environment for a long time period and exhibited strong bile salt tolerance, with a survival rate of 133.75% and the viable cell number of 1.13×105 cfu/mL after being cultured in high bile salt medium (0.5%) for 2 h and 24 h, respectively. In these cases, the other two strains remained undetected. These results indicated that LP-C could tolerate the high bile salt environment. LP-C possessed a high cholesterol-removing rate and could withstand a low pH and high bile salt environment. Therefore, this probiotic can be used for further research and development.
    30  Effects of pH Control Modes on Hyaluronic Acid Fermentation Process
    WANG Wei ,  CAI Hai-Bo ,  TAN Wen-song
    2019, 35(8):207-213. DOI: 10.13982/j.mfst.1673-9078.2019.8.030
    [Abstract](541) [HTML](285) [PDF 36.18 M](764)
    Abstract:
    In this work, the microorganism concentration, HA yield, HA molecular weight and molecular weight distribution of hyaluronic acid (HA) wereanalyzed at different pH and temperature in 5 L bioreactor and 250 mL shake flask. It was found that the best pH for bacteria growth and HA production was 7.00, but under HA synthesis stage, HA generation rate was higher at higher pH condition 8.00. Two regulation styles, the periodic control mode and subsection control mode were designed. The results were as follows: the periodic control mode had no effect to HA yield and HA molecular weight, subsection control mode had no effect to HA yield, but could impove the molecular weight by 10.60% and significantly reduced the dispersion coefficient, and at periodic control mode when culture temperature was 33 ℃，HA molecular weight when harvested was 18.70% higher than temperature 37 ℃. These results could provide directions for subsequent industrialization production molecular weight concentrated HA and reducing the separation cost of HA with different molecular weights.
    31  Effect of Cutting Methods on the Quality of Sizing-free Pork Slices
    CHEN Sheng-shu ,  MENG Xiang-ren ,  TU Ming-liang ,  WANG Heng-peng ,  WU Peng ,  GAO Zi-wu
    2019, 35(8):214-219. DOI: 10.13982/j.mfst.1673-9078.2019.8.031
    [Abstract](475) [HTML](215) [PDF 26.03 M](779)
    Abstract:
    The longissimus dorsi muscle of the ternary crossbred pig (Duroc x Landrace x Yorkshire) was used as the research object. The muscle was sliced by different cutting methods. The first method was perpendicular to the fiber, the second one was parallel to the muscle fiber. The third one was cutting the pork at the angle of 45° to the muscle fiber. Effecte of the cutting methods on the water loss rate, color difference, tenderness, texture characteristics, microstructure and sensory quality of the sizing-free pork slices was investigated. The results showed that the cutting methods had a significant effect on the meat-free water loss rate (p<0.05). When the pork perpendicular to the muscle fibers, the water loss rate of the meat-free pork slices, which was cooked by oil, was small and the tenderness, hardness and chewiness reached the minimum values of 7.52 N, 102.63 N and 78.93 mJ, respectively. The microstructure showed that when the pork perpendicular to the muscle fibers, the muscle-free gap between the sizing-free pork was the largest, which was consistent with the results of tenderness and texture characteristics. The best way to cut the pork according to the sensory evaluation score was perpendicular to the muscle fiber cut (79.6 points). In conclusion, according to the comprehensive index, perpendicular to the muscle fiber cutting is the most suitable way to cut the pork slices.
    32  Kinetic Analysis of Fermentation of Probiotics from Apple Pulp
    YANG Chun-min
    2019, 35(8):220-225. DOI: 10.13982/j.mfst.1673-9078.2019.8.032
    [Abstract](423) [HTML](303) [PDF 11.13 M](662)
    Abstract:
    In this wok, the design process of fermentation kinetics model of probiotics from apple pulp was studied. The fermentation temperature, inoculation amount, feeding amount, initial pH of medium and other factors were invesigated at different levels. The changes of viable bacteria in the fermentation process were recorded. Under the given fermentation conditions, 7 L fermentation tank was used to complete the fermentation, and the probiotic fermentation kinetic model was constructed by fitting the data. Origin 8.0 was used to compare the theoretical and experimental data of the dynamic model to verify the validity of the model. The results showed that the number of viable bacteria was the highest when the fermentation temperature was 36 ℃. The optimum fermentation conditions were as follows: 70 mL, 5% inoculation and 4.0 initial pH. The number of viable bacteria in apple pulp was 6.71 108 cfu/mL. The error between theoretical and experimental values of the design model was less than 8%. In conclusion, the fermentation environment was as follows: the temperature of 36 ℃, the loading amount of 70 mL, the inoculation amount of 5%, and the initial pH of the culture medium of 4.0. The design model could effectively predict the change of the fermentation process of probiotics in apple pomace.
    33  Comparative Analysis of Volatile Components of Five Kinds of Edible Fungi
    ZHANG Xian-chen ,  LIU Gong-yuan ,  ZHANG Jing ,  QIU De-yi
    2019, 35(8):226-235. DOI: 10.13982/j.mfst.1673-9078.2019.8.033
    [Abstract](485) [HTML](252) [PDF 20.55 M](679)
    Abstract:
    In order to investigate the differences of volatile compounds in the bodies of Hericium erinaceus, Armillaria mellea, Armillarialuteo virens, Lentinula edodes and Tricholoma matsutake, dried samples of these five species were detected and analyzed using headspace solidphase micro extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Cluster and principal component analysis were used, and totally 121 various volatile compounds including asters, aldehydes, alcohols, olefins, ketones, acids, nitrogen-containing heterocyclic compounds were identi?ed from these five kinds of dried edible fungi samples. Among them, only nine were identified in all samples, and the other 112 compounds were different among them. The clustering and principal component analysis results for the volatile compounds from these five kinds of dried edible fungi bodies were consistent. Results indicated that hexanol, 1-octen-3-ol, 1-propyl-1-cyclopentanol, methyl cinnamate, methyl tran-cinnamate, dodecanoic acidmethyl este, 5-pentyl dihydro furanone, 1-octen-3-one, pinocarvone, 2,6-dimethyl-pyrazineand D-limonene could be used as effective chemical indicators for the classification of these five kinds of dried edible fungi, and provided some ideas to evaluate their qualities as well.
    34  Quantitative Prediction Model of the Crude Protein Content in the Chicken Freeze-dried Powder Based on the Optimizing Spectral Region of Near Infrared Spectroscopy
    TAO Lin-li ,  YANG Xiu-juan ,  DENG Jun-ming ,  CAO Sheng-xiong ,  CHEN Chen ,  ZHONG Xin-wen ,  SUN Zhao-cheng ,  KONG Fan-hu ,  HUA Xue-fei ,  ZHANG Yu-zhu ,  ZHANG Xi
    2019, 35(8):236-246. DOI: 10.13982/j.mfst.1673-9078.2019.8.034
    [Abstract](398) [HTML](212) [PDF 617.44 K](559)
    Abstract:
    This paper is trying to obtain the optimum spectra to build the calibration model by the spectral characteristics of the chicken protein in near infrared region, interval partial least-squares regression (iPLS) and geneti calgorithm (GA), and aims to improve the prediction accuracy and robustness of the near infrared spectroscopy quantitative prediction model of the crude protein content in the chicken freeze-dried powder.Taking the muscles powders of 260 freeze-dried legs as the research object, the proteins from the muscles powders of 100 freeze-dried legs were extracted, the near infrared reflectance spectra (NIRS) from the freeze-dried leg muscle powder samples and the protein samples of the freeze-dried leg muscle powder were scanned in the 999.7~2502.3 nm wavelength region. The differences between two NIRS were studied. The NIRS of the freeze-dried leg muscles powder was divided into 10 spectral regions based on spectral characteristic and principal component analysis (PCA). The partial least squares regression (PLS) was used to build the quantitative prediction model. First, the modeling results based on full-spectrum and combining spectral regions of the characteristic spectra were compared to select the optimum spectral regions. Next, the PLS (FiPLS) and backward interval PLS (BiPLS). It is the third time the modeling spectra were filtrated by GA and forward and backward regions and the optimum combining region based on the characteristic spectra by forward interval PLS (FiPLS) and backward interval PLS optimum spectral regions were extracted from the full-spectrum (BiPLS). Then, the modeling spectra were filtrated by GA and forward and backward interval partial least squares (FBiPLS). The result showed that the most optimum modeling spectral ranges were 1811.6~1794.0 nm、1756.2~1722.4 nm、1704.4~1688.9 nm、1594.4~1580.8 nm、1510.8~1485.7 nm、1472.1-1424.3 nm、1222.2~1057.6 nm and 1051.2~1008.7 nm by using FBiPLS. In conclusion, to ensure the accuracy and robustness of the calibration model, the selection method of optimum spectral regions was the combination of the spectral characteristics of sample composition and mathematical algorithm of wavelength selection.
    35  Walnut Appearance Defect Detection Based on Computer Vision
    LI Cheng-ji ,  ZHANG Shu-juan ,  SUN Hai-xia ,  CHEN Cai-hong ,  XING Shu-hai ,  ZHAO Xu-ting
    2019, 35(8):247-253. DOI: 10.13982/j.mfst.1673-9078.2019.8.035
    [Abstract](589) [HTML](204) [PDF 13.46 M](802)
    Abstract:
    For rapid and accurate identification of the appearance defects (black spots, ruptures) of walnuts, an image acquisition device was established to collect sample images. After pretreatment, the background was removed by morphological and logical operations. Then, 18 color feature parameters and 20 texture feature parameters were extracted based on the sample images. Morphological and logical operations were used to extract the ratio of the defect portion to the projected pixel area of the sample, as well as the Euler number of the binary image after the sample image threshold was segmented. regression coefficient (RC) and successive projections algorithm were used to optimize the feature parameters and establish a partial least squares (PLS) model. The results showed that the model established based on the preferred SPA method exhibited the optimal performance. The five preferred feature parameters extracted by SPA method were used as input to establish the least squares support vector machine (LS-SVM) model, which was used to predict the prediction set samples. The results showed that the discrimination of normal walnut, walnut with black spot(s) and cracked walnut was accurate with rates as 88.9%, 83.3% and 94.6% respectively, and the overall accuracy rate of discrimination was 88.9%. The method established in this study can well detect the appearance defects of walnut and provides technical support for online detection and sorting of walnut in the future.
    36  Extraction and Purification and Activity Determination Conditions Optimization of α-Amylase Inhibitor in White Kidney Bean
    ZHONG Ying-ying ,  HE Qi-yi ,  FENG Jun-chao ,  ZHU Qiu-yan ,  ZHANG Chun-guo ,  ZHAO Su-qing
    2019, 35(8):254-260. DOI: 10.13982/j.mfst.1673-9078.2019.8.036
    [Abstract](558) [HTML](521) [PDF 2.07 M](1009)
    Abstract:
    In order to develop a simple, effective and low-cost extraction and purification process of α-amylase inhibitor (α-AI) and explore the optimal conditions for its activity test, white kidney beans were used as raw materials to extract α-AI by water extraction in this study. After studying the conditions for the determination of α-AI activity by 3,5-dinitrosalicylic acid (DNS) micropore method, the optimal process conditions for α-AI extraction were determined by orthogonal test on the basis of single factor and the α-AI crude extract was purified by acid precipitation-alcohol precipitation, ultrafiltration and dialysis. The results indicated that the optimal conditions for the determination of α-AI activity were: determination wavelength of 482 nm, DNS dosage of 80 μL, reaction time of 15 min, and the rest time was 10 min. And the optimum process for α-AI extraction were: Extraction temperature of 45 ℃, extraction time of 2.5 h, extraction pH of 6.6 and the liquid-solid ratio was 7.5. Moreover, the α-AI with high purity and activity was obtained after purification, which with an IC50 of 0.89±0.04 mg/mL and a yield of 1.92±0.23%. The extraction and purification process may be can provide some guiding significance for the low-cost industrial production of α-AI.
    37  Optimization of the Extraction of the Volatile Substances in Cyclocarya paliurus Tea Based on GC-TOF-MS
    KOU Xiao-lin ,  LI Ting-ting ,  WU Cai-e ,  FAN Gong-jian ,  FU Xiang-xiang ,  LIN Jie
    2019, 35(8):261-270. DOI: 10.13982/j.mfst.1673-9078.2019.8.037
    [Abstract](396) [HTML](204) [PDF 1.46 M](775)
    Abstract:
    In order to optimize the key variables for the extraction of the volatile substances in Cyclocarya paliurus tea and further provide theoretical methods for the identification of the volatile substances, headspace-solid phase microextraction (HS-SPME) was used in this study to extract volatile substances from Cyclocarya paliurus tea before analysis by high-throughput gas chromatography-time of flight-mass spectrometry. The optimum conditions for HS-SPME were determined by designing different SPME fiber assemblies, extraction temperatures, extraction times and tea-to-water ratios. The results revealed the optimal extraction conditions: the use of CAR/PDMS (75 μm) as SPME fiber for a 60-min extraction at 80 ℃ and a tea-to-water ratio of 1:15. Under these conditions, 229 volatile substances were detected，including acids, aldehydes, ketones, alcohols, esters, alkanes, olefins and heterocyclic compounds. Among them, aldehydes, heterocyclics and alcohols had relatively high contents, with the top five contents derived from hexanal, 1-carophyllene, n-hexanol, 2-methylpropenal, and 2-hexenal.
    38  Performance Analysis and Test of an Intelligent Controlled Freeze Concentrator
    DING Zhong-xiang ,  Frank G F Qin ,  YUAN Jiao-jiao ,  JIANG Run-hua ,  HUANG Si-min ,  SHAO You-yuan
    2019, 35(8):271-280. DOI: 10.13982/j.mfst.1673-9078.2019.8.038
    [Abstract](492) [HTML](262) [PDF 29.94 M](669)
    Abstract:
    Combinations of discrete equipment units were often used in suspension crystallization freeze concentration process in the past, and as a result, the system was large and complicated to run. In this study, a multi-stage intelligently controlled freeze concentrator prototype was tested and validated. This prototype adopted a trinity structure, which combined a scraped surface heat exchanger (SSHE), a crystallizer and a washing column and equipped with an intelligent control unit. Based on the equipment, this study used the concentrated apple juice as an example to test the performance parameters of the freeze concentrator. The concentration ratios of the first, second and third stages of freeze concentration were 1.84, 1.40 and 1.32, respectively. The crystallization rates were 0.44, 0.36 and 0.22, respectively. The partition coefficients of solid solutes in ice crystals and mother liquor were 0.03, 0.04 and 0.11, respectively. The recovery of solid solutes were 0.99, 0.99 and 0.98, respectively. The heat transfer coefficients of SSHE at the cooling stage were 0.23±0.00 kJ·m-2·℃-1, 0.11±0.02 kJ·m-2·℃-1 and 0.22±0.02 kJ·m-2·℃-1, respectively. The heat transfer coefficients of SSHE at the freezing stage were 0.54±0.03 kJ·m-2·℃-1, 0.44±0.02 kJ·m-2·℃-1 and 0.29±0.01 kJ·m-2·℃-1, respectively. The rates of ice production were 0.90±0.05 kg/h, 0.90±0.05 kg/h and 0.30±0.06 kg/h, respectively. The results showed that the system is simple and efficient, and the operational control of complex freeze concentration can be completed by the machine.
    39  A Liquid-phase Microextraction Method Based on Deep Eutectic Solvents Determination for Five Kinds of Fungicides Residues
    ZHAO Tong-tong ,  ZHANG Dong-hao ,  GUO Zhen-fu ,  HE Kuo ,  WANG Su-li
    2019, 35(8):281-286. DOI: 10.13982/j.mfst.1673-9078.2019.8.039
    [Abstract](671) [HTML](250) [PDF 38.30 M](837)
    Abstract:
    A method was developed for the determination of five fungicide residues (triadiconazole, pyrimethanil, triadimefon, carbazole, and cyprodinil) by high performance liquid chromatography with deep eutectic solvent as extraction in liquid-phase microextraction. A DES containing phenol as a hydrogen bond donor and choline chloride as a hydrogen bond acceptor was used as the extraction solvent. THF was used as a dispersant solvent to form small droplets of turbidity. The target analyte was extracted into trace DESs phase. After centrifugation, the upper DESs phase was subjected to high-performance liquid chromatography for analysis. Various parameters affecting extraction efficiency were investigated and optimized. The results were shown that the DESa molar ratio of choline chloride and phenol 1:2 is the best extraction efficiency. Under the optimum conditions are as follows: sample volume 5 mL, DES2 150 μL, and THF 150 μL, ultrasonic time 20 min and centrifugation time 10 min. The recoveries were between 73.7%~102.3%, the relative standard deviations (RSDs) were between 0.7%~7.1%, and the low limits of detection (LOD) were 0.026~ 0.052 μg/L.
    40  Accumulation Characteristics and Safety Evaluation of Heavy Metal in Spinbarbus caldwelli Cultured in Mengtangxi Reservoir
    CHENG Xiao-fei ,  JIANG Hai-feng ,  GAO Jin-wei ,  HONG Bo ,  LIU Ling-li ,  WU Yuan-an ,  LI Cheng ,  LI Hong ,  TANG Hai-bin
    2019, 35(8):287-293. DOI: 10.13982/j.mfst.1673-9078.2019.8.040
    [Abstract](567) [HTML](216) [PDF 764.55 K](610)
    Abstract:
    In order to investigate the current status of heavy metal pollution and food safety in different tissues and organs of Spinbarbus caldwelli farmed in Mengtangxi reservoir in Hunan province, atomic absorption spectrophotometry (AAS) was used to determine the contents of Pb, Cd, Cu, and Zn in the muscle, gill, fin, scales, skin, swim bladder, intestines, kidney, spleen, hepatopancreas, fat and brain of S. caldwelli. The results indicated that the content of Pb (2.90 mg/kg) was the highest in S. caldwelli hepatopancreas, which was less than 0.5 mg/kg in the other tissues or organs. The content of Cd was the highest in S. caldwelli kidney (3.54 mg/kg), followed by hepatopancreas (2.34 mg/kg), intestine (1.71 mg/kg), spleen (1.40 mg/kg) and gill (0.61 mg/kg), which was less than 0.1 mg/kg in the other tissues or organs. The content of Cu was less than 50 mg/kg in all the tissues and organs of S. caldwelli. The comprehensive pollution index (PI) of different tissues and organs of S. caldwelli were ranked as: kidney>hepatopancreas>intestines>spleen>gill>fin>brain>skin>scales>fat>muscle>swim bladder. Based on the maximum allowable consumption rate (CRLim) and target hazard quotients (THQ), the heavy metals in muscle of S. caldwelli farmed in Mengtangxi reservoir have no potential risk for consumers.
    41  Changes of Postharvest Flavor Substance in Different Packages of “Lunnan” Apricots Using Gas Chromatography-ion Mobility Spectroscopy
    ZHU Li-na ,  MENG Xin-tao ,  XU Bin ,  XU Ming-qiang ,  PAN Yan ,  MU Zhi-jie
    2019, 35(8):294-303. DOI: 10.13982/j.mfst.1673-9078.2019.8.041
    [Abstract](497) [HTML](295) [PDF 68.32 M](698)
    Abstract:
    In order to identify the characteristic flavor substances and construct fingerprints of “Lunnan” apricot, the Gas Chromatography-Ion Mobility Spectroscopy (GC-IMS) was used to analyze the changes of flavor substances in ‘Lunnan’ apricot fruit Packaged by CO2 accumulation modified atmosphere and PET box transmission in cold storage (1±1 ℃) for 36 days., which provides a preliminary basis for the study of the mechanism of postharvest flavor quality loss and regulation. According to the fingerprint, a total of 54 kinds of flavor substances were detected after harvesting, mainly including ketones, alcohols and aldehydes, and other substances like terpenes, esters, acids, hydrocarbons and heterocycles. Among them, 2,3-pentanedione, (Z)-3-hexenol, 3-methylbutanaland propionic acid were relatively high. The modified atmosphere package increased the contents of 14 substances of five flavors: green scent, fruity aroma, grass scent, licorice scent and sweet orange flavor; and the synthesis of amyl acetate and α-pinene with sweet fragrance and rosin flavor. However, the 2-hexanone that can be used as a flavor marker for ordinary packaged fruits was reduced. Acetone, butanoic acid and 3-methyl-3-buten-1-ol can be used as characteristic marker substances for different modified atmosphere Packaged apricots. The flavor quality of medium gas transmission packaging (16.30%~16.60% O2+2.50%~ 3.00% CO2) was relatively good during storage.
    42  Analysis of the Characteristic Flavor Components of Cantonese Zhu-hou Sauce
    JIANG Jin-jin ,  JIA Qiang ,  CHEN Feng-hua ,  CHEN Song ,  LAI Zi-jian
    2019, 35(8):304-310. DOI: 10.13982/j.mfst.1673-9078.2019.8.042
    [Abstract](511) [HTML](499) [PDF 20.71 M](628)
    Abstract:
    In order to invesigate the flavor characteristics of Cantonese Zhu-hou sauce, their flavor formation were discussed. In this wok, the content of free amino acids, gas-phase ionic migration spectroscopy fingerprint, volatile flavor components from solid-phase microextraction-gas chromatography-mass spectrometry and nutrient components were analyzed. The results showed that the content of free amino acid of S2 was 3.36 g/100 g, the content of sweet amino acid and bitter amino acid was 1.8 g/100 g and 1.03 g/100 g, respectively. The comprehensive score of S2 was the highest in sensory evaluation. The results of GC-MS analysis showed that the eucalyptol, camphene, D-limonene and methyl heptanone were unique to S2. A variety of aromatic compounds were identified by gas-phase ionic migration spectroscopy. The 2-methoxyphenol, ethyl hexanoate, propyl acetate, hexanedione, propionic acid, butyraldehyde, phenylacetone, butyric acid, methylthiopropionaldehyde, dimethyl disulfide were detected, which were unique to zhu-hou sauce. These compounds can also be regarded as aromatic active substances representing the flavor characteristics of Cantonese zhu-hou sauce.
    43  Study on Lipid Oxidation in Food Distribution Based on Raman Spectroscopy
    ZHANG Sheng-lai
    2019, 35(8):311-316. DOI: 10.13982/j.mfst.1673-9078.2019.8.043
    [Abstract](410) [HTML](313) [PDF 17.32 M](625)
    Abstract:
    In order to investigate lipid oxidation in the long-distance distribution, the reasons for lipid oxidation were analyzed. The pH, transport temperature, shaking speed and time were detected. In this work, indirect iodine method was used to determine lipid oxidation at different pH values, distribution temperature, shaking speed and transportation time. The lipid oxidation process of alga oil, palm kernel oil and olive oil was analyzed based on Raman spectrum. The results showed that when the pH reached 10, the oxidation value of food lipid was only 3 meq/kg. The long-distance distribution temperature exceeded 40℃, the shaking speed was 3 circles/s, and the oxidation value of food fats exceeded 10 meq/kg. The oxidation value of food fats reached a maximum of 15 meq/kg after 4 days. In the process of lipid oxidation, the peak of Raman first increased and then decreased, indicating that the lipid molecular groups changed to a certain extent and deteriorated. It is stated that food should be distributed over long distances under the conditions of high pH, low temperature, short transportation time, and reduced shaking. This could provide a reliable analysis basis for preventing food deterioration.
    44  Near Infrared Spectral Quantitative Model of the Nutrient Content in Rice
    HUANG Lin-sen ,  LIU Dong ,  QIN Tong-jia ,  LIN Xiu-wen ,  ZHOU Zhi-hang ,  HAUNG Jin-ling ,  CONG Yan-li
    2019, 35(8):317-324. DOI: 10.13982/j.mfst.1673-9078.2019.8.044
    [Abstract](492) [HTML](203) [PDF 30.52 M](780)
    Abstract:
    Protein, fat, carbohydrate and moisture in rice are important nutrients in rice. The detection of these components needs to rely on the national standard method. The detection process is tedious and has large pollution. In this experiment, 75 rice samples were studied, and their contents of protein, fat, carbohydrate and moisture were measured by national standard method. Spectral information was collected by AntaresⅡ infrared spectrometer. Samples were divided into verification set and correction set, including 63 samples in correction set and 12 samples in verification set. A quantitative model of protein, fat, carbohydrate and moisture of rice was established through six spectral pretreatment methods and three modeling methods, and the model by running workflow was used to realize rapid detection of four components. The results showed that proteins and carbohydrates followed by the first derivative and Savitzky-Golay filtering, while fat and water followed by the second derivative and Savitzky-Golay filtering. The quantitative model of protein, fat, carbohydrate and water content in rice was established by Least partial square method in combination with the measured values by national standard method and has high prediction accuracy. The internal cross-validation coefficient of the prediction model of protein, fat, carbohydrate and moisture is 0.9266, 0.9333, 0.9198, 0.9175, and RMSECV is 0.280, 0.133, 0.362 and 0.270, respectively. The internal cross-validation R value is above 0.91 and RMSECV is less than 0.35, which can realize the rapid detection of protein, fat, carbohydrate and moisture in rice.
    45  Preparation of Conjugate Antigen and Antibody to Chlorpromazine in the Animal Food
    YUAN Li-peng ,  LIU Bo ,  YIN Kai-dan
    2019, 35(8):325-330. DOI: 10.13982/j.mfst.1673-9078.2019.8.045
    [Abstract](534) [HTML](252) [PDF 23.15 M](799)
    Abstract:
    In this study, an enzyme-linked immunosorbent assay (ELISA) for the determination of chlorpromazine residues in animal foods was established. Chlorpromazine hapten (CPZ-H) was synthesized from chlorpromazine by demethylation, reaction with tert-butyl acrylate and hydrolysis for the first time. Hapten CPZ-H was conjugated with OVA and BSA by active ester method to form the coated antigen and immunogen, respectively. New Zealand white rabbits were immunized with immunogen CPZ-H-BSA to successfully prepare specific polyclonal antibodies against chlorpromazine. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for the rapid determination of chlorpromazine was established based on the antibody. By optimizing the working conditions of ic-ELISA method, it was determined that the dilution fold of coated antigen and antibody was 1:8000. At this time, the IC50 of standard curve was 1.1 ng/mL and the linear range was 0.13 ng/mL~8.8 ng/mL. The prepared polyclonal antibody against chlorpromazine has good specificity and no cross reaction with other chlorpromazine analogues. This study provides a basis for the preparation of specific and rapid detection kit for chlorpromazine in the future.
    Journal introduce

    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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