Volume 36,Issue 7,2020 Table of Contents

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  • 1  Ethanolic Extract of Fermented Brown Rice Improves the Metabolism of Glucose and Lipids in 3T3-L1 Adipocytes
    SONG Jia-le ZENG Zhen QIAN Bo GUI Zhong-yu PARK Kun-young TANG Xing-yong
    2020, 36(7):1-10. DOI: 10.13982/j.mfst.1673-9078.2020.7.0069
    [Abstract](312) [HTML](167) [PDF 52.11 M](926)
    Abstract:
    The effects of fermented brown rice ethanolic extracts (FBREE) on glucose and lipid metabolism in insulin-resistant 3T3-L1 adipocytes were investigated. The insulin-resistant model cells were established through the induction by high glucose concentration together with high insulin. The model cells were treated with different concentrations of FBREE for 24 h, and the levels of glucose, free fatty acid (FFA), glycerol, triglyceride (TG), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the culture medium were determined. The mRNA expression levels of peroxisome proliferator-activated receptors γ (PPARγ), CAATT enhancer binding proteins α (C/EBPα), sterol regulatory element binding protein1c (SREBP1c), adipocyte fatty acid binding protein 2(aP2), protein tyrosine phosphatase-1B (PTP1B), glucose transporter 4 (GLUT4), hormone-sensitive triglyceride lipase (HSL), TNF-α, IL-6, monocyte chemotactic protein (MCP)-1 and C-reaction protein (CRP) were determined by quantitative real-time PCR (qRT-PCR) assay. FBREE could promote cellular glucose utilization, decrease the cellular TG content and reduce the released FFA and glycerol in model cells. The high dose of FBREE (100 μg/mL) reduced the cellular TG (by 52.44%) and FFA (by 37.83%), compared with those of the model cells. FBREE also reduced the TNF-α and IL-6 secretion in model cells. A high dose of FBREE (100 μg/mL) also reduced the mRNA expression levels of TNF-α (by 21.18%),IL-6 (by 31.39%),MCP-1 (by 40.09%) and CRP (by 41.73%) compared with those in model cells. In addition, FBREE was able to reduce effectively the mRNA expressions of PPARγ, C/EBPα,SREBP1c, PTP1B, aP2 and HSL, while up-regulating the mRNA levels of GLUT4. These results suggested that the FBREE treatment can promote effectively glucose consumption, TG decomposition, and reduction of FFA and glycerol release, as well as regulate the glucose and lipid metabolism to ameliorate insulin resistance and reduce the increase of inflammation caused by insulin resistance.
    2  Ginsenoside F2 Interferes with the Cascade Reactions of Caspase to Inhibit H2O2-induced Apoptosis
    LIU Di ZHANG Hao ZHANG Han-xue SUN Hong-yu ZHENG Mei-yu FENG Xian-min
    2020, 36(7):11-16. DOI: 10.13982/j.mfst.1673-9078.2020.7.0006
    [Abstract](275) [HTML](199) [PDF 21.13 M](1099)
    Abstract:
    In this study, the anti-apoptotic effect of ginsenoside F2 on H2O2-induced injury in human embryonic kidney HEK-293 cells was evaluated. Using commercial kits, the activities of Caspase-6 and Caspase-9 of apoptotic cells were examined by measured. Western blot tests were conducted to detect the protein expression of the Bcl-2 family (Bcl-2 and Bax) and Caspase family (Cleaved Caspase-3 and Cleaved PARP). After the cells were injured by H2O2, the activity of Caspase increased and the expressions of pro-apoptotic proteins increased. The activities of Caspase-6 and Caspase-9 decreased in a concentration-dependent manner (p<0.05) after the pretreatment of cells with 1.25, 5, 20 μmol/L ginsenoside F2 to injure cells (p<0.05). At the F2 concentration of 20 μmol/L, the activities of Caspase-6 and Caspase-9 decreased by 6.83 U/mg protein and 5.88 U/mg protein., respectively, and the protein expression levels of Cleaved Caspase-3 and Cleaved PARP were significantly lower than those of the injured group (p<0.05). With the increase of F2 concentration, the expression of Cleaved Caspase 3 dropped to 280.90%, 232.46% and 185.26%, respectively. The expressions of Cleaved PARP decreased to 110.36%, 85.85% and 61.95%, respectively, with the increase of F2 concentration. The ratio of Bcl-2/Bax for the high F2 concentration group (73.94%) was significantly higher than that of the injured group (p<0.05). These results showed that ginsenoside F2 can inhibit the activity of apoptotic protein Caspase, and reduce the expression of Bax pro-apoptotic protein and the upstream, midstream and downstream proteins of the Caspase family, through inhibiting H2O2-induced apoptosis via regulating the Caspase cascade reactions.
    3  Protective Effects of α-linolenic acid Riched Flaxseed Oil on Suppressing Insulin Resistance and Oxidative Stress in Rats with Polycystic Ovary Syndrome
    WANG Ting ZHANG Xiao-xia LI Yi-wei YUE Jiang-dong TIAN Hong-yan WENG Xin LIU Ping DONG You-ping WANG Hao
    2020, 36(7):17-24. DOI: 10.13982/j.mfst.1673-9078.2020.7.1283
    [Abstract](415) [HTML](227) [PDF 48.78 M](999)
    Abstract:
    In this study, the effects of flaxseed oil (FO) rich in α-linolenic acid (ALA) on insulin resistance and oxidative stress level in polycystic ovary syndrome (PCOS) rats were investigated. The PCOS rat model was established by the letrozole modeling method. After successful modeling, the FO control group and the FO intervention model group were administered with FO by gavage for 8 W, while the negative control group and the model group were fed the same amount of normal saline. After the intervention, the contents of sex hormones, blood lipids, as well as the contents of insulin resistance and oxidative stress indicators of the different groups of rats were detected. The results showed that after the dietary FO intervention, the levels of androgen (T), cholesterol (TC), triglyceride (TG), fasting insulin (FINS), insulin resistance index (HOMA-IR) and malondialdehyde (MDA) decreased to 3.26 nmoL/mL, 1.78 mmoL/mL, 1.45 mmoL/mL, 5.37 mIU/L, 1.22 and 5.33 nmoL/mL, respectively, compared with model group, whilst the levels of estradiol (E2), and antioxidant indices total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD), increased to 26.54 pmoL/mL, 5.11 U/mL, 372.10 enzyme activity unit and 80.29 U/mL, respectively, compared with the model group (p<0.05). This study showed that dietary FO ameliorates insulin resistance and oxidative stress in PCOS rats.
    4  Rosa roxburghii Tratt Wine can Improve Glucose Metabolism Disorder in Type 1 Diabetic Rats through Insulin- PI3K Pathway
    AN Yu-hong LU Min-tao LU Xiu LI Dai-yu HUANG Yan PENG Yong-xian
    2020, 36(7):25-33. DOI: 10.13982/j.mfst.1673-9078.2020.7.1254
    [Abstract](324) [HTML](240) [PDF 19.54 M](1171)
    Abstract:
    To investigate the effect of Rosa roxburghii Tratt wine on the glucose metabolism disorder induced by streptozotocin (STZ) in type 1-diabetic rats, the type 1 diabetic rats model induced by intraperitoneal injection of STZ was established. The rats were randomly divided into blank group, model group, positive group, high, middle and low dose groups, blood glucose is measured every 2 weeks. After 28 days of administration, growth status and relative tissue weight were investigated. The contents of insulin (Ins) in serum were determined by enzyme-linked immunosorbent assay (ELISA). The mRNA levels of PI3K, PKB and GLUT2 in liver, and GLUT4 in skeletal muscle were determined by real time polymerase chain reaction (RT-PCR). The results showed that Rosa roxburghii Tratt wine significantly increase body weight and feed efficiency (p<0.05), significantly reduce fasting blood glucose (21.20%, 36.14% and 8.75%) and glucose tolerance (11.32%, 16.65% and 8.33%), relative tissue weight (p<0.05). when compared with model group. Moreover, Rosa roxburghii Tratt wine significantly increased mRNA relative expressions of PI3K, PKB and GLUT2 in liver and GLUT4 in skeletal muscle. In conclusion, Rosa roxburghii Tratt wine increased the concentration of Ins in serum of diabetic rats and reduced blood glucose levels. Its possible mechanism was that Rosa roxburghii Tratt wine promoted glucose uptake and utilization by activation of the Ins mediated PI3K pathway and translocation of GLUT2/4.
    5  Protective Effect of Water Extracts of Orychophragmus violaceus Seeds on Acetaminophen-induced Acute Liver Injury in Mice: Roles of Activating Hepatic AMPK/AKT/GSK-3β Signaling
    PANG Min SHAN Yu WANG Fei-fei YANG Shu-xian LI Li-yong CAO Li
    2020, 36(7):34-41. DOI: 10.13982/j.mfst.1673-9078.2020.7.1240
    [Abstract](344) [HTML](219) [PDF 32.68 M](1110)
    Abstract:
    The antioxidant capacity of water extracts of Orychophragmus violaceus Seeds and the protective effects on liver injury induced by acetaminophen in mice were investigated. C57BL/6J male mice were randomly divided into seven groups: normal group, model group, bicycle control group (200 mg/kg), Kuihua Hugan tablets control group (350 mg/kg), water extracts of Orychophragmus violaceus seeds low-dose group (125 mg/kg), water extracts of Orychophragmus violaceus seeds middle-dose group (250 mg/kg), and water extracts of Orychophragmus violaceus seeds high-dose group (500 mg/kg). The mice were intragastrically administered with drugs or distilled water according to the body weight once a day. Four days later, all of the groups except for the normal group were treated with APAP (450 mg/kg) through intraperitioneal injection to establish the acute liver injury model. The mice were killed. The levels of glutamic-pyruvic transaminase, glutamic oxalacetic transaminase and total bilirubin in serum were detected. What’s more, the activities of superoxide dismutase and the level of glutathione and malondiadehyde in liver tissue were detected. HE staining was used to observe the pathological changes of liver tissue in mice. Western blot was used to detect the expressions of p-AMPK, p-AKT, p-GSK-3β, p-JNK, Bcl-2, Bax, Caspase-9 and Caspase-3. Compared with the model group, water extracts of Orychophragmus violaceus seeds could significantly improve the pathological conditions of liver, and the ALT and AST activities in the middle-dose group were reduced by 48.73% and 59.11%, respectively; and the high-dose group were reduced by 71.38% and 59.33%, respectively, in serum of APAP induced liver injury mice. The activities of SOD and GSH were increased by 45.05% and 219.45% respectively in the middle dose group and 48.68% and 232.80% respectively in the high dose group. Meanwhile, water extracts of Orychophragmus violaceus seeds down-regulated the expressions of p-JNK, Bax, Caspase-3, and Caspase-9 (p<0.05) and up-regulated the expressions of Bcl-2, p-AMPK, p-AKT and p-GSK-3β (p<0.05). It suggested that water extracts of Orychophragmus violaceus seeds has protective effect against APAP induced hepatocyte apoptosis by up-regulating the AMPK/AKT/GSK-3β signaling pathway.
    6  The Antiproliferative Activities in Ganpu Tea on HepG2 and SGC-7901 Tumor Cell Lines
    YU Le-an XIAO Sui HUANG Ya-hui LI Xiao-xiao LAI Hui-qing ZHENG Yi LIANG Da-hua ZHANG Xu
    2020, 36(7):42-49. DOI: 10.13982/j.mfst.1673-9078.2020.7.1222
    [Abstract](793) [HTML](226) [PDF 14.08 M](873)
    Abstract:
    In this study, the changes of components in the processed ganpu tea and their antiproliferative effects on HepG2 and SGC-7901 cells were investigated. The change of quality components in ganpu tea was determined by high performance liquid chromatography, and the activity of ganpu tea extracts against HepG2 and SGC-7901 colonies was determined by the MTT method. Then, the cell cycle and apoptosis of HepG2 cell line with obvious effect were further analyzed. The results showed that after the processing, the content of polyphenols was 17.22% which was lower than the material tea. Among them, the ester catechins and non-ester catechins were remarkably reduced. Moreover, the increase of tea pigments (theaflavins and thearubigins) was prominent. Ganpu tea had a higher tumor inhibition rate on SGC-7901 and HepG2 cell lines than puer tea and citrus peel, and the IC50 values were up to 176.61 μg/mL and 143.60 μg/mL, respectively. The analysis of cell cycle and apoptosis indicated that ganpu tea induced cell apoptosis through retarding the G0/G1 in HepG2 cells. As a result, the special processing of ganpu tea not only prompted the amelioration of flavor but also improved the accumulation of active substances so that ganpu tea showed better antiproliferative activities in HepG2 and SGC-7901 tumor cell lines.
    7  Auxiliary Effect of Jinnan Compound on the Regulation of Blood Glucose in Type 2 Diabetic Rats
    YIN Min-qiang TANG Hai-lian JIANG Ze-kun JIAO Yu-zhi
    2020, 36(7):50-56. DOI: 10.13982/j.mfst.1673-9078.2020.7.0040
    [Abstract](262) [HTML](241) [PDF 44.15 M](832)
    Abstract:
    This study explored the hypoglycemic effect of Jinnan compound on type 2 diabetes in a rat model. Ten SD rats were randomly selected as the normal control group, and the remaining 40 rats were fed a high-fat diet combined with a low-dose streptozotocin and established type 2 diabetes model rats. The type 2 diabetes model rats were randomly divided into three groups: model group, positive group (metformin, 200 mg/kg) and Jinnan compound treatment group (Jinnan compound, 500 mg/kg). After 7 weeks of intervention, the levels of blood sugar and lipids, and the expression levels of γ-aminobutyric acid (GABA) and Bax protein in islet β cells were determined, while the expression of PPAR-α and PPAR-γ genes were detected by RT-PCR. Electron scanning microscopy was used to examine the changes in aortic walls of abdominal rats. The results showed that the levels of fasting blood sugar (18.45 mmol/L), postprandial glucose (21.39 mmol/L), glycosylated hemoglobin (8.97%), insulin (26.78 mIU/L), triglyceride (3.35 mmol/L), total cholesterol (2.53 mmol/L), low-density lipoprotein (0.46 mmol/L) and relative expression of Bax (0.2) in the Jinnan compound treatment group significantly decreased, whilst the relative expression levels of GABA (0.36), PPAR-α (0.79) and PPAR-γ (4.42) in the Jinnan compound treatment group increased markedly (p<0.05), compared with those of the model group (p <0.01). The extent of injury in the Jinnan compound treatment group was lower than that of the model group. It is speculated that the mechanism underlying the hypoglycemic action of Jinnan compound might be related to the increase of islet GABA expression, activation of PI3K/PKB signal pathway, inhibition of islet β cell apoptosis, up-regulation of the expression of PPAR-α and PPAR-γ genes, acceleration of β-oxidation of liver fatty acids, and decrease of fatty acid content.
    8  Betaine Improves Gastrointestinal Function in Anorexic Rats
    ZHOU Wei
    2020, 36(7):57-62. DOI: 10.13982/j.mfst.1673-9078.2020.7.0039
    [Abstract](182) [HTML](195) [PDF 22.32 M](930)
    Abstract:
    In this study, the ameliorating effect of betaine on the gastrointestinal motility of anorexic rats via affecting the Ghrelin signaling pathway was studied. The betaine was prepared while the anorexic rat model was established, which was divided into four groups: the normal group, anorexic group, positive control group, and betaine group. The betaine group was administrated with 100 mg/kg betaine via gavage, the positive control group was administrated with 25 g/kg water-soluble Jianwei Xiaoshi table via gavage, and the normal group and the anorexic group were given 2 mL of distilled water via gavage. After drug intervention, the food intake, body weight, gastrointestinal motility, serum amylase, serum gastrin and the expression of Ghrelin signal pathway protein in the gastric antrum of the four groups were analyzed and compared. The results showed that with the intervention of betanin, the gastric residual rate in anorexic rats decreased from 62.35% to 42.65%, the small intestinal propulsion rate, content of serum amylase, and content of serum gastrin increased from 28.65%, 1779.65 U/L, 25.56 ng/L to 69.68%, 2101.22 U/L, 50.23 ng/L, respectively. The expression levels of the Ghrelin signaling pathway proteins, growth hormone receptor (GHSR), protein kinase C (PKC), alcohol triphosphate (IP3R) and myosin light chain (MLC) increased from 0.73, 0.13, 0.23 and 0.46 to 0.98, 0.95, 0.97 and 0.85, respectively, with the differences being statistically significant (p<0.05). It was found that betanin could increase the expression levels of GHSR, PKC, IP3R and MLC, reduce the residual rate of the stomach, and increase the small intestinal propulsion rate, serum amylase and serum gastrin level, through acting on the Ghrelin signaling pathway, thereby ameliorating the gastrointestinal motility disorder in anorexic rats, increasing the food intake and body weight, and ultimately alleviating the anorexic symptoms.
    9  Regulating the Production of Ethanol and Flavor by Overexpression of GPD1 in Wine Yeast
    GAO Ying-ying LI Ping LI Tong LIN Liang-cai ZHANG Cui-ying
    2020, 36(7):63-69. DOI: 10.13982/j.mfst.1673-9078.2020.7.1198
    [Abstract](209) [HTML](234) [PDF 26.18 M](774)
    Abstract:
    The effects of metabolism regulation of GPD1 gene on ethanol-producing capacity and flavor production in wine yeast were studied, and wine yeast WY1 was used as the parental strain. In this work, three recombinant strains WY1-GPD1, WY1-2GPD1 and WY1-3GPD1 with overexpression of one, two and three copies of GPD1 gene, respectively, were constructed using molecular biology by PCR amplification of the glyceraldehyde-3-phosphate dehydrogenase gene GPD1 in Saccharomyces uvarum WY1. The expression level of GPD1 gene in the recombinant strains and the parental strain was measured by Real-time PCR, and compared with the parental strain WY1, the expression of GPD1 in recombinant strains WY1-GPD1, WY1-2GPD1 and WY1-3GPD1 increased to 1.75 times, 3.02 times and 3.42 times, respectively. The wine fermentation experiment revealed that the overexpression of GPD1 had a significant effect on the reduction of ethanol. Compared to that of WY1, ethanol yields of the recombinant strains WY1-GPD1, WY1-2GPD1 and WY1-3GPD1 were reduced by 8.07%, 14.36% and 15.34%, respectively, while total higher alcohols were decreased by 15.20%, 17.11% and 16.55%, respectively. The contents of ethyl acetate were decreased by 17.63%, 23.81% and 27.42%, and isoamyl acetate concentrations were decreased by 11.78%, 15.87% and 17.79%, respectively. The contents of glycerol were increased to1.02 times、1.80 times and 1.83 times, respectively. This study showed that overexpression of GPD1 gene can affect the ability of wine yeast to produce ethanol and is significant to improve wine flavor.
    10  Comparison of Metabolic Activity and Relationship of Pediococcus pentosaceus in Traditional Chinese Sourdough
    GONG Yun-xia QI Xiao-bao
    2020, 36(7):70-74. DOI: 10.13982/j.mfst.1673-9078.2020.7.1056
    [Abstract](273) [HTML](188) [PDF 32.74 M](798)
    Abstract:
    The molecular properties of P. pentosaceus separated from traditional sourdoughs were investigated in this work. The 8 strains of P. pentosaceus were isolated from different Laomians in central and northern China. Acid producing abilities generated by fermenting glucose were compared. The skimmed milk separation medium was used to investigate the ability of protease production of P. pentosaceus. Extracellular proteins were extracted by precipitation protein method and protein gel electrophoresis was used to analyze extracellular proteins. Furthermore, the Folin-phenol method was used to compare the protease activity produced by different P. pentosaceus. The results showed that these P. pentosaceus had the ability to metabolize glucose and acid production, of which P.P005 had the best ability, and the pH value was reduced by 0.41 at the end of fermentation. All P. pentosaceus can produce obvious hydrolytic circles when cultured on skim milk plates, therefore they had the ability to produce protease. The strain P.P002 and strain P.P008 had the highest concentration of secreted protein, and the highest enzyme activity was between 1057.27 to 1242.56 U/mL by exploring the protease activity of different strains. Under their optimal conditions, the protease production activity were followed by P.P002, P.P001, P.P005, P.P006, P.P003, P.P008, P.P007, and P.P004. Finally, their relationship was analyzed by ERIC-PCR, and the results showed that the similarity of all strains was within 86%. This study provides the foundation for molecular research to explore the role played by P. pentosaceus in traditional Laomian.
    11  Isolation, Identification and Pathogenicity Analysis of Vibrio parahaemolyticus Strains from Maowei Sea, Beibu Gulf
    TANG Jin-li LI Xiao-li CHEN Xing ZHAO Hua-xian LI Nan
    2020, 36(7):75-87. DOI: 10.13982/j.mfst.1673-9078.2020.7.1202
    [Abstract](206) [HTML](173) [PDF 5.12 M](705)
    Abstract:
    To analyze the diversity characteristics of V. parahaemolyticus and safety risks in sea water and aquatic products in Beibu gulf, we collected samples from seawater and aquatic economic animals in the mariculture area of Maowei sea in Beibu gulf in this study. Marine vibrio was isolated from the samples by thiosulfate citrate bile salts sucrose agar culture medium (TCBS). Totally, 109 suspected vibrio strains were obtained. A total of 20 strains of V. parahaemolyticus were identified by DNA sequencing of 16S rDNA genes and specific function gene toxR after PCR amplification. Virulence gene tdh analysis showed that 4 of the 20 strains of V. parahaemolyticus carried the virulence gene tdh, with a detection rate of 20%. In addition, phylogenetic analysis also revealed that horizontal gene transfer happened in both the toxR and tdh gene sequences of V. parahaemolyticus. The results of this study indicated that V. parahaemolyticus in Beibu gulf had high genetic diversity, and some of them carry pathogenic factors, which is a risk of outbreak of aquaculture diseases and food-borne diseases in this area. Therefore, it is suggested to use PCR technology to detect specific species genes and virulence genes of V. parahaemolyticus, accurately evaluate the health safety in seawater and aquatic products in the Beibu gulf region, and reduce the risk of outbreak of aquaculture disease and food-borne diseases.
    12  Low-temperature Drying of Dendrobium officinale Inhibit Polymerization of Water-soluble Polysaccharides
    XING Li MA Hou-yu JIANG Ling MIAO Ye-lian
    2020, 36(7):88-95. DOI: 10.13982/j.mfst.1673-9078.2020.7.0010
    [Abstract](262) [HTML](176) [PDF 27.78 M](952)
    Abstract:
    The present study was carried out to investigate the effects of drying temperature on the molecular structure and antioxidant activity of the polysaccharides in Dendrobium officinale. Four types of water-soluble polysaccharides from D. officinale, i.e., FDOP, 60 DOP, 100 DOP and 140 DOP, were prepared through extraction and purification after hot air drying of fresh D. officinale, and D. officinale at 60 ℃, 100 ℃, 140 ℃, respectively. Molecular structure and antioxidant activity of the polysaccharides from D. officinale were analyzed. It was found that the contents of the reducing end were 1.82% and 1.70% for FDOP and 60 DOP, respectively, but decreased to 1.42% for 100 DOP and 1.10% for 140 DOP. Each D. officinale polysaccharide was composed mainly of mannose and glucose. No obvious correlation was found between drying temperature and the molar ratio of monosaccharides. As the drying temperature increased, the molecular weight distribution curve of D. officinale polysaccharides shifted towards high molecular weight. The mass ratios of the polysaccharide fractions within the molecular weight range of 103~106 u were 70.68%, 67.70%, 62.24% and 58.11%, respectively, for FDOP, 60 DOP, 100 DOP and 140 DOP. At 280 nm of the UV spectra, 140 DOP had an absorption peak whilst FDOP, 60 DOP and 100 DOP hadn't. The polysaccharide constituents with the molecular weights in the range of 103~106 u and containing more reducing ends showed higher free radical scavenging ability and reducing power. During the drying of Dendrobium officinale, the drying temperature set at 60 ℃ facilitated the suppression of polymerization reaction while retaining the antioxidant activity of its polysaccharides. The present study provides technical data and theoretical basis for the production and utilization of D. officinale-containing functional foods.
    13  Texture Comparison of Different Purple Sweetpotato Cultivars
    NIU Li-ying WAN Yu-wei LI Da-jing LIU Chun-quan SONG Jiang-feng XIE Yi-zhi
    2020, 36(7):96-104. DOI: 10.13982/j.mfst.1673-9078.2020.7.1129
    [Abstract](290) [HTML](193) [PDF 24.76 M](887)
    Abstract:
    In order to investigate the texture difference of 16 purple sweetpotato cultivars, texture profile analysis (TPA) using texture analyzer and sensory texture profile evaluation were conducted. The moisture content, starch constitution, thermodynamic properties were also determined. Results showed that some samples displayed as outliers in boxplots and there were significant differences (p<0.05) on the texture parameters among the samples. QZ5070 showed the lowest value of moisture content (59.16%) as well as the highest values of hardness (4880 g), springiness (3.57 mm), adhesiveness (1265 mJ), chewiness (43.34 mJ), and recoverable deformation (1.71 mm). Multiple correlation analysis showed the moisture content negatively correlated with TPA chewiness, sensory hardness, and sensory floury, while it positively correlated with sensory cohesiveness and sensory chewiness (p<0.05). No significant correlations among the starch contents and texture properties. In addition, △H, a thermodynamic parameter, was positively correlated with sensory chewiness (p<0.05). Moreover, 4 sample groups and 5 parameter class were clustered using two-way cluster analysis (CA). From the heatmap of the normalized data and the cluster results, Yuzi-7, Yuenan-zishu, Riben-xinzi and 3 breeding materials (QZ5070, W36-1 and W50-2) were distinguished themselves from the other cultivars. In conclusion, the results will offer valuable texture information for sweetpotato eating, processing and breeding quality improvements.
    14  Spectrum-Activity Relationship of Lipid-Lowering Ethanolic Extracts from Defatted Walnut Meal
    WANG Zu-kun MA Ya-ge YANG Jin-juan ZHANG Xi ZHAO Shen-lan
    2020, 36(7):105-112. DOI: 10.13982/j.mfst.1673-9078.2020.7.0027
    [Abstract](288) [HTML](222) [PDF 23.63 M](968)
    Abstract:
    The spectrum-activity relationship between HPLC fingerprints and lipid-lowering effects of an ethanol extract, and its liquid-liquid extract and purified product (by macroporous resin), from the defatted walnut meal was studied, to provide a basis for determining the foundation material of their lipid-lowering effects. The HPLC fingerprints (S1~S9) of these extracts and purified products of defatted walnut meal were acquired; A free fatty acid (FFA) was added to HepG2 cells at 1 mM/L and treated for 24 h, to establish a model of steatosis. After the model was successfully established, the lipid-lowering effects of S1~S9 samples on steatosis in HepG2 cells were examined; The gray correlation method was used to analyze the spectrum-activity relationship between the common spectral peaks and the lipid-lowering effects of the active ingredient group. Results showed that among the 15 common peaks screened from the similarity range of 0.31~0.96 in the HPLC spectra of S1~S9, the ethyl acetate extract (S5) and the purified product of macroporous resin (S8) had the greatest lipid-lowering effects (p<0.001). The first 6 peaks corresponding to the fractions that made a relatively high contribution to the lipid-lowering effect were peak 14, 6, 12, 10, 13, and 11, respectively. The correlation coefficient of peak 14 was the highest (higher than 0.9), with those of the remaining 5 peaks all higher than 0.85. The lipid-lowering effect of the extract from walnut meal resulted from the combined action of multiple constituents. The substances corresponding to glansreginin A, (4S)-4-hydroxy-α-tetralone-4-O-β-D-(6′-O-4″-hydroxylbenzoyl)-glucopyranoside, (2E,4E)-8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6'-O-β-d-glucopiranosyl ester, glansreginin B, rutin, and quercetin 3-arabinoside or quercetin 3-xyloside were identified a the main lipid-lowering active components in the extracts from the defatted walnut meal.
    15  Analysis of Antioxidant Activity of Aquatic Vegetable Extracts and Its Role in Antioxidation of Rapeseed Oil
    XU Xiao-ying HU Xiao-xiao SHAN Tian-tian YI Yang WANG Hong-xun WANG Li-mei
    2020, 36(7):113-119. DOI: 10.13982/j.mfst.1673-9078.2020.7.1235
    [Abstract](411) [HTML](233) [PDF 8.86 M](963)
    Abstract:
    The antioxidative activities of extracts from different parts of seven common aquatic vegetables and their antioxidative effects on oil were studied. ABTS free radical scavenging and DPPH free radical scavenging were used to determine the antioxidant activity of alcohol extracts and water extracts from different parts of Water chestnut, Citronella, Lotus root, Taro, Water chestnut, and Arrowhead, and oven method was used to determine their effect on rapeseed oil. The IC50 values of the three extracts with stronger DPPH free radical scavenging ability among 30 kinds of extracts were as follows: the alcohol extract of Gordon euryale (0.03 mg/mL) < the water extract of Gordon euryale (0.04 mg/mL) = the water extract of water caldron (0.04 mg/mL). The trolox contents of the three extracts with stronger ABTS free radical scavenging ability were: ethanol extract of Gordon euryale seed shell (1.42 g/g) > water extract of Gordon euryale seed shell (1.41 g/g) > ethanol extract of water caltrop shell (1.15 g/g). The POV values on the seventh day of the five extracts with 0.1% concentration were: 23.86 meq/kg, 24.06 meq/kg, 23.53 meq/kg, 24.43 meq/kg and 22.40 meq/kg, respectively. The results showed that the antioxidant effects of the five extracts on oil were not as good as 0.1% BHA. The determination of the antioxidant activity of extracts from different parts of 7 aquatic vegetables indicated that DPPH free radical scavenging ability of alcohol extract, water extract of Gordon euryale seed shell and water chestnut shell were the strongest, ABTS free radical scavenging ability of alcohol extract and water extract of Gordon euryale seed shell were the strongest. Gordon euryale seed shell aqueous extract and alcohol extract, water chestnut shell water extract and alcohol extract and lotus root section alcohol extract had certain antioxidant effect on rapeseed oil, but the effects were weaker than the same dose of BHA.
    16  Changing Trend of the Vitamin Content in Carrot during Drying
    WANG Qiu-yu
    2020, 36(7):120-124. DOI: 10.13982/j.mfst.1673-9078.2020.7.0032
    [Abstract](257) [HTML](566) [PDF 2.54 M](801)
    Abstract:
    Taking carrot as the research object, the change trend of the vitamin content of carrot during drying. The carrot was dried by vacuum freeze drying, heat pump drying, and hot air drying, then the different vitamin contents were determined during drying, and the obtained experimental data were statistically processed by SPSS 12.0. The results showed that the total vitamin loss in the carrots after drying was greater than that after drying. During the freeze-drying process, the total loss rates of vitamin A, vitamin B1, vitamin B2 and vitamin C were 62.23%, 54.95%, 48.32% and 66.52%, respectively. In the process of hot air drying, the loss rate of the four vitamins reached the highest when the drying temperature was 100 ℃: 80.75% for vitamin A, 77.45% for vitamin B1, 79.63% for vitamin B2, and 80.47% for vitamin C. During the heat pump drying process, the loss rate of the four vitamins reached the highest when the air outlet temperature was 100 ℃: 80.23% for vitamin A, 69.54% for vitamin B1, 64.35% for vitamin B2, and 89.27% for vitamin C. The loss rates of vitamin A and vitamin C in the carrots were the highest during drying. Therefore, in order to reduce the vitamin loss during drying of carrot, the drying process of carrot should be continuously improved.
    17  Synergistic Effects of Modified Atmosphere Packaging and Irradiation for Preserving Fresh Noodles
    OUYANG Meng-yun WANG Yan SUN Zi-qin WU Wei-guo ZHAO Chuan-wen CAO Sheng
    2020, 36(7):125-132. DOI: 10.13982/j.mfst.1673-9078.2020.7.0043
    [Abstract](202) [HTML](244) [PDF 19.49 M](952)
    Abstract:
    In order to prolong the shelf life of fresh noodles, the effects of modified atmosphere packaging alone and in combination with irradiation technology on the quality and freshness of the fresh noodles were studied. The fresh noodles were packaged under different gas conditions (100% CO2, 70% CO2+30% N2, 50% CO2+50% N2), with the air-package as the control to measure the changes in the indicators such as total colony count, moisture content, and cooking characteristics over the storage at 28 ℃. The results showed that 70% CO2+30% N2 modified atmosphere packaging exerted a greater preservative effect, and could extend the shelf life of fresh noodles from 2 d to 3 d. Subsequently, the synergistic preservative effects of the modified atmosphere packaging and irradiation at different irradiation doses (1, 3, 5 kGy) on fresh noodles were investigated, with 70% CO2+30% N2 modified atmosphere packaging as a control. The results also showed that different doses of irradiation exhibited significant preservative effects, with 1~3 kGy capable of prolonging the shelf life of fresh noodles by 5~8 d, and 5 kGy prolonging by 11 d. However, 5 kGy led to a significant impact on other quality indicators of fresh noodles such as cooking characteristics, texture characteristics and sensory quality. Therefore, the combined use of modified atmosphere packaging and irradiation technology at the low irradiation dose of 1~3 kGy is recommended for preserving fresh noodles over the storage. This method can improve eating quality and prolong effectively the shelf life of the fresh noodles.
    18  Regulation of Sulfur Dioxide on Organic Acids Content and Malate Metabolism Pathway of Grapes in Postharvest
    YAN Bo-wen YUAN Yu-yao WEI Jia ZHANG Zheng ZHANG Jian WU Bin
    2020, 36(7):133-141. DOI: 10.13982/j.mfst.1673-9078.2020.7.0037
    [Abstract](318) [HTML](332) [PDF 59.66 M](819)
    Abstract:
    The effects of sulfur dioxide (SO2) on the content of organic acids and the regulation of malate metabolism of ‘Munage’ grapes during postharvest storage were investigated. The changes in the contents of tartaric acid, L-malic acid, L-ascorbic acid and citric acid during fruit storage were measured by high performance liquid chromatography (HPLC), and RNA sequencing (RNA-Seq) was used to analyze the main pathways of SO2 to regulate malate metabolism. The differences in the expression of malate dehydrogenase (MDH), cytoplasmic malate dehydrogenase (cytMDH), mitochondrial malate dehydrogenase (mtMDH), lactate dehydrogenase (LDH), NADP-dependent malic enzyme (NADP-ME), pyruvate decarboxylase 1 (PDC1), pyruvate decarboxylase 2 (PDC2), and ethanol dehydrogenation enzyme dehydrogenase (ADH) genes were determined to verify further the results of RNA-Seq. The results showed that on the 60th day of storage, the contents of tartaric acid, L-ascorbic acid and citric acid in the fruits of the SO2-treatment group were 0.13 mg/g, 0.34 mg/100g, and 0.02 mg/g (which were all higher than those of the CK group), with the content of L-malic acid lower than that of the CK group by 0.64 mg/g. SO2 can maintain the contents of tartaric acid, L-malic acid, L-ascorbic acid and citric acid in ‘Munage’ grapes, through up-regulating the expressions of mtMDH, LDH, NADP-ME and PDC1, while down-regulating the expressions of MDH, cytMDH, PDC2 and ADH, to promote the decomposition of L-malic acid and preserve the flavor characteristics of the fruit. The study can provide a theoretical basis for the investigations on the regulatory role of SO2 in malate metabolism of grapes.
    19  Preservation of Fruit Cucumber Treated by Antibacterial Peptide and Chitosan Composite Film
    LUO Xue-yun WU Xiao-tong XIE Ying-si GONG Jia-hui LIANG Jia-yan DUAN Xing-xing CHEN Jun-li YUAN Miao DU Bing-jian LIN Bi-min BAO Jin-yong CAO Yong MIAO Jian-yin
    2020, 36(7):142-149. DOI: 10.13982/j.mfst.1673-9078.2020.7.1096
    [Abstract](509) [HTML](300) [PDF 15.29 M](1000)
    Abstract:
    In order to extend the shelf life of fruit cucumbers, two different concentrations of antimicrobial peptides (1.00% and 1.25%) and 1.00% chitosan were formulated into edible composite films. After coating the fruit cucumber at room temperature, the surface was covered with a PE film. The treated fruit cucumbers were stored at 25 ℃ and 40%~60% RH. The sensory and physiochemical indexes (weight loss rate, decay rate, hardness, vitamin C content, titratable acid content, chlorophyll content of pericarp) of fruit cucumbers were measured every 2 d. The results showed that after 21 d of storage, the weight loss rate of the 1.00% antimicrobial peptide and chitosan composite membrane treatment group was only 4.97%; the decay rate was 16.67%; the hardness decreased from 9.53 to 6.43, which was 42.50% higher than the blank group; the vitamin C content was 14.01 mg/100 g, which was only 1.40% lower than that before storage; and the chlorophyll content of pericarp was 0.63 mg/g. Therefore, it had the best preservation effect. The results showed that the antibacterial peptide and chitosan composite film treatment could significantly delay the decay and chlorosis of cucumber, reduce the loss of vitamin C and titratable acid, and maintain the hardness of cucumber.
    20  Preservation Effects of Litsea cubeba Essential Oil Combined with 1-MCP Treatment on Averrhoa carambola Fruits
    LIN Yuan LIN Ying CAI Ting
    2020, 36(7):150-156. DOI: 10.13982/j.mfst.1673-9078.2020.7.0340
    [Abstract](286) [HTML](183) [PDF 19.35 M](899)
    Abstract:
    ‘Xiangmi’ Averrhoa carambola (Averrhoa carambola Linn. cv. Xiangmi) fruit was used as experimental material, and treated with Litsea cubeba oil (fumigation concentration 400 μL/L), 1-methylcyclopropene (1-MCP, fumigation concentration 0.6 μL/L) and Their mixture, respectively. In order to distinguish the preservation effect on Averrhoa carambola with different treatments, respiratory intensity, relative permeability of cell membrane and storage quality were detected. The sensory evaluation was also carried out. The results showed that emergence of respiratory peak was delayed by three treatments compared with the control, with peak reduction of 21.60%, 33.52% and 43.92%, respectively. After treatment, the cell membrane relative permeability, weight loss rate and decay index were reduced, and the hardness, soluble solids, titratable acid and the content of vitamin C were maintained in higher level. Among them, Litsea cubeba essential oil combined with 1-MCP treatment had the best effect, which could prolong the shelf life for about 8 days. At the 20th day of storage, their sensory score was 74.27 points, while the other two separated treatments lower than critical value 70.00 points. These results showed that, synergistic effect generated by antibacterial effect of essential oil and ethylene inhibition effect of 1-MCP could improve preservation efficiency of carambola. Results of this work might provide a feasible way for the preservation of perishable fruits.
    21  Comparison of Postharvest Quality and Storability of Different Longan Varieties
    WU Ze-yi CHEN Xiao-dong LUO Tao WU Zhen-xian HAN Dong-mei
    2020, 36(7):157-164. DOI: 10.13982/j.mfst.1673-9078.2020.7.1212
    [Abstract](386) [HTML](434) [PDF 15.26 M](831)
    Abstract:
    The quality of 14 varieties of longan fruits (‘Guangzao’, ‘Dongguan Daguo’, ‘Shixia’, ‘Luosanmu’, ‘Gushan No.2’, ‘Lvzhu’, ‘Shuiyan’, ‘Jidanben’, ‘Cihezhong’, ‘Fuyan’, ‘Shuangmamu’, ‘Dongbi’, ‘Chuliang’ and ‘Fengliduo’) at mature stage, and their storabilities under room temperature (25 ℃) and low temperature (4 ℃) conditions were studied. The results showed that 14 varieties of longan can be devided into big, middle and small fruits by its single fruit weight. ‘Chuliang’, ’Shuangmamu’, ‘Cihezhong’, ‘Luosanmu’, ‘Dongbi’ and ‘Fuyan’ belong to big fruits and the single fruit weight is more than 10 g; ‘Dongguan Daguo’, ‘Gushan No.2’, ‘Lvzhu’ and ‘Shuiyan’ belong to middle fruits and the single fruit weight is among 8~10 g; the other varieties belong to small fruits and the single fruit weight is less than 8 g. Among these varieties, ‘Chuliang’ has the largest single fruit weight, with a fruit shape index bigger than 1.05 and an edible rate more than 70%, showing a good fruit quality. The 14 varieties are classified into the high storability, the low storability and the middle storability based on their storabilities at normal and low temperatures. Among 14 varieties, ‘Fuyan’ is one of the varieties of the low storability. ‘Fuyan’ fruit has the thinnest pericarp thickness, lower contents of TSS and Vc in aril, and higher mass loss rate, pericarp browning index and aril breakdown index during storage. ‘Shixia’ is one of the varieties of the high storability. ‘Shixia’ fruit has the smaller fruit size, lower mass loss rate and pericarp browning index, and higher contents of TSS and Vc in aril during storage.
    22  Comparative Analysis of Color Stability of Sanhua Plum Juice during Storage with Different Phenolic Acids
    LI Yi-na ZOU Ying YU Yuan-shan XIAO Geng-sheng XU Yu-juan ZOU Bo
    2020, 36(7):165-172. DOI: 10.13982/j.mfst.1673-9078.2020.7.1187
    [Abstract](379) [HTML](246) [PDF 69.51 M](986)
    Abstract:
    In order to enhance the stability of anthocyanins in Sanhua plum juice, five different phenolic acids (kuomaric acid, ferulic acid, chlorogenic acid, caffeic acid, vanillic acid) were selected as copigments in this experiment to study the auxiliary color of Sanhua plum juice. They were stored at 4, 25 or 37 ℃ for 21 days. The color, anthocyanin content, antioxidant activity, light transmittance, soluble solids, pH and other physical and chemical indexes of Sanhua plum juice were measured every 3 days. Results showed that with the increase of storage time and temperature, the light transmittance of Sanhua plum juice decreased, and the degradation rate of anthocyanin accelerated. The color of Sanhua plum juice was maintained and the quality of juice was improved by adding phenolic acid. Different phenolic acids have different auxiliary color effects. Among them, the color of kuomaric acid auxiliary color group changed greatly, the light transmittance was 7.74% on the 21 th day of storage at 37 ℃, the anthocyanin retention rate was only 15.32%, and the auxiliary color effect was not significant; In contrast, the total color difference value TCD of Sanhua plum juice supplemented with ferulic acid and chlorogenic acid auxiliary color changed little, and the color was more stable during the storage period. On the 12th day of storage at 37 ℃, the retention rate of anthocyanin increased by 9.91% and 10.36% respectively, and it had little effect on the other physical and chemical color indexes of the juice. The auxiliary color effect was relatively significant. Therefore, ferulic acid and chlorogenic acid could be considered as copigment for Sanhua plum juice.
    23  Optimization of Enzymatic Hydrolysis of Fermented Acid Meat to Produce Antioxidant Peptides
    WU Hui-lin LI Miao-yun ZHU Yao-di ZHAO Gai-ming HAO Yun-peng REN Hong-rong MA Yang-yang ZHAO Li-jun
    2020, 36(7):173-183. DOI: 10.13982/j.mfst.1673-9078.2020.7.1257
    [Abstract](313) [HTML](365) [PDF 86.43 M](888)
    Abstract:
    Dong sour meat and Miao sour meat are used as raw materials, papaya, alkaline, flavor and neutral protease were used for enzymolysis, and the yield of short peptide, hydroxyl radical and DPPH radical scavenging rate of enzymolysis liquid were determined. The results showed that the short peptide yields from alkaline protease enzymolysis were 86.01% (Dong) and 82.52% (Miao), hydroxyl free radical clearance rates were 87.48% (Dong) and 79.88% (Miao), and DPPH free radicals clearance rates were 74.63% (Dong) and 87.87% (Miao). Through comparative analysis, the yield of short peptides from Miao sour meat was higher than that from Dong sour meat. Therefore, protease species, enzyme dosage, enzymatic hydrolysis time and solid-liquid ratio were selected as independent variables, taking the yield of Miao sour meat short peptide and DPPH radical scavenging rate as evaluation index, the optimal enzymatic hydrolysis conditions were determined using response surface. The results showed that the optimal enzymatic hydrolysis process of the antioxidant peptide of sour meat was as follows: the addition of basic protease is 12600 U/g, the enzymatic hydrolysis time is 1 h, and the ratio of feed to liquid is 1:1.09 (m:V). The yield of antioxidant peptide under the optimal conditions was 83.35%, which was the predictive value of 98.99%. DPPH free radical clearance rate was 84.01%, which was the predictive value of 97.33%. This suggests that the peptides from alkaline protease enzymolysis of sour meat have higher antioxidant activity and nutritional value, which provide theoretical basis for further development and utilization.
    24  Rheological Properties of Quinoa-wheat Flour and Development of its Noodles
    LIANG Xia MENG Ting-ting ZHOU Bai-ling TIAN Zhi-fang REN Yuan
    2020, 36(7):184-192. DOI: 10.13982/j.mfst.1673-9078.2020.7.1153
    [Abstract](400) [HTML](273) [PDF 659.86 K](904)
    Abstract:
    The effect of quinoa flour substitution on wheat flour quality and noodle quality was investigated. The results showed that with the increase of quinoa flour substitution, the peak viscosity of flour decreased by 47.73%, wet gluten content decreased by 42.52%, sedimentation value decreased by 53.32%, stabilization time decreased by 56.07%, weakening degree increased by 84.62% and flour processing quality decreased. The contents of glutamic acid and proline in the mixed flour decreased, and the contents of the other 16 amino acids increased. The contents of lysine and histidine increased (p<0.05) by 73.33% and 80.00%, respectively. Lysine and isoleucine accounted for 10.94% and 12.67% of the total amino acids, which were close to the proportion recommended by FAO. The results of noodle sensory evaluation showed that 15% quinoa flour substitution could reduce the elasticity, hardness and toughness of the control wheat flour noodle. Under 15% quinoa flour substitution, the noodle had the flavor and color of quinoa, their surface was smooth, soft and hard moderate, and the taste was good. The results showed that the content of wet gluten, sedimentation value, formation time, stability time, elongation and maximum tensile resistance were positively correlated with the total score of noodles, while the weakening degree was negatively correlated with the total score of noodles, and all of the above indexes were negatively correlated with the taste. Results of this work can provide theoretical basis for the application of quinoa flour in noodle products.
    25  Optimization of Extraction Process of Phillyrin and Its Antibacterial Activity
    ZHANG Jun-shun LUO Jia-yuan JIANG Zhe-hui BAO Yi-hong BAO Hong-tao
    2020, 36(7):193-201. DOI: 10.13982/j.mfst.1673-9078.2020.7.1170
    [Abstract](481) [HTML](200) [PDF 49.14 M](921)
    Abstract:
    Forsythia suspensa leaves were used as raw materials for phillyrin extraction by ultrasonic assisted semi-bionic method. According to the results of one-factor-at-a-time method, a four-factor and three-level response surface methodology was applied with ethanol concentration, liquid-to-solid ratio, extraction time, temperature as influencing factors. The antibacterial activity was determined by the filter paper method, and the effects of temperature, pH and UV on the antibacterial retention rate of phillyin were studied. The results of variance analysis showed that the regression model better reflected the relationship between the yield of phillyrin and ethanol concentration, liquid-to-solid ratio, extraction time, temperature. The optimum extraction conditions were obtained: the ethanol concentration was 40%, the liquid-to-liquid ratio was 36:1, the extraction temperature was 48 °C and the extraction time was 100 min. Under these condition, the yield of phillyrin reached 4.42%, which was higher than other extraction methods. Antibacterial activity test showed that phillyrin could inhibit Staphylococcus aureus, Escherichia coli, Salmonella and Bacillus subtilis. In addition, the diameters of inhibition zone of the four tested strains were 8.33, 9.85, 8.85, and 8.81 mm respectively. The high temperature, strong acid and strong base could weaken the antibacterial effect of phillyrin, while UV had little effect on the antibacterial effect of phillyrin.
    26  Microencapsulation and Characterization of Soybean Protein Hydrolysates
    HUANG Xiao-mei WEI Cui-lan HOU Jun-jie WANG Zhong-he LUO Zhao-jiao WANG Jin-mei
    2020, 36(7):202-208. DOI: 10.13982/j.mfst.1673-9078.2020.7.0977
    [Abstract](447) [HTML](299) [PDF 39.69 M](817)
    Abstract:
    The unacceptable bitterness and strong hygroscopicity restrict the application of soybean protein hydrolysates in the food industry as food source peptides. In this study, soybean protein hydrolysates (SPH) was used as core material, and soybean protein (SPI)-soybean polysaccharide (SPSS) complex as wall material, and spray drying technology was used to prepare SPH microcapsules. The physical and chemical properties of the microcapsules were characterized. The core/wall ratio of the microcapsules was 1/4, and the wall material ratio (SPI/SSPS) was 2:1. The microcapsules had the best embedding effect. The embedding rate was 50.92%, the bitterness could be reduced by 2.68 times, and the hygroscopicity could be reduced by 1.61 times. The microcapsules were spherical in shape with a smooth, continuous surface and no holes or cracks. FTIR analysis confirmed that the electrostatic interaction occurred between SPI and SSPS. It is known that soybean polysaccharide and soybean protein are usually regarded as ideal delivery agents because of their macromolecular structure. The complexation of soybean polysaccharide and soybean protein could effectively improve the structural stability of SPH microcapsules. It also provides a theoretical basis for SPH microcapsules as functional ingredients.
    27  Optimization of Processing Technology of Sweet Corn Buns
    ZHANG Kang-yi WANG Hui-jie ZHANG Guo-zhi KANG Zhi-min SONG Jiang-feng
    2020, 36(7):209-217. DOI: 10.13982/j.mfst.1673-9078.2020.7.1100
    [Abstract](361) [HTML](246) [PDF 88.65 M](864)
    Abstract:
    In this work, sweet corn kernels were subjected to hot-air drying treatment, and the sweet corn flour was mixed with wheat core flour to produce steamed buns. The process of steamed buns was optimized. The texture, sensory and specific volume were used as evaluation indicators, the single factor experiments were carried out. Three factors and three levels were selected for the Box-Behnken response surface experiment. The different proportions of sweet corn flour was added to produce steamed bread. The results showed that the addition ratio reaches 30% (sweet corn flour: wheat cob flour=3:7) could lead to decrease of the texture and specific volume index and its sensory score dropped sharply, which was less than 60 points. Therefore the sweet corn addition amount of 25%was selected, and the response surface was optimized. Finally, the optimal process conditions for sweet corn steamed buns with 25% addition were as follows: fermentation time was of 78.19 min, proofing time was of 19.51 min, stirring time was of 9.98 min, and yeast addition was of 1.02%. Under these conditions, sweet corn steamed buns had a good sensory quality of 79.17 points, which was higher 9.64 points than that before optimization. The specific volume increased by 0.05 ml/g. The texture indicators had improved, and the gluten network structure was more compact.
    28  Optimization of Tomato Sour Soup Fermented by Lactobacillus casei
    ZHENG Sha-sha HU Ping WANG Xiao-yu TIAN Ya XU Li DING Zhu-hong YANG Xiao-ling LI Juan FENG Dan-dan
    2020, 36(7):218-226. DOI: 10.13982/j.mfst.1673-9078.2020.7.1157
    [Abstract](308) [HTML](236) [PDF 8.97 M](826)
    Abstract:
    In order to explore the optimal fermentation process of sour soup, the Lactobacillus casei H1 was used as starter culture inoculated into tomato. The effects of fermentation temperature, fermentation time, inoculum size and salinity on the quality of tomato sour soup were studied and the fermentation conditions were optimized. On the basis of single factor experiment, the four-factor and three-level response surface experiment design was carried out. Based on the two response values of sensory evaluation and total acid obtained by fuzzy mathematics, the fermentation process of tomato sour soup inoculated with Lactobacillus casei H1 was optimized to determine the optimal fermentation process. The results showed that when the fermentation temperature was 25 °C, the fermentation time was 5 days, the inoculum size was 2%, and the salinity was 1.45%, the total acid of the tomato sour soup reached 1.23%, and the sensory evaluation was 8.48±0.58, which was not significantly different from the theoretical value (p>0.05). These results indicated that the experimental values of the response surface were basically consistent with the predicted values of the regression equation. Furthermore, the fermentation conditions of the tomato sour soup determined by the response surface method were stable and reliable, which could provide a theoretical basis for the industrial production of tomato sour soup.
    29  Extraction Optimization of Water-insoluble Dietary Fiber from Rosa roxburghii Tratt Fruit Pomace
    XIA Jie XUE Hao-yan JIA Xiang-ze GAO Qing LI Chao HUANG Qiang
    2020, 36(7):227-234. DOI: 10.13982/j.mfst.1673-9078.2020.7.0683
    [Abstract](389) [HTML](331) [PDF 38.66 M](913)
    Abstract:
    Dietary fiber is an important part of a healthy diet and offers many physiological benefits. In this work, the pomace of Rosa Roxburghii Tract fruit was used as raw material. The insoluble dietary fiber (IDF) from the pomace of R. Roxburghii Tract fruit was extracted by ultrasonic-assisted extraction technology. The effects of ultrasonic power, extraction time, extraction temperature and ratio of material to liquid on the yields of IDF were investigated by single factor experiments. The optimal extraction conditions were optimized by Box-Behnken design (BBD) and response surface methodology (RSM). The results showed that the optimal extraction conditions were as follow: ultrasonic power of 184 W, extraction time of 14.7 min, extraction temperature of 49.5 ℃, and material-to-liquid ratio of 1:16.25 g/mL. Under this optimal extraction, the maximum yield of IDF was 76.00% in accordance with the predicted value, indicating that the optimization of ultrasonic-assisted extraction of IDF from the pomace of R. Roxburghii Tract fruit had good accuracy and reliability. Results of basic component analysis indicated that crude IDF was mainly composed of cellulose (42.06%±0.82%), hemicellulose (13.26%±0.01%) and lignin (12.36%±0.78%). In addition, compared with the conventional hot water method, ultrasonic-assisted extraction could increase the content of IDF.
    30  Improvement of Trehalose on Water Retention and Texture Properties of Dumpling Wrapper
    GAO Wen-qian XING Xue-yu HU Yan-hua CHEN Cui-ling
    2020, 36(7):235-241. DOI: 10.13982/j.mfst.1673-9078.2020.7.1241
    [Abstract](377) [HTML](416) [PDF 4.80 M](954)
    Abstract:
    In order to solve the problem of poor kneading of dumpling skin caused by water loss and cracking in actual production, different concentrations of trehalose (0, 1.0%, 2.0%, 3.0%, 5.0%) were added. Wet gluten content, water loss rate, water absorption and texture properties of dumpling wrapper were determined. The results showed that the wet gluten content of the flour was the largest when the trehalose content was 2.0%, compared with the blank group, it increased by 15.49%. The addition of trehalose could reduce the water loss rate of dumpling wrapper. When the amount of trehalose was more than 1.0%, the water loss rate was significantly decreased, compared with the blank group. When the amount was 5.0%, the water loss rate was 7.46%, which was the lowest. Meanwhile, it could improve the water holding capacity of dumpling wrapper. The water absorption rate was 54.41%, which was the largest and increased by 13.85%, compared with the blank group, when the amount of trehalose was 1.0%. With the addition of trehalose, the dough showed good tensile properties. The maximum resistance to extension was 83.73 g when the addition amount was 1.0%. Trehalose adding could improve the TPA characteristics of raw and cooked dumpling wrapper. Compared with the control group, when the content of trehalose was more than 3.0%, the adhesiveness of raw dumpling skin increased significantly, which made the raw dumpling skin easier to knead in the process of making. The hardness and chewing of dumpling wrapper were improved by 14.60% and 11.66%, respectively, with 2.0% of trehalose addition. As a result, the appropriate amount of trehalose could improve the quality of dumpling wrapper, and it could be considered as a modifier for the production of dumpling wrapper, and the optimal addition amount was 2.0%.
    31  Comparative Analysis on Flavor Changes of Oyster before and after Enzymatic Hydrolysis
    SU Guo-wan HUANG Ke-xin HE Wei-wei ZHAO Mou-ming
    2020, 36(7):242-249. DOI: 10.13982/j.mfst.1673-9078.2020.7.0841
    [Abstract](383) [HTML](273) [PDF 9.06 M](1343)
    Abstract:
    In order to understand the changes of volatile flavors before and after enzymatic hydrolysis of oyster meat and to determine key flavor compounds, in this work, the volatile flavor substances before and after enzymatic hydrolysis of oyster meat were extracted by headspace solid phase microextraction (SPME). The flavor substances were identified by chromatography-mass spectrometry (GC-MS) and the contribution of these flavor substances for the characteristic flavor of enzymatic hydrolysate of oyster meat were quantified according to ROAV values. The sensory evaluation was also used to evaluate the flavor of oyster meat and its enzymatic hydrolysates. The sensory results showed that the oysters mainly showed fruity aroma and grassy taste before enzymatic hydrolysis, and showed heavier fishy smell and scent after enzymatic hydrolysis. The 42 and 41 kinds of volatile substances including aldehydes, ketones, alcohols, esters, hydrocarbons were detected from oyster meat and its enzymatic hydrolysate by GC-MS. The key flavor compounds (ROAV≥1) of oyster hydrolysate are 4 and 8 respectively, and 6 and 5 volatile compounds (0.1≤ROAV<1) are important for the overall flavor of oyster meat and its enzymatic hydrolysates, respectively. Combined with the sensory data, the flavor of oyster was degraded by enzymatic hydrolysis. The sensory results showed that the oysters mainly showed fruity aroma and grassy taste before enzymatic hydrolysis, and showed heavier fishy smell and scent after enzymatic hydrolysis.
    32  Changing Trend of the Volatile Compounds in Robusta Green Coffee Beans during an Accelerated Storage Analyzed by HS-SPME-GC/MS and Electronic Nose Technology
    CONG Sha DONG Wen-jiang ZHAO Jian-ping CHI Xiao-xing CHEN Zhi-hua JIANG Kuai-le SHAN Yun-hui
    2020, 36(7):250-262. DOI: 10.13982/j.mfst.1673-9078.2020.7.0031
    [Abstract](497) [HTML](260) [PDF 46.80 M](807)
    Abstract:
    In this study, Robusta green coffee beans were used as the research object, and head space-solid phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC/MS) and electronic nose technology were used to analyse the volatile compounds of the coffee beans during an accelerated storage. Results showed that a total of 56 volatile compounds were identified in the green coffee bean samples. With the extension of storage time, the content of acids increased first and then decreased, the content of the ester compounds increased gradually, whilst the content of aldehydes decreased first and then increased (increased from 13.72% before storage to 25.46% after the storage at 60 ℃). The higher the accelerated storage temperature, the faster the increasing rate of volatiles (the volatile content increased from 24.12 μg/g DW to 31.34 μg/g DW). Electronic nose data analysis could discriminate samples subjected to different storage periods. The samples derived from different storage stages were clustered into different classes respectively, with a more compact cluster achieved at 60 ℃. Through the analyses of the changes in the contents of volatile compounds and the characteristic response values of electronic nose sensors, as well as the principal component analysis (PCA), it can be preliminarily speculated that hexanal, benzaldehyde, phenylacetaldehyde, acetic acid, hexanoic acid, and benzoic acid were the characteristic compounds that contributed greatly to flavor deterioration of green coffee beans during the accelerated storage. Thus, HS-SPME/GC-MS, electronic nose technology combined with PCA can evaluate comprehensively the flavor characteristics of green coffee beans during storage.
    33  Changes in the Quality of Acid Whey Tofu during Refrigerated Storage
    HUANG Bao-ling WANG Jie LIAO Zhen-lin WANG Li ZHONG Qing-ping FANG Xiang
    2020, 36(7):263-270. DOI: 10.13982/j.mfst.1673-9078.2020.7.1284
    [Abstract](294) [HTML](195) [PDF 43.67 M](979)
    Abstract:
    To investigate the changes of quality and flavor components of acid whey tofu during refrigerated storage at 4 ℃, the pH value, sensory characteristics, texture characteristics and main flavor compounds of the acid whey tofu were determined. The results showed that during the refrigerated storage, the pH value of acid whey tofu remained relatively stable (from 6.03±0.09 on the 1st day to 5.73±0.02 on the 7th day), but the sensory score decreased gradually during the refrigerated storage. The hardness and chewability increased significantly in the first three days (p<0.05), reached the peak values (8.15 N and 6.28 N) on the 3rd day, and then began to decline. A total of 30 volatile components were identified by HS-GC-IMS. During the initial period of the +refrigerated storage, ester and alcohol compounds were the main compounds, however, aldehydes, ketones, alcohols and acids became the major compounds during the middle period of the storage. During the late period of the storage, aldehydes, alcohols and sulfur-containing compounds became dominant. With the extension of the cold storage, the contents of some aroma components such as ethyl acetate and propyl acetate in acid whey tofu decreased, while the contents of some undesirable aroma components such as hexanal,1-octene-3-ol and dimethyl trisulfide increased. Therefore, the changes in texture and flavor components of the acid whey tofu were the main causes of the decline in sensory scores. These results along with those obtained from the analyses of the quality and flavor of the acid whey tofu revealed that at 4 ℃ , the shelf life of the acid whey tofu without preservatives was 5 d, and the acid whey tofu within the shelf life is safe to eat and has a good mouthfeel and flavor.
    34  Differences in the Antioxidant Activities and Volatile Components of Toona sinensis from Different Regions
    WANG Xiao-min SHI Guan-ying WANG Zhao-gai ZHANG Le CHENG Jing-jing JIANG Peng-fei ZHAO Li-li WANG Xu-zeng
    2020, 36(7):271-281. DOI: 10.13982/j.mfst.1673-9078.2020.7.0008
    [Abstract](341) [HTML](294) [PDF 32.09 M](810)
    Abstract:
    The antioxidant activities and volatile composition of T. sinensis from different production places were analyzed and evaluated, to provide a reference for processing and industrial development of high-quality Toona sinensis products. The contents of total flavonoids,total polyphenols, total alkaloids,total saponins, total crude polysaccharides and soluble proteins as well as DPPH free radical scavenging activity and OH· free radical scavenging activity of T. sinensis, were determined by routine physical and chemical methods, and correlation analysis and principal component analysis (PCA) were also performed. The volatile components of T. sinensis were detected by headspace solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS), and the main volatile components were evaluated using relative odor activity value (ROAV). Results showed that the changing trend of the contents of total flavonoids and total polyphenols in T. sinensis from the 12 different growing places was essentially the same, with the contents in those from Yunnan being the highest. The correlation coefficient between the content of total saponins and DPPH clearance rate was 0.475, and those between the content of total flavonoids or the content total polyphenols and OH· free radical scavenging rate, were 0.606 and 0.729, respectively, exhibiting a dose-effect relationship. These compounds were mainly the fundamental substances responsible for the antioxidant activity. A total of 229 volatile compounds were detected in T. sinensisfrom the 12 different places, with 59 found in those from Guizhou, 80 found in those from Yunnan, 73 found in those from Sichuan, 41 found in those from Guangxi, 84 found in those from Hunan, 73 found in those from Zhejiang, 54 found in those from Shanxi, 69 found in those from Anhui, 82 found in those from Hubei, 55 found in those from Henan, 52 found in those from Shandong, and 53 found in those from Hebei. 2-Hexenal, (E,Z)-2,6-nonadienal, hexanal, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one and α-pinene were the main volatile compounds in the T. sinensis from different places. The antioxidant activity and volatile composition of the T. sinensis samples from different places had certain similarities and also large differences, and exhibited their own unique qualities and flavors.
    35  Analysis and Risk Assessment of Seven Conventional Pesticides Residue in Brewing Sorghum Grains Grown in Hebei Province
    WANG Jin-ping DU Rui-heng JI Gui-su XING Guo-sheng LYU Peng
    2020, 36(7):282-288. DOI: 10.13982/j.mfst.1673-9078.2020.7.0343
    [Abstract](239) [HTML](243) [PDF 10.10 M](752)
    Abstract:
    To understand the situation of pesticide residues in sorghum grains grown in Hebei province, 20 sorghum grain samples and one liquor sample were collected, and the sample information in detail, such as producing areas, varieties, cultivation techniques, used pesticides and so on, were recorded. Seven conventional pesticide residues, including, atrazine, imidacloprid, pirimicarb, carbofuran, benzene hexachloride, chlorpyrifos, and chlorantraniliprole, were detected in samples according to GB/T 20770-2008 and GB 23200.113-2018. Each pesticide residue in sorghum was assessed according to GB 2763-2019. The results showed that the percentage of grain samples containing pesticide residues was 80%, and the percentage of grain samples containing pesticide residues exceeding maximum residue limits (MRLs) was 25%, but there was no pesticide residue in liquor sample. The residues of chlorpyrifos and chlorantranliliprole were found at or above the detection limits, with the detection rates were 70% and 25%, respectively. The maximum residue of chlorantranliliprole was 726 μg/kg, which was above MRL. In samples used pesticides, the detection rate and the over-standard rate of chlorpyrifos were 100% and 0, respectively, and that of chlorantraniliprole were both 50%. In samples used pest control methods with and without pesticides, the over-standard rates of pesticide residues were 41.67% and 0, respectively. Of all the varieties tested, the pesticide detection rates in Jiniang No. 2 and Jiniang No. 3 were both 75%, and lower than that in others. The pesticide over-stand rates in Hongmaoliang No. 6 and Jiniang No. 2 were 0 and 12.50%, respectively, and lower than that in others. The findings of this work could provide a theoretical basic for confirming pesticide residues detection items in brewing sorghum, and a reference for distilleries to choose safe brewing sorghum grains.
    36  Arsenic Species Analyses of Mice Brain under Chronic Arsenic Exposure through Food
    WANG Chen-fei SHI Ming WANG Jia-ting ZHANG Gui-wei QIU Jia-yi LI Yin-fei DOU Xin-hao ZOU Tang-bin GUO Lian-xian
    2020, 36(7):289-297. DOI: 10.13982/j.mfst.1673-9078.2020.7.1262
    [Abstract](533) [HTML](285) [PDF 30.88 M](934)
    Abstract:
    In order to explore the effects of chronic arsenic (As) exposure in food on organisms, in this study, As-treated feeds with the proportion of the arsenic composition in rice were prepared and three arsenic-containing dose groups (Simulate dose group: 0.91 mg/kg, Low dose group: 9.10 mg/kg, High dose group: 30 mg/kg) were designed according to the dose gradient, which were used to feed C57BL/6 mice over three months and the contents of total arsenic and five arsenic species (iAsIII, iAsV, MMA, DMA and AsB) in blood and brain tissues of mice were determined. In groups of C, S, L and H, the total arsenic (tAs) contents in blood were 0.022, 0.023, 0.068 and 0.132 mg/kg, respectively, and the total arsenic contents in brain were 0, 0.006, 0.075 and 0.172 mg/kg, respectively. While the five arsenic species can be detected both in blood, and only DMA and some unknown As species (uAs) were detected in the brain in groups of L and H. The results presented a clear dose-related accumulations of total arsenic (tAs) reflected both in blood and brain, the detoxification process of arsenic in vivo also accelerated with the increase of exposure dose, and the ratio of organic arsenic/inorganic arsenic (oAs/iAs) can reflect the dose of arsenic exposure. Thus, the current study indicated that although the toxic iAs in food could not transfer across the blood-brain barrier and the toxicity of As in food especially for the staple should be concerned.
    37  Transgenic Analysis of Soybean Products Sold in Chaozhou City
    WANG Mao-xian XIAO Liang-yuan WU Dan-xia DENG Yu-ting WANG Xin-yan
    2020, 36(7):298-305. DOI: 10.13982/j.mfst.1673-9078.2020.7.1199
    [Abstract](249) [HTML](264) [PDF 64.95 M](871)
    Abstract:
    In order to understand the condition of genetically modified soybean products on the market in Chaozhou City, the soybean products in the main markets were randomly purchased for testing. The DNA components of soybean products were extracted by modified CTAB method, and OD values were measured by nucleic acid protein analyzer. The exogenous genes CP4-EPSPS, NOS and CaMV35S were detected by qualitative and real-time quantitative PCR. A total of 29 soybean products sold in the main markets of Chaozhou City were investigated and tested. The results showed that the concentration and purity of DNA extracted from soybean products were higher, OD260 nm/OD280 nm ranged from 1.9 to 2.1, and the concentration of extracted DNA reached more than 200 ng/μL, which could basically meet the test requirements. More than half of the tested soybean products contain genetically modified ingredients. Except for Darunfa Supermarket’s soybean products, there are no food labels for soybean products, and whether GMF labels are required for all soybean products or not. The implementation of GMF labeling system is still in the initial stage, and a strong market supervision mechanism should be established in China. Therefore, we must attach great importance to the implementation of the GMF labeling system and the corresponding market supervision.
    38  Migration Behavior of Butyl Acrylate from Adhesive to Dry Simulant Tenax
    CHEN Yan-fen MA Ning-ning ZENG Ying LI Dan ZHONG Huai-ning ZHENG Jian-Guo
    2020, 36(7):306-312. DOI: 10.13982/j.mfst.1673-9078.2020.7.0283
    [Abstract](686) [HTML](219) [PDF 25.44 M](5216)
    Abstract:
    The migration behavior of butyl acrylate from adhesive into Tenax was investigated. The migration results and their mechanisms of butyl acrylate in different simulants defined in European legislation were analyzed and compared. The results showed, at different temperatures, the migration of butyl acrylate reached equilibrium (except 175°C) in Tenax after a certain time. The migration process was in the dynamic equilibrium of “adsorption-desorption” for a long time at 20°C. The amount of migration increased with time at 70°C, and reached equilibrium after 72 h. Tenax rapidly adsorbed butyl acrylate in a short time at 100°C and 175°C, and then migration decreased by desorption. When the migration reached equilibrium in Tenax after 72 h at 70°C, it had the highest migration of 65.16 μg/kg. The migration in 95% ethanol, isooctane and Tenax were higher (p<0.05) with that in olive oil. The results of migration in Tenax was closest to that in olive oil, and the relative deviation was from 0.6% to 5.1% at low temperature (20°C, 70°C). The resulted showed that the migration behavior of butyl acrylate in Tenax was affected by various factors. The migration was not positively correlated with temperature and time. The migration in actual system was overestimated that in model test. In order to obtain the accurate and effective safety risk assessment of materials, it should be necessary to select the simulant scientifically according to the actual food contact materials.
    39  Development of a Colloidal Gold Immunochromatographic Assay for the Quantitative Determination of Phenobarbital Residues in Fish and Shrimp
    HUANG Jia-jia LI Yan-jie LIANG Zhi-li YANG Hui-qing LEI Hong-tao XU Zhen-lin
    2020, 36(7):313-320. DOI: 10.13982/j.mfst.1673-9078.2020.7.0304
    [Abstract](265) [HTML](388) [PDF 44.93 M](848)
    Abstract:
    In this study, a colloidal gold immunochromatography assay for the quantitative determination of phenobarbital residue in fish and shrimp was developed. Anti-phenobarbital monoclonal was labelled with colloidal gold nanoparticles as tracers. The assay conditions, including pH value of labelling, concentrations of antibody for labeling, concentration of the coating antigen (T line) and the goat-anti-mouse IgG (C line), as well as the sample pretreatment were optimized. By using a colloidal gold strip reader, the assay was able to achieve quantitative determination of phenobarbital. Under the optimal condition, the assay showed a limit of detection and detection range were 0.07 ng/mL and 0.08~0.94 ng/mL, respectively. The cut-off value by naked eyes was 10.0 ng/mL. The cross-reaction rates with barbital, pentobarbital and amobarbital were less than 10%, indicating a good specificity of the proposed assay. Recovery test was done by using tilapia, grass carp, perch and shrimp sample and the recoveries ranged from 73.50% to 114.17% with RSDs below 15%. The results had a good agreement with those of UPLC-MS/MS. In conclusion, the proposed assay was accurate, sensitive, convenient and rapid. It can be suitable for rapid screening of phenobarbital residues in aquatic products of fish and shrimp.
    40  Determination of Magnolol and Honokiol from Magnolia officinalis Rehd. et Wils by HPLC-MS
    LYU Si-yu CHEN Chi YAN Xu WANG Wei-xiu HE Xing-yao JIAO Lu WANG Zhi-bing
    2020, 36(7):321-330. DOI: 10.13982/j.mfst.1673-9078.2020.7.1285
    [Abstract](324) [HTML](302) [PDF 71.05 M](818)
    Abstract:
    Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction combined with high performance liquid chromatography tandem mass spectrometry was established to extract magnolol and honokiol from Magnolia officinalis Rehd. et Wils. In this study, ionic liquid was used as the extraction solvent. After microwave-assisted extraction, the ion-pairing reagent, ammonium hexafluorophosphate (NH4PF6), was added to the obtained sample extract, and the target analytes were separated and enriched by homogeneous liquid-liquid microextraction, and analyzed qualitatively and quantitatively by high performance liquid chromatography-tandem mass spectrometry. In this study, the conditions affecting the extraction efficiency were optimized by single factor and response surface experiments. The experimental results showed a good linear relationship (R>0.9999) for the target analytes within the detection concentration range, with the limit of detection (LOD) and limit of quantitation (LOQ) being 17.2~23.9 ng/mL and 57.4~79.6 ng/mL, respectively, and the spiked recovery between 89.25% and 95.00%. Compared with the traditional ultrasonic extraction and reflux extraction methods, the present method has advantages in the amount of solvent used and extraction time, and can be used for the extraction of magnolol and honokiol in Chinese herbal medicine and related pharmaceutical products.
    41  Pesticide Residue Analysis and Dietary Risk Assessment of Watermelon in Different Habitats
    WEI Kai-li HUA Zhen-yu CAO Ye-qing TAO Yong-xia WANG Cheng
    2020, 36(7):331-337. DOI: 10.13982/j.mfst.1673-9078.2020.7.1238
    [Abstract](431) [HTML](206) [PDF 16.85 M](724)
    Abstract:
    To clarify the status of pesticide residues in different regions’ watermelons and distinguish the differences of pesticide residues, 80 samples of watermelons from Xingjiang, Shangdong and Guangxi were selected to indentify 60 kinds of pesiticide residue levels. Then, based on the vaterinary drug residue risk ranking method of the committee on veterinary drugs. Safety levels, the pesticide residues of watermelons from three places were assessed by risk assessment for acute and chronic dietary intake. The results showed that 11 kinds of pesticide residues were detected in the three producing areas and the types of pesticide residues were 6, 7, 8 in Xinjiang, Shandong, and Guangxi watermelons, respectively. The residue levels and the pesticide risk scores were all different. Pesticides triazophos, dichlorvos, prochloraz, anisole (24.60, 24.60, 18.30, 18.15) in Guangxi, pesticides anisole and trimethoprim (18.50, 18.10) in Shandong, and pesticides Phenylfenazol (18.20) in Xinjiang had relatively high risk scores. Acute and chronic dietary risk of the detected pesticides showed that the percentages of ADI and ARfD of all pesticide residues in watermelon ranged between 0.01% and 1.53%, 0.03% and 23.30%, respectively, which were far less than 100%. The pesticide residue types, residue levels and risk scores that detected in the three regions were different, and attention should be paid to the corresponding pesticides in the production area, although the levels of pesticide residues fall within the safety limit.
    42  Establishment of a General Method for the Determination of Lycopene and β-Carotene in Raw Materials of Lycopene and Health Food
    LI Bin YU Jia HOU Li-nan LIU Hui-jin HE Huan ZHANG Wei-qing WANG Hai-yan
    2020, 36(7):338-343. DOI: 10.13982/j.mfst.1673-9078.2020.7.0034
    [Abstract](267) [HTML](308) [PDF 44.34 M](901)
    Abstract:
    In this study, a universal method for determining the contents of lycopene and β-carotene in lycopene-containing raw materials and functional foods was established. In general, ordinary samples were dissolved directly in a dichloromethane solution containing 2, 6-di-tert-butyl-4-methylphenol (BHT solution), while the microencapsulated samples were firstly subjected to ultrasonic-assisted extraction with N,N-dimethyl formamide containing 2,6-di-tert-butyl-4-methylphenol, and then dissolved and diluted with BHT solution. High performance liquid chromatography was used for identification and analysis, and the separation and quantification of the target compounds were completed in 40 min. Under the experimental conditions, the degree of separation and the linear relationship of lycopene and β-carotene were satisfactory, with corresponding limits of detection being 0.08 μg/mL and 0.09 μg/mL, respectively. The relative standard deviations (RSDs) of lycopene and β-carotene for the ordinary samples were 3.20% and 3.01%, respectively. The RSD of lycopene in microencapsulated samples was 2.37%, and no β-carotene was detected. The recovery rate of lycopene in the two types of samples ranged from 92.65% to 107.49%, and that of β-carotene ranged from 94.73% to 105.12%. This method is stable, accurate, and adaptable, and can be essentially applied to the determination of almost all kinds of lycopene-containing raw materials and functional foods.
    43  Green Extraction Technology of Chitin from Shrimp Shells and Crab Shells: a Review
    YANG Xi-hong XIN Rong-yu SONG Lin DONG Ze-qun LI Yu-jin XIE Wan-cui
    2020, 36(7):344-350. DOI: 10.13982/j.mfst.1673-9078.2020.7.0856
    [Abstract](603) [HTML](771) [PDF 4.06 M](2048)
    Abstract:
    Chitin extraction requires the removal of proteins, minerals, lipids and pigments. Traditional methods have the disadvantages of high cost, environmental degradation. The method of extracting chitin by biological methods such as microbial fermentation, enzymatic or genetic engineering needs to be developed. The progresses of green extraction techniques such as chemical methods and biological methods using shrimp and crab shells as raw materials were reviewed in this paper. The advantages and disadvantages of biological methods such as microbial fermentation, enzymatic method and genetic engineering were analyzed, and the extraction of chitin from microbial fermentation was discussed. Microbial biotransformation and enzyme treatment utilize organic acids and proteases produced by fermentation, which are economical and efficient and easy to achieve large-scale production. It was proposed that the extraction of chitin by microbial fermentation has industrial potential. Finally, the progress of genetic manipulation and metabolic engineering in recent years was also expected. Therefore, the production of chitin by biological green extraction technology is environmentally friendly and efficient, and has important development prospects.

    Editor in chief:李琳

    Inauguration:现代食品科技

    International standard number:ISSN 1673-9078

    Unified domestic issue:CN 44-1620/TS

    Domestic postal code:46-349

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