+Advanced Search

Volume 38,Issue 9,2022 Table of Contents

  • Display Type:
  • Text List
  • Abstract List
    • 1  Effects of Genistein on PCOS-IR Rats through Adiponectin and RBP4 Pathway
    YANG Qi ,  DONG Jiaping ,  XIE Linlin ,  WANG Helin ,  LIU Shufan ,  CHI Xiaoxing
    2022, 38(9):1-9. DOI: 10.13982/j.mfst.1673-9078.2022.9.1245
    [Abstract](306) [HTML](200) [PDF 1.34 M](536)
    Abstract:
    A rat model of polycystic ovary syndrome with insulin resistance (PCOS-IR) was established by administering subcutaneous injections of dehydroepiandrosterone (DHEA) and human chorionic gonadotropin (HCG) and a high-fat diet to study the effects of genistein (Gen) on insulin resistance through adiponectin (APN) and retinol binding protein-4 (RBP4) pathways. Rats were randomly divided into the control group, model group, low-, medium-, and high-dose Gen treatment groups, and metformin treatment group according to their body weights. Each group had eight rats. After 21 days of continuous treatment, the levels of Fasting Blood Glucose (FBG), Fasting insulin (Fins), APN, and RBP4 were measured, and the expression of APN- and RBP4-related genes and proteins in the ovarian tissue was analyzed. The results showed that in comparison with the model group, the medium-dose Gen treatment group had a significantly decrease of 13.95% in the FBG. Fins levels of the medium- and high-dose Gen treatment groups decreased by 45.80% and 51.80%, respectively, as compared to the level in the model group. The insulin resistance index of the high-dose group significantly reduced by 57.20%. Serum APN and Adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1) levels of the medium-dose group were significantly higher by 69.43% and 36.57%, respectively, and RBP4 level of the high-dose group was significantly lower by 59.01% than those in the model group. The level of phosphoenolpyruvate carboxykinase (PEPCK) of the medium-dose group remarkably reduced by 22.63%. The gene and protein expression levels of APPL1, AMP-activated protein kinase (AMPK), and p-AMPK in the ovarian tissue of the medium- and high-dose groups considerably increased, but those of RBP4 and PEPCK significantly decreased. Thus, medium and high doses (20 and 30 mg/kg) of Gen can effectively improve glucose metabolism and insulin resistance in PCOS-IR rats through adiponectin and RBP4 pathways.
    2  Hypoglycemic Effects of the Extracts from Solanum melongena Peels in Diabetic Mice
    SUN Jing ,  WEI Jing ,  YANG Yang ,  CAI Ruyu ,  CHANG Shimin ,  TONG Litao ,  LIU Jiameng ,  LU Cong ,  TAO Ran ,  SUN Yufeng ,  FAN Bei ,  WANG Fengzhong ,  ZHANG Jingjian
    2022, 38(9):10-17. DOI: 10.13982/j.mfst.1673-9078.2022.9.1154
    [Abstract](295) [HTML](202) [PDF 544.69 K](505)
    Abstract:
    The hypoglycemic effect of Solanum melongena peels extract (SMPE) on diabetic mice was investigated. LC-QTOF-MS was employed to clarify the material basis of SMPE. Different concentrations of SMPE, and the positive control, the drug acarbose, were used for in vitro experiments to conduct the α-glucosidase activity inhibition tests to determine the inhibition rate. In in vivo experiments, the diabetic mouse model was established through injecting alloxan intraperitoneally into mice, and the experimental mice were divided into 7 groups: the control group, normal administration group (normal mice were given 15 g/kg SMPE), SMPE high-dose group (SMPE 15 g/kg), SMPE medium-dose group (SMPE 5 g/kg), SMPE low-dose group (SMPE 2.5 g/kg), positive drug group (acarbose 1 g/kg), and model group. After continuous intragastric gavage for 4 weeks, the body weight, fasting blood glucose level, and glucose tolerance were measured. The results showed that the α-glucosidase inhibitory rate of 10 mg/mL SMPE was 49.13%, and SMPE at different concentrations inhibited α-glucosidase in a dose-dependent manner. SMPE had no effect on body weight and fasting blood glucose in normal mice. Compared with the model group, the body weights of the SMPE low-, medium-, and high-dose groups increased by 20.34%, 23.91%, and 15.20%, respectively, and the fasting blood glucose values decreased by 5.97%, 11.91%, and 42.20%, respectively. SMPE exhibited a significant hypoglycemic effect in diabetic mice, and the underlying mechanism may be related to the abilities of SMPE to inhibit the activity of α-glucosidase and delay the intestinal absorption of glucose.
    3  Improving the Bioavailability of Algal-derived Astaxanthin by Adding Inulin
    LI Chunjun ,  GAO Yuan ,  HUAN Yuchen ,  XU Jie ,  XUE Changhu ,  TANG Qingjuan
    2022, 38(9):18-26. DOI: 10.13982/j.mfst.1673-9078.2022.9.1254
    [Abstract](214) [HTML](232) [PDF 1.46 M](442)
    Abstract:
    Three different prebiotics (inulin, fructose-oligosaccharide, and oligo-chitosan) were added to the diets of mice to explore their effects on the digestion and absorption of astaxanthin. The results showed that inulin and oligo-chitosan had no significant effects on the bioaccessibility of algal-derived astaxanthin (p>0.05), whereas fructose-oligosaccharide reduced its bioaccessibility (p<0.01). The bioavailability of algal-derived astaxanthin could be reasonably improved with inulin supplementation. In comparison with the control group, the inulin-treated group showed a significant increase of 36.37% in the area under curve (AUC) of astaxanthin in the liver. The content of short-chain fatty acids (SCFAs) also significantly increased (p<0.05) in the feces of the mice from the inulin-treated group. In particular, the level of acetic acid increased by 139.54% and that of propionic acid increased by 40.04%. 16SrRNA amplicon sequencing results indicated that the relative abundance of Dubosiella and Akkermansia in the insulin-treated group increased by 70.55% and 83.33%, respectively. In conclusion, dietary inulin supplementation may improve the absorption and utilization of algal-derived astaxanthin in the body by changing the composition of intestinal flora. The results of this study highlight a new idea for improving the bioavailability of astaxanthin and provide scientific and technological support for the development of astaxanthin products.
    4  Regulation of Flaxseed Oil on Inflammatory Cell in Rats with Polycystic Ovary Syndrome
    WANG Ting ,  LI Yiwei ,  LIU Yuanyuan ,  YU Wenwen ,  HU Funing ,  LUO Xiaojing ,  LU Yinan ,  ZHANG Xiaoxia ,  WANG Hao
    2022, 38(9):27-37. DOI: 10.13982/j.mfst.1673-9078.2022.9.1425
    [Abstract](237) [HTML](256) [PDF 3.95 M](541)
    Abstract:
    The regulatory effects of alpha-linolenic acid (ALA)-rich flaxseed oil (FO) on myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and macrophages (Mψs) in a rat model of letrozole-induced polycystic ovary syndrome (PCOS) were investigated. Changes in the estrous cycle were also monitored every day. After successful model establishment, the FO control group and FO-treated model group were administered FO via gavage feeding for 8 w, whereas the negative control group and model group were administered the same as well as Mψs, M1 Mψs and M2 Mψs in ovary of rats in diverse groups were respectively detected by flow cytometry; the expression of Mψs amount of normal saline. After 8 w of treatment, the percentages of MDSCs in the peripheral blood, spleen, and bone marrow, those of Tregs in the peripheral blood and spleen, and those of Mψs, M1 Mψs, and M2 Mψs in the ovaries of rats in all four groups were evaluated using flow cytometry. The expression of Mψs in the ovarian tissues was determined using immunofluorescence staining. According to the results, letrozole-induced PCOS was successfully established in the rats. Moreover, dietary FO treatment significantly increased the percentages of MDSCs in the peripheral blood, spleen, and bone marrow to 25.87%, 5.63%, and 28.36%, respectively. Additionally, the percentages of Tregs in the peripheral blood and spleen were increased to 2.06% and 1.07%, respectively (p<0.05). By contrast, the percentages of ovarian Mψs and M1 Mψs had declined to 13.51% and 2.27%, respectively, whereas the fluorescence intensity of ovarian Mψs had decreased to 1.59% (p<0.05). Our results indicate that dietary ALA-rich FO supplementation may ameliorate PCOS by recruiting MDSCs in the peripheral blood, spleen, and bone marrow; increasing Tregs in the peripheral blood and spleen; and suppressing Mψ proliferation and M1 Mψ polarization in the ovaries.
    5  The Protective Effect of Petroleum Ether Extract from Ficus carica Latex on Endothelial Cells Damaged by High Glucose
    LI Baohong ,  LI Zhongyuan ,  LIU Miaomiao ,  NI Wenting ,  YIN Yiming ,  ZHAO Fangshu ,  TIAN Jingzhen ,  ZHANG Xiaoping ,  CUI Qinghua
    2022, 38(9):38-45. DOI: 10.13982/j.mfst.1673-9078.2022.9.1318
    [Abstract](186) [HTML](210) [PDF 3.90 M](488)
    Abstract:
    Different polar concentrations of Ficus carica latex were obtained by systematic solvent extraction, and a high glucose human umbilical vein endothelial cell (Huvec) model was established. The MTT assay, scratch test, Transwell invasion test, apoptosis detection by flow cytometry, angiogenesis test, and ELISA were used to investigate the detrimental effects and mechanism of action of high glucose on Huvec and the protective effect of Ficus carica latex. The rate of proliferation, migration, and invasion of Huvec decreased to 76.04%, 28.36%, and 22.09% (p<0.001), respectively. The rate of apoptosis increased to 24.23% (p<0.001), and angiogenesis decreased in 48 h under a high glucose environment. Contents of lactate dehydrogenase (LDH), vascular endothelial growth factor (VEGF), and endothelin-1 (ET-1) increased to 20.96 μg/L, 90.03 ng/L, and 839.41 ng/L (p<0.01), respectively. The concentration of superoxide dismutase (SOD), nitric oxide (NO), and endothelial nitric oxide synthase (eNOS) decreased to 3.52 μg/L, 184.75 μmol/L, and 0.59 IU/mL (p<0.01), respectively. The extracts of petroleum ether from Ficus carica latex (100, 200, and 400 mg/L) increased the proliferation, migration, and invasion of Huvec; reduced the rate of apoptosis (p<0.001); and restored disturbed vascular blood flow. Petroleum ether extract of Ficus carica latex can reduce Huvec damage caused by high levels of glucose, demonstrating an obvious protective effect.
    6  Antitumor Activity of Ganoderma Spore Oil-lycopene Complex
    JING Ziliang ,  WU Chunyu ,  ZHANG Huimin ,  SUN Jianbo
    2022, 38(9):46-51. DOI: 10.13982/j.mfst.1673-9078.2022.9.1160
    [Abstract](260) [HTML](208) [PDF 757.50 K](645)
    Abstract:
    The in vitro and in vivo antitumor activities of Ganoderma lucidum spore oil-lycopene complex (LZFQ), and its mechanism of action in A549 cells were investigated. The MTT method was used to measure the viability of human non-small cell lung cancer cells (A549), human gastric cancer cells (BGC823), human breast cancer cells (MCF-7) and human colon cancer cells (HCT116). A nude mouse transplanted tumor model was established to study the in vivo inhibitory effect of LZFQ on tumor. The changes in apoptosis and the expression of apoptosis-related proteins were examined by flow cytometry, and its anti-tumor mechanism was preliminarily explored. In vitro cell viability experiments showed that LZFQ had certain inhibitory effects on the growth of four kinds of tumor cells, with its inhibition on A549 cells being the greatest (IC50=0.49 mg/mL). Flowcytometry experiments showed that LZFQ could induce apoptosis in a concentration-dependent manner. Western blot experiments showed that LZFQ could reduced the level of anti-apoptotic protein Bcl-2 and increased the levels of pro-apoptotic proteins Bax and Caspase-3 in a concentration-dependent manner. The nude mice transplanted tumor experiments showed that when LZFQ was administered at doses of 2.00 g/kg (high dose group), 1.00 g/kg (medium dose group) and 0.50 g/kg (low dose group), the inhibition rates of transplanted tumor in nude mice were 60.58%, 51.92% and 43.27% respectively, with significant differences detected between the high-/medium-/low-dose groups and the model group (p<0.01). Mechanism studies showed that LZFQ could induce apoptosis in a concentration-dependent manner, and induce apoptosis by affecting the expressions of apoptosis-related proteins. The research results show that LZFQ has a certain anti-tumor effect, which can provide an experimental basis for the research and development of Ganoderma lucidum spore oil products.
    7  Lipid-lowering Effect of Lactobacillus fermentum Isolated from Naturally Fermented Dough in Mice Fed a High-fat Diet
    LI Hui ,  LI Xiaolin ,  LI Jinlong ,  LI Baoling ,  LIU Wenjun ,  SHI Xinrui
    2022, 38(9):52-59. DOI: 10.13982/j.mfst.1673-9078.2022.9.1283
    [Abstract](143) [HTML](185) [PDF 841.87 K](479)
    Abstract:
    Lactic acid bacteria (LAB) were isolated and purified from naturally fermented dough obtained from farmers in the areas surrounding Harbin. The tolerance capacities of LAB were evaluated under acidic pH and bile salt conditions. The antimicrobial capacities of the isolated strains were evaluated using a bacteriostatic test, and the safety of LAB was evaluated using hemolytic and antibiotic sensitivity tests. The cholesterol-lowering ability of the isolates was further analyzed using the ortho-phthalaldehyde method in vitro, and the cholesterol-lowering function was studied using a high-fat diet mouse model. The results showed that a total of 16 LAB strains were isolated, among which the survival rate of Lactobacillus fermentum FD-8 was 80.21% and 75.98% under acidic and bile salt conditions, respectively. FD-8 had certain bacteriostatic activity and good safety against pathogenic Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium. The cholesterol degradation rate of FD-8 reached 85.66% in vitro. FD-8 intervention in the high-fat diet mouse model showed that after feeding FD-8 for 5 weeks in vivo, this strain could significantly reduce the body weight and liver indexes to alleviate obesity in the mice. FD-8 also significantly regulated the variations induced by the high-fat diet in TC, TG, and LDL levels in the serum and liver of the mice, and thus achieved the goal of reducing blood lipid levels. To summarize, the results indicated that L. fermentum FD-8 isolated from naturally fermented dough has good tolerance to acid and bile salts as well as good antibacterial property, and can play a role in cholesterol-lowering in vitro and in vivo, which is of great significance for the development of cholesterol-lowering products in the future.
    8  Effects of Wild Rosa roxburghii Juice from Different Altitudes in Guizhou on Glycolipid Metabolism and Oxidative Stresses in Type 2 Diabetic Mice
    CHEN Zhen ,  REN Tingyuan ,  TAN Shuming
    2022, 38(9):60-70. DOI: 10.13982/j.mfst.1673-9078.2022.9.1231
    [Abstract](245) [HTML](204) [PDF 1.55 M](541)
    Abstract:
    To investigate the therapeutic effects of Rosa roxburghii juice from different altitudes on the glycolipid metabolism and oxidative damages in mice with type 2 diabetes mellitus (T2DM), T2DM mouse models were established using high fat and high sugar diets combined with streptozotocin (STZ). The mice were divided into the blank group (NC), the model group (MC), the high-altitude R. roxburghii juice-treated group (HF), the medium-altitude R. roxburghii juice-treated group (MF), the low-altitude R. roxburghii juice-treated group (DF) and the control group (PC), each of which contained 10 mice. The feed intake, water intake, body weight, and fasting blood glucose (FBG) of the mice were measured during the 28 day intervention, which was followed by dissection to measure the glucose tolerance and the glycosylated serum protein (GSP) and glycosylated hemoglobin (GHb) contents. In addition, the total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) contents in the serum, kidney and liver were determined. The liver tissues from each group were observed by hematoxylin & eosin (HE) staining. The results show that all-altitude R. roxburghii juice reduces the FBG, GSP, GHb, TG, TC, LDL-C, and MDA contents, but increases the CAT, SOD, and GSH-Px activities and the HDL-C level. Compared with those in the MC group, the liver CAT, SOD, and GSH-Px activities in the HF group increase by 151.27%, 63.79%, and 67.46% respectively. HE staining results demonstrate that liver tissue damages are alleviated in all R. roxburghii juice-treated groups. The results indicate that Rosa roxburghii juice from all altitudes can, to a certain degree, improve glycolipid metabolism disorder and oxidative stress homeostasis in T2DM mice.
    9  In Vitro Antioxidant and Anticancer Properties of Dehydroepiandrosterone from Sweet Potato
    CHEN Pengfeng ,  ZOU Haofeng ,  HUANG Shirong ,  CAI Fang ,  SUI Yong ,  XIONG Tian ,  SHI Jianbin ,  CAI Sha ,  CHEN Xueling ,  MEI Xin
    2022, 38(9):71-79. DOI: 10.13982/j.mfst.1673-9078.2022.9.1171
    [Abstract](154) [HTML](171) [PDF 2.92 M](484)
    Abstract:
    In this study, sweet potato was selected as the raw material, dehydroepiandrosterone (DHEA) was prepared by Aspergillus oryzae fermentation. The in vitro antioxidant, anti-aging, hypoglycemic and anticancer effects of the DHEA extract from the fermented sweet potato before and after purification were examined. The results showed that the retention time was 11.21 min and the peak area was accounted for 76.44% when the sweet potato DHEA extract was purified by silica gel adsorption. With the increase of concentration, the scavenging abilities for DPPH, ABTS and hydroxyl radicals and the total reducing ability of the DHEA extract before and after purification increased significantly (p<0.05), and reached the maximum at 0.10 mg/mL. The α-amylase activity inhibitory rates of the purified DHEA extract ranged from 2.16% to 55.54%, and reached the maximum at 0.80 mg/mL. The tyrosinase activity inhibitory rates of the purified DHEA extract were in the range of 5.55%~50.57%, and reached the maximum at 0.10 mg/mL. The purified DHEA extract only exhibited a significant inhibitory effect against the breast cancer cell MCF-7 at a concentration of 2.30 mmol/L (p<0.05), with the inhibition rate being 47.50%. But the purified DHEA extract had insignificant effects against lung cancer cell A549 and cervical cancer cell Hela (p>0.05). This study provides a reference for the development of functional foods using sweet potato DHEA, which is conducive to the development of sweet potato natural products.
    10  Immune-regulatory Functions and Safety of Chewable Ginseng-Fritillary Bulb Tablet
    ZHANG Tingting ,  YE Zi ,  WANG Meng ,  ZHAO Fan ,  YI Yanglei
    2022, 38(9):80-91. DOI: 10.13982/j.mfst.1673-9078.2022.9.1217
    [Abstract](213) [HTML](204) [PDF 1.30 M](477)
    Abstract:
    In this study, the immune-regulatory functions and safety of chewable Ginseng-Fritillary bulb tablets were evaluated in vivo. For the immune-regulatory function evaluation, Kunming mice were administered chewable Ginseng-Fritillary bulb tablets by oral gavage at daily doses of 1.20, 0.80, and 0.40 g/kg (measured by body weight of mouse) for 30 days, and then body weight, organ/body weight ratio, cellular immunity, humoral immunity, monocyte-macrophage function and NK cell activity were measured. To assess the safety of the tablets, the acute toxicity, genotoxicity (via the Ames test, the bone marrow micronucleus test and the mouse sperm malformation test), and the 30-day feeding test were performed by using SD rats under a dose of 20.00 g/kg. The results show that the chewable Ginseng-Fritillary bulb tablets at all tested doses have no significant effects on the body weight and the lymphoid organ/body weight ratio of mice. In the high-dose group (1.20 g/kg), the tablets could significantly induce the delayed-type hypersensitivity (DTH) in mice and increase the number of antibody-producing cells, the macrophage phagocytosis index (7.04), and the serum hemolysin level (p<0.5). Furthermore, the safety evaluation results suggest that the tablets have no significant effects on the body weight, food intake, food utilization rate, hematological indices, blood biochemical indices and organ coefficients of mice. In addition, under the tested doses, no significant mutation or abnormality in the micronucleus formation of bone marrow cells and sperm cells were observed. In conclusion, the chewable Ginseng-Fritillary bulb tablets can enhance immunity reasonably safely.
    11  Lycium barbarum Cyclic Peptide Regulates NLRP3 and NF-κB Signaling Pathways to Reduce BaP-Induced Inflammatory Airway Epithelial Cell Injury
    ZHAO Chuanxin ,  LI Yeting ,  BU Fanli ,  ZHENG Man
    2022, 38(9):92-99. DOI: 10.13982/j.mfst.1673-9078.2022.9.0835
    [Abstract](166) [HTML](192) [PDF 1.58 M](586)
    Abstract:
    In this study, Lycium barbarum L. bioactive peptide (LBP) was isolated by the activity tracking method, and its activity against benzopyrene (BaP)-induced airway epithelial cell injury and the potential underlying mechanism were investigated. The cytotoxicity of LBPs was examined by the CCK-8 method; The inhibitory effects of LBP-1 against BaP-induced secretion of inflammatory factors (TNF-α, IL-1β, IL-6, IL-18, NO and PGE2) in human bronchial epithelial cells (16-HBE cells) were examined by ELISA; Western Blot method was used to examine the effects of LBP-1 and BaP on the expressions of COX-2, iNOS, NLRP3 inflammasomes and NF-κB signaling pathway-related proteins in 16-HBE cells. The results showed that LBP-1 could significantly reduce the decrease of 16-HBE cell viability caused by BaP exposure, and there was insignificant cytotoxicity when the concentration was lower than 1 mmol/L; LBP-1 decreased BaP exposure-induced increase in the secretion of cytokines, and the concentrations of TNF-α, IL-1β, IL-6, IL-18, NO and PGE2 decreased by 34.93%, 27.41%, 31.05%, 35.28%, 51.15% and 27.46% respectively, while the expressions of the key enzymes (COX-2 and iNOS) of PGE2 and NO decreased by 81.72% and 41.70% respectively; Western Blot results showed that LBP-1 could inhibit the phosphorylation of IκBα and p65, reduce the expressions of NLRP3 and apoptosis-associated speck-like protein containing CARD (ASC), thereby inhibiting the activation of NLRP3 and NF-κB signaling pathways. The above results confirmed that LBP-1 could play a role in counteracting BaP-induced inflammatory airway epithelial cell injury through regulating the expressions of inflammatory cytokines and NLRP3 and NF-κB signaling pathway-related proteins.
    12  Immunomodulatory Effect of Physalis pubescens L. Fruit Extract in RAW264.7 Cells
    WANG Jian ,  WANG Ping
    2022, 38(9):100-110. DOI: 10.13982/j.mfst.1673-9078.2022.9.1106
    [Abstract](167) [HTML](224) [PDF 1.83 M](598)
    Abstract:
    To investigate the immunomodulatory effect of Physalis pubescens L. fruit extract (PPFE) in RAW264.7 cells, the cytotoxicity and proliferative activity were determined by the thiazole blue colorimetric method (MTT). Griess assay, enzyme-linked immunosorbent assay (ELISA), fluorescent probe technique and neutral red phagocytosis assay were used to measure the contents of nitric oxide (NO), tumor factor-α (TNF-α), IFN-γ, IL-6 and reactive oxygen species (ROS) as well as the phagocytosis rate. The changes in cell cycle and apoptosis were measured by flow cytometry, and the mRNA expression levels of cytokines such as TNF-α, IFN-γ and IL-6 were determined by fluorescence quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results showed that UHPLC-Q-TOF-MS was used to determine the chemical composition of PPFE, and a total of 14 flavonoids were identified. The safe concentration of PPFE for RAW264.7 cells was in the range of 25~250 μg/mL. Compared with the blank group, the immunoenhancing effect was the strongest at 25 μg/mL, with the corresponding cell proliferation rate, content of released NO, phagocytosis rate, relative ROS level, and contents of secreted TNF-α, IFN-γ and IL-6 were 130.53%, 27.79 μmol/L, 189.88%, 137.75%, 150.54 pg/mL, 119.36 pg/mL, 15.41 pg/mL, respectively. The percentages of G0/G1 phase, S phase and G2/M phase of the cell cycle were 53.08%, 17.40%, and 29.52%, respectively. Compared with the blank group, the apoptosis rate was reduced by 52.80%, while the expressions of TNF-α, IFN-γ and IL-6 were significantly up-regulated (p<0.01) for the PPFE treated group. In summary, PPFE can enhance the immunomodulatory effect of RAW264 cells by regulating the phagocytosis, secretion of immune factors, cell cycle distribution and apoptosis, as well as up-regulating the mRNA expression levels of cytokines.
    13  Heterologous Expression and Enzymatic Properties of Recombinant β-Galactosidase from Microbulbifer sp. ALW1
    TANG Guijun ,  LI Hebin ,  ZHU Yanbing ,  JIANG Zedong ,  NI Hui ,  LI Qingbiao ,  CHEN Yanhong
    2022, 38(9):111-118. DOI: 10.13982/j.mfst.1673-9078.2022.9.1035
    [Abstract](213) [HTML](215) [PDF 3.65 M](551)
    Abstract:
    β-Galactosidase, which catalyzes the hydrolysis of lactose into glucose and galactose, is one of the most important enzymes used in dairy processing. In this study, the β-galactosidase from Microbulbifer sp. ALW1 was heterologously expressed and purified in Escherichia coli BL21 (DE3), and the enzymatic properties of the purified enzyme were examined. The results showed that the β-galactosidase from Microbulbifer sp. ALW1 belonged to the glycoside hydrolase (GH) family 1. The recombinant β-galactosidase obtained by Ni-NTA agarose affinity chromatography had a molecular weight of 64 ku. The optimal reaction temperature and pH of the recombinant β-galactosidase were 30 ℃ and 4.5, respectively. The β-galactosidase exhibited good stability when the temperature was lower than 25 ℃ and pH was in the range of 4.0~5.0. The recombinant β-galactosidase had good tolerance to DTT, Tween 20, and Tween 80. In the presence of ionic detergents, SDS and CTAB, β-galactosidase almost lost its activity. The catalytic constants Km and Vmax of the recombinant β-galactosidase were 10.98 mmol/L and 7.48 U/mg, respectively. Structure simulation studies revealed that the catalytic acid/base residue was Glu186 and the nucleophilic residue was Glu370 for the β-galactosidase from Microbulbifer sp. ALW1. The results layed a theoretical foundation for the applications of β-galactosidase from Microbulbifer sp. ALW1 in the food field.
    14  Growth Characteristics of a Nitrite-degrading Lactobacillus plantarum and Its Application in Pickle Production
    LIU Wei ,  QIU Chongshun ,  HE Yuxing ,  TA Na ,  LIANG Chengyuan ,  ZHANG Enxin ,  Wuyundalai
    2022, 38(9):119-125. DOI: 10.13982/j.mfst.1673-9078.2022.9.1264
    [Abstract](206) [HTML](205) [PDF 693.45 K](527)
    Abstract:
    The application of nitrite-degrading Lactobacillus plantarum 36 in pickle production was evaluated by determining its growth characteristics using the naphthalene ethylenediamine hydrochloride and plate counting methods. The results showed that strain 36 had the largest number of viable bacteria (9.49 lg CFU/mL) after 12 h culture and exhibited strong acid and salt tolerance. The pH value of pickle prepared under natural fermentation decreased to 3.42 on day 7, whereas that of the test group using strain 36 dropped to 3.34 on day 3. The total acid content peaked and became stable on day 7 for the natural fermentation group, whereas that of the test group peaked (6.16 g/kg) and stabilized on day 5. Hence, the treatment shortened the pickle production cycle. The nitrite content in the natural fermentation group reached 2.10 mg/kg on day 9, whereas that of the test group remained at approximately 1.13 mg/kg by day 9, which was significantly lower than that of the natural fermentation group (p<0.05). This indicates that strain 36 can degrade the nitrite in the pickle reasonably well. The number of lactic acid bacteria reached a maximum on day 3 for the natural fermentation group (8.16 lg CFU/mL), but that of the test group reached the highest value on day 7 (9.95 lg CFU/mL) and was an order of magnitude higher than that of the natural fermentation group. Moreover, the sensory evaluation scores of the two groups of pickles was not significantly different (p>0.05). The findings on L. plantarum 36 in this study provide a theoretical basis for reducing the nitrite content in pickles and the stain is of practical significance in pickle production.
    15  Recombinant Expression of Glutaminase from Aspergillus oryzae in Aspergillus niger and Its Enzymatic Properties
    CHEN Ying ,  WANG Bin ,  PAN Li
    2022, 38(9):126-134. DOI: 10.13982/j.mfst.1673-9078.2022.9.0652
    [Abstract](210) [HTML](160) [PDF 1.16 M](543)
    Abstract:
    In this study, glutaminase (Gahb) from Aspergillus oryzae RIB40 was recombinantly expressed in Aspergillus niger. Based on the high-throughput screening method (phenotypic identification plate and pore plate culture) established in this study, the transformant of the recombinant glutaminase H-GahB was successfully obtained, and its highest enzyme activity was 1.35 U/mL. In order to increase the copy number of the target gene in the host, was reconstructed a high-copy glutaminase expressing strain C-GahB using the CRISPR/cas9 genome editing technology, and its enzyme activity increased to 3.56 U/mL (about 2.64 times that of H-GahB). Furthermore, C-GahB was subjected to traditional mutagenesis and breeding using ARTP mutagenesis technology, and an engineering strain of glutaminase, A-GahB, was obtained, with its enzyme activity upto 4.16 U/mL (0.17 times higher than that of the starting strain C-GahB). The specific enzyme activity of the purified recombinant GahB reached 40.63 U/mg, with the optimum temperature being 37 ℃ and the optimum pH being 7.0. The purified enzyme showed good stability from 20 ℃ to 40 ℃ and from pH 5.5 to 8.0. K+ could activate the enzyme activity of GahB, while Zn2+ and Mn2+ could strongly inhibit the enzyme activity of GahB. When the salt concentration was 18%, GahB showed a relative enzyme activity of 35.38%. In this study, glutaminase GahB from A.oryzae RIB40 was recombinantly expressed in A. niger for the first time, which provides a basis for subsequent investigations on the glutaminase from A. oryzae.
    16  Comparative Analysis of the Structural and Physicochemical Properties of Different Proteins in Lotus Seeds
    SUN Qian ,  HUANG Minli ,  ZENG Muhua ,  LIU Sidi ,  GUO Zebin
    2022, 38(9):135-142. DOI: 10.13982/j.mfst.1673-9078.2022.9.1292
    [Abstract](216) [HTML](281) [PDF 1.85 M](653)
    Abstract:
    Lotus seed protein isolates and lotus seed fractionated proteins (albumin, globulin, prolamin, glutenin) were extracted, and the solubility, emulsification, molecular properties, and structural properties were compared. The results showed that protein in lotus seeds accounts for about 16.14% of the total dry weight, and the proportion of four graded proteins was about 55:6:0.1:25. Respectively, compared with the five different lotus seed proteins, The solubility of albumin was the highest, the Zeta potential had the lowest value of -21.3 mV, the particle size had the minimum value of 75.47 μm, and the emulsification of the isolated protein was the best. The isoelectric points of five different proteins were all around 4.9. Spectroscopic studies have shown that gliadin and glutenin fluoresce more strongly, the content of albumin and globulin α-helix was lower, while the content of gliadin and glutenin β-turn was higher. These results also indicate that the molecular flexibility of albumin and globulin is higher, which is closely related to solubility, ability to emulsify, and hydrophobicity. The experiments revealed the active structural relationship between the physicochemical properties and molecular structure of lotus seed protein isolates and fractionated proteins. This provides a theoretical basis for the further study of the functional properties of lotus seed protein.
    17  Effects of High-temperature and High-pressure Steam on Physicochemical and Nutritional Properties of Rice Bran
    PAN Bihui ,  WEI Zhencheng ,  DENG Yuanyuan ,  ZHANG yan ,  TANG Xiaojun ,  LIAO Na ,  LIU Guang ,  ZHANG Mingwei
    2022, 38(9):143-152. DOI: 10.13982/j.mfst.1673-9078.2022.9.1224
    [Abstract](176) [HTML](320) [PDF 1.65 M](630)
    Abstract:
    In order to investigate the effects of high-temperature and high-pressure steam on the properties of rice bran, different high-temperature (121 ℃) and high-pressure steaming treatment durations were investigated. Lipase activity, physical properties (viscosity, chromaticity and microstructure), nutritional composition (soluble protein content, crude fat content and composition) and phytochemical composition (contents and activities of phytic acid, γ-oryzanol, phenolics) were determined. The results showed that the loss rate of lipase activity reached 81.86% after 1 min of steaming, and longer treatment did not significantly increase the lipase activity loss rate. The viscosity of the rice bran decreased from 14.67 cP to 7.00 cP, and the color deepened as the treatment time increased. Meanwhile, the micro-structure of rice bran became denser after treatment. The soluble protein content of rice bran decreased by 71.89%, while the extraction rate of crude fat increased by 5.94% after 1 min of steaming. The contents of phytic acid, γ-oryzanol and bound phenolics are not affected by steaming. However, the content of free phenols in rice bran reduces from 0.51% to 0.46%, and its ORAC (oxygen radical absorbance capacity) antioxidant activity decreases from 183.20 µmol TE/g DW to 149.22 µmol TE/g DW. The results revealed that 1 min high-temperature and high-pressure steaming at 121 ℃ is the optimal treatment for rice bran. These findings provide a theoretical guidance for the application of high-temperature and high-pressure steam in rice bran processing.
    18  Inhibitory Effect of Dihydromyricetin on Rice Starch Retrogradation
    ZHONG Xiaoyu ,  YANG Zhiwei
    2022, 38(9):153-158. DOI: 10.13982/j.mfst.1673-9078.2022.9.1362
    [Abstract](175) [HTML](184) [PDF 1.63 M](411)
    Abstract:
    Starch is the main ingredient in rice, and the quality and shelf life of rice products are directly affected by its retrogradation degree. Dihydromyricetin (DMY), a polyphenolic compound, was added to rice starch to improve the retrogradation properties of rice starch. The effects of different amounts of DMY on the solubility, expansion, retrogradation enthalpy, and microstructure of rice starch were investigated, and the interaction between DMY and rice starch was analyzed. With the addition of DMY, the solubility of rice starch increased from4.49%to12.83%, and expansion decreased from 11.41% to 10.12%. The starch surface changed from a compact to a loose and porous structure. The FT-IR ratio of 1 047 cm-1/1 022 cm-1 decreased from 0.87 to 0.78. Compared with rice starch without DMY, a low concentration of DMY significantly affected the retrogradation characteristics of rice starch. When the amount of DMY was 5%, the retrogradation enthalpy, retrogradation rate, and relative crystallinity of rice starch decreased by 68.75%, 71.86%, and 59.07%, respectively. In general, rice starch retrogradation was inhibited by DMY. Therefore, DMY can be used to regulate the retrogradation of starch-based foods during the processing of starch products.
    19  Grass Carp Scale Collagen Peptide Preparation by Ultrasound-assisted Enzymatic Hydrolysis and Their Physicochemical Property Evaluation
    ZHAO Yu ,  YU Xiaoyue ,  XIONG Zhe ,  QIN Zibo ,  WANG Xibo ,  RONG Jianhua ,  XIONG Shanbai ,  HU Yang
    2022, 38(9):159-170. DOI: 10.13982/j.mfst.1673-9078.2022.9.1227
    [Abstract](228) [HTML](188) [PDF 1.89 M](496)
    Abstract:
    Collagen peptides were extracted from grass carp scales by ultrasound-assisted enzymatic hydrolysis to explore the effects of ultrasonic power (0~600 W) and duration (0~40 min) on the yield, degree of hydrolysis, and physicochemical properties of the collagen peptides obtained. Alkaline proteinase, compound proteinase, and neutral protease were used during single-enzyme enzymatic hydrolysis. Ultrasound treatment significantly influenced the yield. However, the degree of hydrolysis and nitrogen yield initially increased and then decreased upon ultrasound application. In particular, 300 W ultrasound treatment for 20 min during alkaline protease-mediated hydrolysis increased the degree of hydrolysis from 5.37% to 7.27%. In addition, a 10 min 300 W ultrasound treatment during step-wise enzymatic hydrolysis with alkaline protease and flavourzyme, increased the degree of hydrolysis from 9.26% to 11.05%. Ultrasound also influences the molecular weight distribution and amino acid composition of the products. The molecular weight of the products was mainly within 500 and 1000 u. The content of collagen peptides extracted by single-enzyme enzymatic hydrolysis increased from 24.26% to 33.99%, while the content of collagen peptides prepared by step-by-step enzymolysis increased from 31.99% to 39.28%. Meanwhile, the amino acid content of products from single-enzyme enzymatic hydrolysis and step-by-step enzymolysis increased from 66.30 g/100 g to 73.75 g/100 g and 66.05 g/100 g to 70.70 g/100 g, respectively. Furthermore, ultrasound treatment also significantly affected the emulsification performance, foaming capability, and foam stability of the products. To sum up, single-enzyme hydrolysis can be optimized by 20 min 300 W ultrasound treatment during alkaline protease hydrolysis, while step-by-step enzymolysis can be optimized by 10 min 300 W ultrasound treatment during alkaline protease hydrolysis and another 10 min 300 W treatment during flavourzyme hydrolysis.
    20  Physicochemical Characteristics of Polygonatum sibiricum Root and Evolution of Its Polysaccharide Components during the Nine-steam-nine-bask Process
    ZHANG Fan ,  ZHONG Weihua ,  LYU Chunqiu ,  LIANG Qinmei ,  WANG Jie ,  LIN Ying
    2022, 38(9):171-180. DOI: 10.13982/j.mfst.1673-9078.2022.9.1184
    [Abstract](220) [HTML](211) [PDF 2.31 M](735)
    Abstract:
    Sensory evaluation combined with colorimeter, gas chromatography-mass spectrometry, electronic tongue and scanning electron microscope were used to describe the "color, aroma, taste and shape" of Polygonatum sibiricum root. The molecular weight distribution, monosaccharide composition and structure of the polysaccharides were analyzed by size exclusion gel chromatography, ion chromatography and Fourier transform infrared spectroscopy. The results showed that during the steaming process, the Polygonatum sibiricum root changed from yellowish white to dark brown. The bitterness score and sweetness score decreased, and the bitterness appeared after being steamed five times. Internal pores appeared during the second steaming, with the tissue structure changing from dense to loose and porous. The molecular weight of polysaccharide in the raw Polygonatum sibiricum root was about 12.8 ku. The molecular weight distribution of the Polygonatum sibiricum root polysaccharides increased after the nine-steam-nine-dry-bask process, leading to the presence of fractions containing components with molecular weights greater than 670 ku and around 2 000 u. D-ribose and galacturonic acid were found in the monosaccharides from the Polygonatum root steamed once, whilst the glucuronic acid and fucose disappeared after the third and fourth steaming, respectively. The IR spectra showed relatively strong characteristic absorption at 3 410 cm-1 and 2 930 cm-1 for the polysaccharides from the Polygonatum root steamed for 0~9 times, and the absorption peaks at 1 200~1 000 cm-1 and 880 cm-1 indicated the occurrence of pyranose and β-glycosidic bonds in the polysaccharides. Investigations on the development of the physicochemical quality of Polygonatum root and the changing trend of its polysaccharide during the nine-steam-nine-bask process allow us to provide a reference for the standardization of nine-steam-nine-bask process and the establishment of quality standards.
    21  Quality Changes and Shelf-life Prediction of Self-heating Food Products: A Case Study of Stir-fried Chicken with Bamboo Sprouts
    FU Feng ,  FAN Huiping ,  HUANG Zhongmin ,  PAN Zhili ,  HOU Bingjie
    2022, 38(9):181-189. DOI: 10.13982/j.mfst.1673-9078.2022.9.1185
    [Abstract](193) [HTML](197) [PDF 493.39 K](494)
    Abstract:
    In order to explore the quality change and shelf-lives of self-heating food products during storage and to predict the shelf-lives of these products, self-heating stir-fried chicken with bamboo sprouts was researched as an example. The color, texture, acid value, peroxide value and malondialdehyde content were used as evaluation indicators. The quality changes of self-heating stir-fried chicken with bamboo sprouts at different storage temperatures (52 ℃ and 62 ℃) were studied and shelf-life was predicted using the accelerated shelf-life test. As the storage temperature increased, the quality deterioration became more rapid. At a storage temperature of 62 ℃, the hardness of the bamboo shoot and the bamboo tip decreased by 74.50% and 70.31%, respectively, after 84 days. Similarly, at a storage temperature of 52 ℃, the hardness of the bamboo shoot and the bamboo tip reduced by 67.37% and 60.87%, respectively, after 112 days. The sensory score of self-heating stir-fried chicken with bamboo sprouts dropped to 62.6 on the 112th day when stored at 52 ℃, and to 52.8 on the 84th day when the storage temperature was 62 ℃. In general, the quality indicators of self-heating stir-fried chicken with bamboo sprouts exhibited more rapid changes in the early stage of storage, and the rates of change alleviated as the storage time increased. According to the correlations between the measured indices and the sensory scores during storage, the model predicted that the shelf life at 25 ℃ is 714 days.
    22  Effects of Different Preservation Methods on Ascorbate Peroxidase Gene Expression and Phytohormone Content of Lycium chinense
    FANG Jie ,  LUO Yihao ,  SUN Wancheng
    2022, 38(9):190-197. DOI: 10.13982/j.mfst.1673-9078.2022.9.1037
    [Abstract](217) [HTML](225) [PDF 733.66 K](612)
    Abstract:
    In order to explore the mechanism of fresh Lycium chinense fruit preservation, fresh Lycium chinense fruits were subjected to preservation treatments, 75% etohanol solution, lactic acid coating, chitosan coating and modified atmosphere treatment. The changes of nutrients and the activities of related enzymes before and after preservation were determined, Real-time quantitative PCR (qRT-qPCR) technology was used to determine the relative gene expression of ascorbate peroxide (LcAPX) in Lycium chinense, while the hormone content of fresh Lycium chinense fruit after storage was determined. The effects of different treatments on the preservation of fresh Lycium chinense and the relative expressions of key genes were studied. The results showed that different treatments could significantly improve the fresh-keeping effect. Among them, the best preservation was with the chemical, the chitosan coating solution with a degree of deacetylation of 96.1% and a concentration of 1.5 g/L. The modified atmosphere treatment could maintain the sensory quality of fresh fruits and reduce the activities of related enzymes. In the meantime, the relative expression levels of LcAPX gene in the fresh Lycium chinense fruits subjected to preservation treatments were all lower than 1, with that being 0.35 (the best) for the modified atmosphere treatment. After storage, the content of auxin (ICAld) of the fresh fruit exhibited the largest increase (increased from 2.43 to 28.71), while the content of ABA increased from 3.59 to 18.10, which were all higher than those of the blank control group. The content of ethylene (ETH) decreased from 17.70 to 8.56, and the content of gibberellin (GA) decreased from 17.7 to 6.49, which were essentially consistent with the changing trends of hormones.
    23  Inhibition of Nitrosation in Dry-cured Bacon by Ginger Extract
    GU Ruxia ,  GE Fengqin ,  LIU Buyun ,  LI Feng ,  WANG Yongli
    2022, 38(9):198-205. DOI: 10.13982/j.mfst.1673-9078.2022.9.1319
    [Abstract](172) [HTML](228) [PDF 485.94 K](507)
    Abstract:
    In vitro antioxidant activity and total phenolic content of ginger extract were investigated. Four concentrations of ginger extract (0.15%, 0.30%, 0.45%, and 0.75%) were added during the salting process of dry-cured bacon to study the effect on nitrate and nitrosamine content in the bacon. High free radical scavenging activity of DPPH and ABTS+ radicals was demonstrated using ginger extract. The nitrite content decreased during dry-curing (p<0.05). At the end of the curing process, the bacon treated with 0.75% ginger extract had the lowest (p<0.05) nitrite content (15.91 mg/kg), a 41.55% reduction compared to the control samples. The bacon treated with 0.45% ginger extract inhibited 3-nitrotyrosine content after 12 d drying (p<0.05), a reduction of 8.55% compared to the control samples. Regardless of ginger treatment, N-nitrosodimethylamine (NDMA) content was not detected in the raw material or at the end of the salting process; NDMA values gradually increased (p<0.05) during dry-curing. The lowest NDMA content (0.65 μg/kg) was observed in the bacon treated with 0.75% ginger extract at the end of drying, a reduction of 36.89% compared to the control. The profile of ginger extract was analyzed using high performance liquid chromatography coupled with mass spectrometry. A total of 13 compounds were identified. In summary, ginger extract effectively inhibited nitrosation during the curing process of bacon. This study scientifically elucidates the effect of ginger extract on the formation of nitrite, 3-nitrotyrosine, and nitrosamine in improving the safety and quality of meat.
    24  Comparative Analysis of Cold Plasma and Thermal Sterilization of Eucommia ulmoides Seed Oil-apple Juice Beverage
    WANG Xiaoyuan ,  NIU Han ,  JIN Xueyuan ,  ZHAO Guangyuan ,  ZONG Wei
    2022, 38(9):206-214. DOI: 10.13982/j.mfst.1673-9078.2022.9.1134
    [Abstract](149) [HTML](204) [PDF 1.26 M](530)
    Abstract:
    Eucommia ulmoides seed oil-apple juice beverage was used as the research object, and sterilized by cold plasma (discharge power 750 W, treatment 90, 120, 150 or 180 s) or thermal treatment (65 ℃ 30 min, 80 ℃ 20 min, 90 ℃ 10 min or 90 ℃ 15 min). The physical and chemical indexes were determined for analysis and comparison. The results showed that the total number of colonies was not detected for both the thermal treatment and cold plasma treatment with insignificant change in pH (p>0.05). The plasma treatments increased the soluble solids content (by up to 7.73%), whilst the heat treatments had insignificant effect (p>0.05). The total phenolic content and content of flavonoids were well maintained after the plasma treatments, whilst the thermal treatments decreased the flavonoids content (by up to 6.34%). The cold plasma treatment and heat treatment led to the maximum decreases of total sugar content by 11.42% and 20.48% respectively, and the maximum increases of reducing sugar content by 18.46% and 10.34% respectively. The cold plasma treatments increased the total acid content of the beverage (by up to 26.23%). Both treatments caused a certain degree of reduction in the antioxidant activity of the beverage, and the changes were similar. In terms of stability, the heat treatments increased the particle size by up to 8.19% and decreased the absolute value of ζ-potential by up to 6.54%. Whereas, the plasma treatments had insignificant effects on ζ-potential (p>0.05). In general, compared with thermal sterilization, cold plasma sterilization is more suitable for the Eucommia ulmoides seed oil-apple juice beverage, with a shorter sterilization time, higher efficiency and better maintenance of beverage quality.
    25  Processing Technology of Non-rinsed Surimi Instant Food
    CHEN Yao ,  JIANG Caiyan ,  ZHENG Jie ,  SHANG Shan ,  JIAO Tiantian ,  JIANG Pengfei
    2022, 38(9):215-227. DOI: 10.13982/j.mfst.1673-9078.2022.9.1278
    [Abstract](215) [HTML](206) [PDF 2.80 M](564)
    Abstract:
    In order to determine the best formula of non-rinsed surimi instant food and investigate the quality changes during processing, single factor and orthogonal experiments were used to determine the optimum addition amounts of mashed potatoes, egg white powder, lard, and water using sensory and texture characteristics as reference indexes. Subsequently, the best processing technology was determined by analyzing the effects of drying methods and sterilization temperature on the water holding capacity, water loss rate, and product color. The results showed that the optimal formula of non-rinsed surimi instant food was 25% egg white powder, 30% mashed potatoes, 6% lard, and 100% water; the optimal drying process was cold air drying for 10 h; and the optimal sterilization temperature was 105 ℃. During processing of non-rinsed surimi instant food, the water loss rate increased significantly with the extension of drying time. When the cold air drying time was 10 h, the water loss and water holding rates of non-rinsed surimi were 39.06% and 84.33%, respectively. When the hot air drying time was 150 min, the water loss and water holding rates were 34.58% and 83.5%, respectively. As the sterilization temperature increased, the L* value of non-rinsed surimi products gradually decreased, whereas the a* and b* values gradually increased. These results could provide a theoretical basis for the development and utilization of non-rinsed surimi instant food.
    26  Preparation and Physicochemical Properties of β-glucan/Pectin Composite Films
    ZHOU You ,  FENG Hong ,  LI Ting ,  LYU Qingyun ,  LIU Gang ,  DING Wenping ,  ZHUANG Kun ,  CHEN Xi
    2022, 38(9):228-235. DOI: 10.13982/j.mfst.1673-9078.2022.9.1238
    [Abstract](164) [HTML](173) [PDF 6.30 M](831)
    Abstract:
    β-glucan/pectin composite films were prepared by mixing proper amounts of pectin and glycerin with β-glucan. The mechanical properties, barrier properties (against moisture and oxygen), thermal properties, film forming mechanisms, and water distributions of the composite films were compared using a texture analyzer (TA), a X-ray diffraction instrument (XRD), a scanning electron microscope (SEM), an infrared spectroscopy analyzer (FTIR), a differential scanning calorimeter (DSC), a nuclear magnetic resonance imaging analyzer (NMR) and a thermogravimetric analyzer (TGA). Moreover, the structure and properties of different β-glucan/pectin composite films were studied, and the optimal ratio of raw materials for composite film preparation was determined. The film obtained using 3:1 β-glucan-to-pectin mass ratio (film BP4) exhibits better mechanical properties and higher oxidation resistance due to the stronger interactions between β-glucan and pectin and denser film structures than those of films comprising the same materials at other proportions. Furthermore, β-glucan and pectin have good compatibility, and the thermal stability of the film is the best. The findings could provide reference for the rational application of polysaccharide composite films in food packaging.
    27  Analysis on Processing and Digestion Characteristics of Germinated Tartary Buckwheat Powder
    BAI Yongliang ,  XIE Jing ,  LI Tuowen ,  WANG Haiyan ,  TIAN Tiane ,  BAI Weidong
    2022, 38(9):236-244. DOI: 10.13982/j.mfst.1673-9078.2022.9.1235
    [Abstract](178) [HTML](273) [PDF 1.09 M](511)
    Abstract:
    To explore the application of germinated Tartary buckwheat powder in food, moisture content changes during Tartary buckwheat germination were studied. The processing characteristics of germinated Tartary buckwheat powder, such as its freeze-thaw stability, gel-forming capacity, hydration characteristics, and transmittance, were analyzed and compared against those of normal Tartary buckwheat powder (control). In addition, the reducing sugar release rate during in vitro digestion simulation, starch composition, and the estimated glycemic index were measured. The results show that the moisture content of Tartary buckwheat increases rapidly in the initial stage of germination (0~3 h) and then continues to increase slowly. Germination significantly reduces the freeze-thaw stability of the Tartary buckwheat powder, and the water release rate reaches 18.94%, which is 3.01 times that of the original powder (control). The sedimentation volume decreases by 11.30%, indicating enhanced gel-forming capacity. Moreover, the water holding capacity and degree of swelling decrease, but the solubility increases significantly by 26.70%. The light transmittance of germinated Tartary buckwheat powder is 4.29%, which is 0.38% lower than that of the control. The release amounts of reducing sugars increase continuously in the first 15 h of soaking and the first 12 h of germination, reaching the maximum release amount of 13.85% and 10.67%, respectively. Subsequently, the release amounts decline. The starch content of the Tartary buckwheat powder drops from 66.94% to 59.43% after soaking at 20 ℃ for 40 h and germination for 48 h at 25 ℃, 80% humidity and 7500 Lx light intensity. The content of rapidly digestible starch increases to 85.69%, while the resistant starch content decreases to 9.45%. The germinated Tartary buckwheat flour digestion rate rises significantly, and the final hydrolysis rate reaches 92.80%. However, the hydrolysis index (88.24) and the estimated glycemic index (88.15) did not increase significantly. Therefore, compared with normal buckwheat powder, germinated buckwheat powder has better gel-forming capability, solubility, and digestibility; thus, it is applicable for preparing gelled and easily digestible food. The findings of this study provide a theoretical basis for the development of germinated buckwheat food.
    28  Effects of Fixation Methods on the Quality of Huangjinya Green Tea Produced in Autumn
    YE Yutong ,  AI Zeyi ,  LI Ronglin ,  MU Bing ,  TIAN Yang ,  YANG Yiyang
    2022, 38(9):245-253. DOI: 10.13982/j.mfst.1673-9078.2022.9.1162
    [Abstract](259) [HTML](182) [PDF 487.90 K](479)
    Abstract:
    In this study, the fresh leaves of Huangjinya green tea obtained in Autumn were used as the raw materials to process green tea, and the effects of three different fixation methods, drum rolling, steaming and microwaving, on the quality of Huangjinya green tea products were studied. The sensory evaluation combined with quality analysis revealed that the Huangjinya green tea products produced with the three different fixation methods were all of excellent quality, but there were great differences in tea color, aroma and taste. The dry tea fixed by drum rolling had the greenest color and best aroma with an obvious chestnut aroma. Compared with thosed fixed by steaming and microwaving, the tea fixed by drum rolling had a higher amino acid content (increased by 11.01% and 5.20%, respectively) and lower content of tea polyphenols is (decreased by 3.54% and 3.94%, respectively), making the green tea taste mellow and fresh. The tea fixed by steaming had the highest taste score with the highest theanine content (7.69 mg/g) and the lowest caffeine content (27.91 mg/g), and exhibited the highest umami taste and abundance but lowest bitterness in the electronic tongue analysis. The correlation analysis of taste attributes detected by the electronic tongue and chemical composition showed that the umami value of the Autumn Huangjinya green tea was significantly and positively correlated with the theanine content (p<0.05), with the correlation coefficient as 0.99. There was a significant positive correlation between the bitterness value and the bitter-tasting catechin content (p<0.05), with the correlation coefficient as 0.99; In addition, the Huangjinya green tea fixed with different methods had different abilities to scavenge different free radicals, with the total antioxidant capacity decreased in the order of microwaving (0.83) > steaming (0.80) > drum rolling (0.66). In summary, the tea fixed by drum rolling tastes mellow with a strong and long aroma; the tea fxied by steaming had a mellow and thick taste and yellow-green color. Although there are some distinct favorable attributes, the Huangjinya green teas all show variety advantages.
    29  Antioxidant and Whitening Activities of Heat-transformed American Ginseng Stem-leaf Saponins
    ZHANG Biao ,  TENG Cong ,  YANG Xiushi ,  ZHANG Rui ,  WANG Yingping ,  REN Guixing
    2022, 38(9):254-263. DOI: 10.13982/j.mfst.1673-9078.2022.9.1285
    [Abstract](133) [HTML](182) [PDF 863.07 K](565)
    Abstract:
    The levels of less-polar ginsenosides in American ginseng stem-leaf saponins and the antioxidant and whitening activities of American ginseng stem-leaf saponins before and after heat transformation were studied. The results showed that the content of less-polar ginsenosides in American ginseng stem-leaf saponins increased from 0.07 mg/mg to 0.66 mg/mg during heat transformation. Moreover, when the concentration of American ginseng stem-leaf saponins before and after transformation was in the range of 0.1~5 mg/mL, the maximum of DPPH free radical scavenging rates were 16.65% and 38.28%, respectively, ABTS free radical scavenging rates were 8.20% and 41.94%, respectively, and the reducing capacity was 3.24 mg TEAC/g DW and 25.22 mg TEAC/g DW, respectively. In addition, the concentration of American ginseng stem-leaf saponins before and after thermal transformation was in the range of 0.025~0.1 mg/mL, the maximum inhibition rates of tyrosinase activity in B16 cells were 30.22% and 33.54%, respectively, and the maximum inhibition rates of melanin production in B16 cells were 17.27% and 29.33%, respectively. In conclusion, the content of less-polar ginsenosides in American ginseng stem-leaf saponins was increased, and the antioxidant and whitening activities of American ginseng stem-leaf saponins were enhanced after heat transformation treatment, which has great application value in the fields of beauty and medicine.
    30  Comparative Study on the Structure and Activity of Horse Bone Marrow Protein Extracted by Different Methods
    UGULNISA Mamattohti ,  PARHAT Rozi ,  ZILALA Ismayil ,  GULMIRA Ababakri ,  YANG Xiaojun ,  GUZALNUR Askar ,  WANG Juan
    2022, 38(9):264-274. DOI: 10.13982/j.mfst.1673-9078.2022.9.1078
    [Abstract](133) [HTML](189) [PDF 2.47 M](581)
    Abstract:
    The effects of different extraction methods on extraction rate, structure, antibacterial activity and antioxidant activity of horse bone marrow protein were studied, and its edible and medicinal values were examined. Twelve extraction methods were screened through using protein content, extraction rate, molecular weight and antioxidant activity as the indicators, and structural characterizations were performed by UV, SDS-PAGE, FT-IR, and SEM-EDX analysis. The biological properties of the obtained proteins were evaluated by in vitro antibacterial and antioxidant activities. After comprehensive investigations, it was found that the index scores of the horse bone marrow proteins extracted with water, 0.25% NaCl, and normal saline were higher, with their corresponding protein contents being 41.91, 39.93 and 37.82 mg/mL, and extracted rates being 19.26%, 14.86% and 23.22%, respectively. UV spectra showed that the horse bone marrow proteins prepared by different methods had the maximum absorption peak around 270 nm. SDS-PAGE revealed that the molecular weights of the obtained proteins were mainly around 66 ku, with the presence of corresponding polypeptide bands. FT-IR spectra showed typical protein absorption signals in the region of 4000~400 cm-1. SEM-EDX analysis showed that the obtained proteins were composed of spherical, striped and irregular particles. The results of biological activity experiments demonstrated that the horse bone marrow proteins prepared by the three methods exhibited sound antibacterial and antioxidant effects, and the zone diameters of inhibition against Staphylococcus aureus were 12.0, 16.0 and 11.0 mm, respectively. The IC50 values of DPPH and ABTS free radicals scavenging activities were 0.32, 0.29 and 0.31 mg/mL, and 0.26, 0.15 and 0.20 mg/mL, respectively. The research results can provide a scientific basis for further development and utilization of horse meat processing by-products, bone resources. Key words:
    31  Development and Efficacy Evaluation of a Red Ginseng-Bird's Nest-Jujube Seed Compound Sleep Aid Drink
    FENG Yanyu ,  FAN Qunyan ,  WANG Dehua ,  WANG Peixin ,  HU Jiamiao ,  ZHANG Yi
    2022, 38(9):275-284. DOI: 10.13982/j.mfst.1673-9078.2022.9.1040
    [Abstract](214) [HTML](218) [PDF 474.02 K](438)
    Abstract:
    In the currently study, the optimal formula of a "red ginseng-bird's nest-jujube seed compound sleep aid drink" was developed using red ginseng, bird's nest and cooked sour jujube seeds as the main raw materials. The effect of the compound drink on sleep improvement was determined in the Balb-c male mice subjected to 30-day continuous oral gavage of the compound drink by the direct sleep test, prolonged pentobarbital sodium sleep time test, pentobarbital sodium subthreshold dose hypnotic test, and barbital sodium sleep latency test. The related indicators of mouse’s brain tissues were measured. With the results showed that red ginseng-bird's nest-jujube seed compound sleep aid drink at low, medium and high doses could prolong sleep time of the mice under the action of pentobarbital sodium by 24.72%, 66.11%, and 85.12%, respectively. The compound drink at the medium and high doses could also increase the sleep-onset rate to 80% in the mice treated with pentobarbital sodium at the subthreshold dose, while shortening effectively the sleep latency for the mice barbital sodium hypnosis. In addition, compared with the blank group, the 5-HT contents of the treatment groups increased significantly (increased by 398.28, 742.34, and 830.08 ng/mL for the low, medium and high dosage groups, respectively). The TPH contents of the medium and high dosage groups increased significantly (increased by 433.82 and 663.74 pg/, respectively). The GABA contents in the brain tissues of the mice in the medium and high dosage groups increased significantly (increased by 0.04 and 0.06 µmol/L, respectively), while the Glu contents of these two groups of mice also increased significantly (increased by 0.20 and 0.50 µmol/L, respectively). In summary, the red ginseng-bird's nest- jujube seed compound sleep aid drink can improve sleep, and such an effect is related to the regulation of the serotonin system and neurotransmitters in the brain tissue.
    32  Effects of Enzyme-assisted Cavitation on Structural and Physicochemical Properties of Okara Fibers
    SHEN Xiaomei ,  LUO Zhaojiao ,  HOU Junjie ,  XIE Chunyan ,  WANG Jinmei ,  CHEN Weihan
    2022, 38(9):285-291. DOI: 10.13982/j.mfst.1673-9078.2022.9.1260
    [Abstract](160) [HTML](169) [PDF 2.05 M](358)
    Abstract:
    The effects of hydrodynamic cavitation and enzymatic hydrolysis on the structure and physicochemical properties of skimmed okara fibers were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The physicochemical properties of okara fibers were strongly affected by cavitation. After 10 min cavitation, the water- and oil-holding capacities of okara fibers reached 18.43 g/g and 7.35 g/g, respectively. After 20 min cavitation, the soluble dietary fiber (SDF) content changed from 2.87% to 6.79%. Both the apparent solution viscosity and the okara fiber crystallinity decreased, and the fibers existed in the form of honeycomb sheets. In addition, enzyme-assisted cavitation could further improve the physicochemical properties of okara fibers. The properties of the products were strongly affected by the sequence of enzymatic hydrolysis and cavitation. Up to 12.52% of SDF content was obtained in okara fibers and the apparent viscosity decreased significantly when enzymatic hydrolysis was performed before cavitation. On the contrary, when enzymatic hydrolysis was carried out after cavitation, higher water- and oil-holding capacities were noted. Enzyme-assisted cavitation of okara fibers results in increased debris and small fibers. In short, the method can be an effective means to improve structural and physicochemical properties of okara fibers.
    33  Antioxidant Components and Activity of Triticum aestivum Flour
    NIU Xinkui ,  HAN Xiaoxian ,  ZHENG Xueling
    2022, 38(9):292-297. DOI: 10.13982/j.mfst.1673-9078.2022.9.1276
    [Abstract](271) [HTML](209) [PDF 1.25 M](432)
    Abstract:
    Triticum aestivum is a high-quality wheat with special nutritional quality. In this experiment, two kinds of characteristic Triticum aestivum, 16W16 and Yunhei 14207, were selected as the research objects to analyze the antioxidant active components and capacity of Triticum aestivum whole wheat flour, flour, and bran. The results showed that the levels of anthocyanins, polyphenols, and flavonoids in Triticum aestivum were higher than those in the control wheat. The levels of polyphenols, flavonoids, and anthocyanins in 16W16 whole wheat flour were 3.73 mg GAE/g, 2.45 mg RE/g, and 111.33 mg/kg, respectively. The iron ion reduction ability of 16w16 whole wheat flour was 2.34 mg TE/g, and the scavenging rates of DPPH and OH free radicals were 48.18% and 42.46%. 16W16 crude bran had the highest content of antioxidant components and strongest antioxidant activity. The levels of anthocyanins, polyphenols, and flavonoids were 672.31 mg/kg, 6.77 mg GAE/g and 6.67 mg RE/g, respectively. The iron ion reduction capacity of the bran was 5.73 mg TE/g, and the DPPH and •OH free radicals scavenging rates were 97.00% and 88.30%, respectively. Analysis of the antioxidant components in Triticum aestivum showed that anthocyanins, polyphenols, and flavonoids in the bran accounted for approximately 99.00%, 50.00%, and 80.00% of the total antioxidant components content, which indicated that the antioxidant substances in Triticum aestivum were mainly distributed in the seed coat structure. The levels of polyphenols, flavonoids, and anthocyanins as well as antioxidant activity of Yunhei 14207 were significantly lower than those of 16w16 and higher than those of the control wheat Yongliang 4. Analysis of the content of antioxidant components in Triticum aestivum showed that the antioxidant active substances in triticale were mainly distributed in the bran. Comprehensive analysis showed that the content of active components in Triticum aestivum was higher and antioxidant ability was stronger than that in Triticum aestivum. Therefore, Triticum aestivum is a good material for developing functional and health foods.
    34  Comparison of Quality Components and Sensory Flavor of Green Tea with Different First-firing Degrees
    WU Rongmei ,  HUA Jinjie ,  YUAN Haibo ,  YE Hao ,  WANG Yongqi ,  YU Xiuhong ,  WANG Jinjin ,  YU Shuping
    2022, 38(9):298-307. DOI: 10.13982/j.mfst.1673-9078.2022.9.1346
    [Abstract](147) [HTML](279) [PDF 1.41 M](575)
    Abstract:
    Two leaves and a bud of the Jiukeng tea variety were selected as the raw material to conduct trial production of green tea. Three different first-firing degrees, namely heavy, moderate, and mild, with a leaf water content of 15%, 20%, and 25%, respectively, were achieved through first-firing treatments. The effects of the three levels of first-firing on the biochemical components, the dry tea color parameters, the tea liquor color parameters, and the sensory quality of the tea samples were analyzed to determine the appropriate water content degree of first-firing green tea processing. The results showed that with a high first-firing degree, the total flavonoid glycosides, appearance greenness (Sa), and liquor greenness (La) were significantly high (p<0.05), whereas the sweetness value and the Sb/Sa or yellowness to greenness ratio for appearance, was significantly low (p<0.05). Furthermore, compared with mild first-firing, under heavy first-firing, the sweetness value and Sb/Sa value decreased by 38.53% and 78.88%, respectively, and the values of Sa, La, and total flavonoids increased by 47.11%, 11.02%, and 3.17%, respectively. Moderate first-firing treatment (20% moisture content) also led to relatively high amino acid, glucose, sweetness value, the ratio of yellowness to greenness (Lb/La) of the liquor, and relatively low phenol-ammonia ratio, total catechin, andtotal flavonoid glycosides providing the material basis for high-quality green tea. This treatment resulted in improved light green and bright color, tender aroma, fresh and mellow taste quality of the green tea, and a total sensory score (92.2) of 1.25 and 2.25 points higher than those of heavy and mild first-firing treatments, respectively. In addition, the Lb/La value of moderate first-firing was significantly higher than that of heavy and mild first-firing green tea by 3.14% and 4.25%, respectively (p<0.05). PLS-DA results showed that Lb/La, brightness of liquor color (LL), ester catechins, kaempferol-3-O-rutin glycoside, and phenol-ammonia ratio were the distinctive characteristic components of green tea under different first-firing degree conditions, and can serve as the control indexes for the drying process of green tea. In conclusion, a leaf moisture content of 20% could serve as the standard of moderate first-firing.
    35  Optimization of Enzymolysis of Sarcodon aspratus and Comparative Analysis of Its Flavor Components before and after Enzymatic Hydrolysis
    WANG Qiuting ,  LI Zelin ,  GUI Haijia ,  GU Dahai ,  WANG Xuefeng ,  XIAO Zhichao ,  WANG Guiying ,  PU Yuehong ,  FAN Jiangping
    2022, 38(9):308-320. DOI: 10.13982/j.mfst.1673-9078.2022.9.1248
    [Abstract](185) [HTML](195) [PDF 1.85 M](394)
    Abstract:
    The process of enzymatic hydrolysis of Sarcodon aspratus and the difference in flavor before and after the process were studied. The enzymatic hydrolysis of S. aspratus was optimized using response surface design experiments based on single-factor tests. The key free amino acids and volatile aromatic compounds that contribute to the flavor of S. aspratus were detected and selected using an amino acid automatic analyzer and headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) combined with the taste activity value (TAV) and odor activity value (OAV). The results showed that the optimal conditions were as follows: a solid-liquid ratio of 1:15 (m/V), an enzymolysis time of 4.4 h, an enzyme addition amount of 0.4%, an enzyme ratio (papain: flavor enzyme) of 1: 1, and a hydrolysis degree of 57.82%. A total of 11 free amino acids with a TAV greater than 1 were obtained. The contents of glutamic acid and glycine increased by 14.68 and 14.45 times, respectively, after enzymolysis, and the fresh and sweet taste was enhanced. A total of 108 volatile compounds were identified, including 55 before and 71 after enzymatic hydrolysis. Among them, 13 and 22 volatile compounds had an OAV≥1 before and after enzymatic hydrolysis, respectively. These included linalool, 2-octenol, 1-octene-3-ol, guaiacol, and heptanal. Before and after enzymatic hydrolysis, the main flavor components of S. aspratus were flavors of fruits, flowers, soap, and fat, and it primarily had a melon-like aroma. However, 1-octene-3-ol (OAV=1726) produced after enzymatic hydrolysis enhanced the mushroom aroma. This study provides a preliminary basis for future flavor research on S. aspratus.
    36  Exposure Assessment of Typical Toxic Substances in Different Plastic Tableware Sets
    LI Ning ,  XIAO Haiqing ,  WANG Hongwei ,  HUANG Guozhong ,  XIE Jiaying ,  SI Nianpeng
    2022, 38(9):321-332. DOI: 10.13982/j.mfst.1673-9078.2022.9.1143
    [Abstract](184) [HTML](180) [PDF 1.32 M](399)
    Abstract:
    The risk levels of different plastic tableware sets exposed to humans were evaluated by establishing an exposure assessment model. Taking the commonly used polystyrene, polypropylene, melamine and polyethylene plastic tableware sets as the objects, the typical toxic substances in tableware were divided into five categories. Then the risk transfer path was constructed based on the interpretative structural model, and the exposure assessment model was further established based on the three stages of the risk transfer path. Finally, the model was programmed by MATLAB software. The real applications showed that four types of plastic tableware sets were ranked according to the total hazard index of toxic substances: polystyrene (2.24E+00) > melamine (6.94E-01) > polypropylene (2.98E-01) > polyethylene (2.66E-01), and the polystyrene tableware had an unacceptable exposure risk level to the human body (the acceptable risk value was determined by the U.S. Environmental Protection Agency as 1.00). The total hazard index of the tableware in contact with greasy foods was the highest (2.62E+00), which was about 6.30, 2.63 and 5.72 times that of water-based, acidic and alcoholic foods. Among them, the polystyrene tableware had an unacceptable exposure risk to the human body when it came into contact with greasy foods. In addition, food storage cycle and microwave heating time were positively correlated with the exposure risk of tableware to the human body, and they may pose an unacceptable risk to the human body in some cases. These results show that some plastic tableware meeting the standard may have an unacceptable exposure risk to the human body, and the risk is also related to the type of food and consumer's tableware usage habits (storage cycle and microwave heating preference).
    37  Rapid Screening and Risk Assessment of 623 Pesticide and Metabolite Residues in Cucumber in Weifang, Shandong Province
    LI Xiaohui ,  WANG Qi ,  ZHANG Chen ,  YUE Ning ,  LI Minjie ,  SHAO Yong ,  SHAO Hua ,  ZHENG Lufei ,  WANG Jing ,  JIN Fen
    2022, 38(9):333-344. DOI: 10.13982/j.mfst.1673-9078.2022.9.1194
    [Abstract](187) [HTML](189) [PDF 1.06 M](404)
    Abstract:
    In order to understand the status of pesticide residues in cucumbers in Weifang, Shandong Province, 623 pesticides and metabolites in 392 cucumber samples produced and circulated in Weifang were qualitatively screened and quantitatively measured by retention index-gas chromatography-tandem mass spectrometry (RI-GC-MS/MS). Dietary intake risks of the pesticide residues were assessed and ranked. In total, 55 pesticides and metabolites were detected in 392 cucumber samples with detection rates of 0.26%~92.09%. In particular, 19 pesticides which are not covered by the national food safety standard methods (GB 23200.113-2018 and GB 23200.8-2016. 19) were found. Among the pesticides detected, five pesticides exceeded the maximum residue limits. They are spirodiclofen (2.30%), endosulfan (1.02%), metalaxyl (0.51%), pyraclostrobin (0.26%), and pyridaben (0.26%). The chronic dietary intake and acute dietary intake risks of the 55 detected pesticide residues were all less than 100%, and the intake risks were acceptable. According to the residual risk score ranking, medium- and high-risk pesticides accounted for a relatively high proportion (60%) of the samples. In particular, the detection of some banned and restricted pesticides (endosulfan and 2,4-D butyl ester) may be related to the illegal addition of agricultural inputs. The present study found more residues in the circulation stage (33.5% of the samples having more than 15 pesticides) than in the production stage (4.08%). This phenomenon may be related to the existence of risk points and lack of effective supervision in the first three stages of transportation from the production base to the market. It is suggested that monitoring of these three stages and management of pesticide use should be strengthened to ensure the quality and safety of agricultural products.
    38  Establishment and Stability Comparison of Detection Methods for Toxicflavin and Fervenulin in Fermented Corn Flour, Tremella Fuciformis and Its Processed Products
    WANG Hui ,  DENG Nan ,  CUI Xiaojiao ,  CHEN Xiangui ,  WANG Lu ,  YUAN Yuan ,  CHEN Gaochao ,  ZHOU Cerui
    2022, 38(9):345-354. DOI: 10.13982/j.mfst.1673-9078.2022.9.1256
    [Abstract](183) [HTML](253) [PDF 1.41 M](357)
    Abstract:
    A high-performance liquid chromatography method was developed to determine toxoflavin and fervenulin, in fermented corn flour, as well as in Tremella fuciformis and its products. After extraction, the target compounds were separated using a C18 column. The retention times and spectrograms were used for qualitative determination, and the levels were quantitatively measured using external standards. The established method was compared with the existing methods. The stability of the two target compounds, namely toxoflavin and fervenulin, under different conditions were also compared. The results suggest that the two target compounds show good linearity in the concentration range of 0.20~20.00 mg/L, R2>0.999. The limits of detection of toxoflavin and fervenulin were 0.15 mg/kg (fermented corn flour) and 0.30 mg/kg (T. fuciformis and its products), respectively. The recovery rates were 79.77%~104.36% with relative standard deviations (RSDs) of 0.96%~8.91% (n=6). The levels of both toxoflavin and fervenulin rapidly decreased to less than 40% under alkaline conditions. In contrast, the toxoflavin content reduced to less than 26% under acidic conditions in 5 months, whereas fervenulin remained stable under the same condition. Both compounds were stable in methanol within the tested period (5 months). The RSDs of absorbance were less than 3.18%. Compared with the existing methods, the proposed method is simple and rapid, with low interference and high accuracy. It could be applied for the determination of toxoflavin and fervenulin in fermented corn flour as well as in T. fuciformis and its products. The stability test can provide an excellent reference for detoxification or poisoning avoidance in future.
    39  Comparative Study on GB and AOAC Methods to Determine Primary B Vitamins in Milk Powder
    GE Cheng ,  ZHOU Rongjie ,  ZHAN Shengqun ,  ZHOU Jun ,  CHU Xiaogang
    2022, 38(9):355-360. DOI: 10.13982/j.mfst.1673-9078.2022.9.1272
    [Abstract](367) [HTML](395) [PDF 718.52 K](475)
    Abstract:
    The equivalence between the national standard and official AOAC methods for determining vitamins B1, B2, B3 (niacin), and B6 in milk powder was analyzed by performing the F-test and significance test on the obtained measurements to explore the comparability and error sources between these methods. Furthermore, vitamin B2 results were compared and analyzed in detail by a two-way one-sided t-test (TOST). The results indicated no significant difference between the national standard and AOAC official methods in determining vitamins B1, B3, and B6. However, for vitamin B2, a difference was observed between the two methods in terms of their mechanisms. The equivalence analysis results showed that the two methods are not effectively equivalent. Addition of acid phosphatase to the milk powder matrix was found to help obtain comparable results.
    40  Research Progress in Functional Components and Bioactivity of Common Scented Tea
    LI Maiquan ,  DONG Yunxia ,  ZHANG Can ,  LIU Xia ,  LI Pao ,  LI Jie ,  LIU Zhonghua
    2022, 38(9):361-373. DOI: 10.13982/j.mfst.1673-9078.2022.9.1388
    [Abstract](304) [HTML](483) [PDF 1.05 M](791)
    Abstract:
    Scented tea is a kind of tea prepared from flowers or leaves after deep processing. It is rich in nutritional and functional components and has a positive effect on human health. Scented tea not only has the function of maintaining good health, but also has a certain effect on fitness; therefore, people like to use it as a drink in daily life, and during study and work. With the rapid development of the economy in recent years, the scented tea market has become increasingly prosperous. There are more than a hundred kinds of scented teas, including rose, jasmine, honeysuckle, chrysanthemum, osmanthus, and dandelion teas. In this study, the nutritional components, functional components, and bioactivity of jasmine, rose, chrysanthemum, and honeysuckle teas were reviewed. These four kinds of scented teas were found to contain proteins, vitamins, polysaccharides, catechins, theophylline, flavonoids, volatile oils, and other nutritional and functional components, which can effectively resist oxidation, delay aging, improve immunity, prevent and cure cardiovascular diseases, and kill and inhibit bacteria, among other bioactivities.
    41  Research Progress on Moisture and Heat Transfer Model for Ventilation Drying of Grain under Bulk Storage
    CHEN Pengxiao ,  LIU Ye ,  WU Jianzhang ,  JIANG Mengmeng ,  LU Xuezhong ,  ZHANG Debang ,  ZHU Wenxue
    2022, 38(9):374-386. DOI: 10.13982/j.mfst.1673-9078.2022.9.1054
    [Abstract](202) [HTML](185) [PDF 1.92 M](354)
    Abstract:
    Food security has been at the forefront of state governance throughout history. The safety of grain storage is particularly important, which is related to the national security of a country. A large amount of grain is lost after harvest every year owing to reasons such as the primitive grain drying and storage methods and the backward drying technology. The uneven distribution of moisture and heat in stored grain will not only lower the quality of grain, but also seriously affect the food safety of grain caused by mildew, insect pests and other problems. Therefore, how to reduce quickly and uniformly the moisture content or temperature of bulk grain piles with low energy consumption to ensure grain quality while saving energy is an important direction for grain drying and storage research, which has profound theoretical and practical significance. Ventilation drying is an important measure to ensure the uniform distribution of moisture and heat in stored grain, and constructing a drying model to predict the moisture and heat distribution of grain pile is an important means to study the moisture and heat transfer during the drying process of grain piles. This paper reviewed three models of moisture and heat transfer in bulk grain piles, the empirical model, continuum model and discrete model. The empirical model is easy to obtain but rarely used. The continuum model is widely used, but it cannot reflect the pore characteristics of grain piles. The discrete model reflects well the pore structure of grain piles, though it relies on large amounts of calculations and is difficult to understand and construct. Finally, it is pointed out in this paper that corresponding models can be established in combination with advanced calculation methods and processing techniques according to different moisture and heat transfer processes to meet different simulation requirements. In addition, the future research direction of moisture and heat transfer models for ventilation drying of grain pile under storage is also prospected in this paper.
    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

    • Most Read
    • Most Cited
    • Most Downloaded
    Quick search
    Press search
    Search term
    From To
    Periodical Search
    You are the first Visitors
    版权所有：MODERN FOOD SCIENCE & TECHNOLOGY
    Governing Body：华南理工大学    Organizer：华南理工大学
    Phone：020-87112373  Email：mfood@scut.edu.cn
    Address：广州天河五山路381号华南理工大学麟鸿楼506室
    信息咨询：QQ: 2553003667  稿件处理1：QQ: 1542354573  稿件处理2：QQ: 2195608851  财务咨询：QQ: 1347040116
    MODERN FOOD SCIENCE & TECHNOLOGY ® 2025 All Rights Reserved ICP：京ICP备09084417号-24