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Volume 39,Issue 1,2023 Table of Contents

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    • 1  Capsaicin to Alleviate Gastrointestinal Inflammation in Mice under Low Temperature and Low Humidity Conditions
    LUO Xin ,  NIU Sumin ,  DONG Yiqun ,  XIE Dingyuan
    2023, 39(1):1-10. DOI: 10.13982/j.mfst.1673-9078.2023.1.0250
    [Abstract](10) [HTML](33) [PDF 1.45 M](45)
    Abstract:
    The effects of different capsaicin doses were investigated for the alleviation of gastrointestinal inflammation in mice under low-temperature and low-humidity conditions. Mice were randomly divided into control, low-temperature and low-humidity model, and capsaicin-treated groups (10, 15, 20 mg/kg) for a 7-day test period. The body weight of the mice was recorded, and the histopathological changes in the stomach and duodenum were observed. The serum levels of inflammatory factors, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interferon-γ (IFN-γ) were detected. NF-κBp65, IκB-α, IL-1β, and TNF-α expression levels, along with other mRNAs and proteins, were measured in gastric and duodenal tissues. A low-temperature and low-humidity environment significantly decreased the body weight of mice, significantly increased serum levels of inflammatory factors, significantly upregulated inflammatory factor gene expression in gastric tissues, and significantly downregulated NF-κBp65 protein levels in duodenal tissues. Capsaicin treatment at 15 mg/kg significantly increased body weight and decreased serum levels of inflammatory factors in mice. Capsaicin treatment down-regulated the expression of inflammatory factors in gastric tissues and significantly upregulated key pathway protein expression in duodenal tissues to restore normal levels. The results imply that capsaicin consumption (10~20 mg/kg) under low-temperature, low-humidity conditions (10 ℃, 30%) could alleviate gastric mucosal damage and restore duodenal villi breakage, providing guidance for healthy consumption of chili peppers under low-temperature and low-humidity conditions.
    2  16S rRNA Sequencing-based Investigation of the Effects of Gegen Qinlian Decoction on Intestinal Flora Structure in Antibiotic-associated Diarrhea
    SU Gang ,  YANG Guangyong ,  ZHANG Gengxin ,  DU Haiyang ,  TIAN Weiyi ,  WANG Wenjia ,  WANG Ping ,  TU Xiaohua ,  HE Guangzhi
    2023, 39(1):11-19. DOI: 10.13982/j.mfst.1673-9078.2023.1.0235
    [Abstract](11) [HTML](37) [PDF 1.63 M](47)
    Abstract:
    The effects of Gegen Qinlian decoction (GQD) on intestinal flora structure in SD rats with antibiotic-associated diarrhea (AAD) were investigated using 16S rRNA sequencing. First, 60 SD rats were subjected to 1 week of adaptive feeding, after which they were randomly divided into two groups: the blank control (C) group of 10 rats and the model construction group of 50 rats. The model construction group was administered 250 mg/(kg•day) clindamycin by gavage for 7 consecutive days for model establishment, whereas the blank control group was administered saline by gavage once daily during the same period. After successful model construction, the model construction group was randomly divided into five groups of 10 rats each: the model (M), live bifidobacterium capsule (P), high-dose GQD (GQD-H), medium-dose GQD (GQD-M), and low-dose GQD (GQD-L) groups. The P group was administered 0.15 g/kg of bifidobacteria and the GQD-H, GQD-M, and GQD-L groups were respectively administered 10.08, 5.04, and 2.52 g/kg GQD by gavage once daily for 7 consecutive days; the C and M groups were administered equivalent volumes of saline by gavage once daily during the same period. After treatment, fecal DNA was extracted from each group aseptically and subjected to 16S rRNA sequencing. Alpha and beta diversity analysis showed that GQD increased the diversity of intestinal flora in rats with AAD. GQD increased Firmicutes and Bacteroides abundance at the phylum level and Lactobacillus and Bacteroides abundance at the genus level. LEfSe analysis revealed that GQD increased Lactobacillus and Bacteroides abundance but reduced Proteobacteria abundance. These results suggest that GQD may effectively treat AAD through the improvement of intestinal microecological structure.
    3  High-amylose Maize Starch-unsaturated Fatty Acid Complexes: In Vitro Large Intestine Fermentation Characteristics and Effects on Gut Microbiota
    XU Shiqi ,  ZHOU Qianwen ,  FU Xiong ,  HUANG Qiang ,  ZHANG Bin
    2023, 39(1):20-30. DOI: 10.13982/j.mfst.1673-9078.2023.1.0169
    [Abstract](10) [HTML](40) [PDF 1.53 M](29)
    Abstract:
    In this study, high-amylose maize starch (HAMS) and four fatty acids with different saturation degrees were used as the raw materials to form starch-unsaturated-fatty-acid complexes. The effects of the different complexes on the in vitro large intestine fermentation characteristics and regulation of microbiota were investigated. The results showed that with the increase of the unsaturation of fatty acids, the formation of V-type starch complexes (30.42%~32.93%) decreased, except for the starch-oleic-acid complex (34.87%). There were no significant differences in the fermentation rate for the starch-unsaturated fat complexes during the entire fermentation process (p>0.05), with their final gas productions being essentially the same (13.8~14.2 mL). The starch-unsaturated fatty acid complexes produced a lower concentration of butyrate (14.83~17.91 mmol/L; compared with HAMS 22.42 mmol/L), but produced higher concentrations of acetate (60.25~63.73 mmol/L) and propionate (21.22~24.81 mmol/L). The starch-unsaturated fatty acid complexes all significantly increased the relative abundance of Prevotella, which might be associated with their higher propionate productions. Taken together, the in vitro large intestine fermentation characteristics of HAMS-unsaturated-fatty-acid complexes were less affected by the fatty acid saturation, but related mainly to their own complex structure. The saturation of the fatty acids in the HAMS-unsaturated fatty acid complexes has a certain effect on the microbiota structure.
    4  Anti-inflammatory Effects of Dendrobium aphyllum Fermentation Polypeptides, Asp-Asp-Asp-Tyr and Asp-Tyr-Asp-Asp, on LPS-induced RAW264.7 Cells
    LIANG Churong ,  WANG Qin ,  XIAO Gengsheng ,  MA Lukai ,  WU Hui ,  XIAO Jianbo ,  LIU Huifan
    2023, 39(1):31-40. DOI: 10.13982/j.mfst.1673-9078.2023.1.0478
    [Abstract](11) [HTML](32) [PDF 1.25 M](32)
    Abstract:
    In this study, we aimed to investigate the anti-inflammatory activity of polypeptides Asp-Asp-Asp-Tyr (DDDY) and Asp-Tyr-Asp-Asp (DYDD) discovered in fermentation media from Dendrobium aphyllum towards LPS-induced RAW264.7 macrophages. Synthetic D. aphyllum fermentation polypeptides were prepared and subjected to experimentation. Concentrations of fermentation polypeptides that resulted in the highest cell proliferative activity were screened for using the methyl thiazolyl tetrazolium (MTT) assay. The effects of fermentation polypeptides on the phagocytic activity of RAW264.7 cells were determined using neutral red phagocytosis assay. Cell differentiation and changes in morphology were observed under an inverted microscope. Secretion levels of NO, cytokines IL-1β, IL-6, and IL-10, and tumor necrosis factor-alpha (TNF-α) were determined by enzyme-linked immunosorbent assay (ELISA). Fermentation polypeptide concentrations of 12.5, 25, 50, and 100 μg/mL exerted no cytotoxic effects and promoted cell proliferation. Approximately 100 μg/mL DDDY and DYDD and 1 μg/mL LPS enabled cell activation and enhanced RAW264.7 cell phagocytic ability, with relative phagocytic rates of 2.05%, 1.97%, and 2.19%, respectively. An LPS-induced RAW264.7 cell inflammation model was constructed, in which both types of fermentation polypeptides effectively inhibited cell differentiation and restored normal cell morphology. The respective NO secretion capacities of cells in the 100 μg/mL DDDY and DYDD treatment groups decreased to 0.41- and 0.49-times, respectively, compared with that of the LPS group. DDDY and DYDD also significantly and dose-dependently increased anti-inflammatory cytokine secretion and decreased the secretion of pro-inflammatory cytokines. Therefore, DDDY and DYDD exert anti-inflammatory effects on the LPS-induced RAW264.7 macrophages. The results of this study may provide a scientific basis for future investigations of the anti-inflammatory mechanisms of fermentation polypeptides.
    5  Efficient Expression and Enzymatic Characterization of Lysozyme LyAa in Aspergillus niger
    GU Lixing ,  WANG Bin ,  PAN Li
    2023, 39(1):41-49. DOI: 10.13982/j.mfst.1673-9078.2023.1.0258
    [Abstract](17) [HTML](38) [PDF 1.15 M](43)
    Abstract:
    Single- and double-copy expression vectors of lysozyme-containing glucoamylase signal peptide, controlled by promoter Pna II, were constructed following codon optimization of the GH25 lysozyme gene derived from Acremonium alcalophilum. The double-copy expression vector and CRISPR/cas9 techniques were applied. Lysozyme expression strains with high enzyme activity levels were obtained through PEG-mediated transformation of Aspergillus niger host HL-1. The lysozyme activity of the recombinant LyAa-C strain reached 2 291.37 U/mL, which is 2.63 times that of the LyAa-F strain transformed by double-copy expression vector only (869.74 U/mL) and 6.39 times that of the LyAa-T strain transformed by traditional single-copy expression vector only (358.41 U/mL). The recombinant lysozyme LyAa was purified with 6×His-tagging through nickel affinity chromatography, and its enzymatic properties were analyzed. The purified lysozyme LyAa had a size of 25.0 ku, an optimal pH value of 4.0, an optimal temperature of 30 ℃, and exhibited good pepsin stability. In conclusion, this study successfully optimized and improved the lysozyme expression in Aspergillus niger using double-copy vector and CRISPR systems.
    6  Enzymatic Characterization and Application of Thermophilic Chitosanase CsnSH50 from Marine Strain Mitsuaria sp. SH-50
    LU Bosi ,  CUI Dandan ,  SHEN Hong
    2023, 39(1):50-58. DOI: 10.13982/j.mfst.1673-9078.2023.1.0298
    [Abstract](9) [HTML](41) [PDF 1.23 M](37)
    Abstract:
    This study screened a marine strain of Mitsuaria sp. SH-50 with high chitosanase activity levels from soil samples of the coastal shrimp and crab culture area in Hainan province, China. After optimization, the enzyme production cycle of strain SH-50 was only 12 h, with the enzyme activity reaching 26.6 U/mL. To further clarify the practical significance of SH-50 in the production of chitosan oligosaccharide, its chitosanase was isolated and purified for the characterization of enzymatic properties and a small-scale test of chitosan oligosaccharide preparation. The results show that CsnSH50 has a molecular weight of approximately 41 ku, an enzymatic activity level of 7 462.50 U/mg, an optimum reaction pH of 4.5, an optimum reaction temperature of 75 ℃, and was stable at pHs 2.5~8.5 and temperatures < 50 ℃. Under optimal conditions, the Vmax and Km of diluted CsnSH50 were 29.41 U/mL and 1.71 mg/mL, respectively, and 1 mmol/L K+, Ca2+, Cu2+, and Mn2+significantly activated CsnSH-50 enzyme activity. The positive activation effect of Mn2+ at 10 mmol/L was up to 412%. TLC and ESI-MS demonstrated that the final products of chitosan hydrolysis by CsnSH50 were mainly chitobiose, chitotriose, and chitotetraose. When preparing 5% chitosan oligosaccharide solution in small-scale experiments, the initial pH was 3.5, the temperature was 75 ℃, and the chitosan oligosaccharide yield rate reached 92.1% after 120 min of hydrolysis with an average degree of polymerization of 10.2. In conclusion, CsnSH50 has high enzyme activity levels, good thermal stability, and acid resistance. CsnSH50 is also a rarely reported thermophilic chitosanase and has the potential for industrial application.
    7  Modeling and Optimization of Fermentation by Lipase MAS1-producing Recombinant Escherichia coli Based on Support Vector Machine
    XIAO Yang ,  WANG Yonghua ,  YANG Bo
    2023, 39(1):59-68. DOI: 10.13982/j.mfst.1673-9078.2023.1.0136
    [Abstract](16) [HTML](39) [PDF 1.30 M](42)
    Abstract:
    In this study, the lipase MAS1 from marine actinomycetes (Streptomyces sp.) W007 was used as the research object, which was expressed in Escherichia coli BL21 (DE3) and associated fermentation conditions were optimized. First of all, the optimal induction time for the expression of lipase in recombinant Escherichia coli (E. coli) was determined by the single factor experiments to be the late logarithmic growth phase, with the optimal Isopropyl-β-D-thiogalactopyranoside (IPTG) concentration being 0.6 mmol/L, the optimal induction pH being 6.5, and the optimal induction temperature being 20 ℃. Then, the Box-Behnken test was designed by the R language rsm package, and was conducted in a 7 L fermentor to obtain the data. Finally, the optimal fermentation conditions for the expression of lipase MAS1 in the recombinant E. coli BL21(DE3) were calculated by support vector machine (SVM)-genetic algorithm (GA): the optimized IPTG concentration, induction temperature and induction pH were 0.65 mmol/L, 23 ℃ and 6.7, respectively, which led to the theoretical enzyme activity of lipase MAS1 as 2 276.99 U/mL. In the 7-L fermentor, the maximum enzyme activity of lipase MAS1 was 2 316.02 U/mL under the optimized fermentation conditions for culturing recombinant E. coli BL21(DE3). The above research results show that the SVM-GA exhibits good performance during the optimization of fermentation conditions for recombinant E. coli, which provides a research basis for the efficient preparation of lipase MAS1.
    8  Sample Preparation for Microbial Proteomics Analysis of Cantonese Soy Sauce
    CHEN Cong ,  LI Jun ,  WEN Linfeng ,  XU Ting ,  ZHANG Huiting ,  ZHONG Mengli ,  LIN Yinshan ,  CAO Yong ,  FU Jiangyan ,  LIU Zhan
    2023, 39(1):69-74. DOI: 10.13982/j.mfst.1673-9078.2023.1.0287
    [Abstract](15) [HTML](32) [PDF 929.01 K](32)
    Abstract:
    The long fermentation period, diverse microbial populations, and complex metabolites of Cantonese soy sauce have prevented the development of a standardized sample preparation method for microbial proteomics analysis. In the present study, two modified protein purification methods were compared, namely trichloroacetic acid (TCA) precipitation and ultrafiltration. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and LTQ Orbitrap Velos Pro ETD mass spectrometry were used to determine the efficacy of the two sample preparation methods for metaproteomics analysis of soy sauce microbes. Twenty-six distinct bands were observed in the SDS-PAGE patterns of protein samples prepared by TCA precipitation, and 13 were observed in samples prepared by ultrafiltration. 2 495 and 1 682 respective peptides were identified from the mass spectra obtained after trypsin digestion of protein samples prepared by the two methods, indicating that protein samples prepared by TCA precipitation were digested to a greater extent. Protein samples were prepared from soy sauce at different fermentation stages (0, 60, and 120 days) using the TCA precipitation method. After alkylation and enzyme digestion, these samples were subjected to protein analysis using LTQ Orbitrap Velos Pro ETD mass spectrometry and Proteome Discoverer 2.5 software, from which 1 035, 1 104, and 1 046 proteins were respectively identified. These results indicate that the preparation of samples for proteomics analysis by TCA precipitation provides the advantages of simple operation, rapid experimentation, and a high protein identification rate. It is thus suitable for use in proteomics testing and analysis of microbes in Cantonese soy sauce. The results of this study provide a scientific basis for proteomics analysis of the molecular mechanisms of microbial fermentation in Cantonese soy sauce.
    9  Microbial Community Structure of Huaiji Huangcai and Its Correlations with Physicochemical Properties and Quality
    YANG Xiao ,  LI Biansheng ,  RUAN Zheng ,  ZHANG Derun ,  LI Dandan ,  LEI Luehuan
    2023, 39(1):75-81. DOI: 10.13982/j.mfst.1673-9078.2023.1.0230
    [Abstract](14) [HTML](33) [PDF 1.08 M](45)
    Abstract:
    Huaiji Huangcai is a fermented radish greens product unique to Huaiji County in Zhaoqing City of Guangdong Province, China. It is produced through a meticulous, time-consuming, traditional fermentation process. Herein, we aimed to improve the traditional processing method to enhance Huaiji Huangcai quality and to elucidate the microbial community structure of naturally fermented Huangcai for the exploitation of its microbial resources. Four naturally fermented Huangcai products representative of the region were selected for microbial diversity analysis using amplicon sequencing. The core microorganisms affecting the quality of Huangcai were identified through redundancy and Spearman’s correlation analysis, with the aim of providing theoretical guidance for future industrialization of Huangcai production. The results indicate that naturally fermented Huangcai had high microbial diversity, with Lactobacillus, Weissella, Pediococcus, Methylobacterium, Pseudomonas, Sphingomonas, and Allorthizobium-Neorhizobium-Pararhizobium-Rhizobiu being the main bacterial genera. Bacterial species with the highest abundances included Lactobacillus plantarum subsp. plantarum, Lactobacillus alimentarius, Weissella cibaria, Pediococcus acidilactici, Agrobacterium larrymoorei, Lactobacillus ginsenosidimutans, and Pseudomonas azotoformans. Salinity, pH, water activity, and total acidity were the main factors affecting the bacterial community composition of Huangcai. Lactobacillus, Pediococcus, and Weissella were essential bacterial genera that enhanced Huangcai quality; at the species level, Lactobacillus plantarum subsp. plantarum, Pediococcus acidilactici, and Weissella cibaria contributed to the improvement of sour taste and color as well as maintaining Huangcai texture. Our study enabled the characterization of the microbial community structure of naturally fermented Huangcai and elucidated the relationships between the dominant bacteria and Huangcai quality, which is beneficial to quality control during Huangcai fermentation.
    10  Characterization of the Preparation and Optimization of Fucoxanthin Solid Lipid-core Microcapsules
    CHEN Yaxin ,  LIN Yongjie ,  YANG Ting ,  HE Niaoniao ,  CAI Shuyun ,  CHEN Hui ,  FANG Hua ,  HONG Zhuan ,  ZHANG Yiping
    2023, 39(1):82-91. DOI: 10.13982/j.mfst.1673-9078.2023.1.0091
    [Abstract](8) [HTML](44) [PDF 1.50 M](36)
    Abstract:
    Fucoxanthin solid lipid-core microcapsules (FX-MC) were prepared and subsequently characterized in this study. The conditions for the preparation of the microcapsules were optimized through a single factor experiment using the response surface methodology (RSM). Physiochemical properties of the microcapsules were then characterized using a scanning electron microscope (SEM), particle-size zeta potential analyzer, Fourier-transform infrared spectrometer (FT-IR), and a differential scanning calorimeter (DSC). The results revealed that the best microencapsulation process conditions were: Palm stearin: cholesterol 60:40 (m/m), FX:lipid 0.2:1 (m/m), wall-to-core ratio 25:1 (m/m), pH 4.5, and ultrasonic condition 240 W/3 min. The resultant encapsulation rate of the microcapsules was 96.24%, with a drug loading rate of 0.85% After freeze-drying the samples, the average particle size of the FX-MCs was 1 154 nm, with a PDI value of 0.27, and potential of -20.71 mV. A uniform particle size distribution and relatively stable solution was obtained. FT-IR analysis showed that fucoxanthin was successfully encapsulated within the microcapsule wall shell. DSC analysis confirmed that the highest enthalpy was required for FX-MC during phase change, and thermal stability showed a remarkable improvement. The results of this study can provide a reference for the further development and application of fucoxanthin in the food and healthcare industries.
    11  Comparison of the Structures and Physiochemical Properties of Polysaccharides Extracted from Plumula Nelumbinis by Different Methods
    FANG Jiaqin ,  ZHENG Qingsong ,  WEN Yuxin ,  ZHENG Danchun ,  YANG Yunjun ,  ZHAI Yongzhen ,  ZHANG Xia ,  LI Bing
    2023, 39(1):92-103. DOI: 10.13982/j.mfst.1673-9078.2023.1.0112
    [Abstract](10) [HTML](39) [PDF 1.82 M](73)
    Abstract:
    In this study, the effects of four different extraction methods, namely hot water extraction (HWE), ultrasonic-assisted extraction (UAE), enzyme-assisted extraction (EAE) and microwave-assisted extraction (MAE), on the physicochemical properties of polysaccharides from plumula nelumbinis were investigated. The results showed that compared with the traditional hot water extraction, the other three extraction methods could improve the yield, purity and uronic acid content of the plumula nelumbinis polysaccharides, with the microwave-assisted extraction method leading to the highest polysaccharide yield, polysaccharide purity and uronic acid content (4.37 %, 67.85% and 7.10%, respectively). The molecular weights of the polysaccharides obtained by the three auxiliary extraction methods were all reduced to different degrees. The contents of galactose in the plumula nelumbinis polysaccharides extracted by ultrasound-assisted and enzyme-assisted extraction were 16.51% and 9.66%, respectively, which were higher than that (4.93%) of the plumula nelumbinis polysaccharide prepared by the traditional hot water extraction, though no xylose was detected; the microwave-assisted extraction method and the hot water extraction method led to the same types of monosaccharides in the polysaccharides, with the former having a galacturonic acid content of 7.59% (which was higher than that of the latter). The endothermic peak ΔH value and crossover frequency of the plumula nelumbinis polysaccharide obtained via the microwave-assisted extraction were the highest (54.89 J/g and 50.23 rad/s, respectively), and this polysaccharide solution had a higher apparent viscosity compared with the solutions of the other polysaccharides. Therefore, the microwave-assisted extraction method is more suitable for the extraction of polysaccharides from plumula nelumbinis.
    12  Comparison on the Antioxidant and Anti-inflammatory Activities of Extracts from Canarium album L before and after Pickling
    NIE Wen ,  DENG Guangdie ,  XU Xinyu ,  HU Haie ,  LI Xueli ,  HE Liping
    2023, 39(1):104-112. DOI: 10.13982/j.mfst.1673-9078.2023.1.0144
    [Abstract](14) [HTML](35) [PDF 1.41 M](71)
    Abstract:
    The changes in the antioxidant and anti-inflammatory activities of the extracts from Canarium album L after pickling were investigated. The antioxidant activities of different extracts were evaluated by the DPPH•scavenging assay, ABTS+• scavenging assay and total reducing power assay. The anti-inflammatory activity was evaluated through establishing a lipopolysaccharide-induced RAW264.7 macrophage model. The compositions of the extracts from Canarium album L after pickling were identified by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass/mass spectrometry (UPLC-Q-TOF-MS). The results showed that the water, 70% ethanol and ethyl acetate extracts from the fresh Canarium album L had total phenolic contents of 70.33~126.42 mg/g and total flavonoid contents of 3.46~6.19 mg/g. After pickling, the three corresponding extracts had total phenolic contents of 78.67~150.92 mg/g and total flavonoid contents of 4.09~6.65 mg/g, with 11 polyphenolic compounds being identified by UPLC-Q-TOF-MS/MS. The order of the antioxidant capacity for the extracts from fresh Canarium album L was 70% ethanol > ethyl acetate > water, with the IC50 values of the 70% ethanol extract for scavenging DPPH and ABTS+ free radicals being 0.09 mg/mL and 0.03 mg/mL, respectively. After pickling, the ethyl acetate extract had the highest antioxidant capacity, with its IC50 values for scavenging DPPH and ABTS+ free radicals being 0.05 mg/mL and 0.02 mg/mL, respectively. At the concentration of 0.10 mg/mL, the NO inhibitory rates in the LPS-induced inflammation model were 7.51%~30.47% for the extracts from fresh Canarium album L extract and 10.84%~34.85% for the extracts from pickled Canarium album L. The above results showed that the antioxidant and anti-inflammatory activities of the extracts from pickled Canarium album L were higher than those of the fresh Canarium album L. Therefore, pickled Canarium album L has a potential to be used as raw materials for developing related functional food products.
    13  Comparison of the Antioxidant and Tyrosinase Inhibitory Activities of Different Types of Honey
    ZHANG Min ,  HUANG Jingping ,  ZHAO Wen ,  WANG Peng ,  JIN Yue ,  HU Han ,  XUE Xiaofeng ,  ZHANG Jinzhen
    2023, 39(1):113-119. DOI: 10.13982/j.mfst.1673-9078.2023.1.0202
    [Abstract](36) [HTML](49) [PDF 867.48 K](30)
    Abstract:
    In this study, the spectrophotometric method was used to determine the total phenolic acid contents, total flavonoid contents and tyrosinase inhibitory activities of 10 kinds of honey. Their antioxidant activities were evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity and ferric ion reducing antioxidant power (FRAP) assays. The results showed the contents of the total phenolic acids and flavonoids in the 10 kinds of honey were 116.16~2 133.33 mg PCA/kg and 8.31~120.81 mg QUE/kg, respectively. The IC50 values of DPPH honey samples were 16.25~674.22 mg/mL. The FRAP values were 0.50~7.39 mmol Fe2+/kg. The IC50 values of tyrosinase inhibition were 9.15~350.26 mg/mL. The buckwheat honey exhibited a significantly higher DPPH radical scavenging ability (16.25 to 45.83 mg/mL), FRAP (3.21 to 7.39 mmol Fe2+/kg) and tyrosinase inhibitory activity (9.14 to 14.16 mg/mL), compared with other kinds of honey (p<0.05). The antioxidant and tyrosinase inhibitory activities of honey were significantly correlated with the contents of total phenolic acids and flavonoids in honey (p<0.05). This study provides a basis for the development of honey-based functional products.
    14  Antibacterial Effect of Citronellal against Staphylococcus aureus
    ZHANG Mao ,  ZHANG Yehui ,  LI Hui ,  XIAO Xinglong ,  YU Yigang
    2023, 39(1):120-126. DOI: 10.13982/j.mfst.1673-9078.2023.1.0207
    [Abstract](5) [HTML](34) [PDF 1.00 M](40)
    Abstract:
    The minimal inhibitory concentration of Citronellal against Staphylococcus aureus was determined using broth dilution, and the results were analyzed using a time-kill curve. Citronellal showed a rapid bactericidal effect at a minimum concentration of 0.80 mg/mL. After treating Staphylococcus aureus with 1.60 mg/mL of Citronellal for 0.5 h, the live bacteria count decreased from 5.65 log CFU/mL to 0.00 CFU/mL. After Citronellal treatment, the extracellular potassium ion concentration of Staphylococcus aureus increased significantly to 2.63 mg/L, and the fluorescence intensity of propidium iodide was 5 326.83 A.U. greater than that of the control group. This demonstrated that Citronellal can affect the permeability of Staphylococcus aureus cell membranes, causing leakage of intracellular micro- and macromolecules. Scanning electron microscopy results showed that high concentrations of Citronellal could seriously damage the morphology and structure of Staphylococcus aureus cells. UV-visible spectrum analysis showed that after adding Staphylococcus aureus DNA to Citronellal, the absorption peak exhibited a clear enhancement effect, with a maximum difference of 0.45 A.U. compared with the control group. This suggested that Citronellal interacts with DNA via groove binding, interfering with the normal biological function of DNA, and inhibiting cell growth. In conclusion, Citronellal could be used as a natural and efficient bacteriostatic agent preventing the growth of Staphylococcus aureus by destroying cell membrane integrity, altering DNA structure, and interfering with normal physiological activities of the bacterial cells. This study provides a theoretical basis for the application of Citronellal in the food industry.
    15  Changes in the Stability of Folate in Strawberries after Ascorbic Acid Impregnation
    TAN Mei ,  ZHANG Jingxuan ,  PAN Jingru ,  MENG Ziyi ,  HU Qingxin ,  LIN Zhiyi ,  WANG Chao ,  DUAN Hanying
    2023, 39(1):127-133. DOI: 10.13982/j.mfst.1673-9078.2023.1.0243
    [Abstract](13) [HTML](39) [PDF 933.92 K](29)
    Abstract:
    Ascorbic acid (AsA) was impregnated in strawberries under vacuum (0.09 MPa) and atmospheric pressure to compare the impregnation rate and stability of folate and freshness of strawberries after impregnation. The texture and folate content in strawberries impregnated with AsA during a 8-day cold storage were also investigated. The results indicated that vacuum impregnation resulted in a faster mass transfer rate (k2 = 0.01) with a higher AsA concentration (1.24 mg/g). The folate content in strawberries was 100–128 μg/100 g; the main types of folate were 5-methyltetrahydrofolate, tetrahydrofolate, 5,10-methylenetetrahydrofolate, and folate degradation products or synthetic substrates para-aminobenzoic acid. After 8 days of refrigeration, the tetrahydrofolate content decreased by 7.70% and 42.51% in the vacuum impregnation and control groups, respectively. The para-aminobenzoic acid content in the vacuum impregnation and control groups increased by 57.13% and 77.89%, respectively. No significant change was observed in the 5-10 methylenetetrahydrofolate content (p>0.05). The 5-methyltetrahydrofolate content in the vacuum impregnation and control groups increased by 24.47% and 12.67% on day 4, respectively. Microstructure analysis indicated that after 8 days of refrigeration, hardness of strawberries in the vacuum impregnation group (92.60 N) was significantly higher than that in the control group (57.20 N). Therefore, vacuum AsA impregnation inhibited the degradation of tetrahydrofolate (p<0.05), thereby enhancing the stability of folate in cold storage and protecting the texture of strawberries. This study provides a theoretical basis and reference for improving the stability of folate in strawberries.
    16  Effect of Ozonated Water Treatment on the Microbial Community Structure of Grass Carp Fillets during Storage
    XU Guodong ,  AN Yueqi ,  XIONG Shanbai ,  YIN Tao ,  QIN Fengyang ,  CHEN Ping ,  YOU Juan
    2023, 39(1):134-143. DOI: 10.13982/j.mfst.1673-9078.2023.1.0255
    [Abstract](8) [HTML](29) [PDF 1.63 M](25)
    Abstract:
    To determine the effect of ozonated water treatment on the microbial community structure of prepared aquatic products, high-throughput sequencing technology was used to investigate the effects of different ozonated water treatment methods (rinsing and soaking) and storage temperatures (4 and 10 ℃) on the bacterial community composition and diversity of grass carp fillets. The sensory score and total volatile basic nitrogen content in the ozonated water rinsing group 1 day after storage at room temperature were significantly higher than the ozonated water soaking and control groups. Compared with the control group, the ozonated water rinsing and soaking groups had decreased Shannon, ACE, and Chao1 indices, increased Simpson index, and significantly decreased Streptococcaceae and Aeromonadaceae relative abundance. The Shannon index of the ozonated water-treated grass carp fillets decreased when stored at 4 or 10 ℃ and the Simpson index increased compared with the control group. After storage at 4 ℃, Acinetobacter and Serratia abundances were significantly decreased, whereas Buttieuella and Lactococcus abundances were significantly increased in the ozonated water-treated grass carp fillets compared with the control group. At 10 ℃, Acinetobacter was significantly decreased, but Serratia and Pseudomonas abundances were significantly increased in the ozonated water-treated grass carp fillets (p<0.05). In conclusion, ozonated water treatment significantly altered the bacterial community structure and decreased the bacterial diversity of grass carp fillets. Post-treatment storage temperature also exerted a substantial effect on bacterial community structure.
    17  Application of Different Varieties of Potato Flakes in Instant Mashed Potatoes
    ZHAO Yuci ,  LIU Lin ,  DUAN Wensheng ,  ZENG Fankui ,  SHI Ying ,  ZHANG Hai ,  LIU Gang
    2023, 39(1):144-151. DOI: 10.13982/j.mfst.1673-9078.2023.1.0221
    [Abstract](8) [HTML](33) [PDF 1.03 M](35)
    Abstract:
    Dongnong 310 is an indigenous potato variety suitable for whole powder processing. Herein, mashed potatoes prepared using Dongnong 310 and Atlantic (introduced for potato flakes variety) were compared in terms of nutrients, texture, volatile flavor compounds, and sensory evaluation. The results showed that the content of dry matter, protein, and starch of Dongnong 310 potato flakes were lower than those of Atlantic potato flakes. Regarding mineral elements, the calcium content was lower, whereas phosphorus, iron, magnesium, and potassium contents were higher in the Dongnong 310 samples than in the Atlantic samples. Water absorption was lower in the Dongnong 310 sample than in the Atlantic sample. The two potato flakes had the same lightness but Dongnong 310 was yellower and greener. When the same proportion of potato flakes was added, the hardness and cohesiveness of Atlantic mashed potato were more similar to those of mashed potatoes made commercially, whereas Dongnong 310 potato had a softer texture and lower cohesion and was more palatable. Gas chromatography-mass spectrometry analysis showed that Dongnong 310 was the key aroma substance of potato because of its high content of aldehydes and low odor threshold, and thus had a greater impact on the intense flavor. Mashed potatoes prepared from Dongnong 310 potato flakes were richer in nutrients, had more intense flavor and softer texture than those prepared from Atlantic potato flakes. A slight increase in the proportion can lead to a texture similar to that of commercially available mashed potatoes, which is suitable for processing into mashed potatoes.
    18  Quality Change of Fried Chicken Nuggets with Chicken Breast Substituted by Mycoprotein
    ZENG Yan ,  ZHANG Xuewen ,  LI Demao ,  WANG Qinhong ,  SUN Yuanxia
    2023, 39(1):152-159. DOI: 10.13982/j.mfst.1673-9078.2023.1.0073
    [Abstract](16) [HTML](33) [PDF 905.50 K](37)
    Abstract:
    To explore the application feasibility of mycoprotein in meat products, mycoprotein was used to replace different proportions of chicken breast during the preparation of fried chicken nuggets. The nutritional composition as well as the cooking loss, color, texture properties and sensory scores of the products were evaluated. The results showed that the contents of protein, fat and total dietary fiber for the fried chicken nuggets with 20%~60% of chicken breast replaced by mycoprotein were 21.12~18.78 g/100 g, 9.98~10.48 g /100 g and 2.22~5.23 g/100 g, respectively. With an increase in the proportion of mycoprotein, the cooking loss of fried chicken nuggets decreased from 19.19% to 16.28%, the hardness increased from 4.48 N to 5.97 N, with the elasticity showing a trend of initial increase then decrease. Compared to the product without mycoprotein, the chicken nuggets with 20% chicken breast replaced by mycoprotein had a slightly different nutritional composition and essentially identical tenderness (p>0.05), although its brightness (L* 67.60) increased and its chewiness and elasticity increased by 43.95% and 17.95%, respectively (p<0.05), resulting in good sensory acceptance. Taken together, mycoprotein can be used in production of new fried chicken nuggets. Thus, this study provides technical support for the application and development of mycoprotein as a substitute/alternative for animal protein.
    19  Development of Nutritionally Balanced Animal and Plant Blend Oil
    YU Haikun ,  LIU Aicheng ,  CHEN Jiali ,  LI Mohan ,  YANG Mei ,  YANG Liu ,  YUE Xiqing
    2023, 39(1):160-169. DOI: 10.13982/j.mfst.1673-9078.2023.1.0215
    [Abstract](13) [HTML](41) [PDF 1.35 M](43)
    Abstract:
    In order to better meet the requirements of fatty acid balance for adults and meet the demands of consumers for nutritional and healthy oils, 11 kinds of common vegetable oils and fractionated butter were used as the raw materials. On the premise of meeting the requirements of fatty acid balance and nutrient content, the price is taken as the index, and the MATLAB software was used for modeling and programming to obtain the formula of nutritionally balanced animal and vegetable blend oil. The blending process was optimized by the single factor and orthogonal experimental designs, and the shelf life was predicted. The results showed that the proportion of nutritionally balanced animal-plant blend oil was as follows: fractionated butter 8.00%, corn oil 16.40%, flaxseed oil 72.20%, sesame oil 3.40%; the unit price was 0.28 yuan per 100 ml, The actual measurements revealed the composition as follows: saturated fatty acids, 12.78%; ω-6/ω-3 polyunsaturated fatty acids (PUFA) ratio, 5.99 (which was between 4 and 6:1); the mass ratio of monounsaturated fatty acids (MUFA) to PUFA, 0.96 (which basically meets the required MUFA-to-PUFA ratio of 1:1). The fatty acid ratio of the blend oil was consistent with the expected value. The optimum blending process was as follows: stirring time, 30 min; TBHQ addition, 15 mg; stirring temperature, 20 ℃. The nutritionally balanced animal and plant blend oil had a shelf life of 18 months. The results of this study lay a theoretical foundation for the development of nutritionally balanced and healthy blend oils, and provide a new path for edible oil enterprises to develop new products.
    20  Discriminant Model of Maturity of Red Globe Grapes Based on Visible/Near-infrared Spectroscopy
    GAO Sheng ,  XU Jianhua
    2023, 39(1):170-176. DOI: 10.13982/j.mfst.1673-9078.2023.1.0252
    [Abstract](11) [HTML](34) [PDF 1.05 M](30)
    Abstract:
    Maturity is an important criterion for evaluating fruit, as it directly affects the quality and economic value. A discriminant model based on visible/near-infrared spectroscopy was established to determine the maturity of red globe grapes to simplify the process of assessing the maturity, uneven nutritional value, and low competitiveness of red globe grapes. Spectral information on the samples was collected from four stages of the red globe grapes growth period (immature, semi-mature, mature, and super-mature). The spectral band of 550~1 000 nm was selected for modeling. Pre-processed spectra were extracted by competitive adaptive reweighted sampling, uninformative variable elimination, and successive projection algorithm (SPA) to establish the discriminant models of support vector machine, extreme learning machine (ELM), and partial least squares discriminant analysis (PLS-DA), respectively. The best discriminant classification model for the maturity of red globe grapes based on visible/near-infrared spectroscopy was established. The results showed that the ELM model for discrimination and classification of maturity, established by applying the SPA for feature wavelength extraction after spectral pre-processing using the Savitzky–Golay (SG) algorithm showed the best results, followed by the support vector machine model and then the PLS-DA model. Therefore, the best discriminant classification model for red globe grape maturity was SG-SPA-ELM. The accuracy of this model was 97.50% and 96.67% for the training sets and test sets. Therefore, visible/near-infrared spectroscopy can be applied to determine the maturity of red globe grape using a non-destructive method.
    21  Anticancer Activity Evaluation of Selenium-enriched Pleurotus ostreatus Fungus Powder and Development of Selenium-enriched Sugar Substitute Bread
    YU Jialian ,  DING Jinghua ,  LUO Xiaoqi ,  LI Guokun ,  DONG Jiahua ,  HUANG Yongying ,  CHEN Xiaoyi
    2023, 39(1):177-184. DOI: 10.13982/j.mfst.1673-9078.2023.1.0220
    [Abstract](10) [HTML](28) [PDF 1.05 M](30)
    Abstract:
    Selenium (Se)-enriched Pleurotus ostreatus fungus powder with different total Se concentrations was used in combination with 5-FU to treat HepG2 hepatocellular carcinoma cells. The CCK-8 and flow cytometry double staining methods were applied to investigate the tumor suppressive effect of Se-enriched P. ostreatus fungus powder combined with 5-FU. The Se-enriched P. ostreatus fungus powder was then used as the raw material to develop a Se-enriched sugar substitute bread, providing scientific evidence for the development of Se-enriched functional foods. The results demonstrate that the Se-enriched P. ostreatus fungus powder had an inhibitory effect on the proliferation of HepG2 hepatocellular carcinoma cells, with the inhibition rate ranging from 13.89% to 27.39%. The number of apoptotic cells in HepG2 hepatocellular carcinoma increased in a concentration-dependent manner after treatment with different total Se concentrations of Se-rich P. ostreatus fungus powder combined with 5-FU for 36 h (p<0.05). The total apoptosis rates were 26.36%~49.72%, respectively, and the apoptosis rates were higher than those in the 5-FU group (p<0.05). The optimal processing formula of Se-enriched sugar-substitute bread was as follows: 0.06 g Se-enriched P. ostreatus fungus powder was added to 200 g flour with 25 g compound sugar substitute and baked at 175 °C for 20 min; the total Se content was 0.174±0.011 mg/kg. In conclusion, when HepG2 hepatoma cells were treated with Se-enriched P. ostreatus fungus powder at different total Se concentrations combined with 5-FU, HepG2 hepatoma cell growth was inhibited, increasing the efficiency of detoxification. The optimal processing formula of Se-enriched sugar substitute bread, which has various research and application values, was also developed.
    22  Inhibition of Fructose Hygroscopicity by Wheat Gluten and Its Main Components
    WANG Shuangshuang ,  LI Bin ,  LI Jing
    2023, 39(1):185-195. DOI: 10.13982/j.mfst.1673-9078.2023.1.0305
    [Abstract](13) [HTML](48) [PDF 1.69 M](30)
    Abstract:
    In order to improve the agglomeration and deliquescence of fructose owing to its strong hygroscopicity, the effect of adding wheat gluten (WG) on the hygroscopic properties of freeze-dried fructose were investigated using characterization methods, including hygroscopic curves and isotherms, macroscopic morphological analysis, determination of contact angles, and low-field NMR. Subsequently, the differences in the effects of the two main components of WG, gliadin and glutenin, were compared. The results showed that the addition of WG considerably reduced the equilibrium moisture content (EMC) of the freeze-dried fructose samples. Under conditions of 25 ℃ and 75% relative humidity, the EMCs were 36.33%, 16.00% and 14.61% when the respective mass ratios of fructose to WG were 10:0, 3:7, and 2:8. As the proportion of WG increased, the degree of agglomeration of the sample decreased, whilst the contact angle increased from 11.3 ° to 94.8 °. The Peleg model accurately described the water adsorption process of the fructose-protein system. The EMC of the sample with the addition of glutenin was lower, with a smaller amount of agglomeration compared to that of gliadin. Furthermore, the contact angle of glutenin (88.2 °) was greater than that of gliadin (64.6 °). Low-field NMR results showed that glutenin was more effective at reducing the degree of moisture freedom compared to gliadin. These results demonstrate that WG and its main components have a significant inhibitory effect on the hygroscopicity of fructose, and that glutenin is more effective compared to gliadin for the inhibition of moisture absorption.
    23  Comparison of FT-NIR Spectral Pretreatment and Characteristic Band Screening for Baijiu-based Liquor
    ZHU Xuemei ,  TUO Xianguo ,  ZHANG Guiyu ,  ZHAI Shuang ,  LUO Lin ,  LUO Qi
    2023, 39(1):196-204. DOI: 10.13982/j.mfst.1673-9078.2023.1.0271
    [Abstract](32) [HTML](42) [PDF 1.33 M](27)
    Abstract:
    To classify baijiu base wine, reduce the classification error of baijiu base wine, and reduce the harm of base wine to the body of Baijiu Based Liquor pickers, 18 pretreatment methods and three characteristic wave screening methods were selected to reduce irrelevant interference information in the spectrum and complexity of the modeling data. The Fourier-transform near infrared spectra of baijiu base wine were divided into datasets using SPXY and preprocessed, and then subjected to Mahalanobis distance anomaly elimination, eigenwave screening, and support vector machine regression prediction. After multiplicative scatter correction, the classification accuracy of training set prediction was 100%. Principal component analysis can be combined with specific algorithms to achieve accurate classification; studies are needed to combine this analysis with other algorithms. Uninformative variables elimination and competitive adaptive reweighted sampling can achieve efficient feature wavelength extraction, with an average accuracy of prediction of close to 90%. The experimental results showed that the processed spectral data accounted for up to 47.57% of the original data, the complexity of the regression model was reduced, and the accuracy of the model was improved after pretreatment and characteristic wavelength selection of the near-infrared spectrum of the base wine.
    24  Comparison on Sterilization Effect and Quality Change of Passion Fruit Pulp Prepared by Different Non-thermal Processing Technologies
    ZHENG Chuyao ,  ZHANG Sinan ,  WU Yuanbin ,  JIANG Zhuo
    2023, 39(1):205-212. DOI: 10.13982/j.mfst.1673-9078.2023.1.0133
    [Abstract](6) [HTML](44) [PDF 1.28 M](26)
    Abstract:
    To evaluate the influences of different non-thermal methods on the sterilization effectiveness and quality of raw fruit and vegetable materials, high hydrostatic pressure (HHP) technology, cold plasma (CP) technology, and irradiation technology were applied to sterilize freshly pressed passion fruit pulp. The results indicated that the three non-thermal treatments could inhibit and kill to certain extents the microorganisms in the pulp (2.15 lg(CFU/g), 2.44 lg(CFU/g), 2.34 lg(CFU/g), respectively). The number of colonies in the pulp was lower than 1 lg (CFU/g) after the treatment at a pressure of 300 MPa and above and the treatment with an irradiation dose of 3 kGy, indicating that both methods had a good sterilizing effect on passion fruit pulp. In order to explore further the effect of HHP treatment on the storage period of fruit pulp, this study also investigated the changes in the microbial contents of fruit pulps with and without a high hydrostatic pressure treatment during the storage at -18 °C for 9 months. The experiments showed that the microbial contents of the passion fruit pulps treated at 500 MPa and 600 MPa were still in compliance with the National Safety Regulation after being stored at -20 °C for 9 months (both<2 lg (CFU/g)). In terms of physico-chemical characteristics, the HHP technology and CP technoldogy coul effectively retain the color (ΔE<2) and flavor (p>0.05) of the fruit pulp, and exerted certain inhibitory effects on the activities of POD and PPO enzymes, although the irradiation treatment could not inactivate the PPO enzyme. In summary, the HHP technology can effectively kill the microbiam colonies in the passion fruit pulp while retaining better the quality of the pulp. Therefore, HHP technology has good commercial application prospects in processing passion fruit pulp.
    25  Comparison of Roasting Process of Naked Pumpkin Seeds under Different Roasting Pretreatment Methods
    LIU Zhanxia ,  WU Hong ,  GUO Huijing ,  LI Binbin ,  WU Hongbin ,  JIA Wenting ,  YANG Hui
    2023, 39(1):213-221. DOI: 10.13982/j.mfst.1673-9078.2023.1.0280
    [Abstract](6) [HTML](51) [PDF 1.08 M](24)
    Abstract:
    To explore the effect of different baking pretreatment methods on the roasting process of naked pumpkin seeds, the basic components; color; texture; sensory evaluation by electronic nose; fatty acid, mineral, total phenol, and tocopherol contents; and antioxidant activity of roasted pumpkin seeds were assessed after four different types of roasting pretreatments: sun dried unroasted, wet salted roasted, dry salted-roasted, and unsalted-roasted. The results showed that wet salted roasting pretreatment retained the highest levels of basic nutrients in pumpkin seeds, with a total fatty acid content of 99.46 mg/100 g. Unsaturated fatty acid content accounted for 79.50%. The total contents of five minerals reached 203.96 mg/100 g, and the total phenol and tocopherol contents were 2.65 and 11.65 mg/g, respectively; OH, DPPH, and ABTS+ clearance rates were 55.36%, 69.25%, and 85.12%, respectively, which were significantly higher than those in the other treatment groups (p<0.05). Thus, wet salt soaking is an important step and most suitable pretreatment method for roasting pumpkin seeds. Therefore, the naked pumpkin seeds roasted with wet salt can be incorporated into vegetable protein food with good sensory qualities, good flavor, and a strong antioxidant capacity.
    26  Evaluation on the Skin-care Efficacy of the Viscera Enzymatic Hydrolysates and Body Wall Extracts of Sea Cucumber Apostichopus japonicus
    MI Rui ,  ZHOU Zunchun ,  MENG Nan
    2023, 39(1):222-229. DOI: 10.13982/j.mfst.1673-9078.2023.1.0092
    [Abstract](10) [HTML](46) [PDF 1.15 M](30)
    Abstract:
    The by-products of sea cucumber Apostichopus japonicus processing were taken as the experimental materials in this study. The enzymatic hydrolysates from the body wall of sea cucumber were used as the controls. The moisturizing, sunscreen, anti-oxidation, whitening and anti-aging functions of the enzymatic hydrolysates of the viscera and the body wall extracts were examined, with the aim to evaluate the skin-care effects of the by-products from sea cucumber processing. The experimental data showed that the enzymatic hydrolysates of viscera and the body wall extracts were more potent than the enzymatic hydrolysates of body wall in moisturizing, sunscreen, anti-oxidation and anti-aging functions. The comprehensive evaluations revealed that the moisturizing and anti-aging functions of the viscera enzymatic hydrolysates were the best: at of 81% RH for 12 h, the moisture absorption and retention were 52.51% and 95.04%, respectively, and the elastase inhibition rate was 26.34%. The body wall extracts showed the greatest sunscreen and anti-oxidation effects: in UVC and UVB wavelength ranges, the average UV absorption rates were 94.52% and 33.89%, the IC50 value for the DPPH free radical was 3.00 mg/mL, and the total antioxidant capacities were 4.48 mmol/g and 5.91 mmol/g for ABTS and FRAP, respectively. In terms of the whitening function, the IC50 values of tyrosinase inhibition for the body wall extracts and the viscera enzymatic hydrolysates of were 49.43 mg/mL and 40.00 mg/mL, respectively, which were lower than that of the body wall enzymatic hydrolysates (IC50=16.82 mg/mL). However, they could still exert a significant whitening effect. In practice, the combined application of two kinds of by-products by taking advantage of their skin-care functions, or the use of body wall enzymatic hydrolysates as the complementary products in skin care could realize the highly effective development and utilization of the by-products from sea cucumber processing.
    27  Effects of Physical Treatments on the Physicochemical and Digestive Properties of Tenebrio molitor Larvae Protein Isolates
    WANG Jinmei ,  JIANG Yiqun ,  MU Lixia ,  LUO Zhaojiao ,  MENG Hecheng
    2023, 39(1):230-237. DOI: 10.13982/j.mfst.1673-9078.2023.1.0260
    [Abstract](8) [HTML](44) [PDF 1.17 M](40)
    Abstract:
    The Tenebrio molitor larvae protein isolate (TPI) was first extracted via alkaline solubilization and acid precipitation. Subsequently the effects of heat treatment and dynamic high-pressure microfluidization on the physicochemical, functional properties and the in vitro bioaccessibility of the TPI were investigated. The results showed that the higher order structure of native TPI was mainly stabilized through hydrophobic interaction, hydrogen bonds, and disulfide bonds. TPI aggregates could be induced by both heat and microfluidization, of which the aggregation was possibly dominated by hydrophobic interactions. The solubility of the TPI decreased slightly after heat treatment, likely due to the exposure of the hydrophobic groups inside the protein impairing the interaction between the TPI and water molecules. The mechanical force of microfluidization improved the interaction between the TPI and water molecules and distinctly increased TPI solubility, which was positively correlated with the pressure level. Under neutral conditions, the solubility of the TPI after microfluidization at 50 and 100 MPa was elevated from 24.05% to 50.08% and 64.81%, respectively. The emulsifying and foaming properties of the TPI were improved by heat treatment, although this weakened the emulsifying stability. Microfluidization increased the foaming stability of the TPI yet had no considerable impact on its emulsifying properties and foaming capacity. Both types of physical treatments increased the in vitro bioaccessibility of the TPI, since the nitrogen releases of 90 ℃ and 120 ℃ heat-treated TPI were reduced from 39.53 % to 35.58% and 33.90%, respectively. Furthermore, the TPI subunits at approximately 17 ku could not be hydrolyzed thoroughly after microfluidization.
    28  Optimization of Superfine Comminution Technology and Properties of Zizyphus Jujube using Response Surface Methodology
    DING Hua ,  WEI Jia ,  LIN Lijing ,  LIU Yijun ,  ZHANG Ping
    2023, 39(1):238-246. DOI: 10.13982/j.mfst.1673-9078.2023.1.0218
    [Abstract](7) [HTML](38) [PDF 1.35 M](47)
    Abstract:
    Xinjiang jujube was used as the raw material and optimized using response surface methodology in combination with superfine comminution technology to investigate the effects of pretreatment time, ethanol concentration, material-to-liquor ratio, and superfine comminution time on particle size, physical and chemical properties, and apparent properties of superfine jujube powder. The optimal preparation conditions were as follows: material-to-liquor ratio of 1:3 (g/mL), pretreatment time of 53 h, alcohol concentration of 60% (V/V), and comminution time of 4 min. The powder particle size was 28.47 μm under these conditions. After superfine comminution, the total sugar, reducing sugar, and sucrose contents decreased by 42.22%, 39.06%, and 74.78%, respectively, in superfine jujube powder. The dissolution rate of amino acids and proteins increased significantly (p<0.05). The brightness, angle of repose, slip angle, and bulk density were also increased after superfine comminution. Additionally, the wetting time was shortened by 41.99%, indicating that the wettability of the powder was improved. The water-holding capacity and swelling capacity of the superfine jujube powder decreased by 60.30% and 56.28%, respectively, suggesting that superfine comminution reduced the hydration capacity of the powder. The main structure and functional groups of the superfine jujube powder were only slightly changed according to scanning electron microscope analysis and Fourier-transform infrared spectroscopy. Compared with the traditional pulverizing process, the superfine jujube powder obtained using this method was of higher quality and free of additional materials, which is beneficial for patients who require blood glucose monitoring. We developed an efficient method with broad application prospects for preparing superfine jujube powder.
    29  Polyphenol Fraction and Prebiotic Activity of Apple Peel Extract
    HE Ziqian ,  ZHENG Bisheng ,  DENG Na ,  YUAN Ling ,  LI Wenzhi
    2023, 39(1):247-253. DOI: 10.13982/j.mfst.1673-9078.2023.1.0108
    [Abstract](11) [HTML](46) [PDF 1.60 M](58)
    Abstract:
    Apple peel extract is a by-product of apple sauce, apple juice and other products. To investigate its probiotic properties, apple peel extract (APE) was extracted using 80% acetone. The polyphenol components of the extract were determined using high-performance liquid chromatography. Changes in biomass, pH and polyphenol components were then tracked for 24 h using in vitro anaerobic fermentation. The pH value of the fermentation broth was kept at 3.66~4.00 (42.86%~47.71% lower than that of the control group). A total of 13 types of polyphenol were identified from APE. The main polyphenols were phlorizin (515.54 mg/100 g), hyperoside (530.06 mg/100 g) and quercitrin (459.04 mg/100 g). The growth of Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus paracasei, and Lactobacillus rhamnosus was significantly promoted by the apple peel extract compared with the control group. During the fermentation process, phlorizin was consumed 93.36%, 89.21%, 86.31%, and 0.41% by each bacterium, respectively. The results showed that apple peel extract possesses a rich composition of polyphenol monomers, which potentially could regulate the growth and metabolism of intestinal probiotics.
    30  Changes in the Oxidation Stability of Walnut Blend Oil at Different Cooking Temperatures
    XU Danya ,  JIAO Yunqi ,  YAN Hao ,  LU Liangliang ,  LI Xiaoman ,  LIU Fenglan ,  KONG Lingming ,  SUN Li’na
    2023, 39(1):254-261. DOI: 10.13982/j.mfst.1673-9078.2023.1.0044
    [Abstract](8) [HTML](45) [PDF 1.23 M](76)
    Abstract:
    In order to maintain nutritional and thermal stability of walnut oil during thermal processing, walnut oil was blended with flaxseed oil, peanut oil, safflower oil and rapeseed oil. According to the intake of fatty acids recommended by the Chinese Nutrition Society, the proportion of each raw material in walnut blend oil was calculated by a mathematical model. Nutritionally balanced walnut blend oils containing 1%, 5%, 15% and 25% walnut oil, respectively, were developed. The changes in peroxidation value, anisidine value and total oxidation value as well as quality and fatty acid content of walnut oil were analyzed at the temperatures of Chinese cooking. The results showed that the ratios of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) of the four kinds of blended oils were close to 0.27:1:1, and n-6/n-3 fatty acids were all within the recommended value range of (4~6):1, which met the human body’s requirement for a balanced intake of fatty acids. The peroxidation value, aniside value and total oxidation value of the 1%, 5%, 15% and 25% blend oils increased with an increase of heating temperature, and the PUFA/SFA ratio at 210 ℃ decreased by 0.30%, 0.39%, 0.70% and 0.96% compared with pure walnut oil, respectively. Compared with the pure walnut oil, the MUFA/PUFA ratio increased by 0.03%, 0.07%, 0.11% and 0.14%, respectively. The ratio of n-6/n-3 fatty acids ranged within 4.42~5.76, with the peroxide value, anisidine value and total oxidation value all lower than those of the pure walnut oil. These results indicate that the blending of pure walnut oil with certain oils could help to slow down the formation of oxides while improving oil’s thermal stability and maintaining a dietary balance of fatty acids.
    31  Process Analysis of the Stewing Method of Chicken Soup Based on A Combi-steamer
    CHEN Lilan ,  CHEN Zuming ,  YUAN Can
    2023, 39(1):262-269. DOI: 10.13982/j.mfst.1673-9078.2023.1.0262
    [Abstract](13) [HTML](46) [PDF 1.22 M](41)
    Abstract:
    To explore the relationship between the stewing mode and chicken soup quality, the free amino acid and volatile flavor substance contents of chicken soup under different stewing modes were analyzed using a combi-steamer. Differences in the odor and taste of chicken soup under different stewing modes were analyzed using electronic nose and electronic tongue. The differences in the flavor of chicken soup were examined using principal component, cluster analysis, and Pearson correlation coefficients to determine the stewing conditions of chicken soup in the universal steam oven. The results showed that the chicken soup stewed under this condition was light yellow with small oil slick on the surface; the soup had an obvious fresh flavor, strong aroma, mellow taste, and clear sweet aftertaste. The total content of free amino acids in the soup reached 117.97 mg/100 g. There were 39 volatile flavor substances, including 15 aldehydes, 9 alcohols, 8 esters, 3 ketones and 4 others. Comparison of samples prepared using six stewing modes showed that those stewed in mode 4 (steaming mode, 100% humidity; after cooking at 140 ℃ for 20 min; after cooking at 100 ℃ for 60 min), which is an energy-saving stewing mode, had good flavor, relatively high total free amino acid content, rich volatile flavor substances, and relatively short stewing time, which imparts a good flavor to the finished product.
    32  Correlation Analysis of Bacterial Communities and Volatile Flavor Compounds of Naturally Fermented Mutton Sausages from Different Processing Environments
    NIU Yin ,  YIN Liguo ,  YANG Ziyao ,  WANG Jie ,  DAO Xiaofang ,  LIN Yaqiu ,  CHEN Juan
    2023, 39(1):270-280. DOI: 10.13982/j.mfst.1673-9078.2023.1.0257
    [Abstract](31) [HTML](42) [PDF 1.52 M](28)
    Abstract:
    To investigate the differences in the physical and chemical properties and flavor quality of mutton sausages under different processing environments, the conventional physical and chemical characteristics, bacterial diversity, and volatile flavor substances of naturally fermented mutton sausages hand-made in Chengdu and Leshan in Sichuan Province and Anqing in Anhui province were compared and analyzed using high-throughput sequencing and metabolomics techniques. The results revealed that the richness and species diversity levels of microorganisms were highest in Anqing samples; the relative abundances of Staphylococcus spp., Cyclospora spp., Lachnospiraceae NK4A136 group spp., Bacteroides spp., Odoribacter spp., and Lactobacillus spp. were high in the three processing environment samples. The differential species detected in the Chengdu samples and Leshan samples were Staphylococcus spp. Cyclospora spp., respectively, and the differential species in Anqing samples were Lachnospiraceae NK4A136 group spp., along with an unidentifiable genus. The volatile flavor composition of Chengdu and Leshan samples was similar and mainly conferred by aldehydes, whereas the flavor of Anqing samples was mainly conferred by esters. A significant positive correlation was detected between the dominant flora and key volatile flavor substances in mutton fermented sausages, indicating that the dominant microbial species determined the key volatile flavor substances present. The bacterial flora structure and volatile flavor characteristics of mutton sausages vary under different processing environments. The results of this study provide a basis for determining the effect of dominant flora in traditional fermented sausages on key volatile flavors from the processing environment.
    33  Analysis of Volatile and Key Aroma Components in Congou Black Tea Varieties
    XU Mengting ,  SHAO Shuxian ,  CHEN Jing ,  TIAN Hongwu ,  XIE Weiwei ,  CHEN Xiaomin ,  YE Naixing ,  GAO Shuilian
    2023, 39(1):281-290. DOI: 10.13982/j.mfst.1673-9078.2023.1.0219
    [Abstract](12) [HTML](38) [PDF 1.33 M](69)
    Abstract:
    In order to identify and analyze the characteristics of the volatile and key aroma components of Congou black tea varieties, automatic thermal desorption-gas chromatography-mass spectrometry (ATD-GC-MS) was used in combination with relative odor activity values (ROAVs). The results revealed that 96 types of volatile components were identified from five Congou black tea varieties, including 18 types of common volatile substances. Examples of these were alcohols, aldehydes, ketones, alkenes, esters, acids, and alkanes, amongst other components. The five Congou black tea varieties mainly presented floral, fruity, and sweet aromas, with the six of main aroma components being decanal, linalool, benzyl alcohol, geraniol, hexanal, and isovaleraldehyde. The volatile components and their relative contents across the five Congou black tea varieties were significantly different. Among them, Golden Peony had a higher content of esters and ketones, whereas Golden Guanyin had a higher content of alcohols and aldehydes. Purple Rose had a higher content of alcohols and ketones, and the Meizhan variety was rich in alcohols. Fuyun 6 also had a higher content of alcohols and ketones. In addition, in combination with the ROAV values, this study selected 7 to 15 aroma components which contributed remarkably to the aroma quality characteristics of the five Congou black tea varieties (ROAV≥1.00).
    34  Identification of Characteristic Aroma Components and Evaluation of the Synergism Among Aromas in Dried Flowers of Anthemideae
    XU Zhiqiang ,  XIONG Wen ,  FENG Junqiao ,  NIU Yunwei
    2023, 39(1):291-299. DOI: 10.13982/j.mfst.1673-9078.2023.1.0102
    [Abstract](8) [HTML](31) [PDF 1.68 M](59)
    Abstract:
    In this study, the dried flowers of Anthemideae were used as the research object. The aroma compounds and the synergies aomng the aroma substances were studied. Headspace solid-phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS) and gas chromatography-smelling apparatus (GC-O) were used, and a total of 53 volatile aroma compounds were identified, including 13 esters, 6 aldehydes, 8 alcohols, 2 ketones, and 11 olefins. (E)-β-Acacia (6.06 mg/L), acetic acid (4.61 mg/L), and bisabolol oxide B (1.12 mg/L) has higher contents in the samples. Through GC-O and OAV analyses, 18 key aroma compounds (OAV>1.00) were obtained, among which valerate, ethyl decanoate and acetic acid had higher values, thus might be the main characteristic aroma compounds. The electronic nose was used to provide the flavor fingerprint. According to the sensory analysis, four esters including ethyl octanoate and ethyl decanoate, along with two kinds of acids, acetic acid and valerate acid, were selected for further examination by the s-curve method. Acetic acid and ethyl capric acid exhibited a synergistic effect (R=0.48), whilst additive effects were found between acetic acid and ethyl capric acid (R=0.97), and between valeric acid and ethyl decanoate (R=0.80).
    35  Predictive Early Warning Analysis of Dairy Product Quality and Safety Risks Based on Grey Data Pre-processing using the WD-LSTM Model
    CHEN Chen ,  YIN Jia ,  DONG Man ,  MU Shumin ,  CHEN Li ,  GUO Pengcheng ,  WEN Hong ,  GUI Yufeng
    2023, 39(1):300-310. DOI: 10.13982/j.mfst.1673-9078.2023.1.0291
    [Abstract](11) [HTML](44) [PDF 1.52 M](46)
    Abstract:
    Dairy products are important nutritious food items in people’s daily life. To improve the analysis of dairy product quality and safety risk prediction, the randomness, fuzziness, and incomplete information of detection products and inspection data obtained during dairy product evaluation in different regions were divided into grades using an improved softmax formula and processed in boxes according to the natural day. The risk grades were determined from the risk weight and other proportional mapping methods, and the dairy gray data were used to determine the potential risks in the qualified inspection data. Wavelet decomposition combined with the long short-term memory (LSTM) model was used to predict the risk of dairy product detection data in different regions. The results showed that the combined model exhibited an average accuracy of 97.54% and a standard deviation of 0.03, indicating higher accuracy and better stability compared to those of the empirical mode decomposition-LSTM model and wavelet decomposition-LSTM model with selective reconstruction and an interval of 2. Thus, risks associated with dairy product can be predicted and prevented. These results provide a reference and technical support for supervising risks associated with dairy products.
    36  Rapid Screening and Quantitative Analysis of 22 Illegally Added Compounds in Gut Health-improving Foods by High-resolution Mass Spectrometry
    YUAN Yanglei ,  YUAN Lijie ,  GUO Lijing ,  SHI Lu
    2023, 39(1):311-319. DOI: 10.13982/j.mfst.1673-9078.2023.1.0196
    [Abstract](7) [HTML](33) [PDF 1.12 M](33)
    Abstract:
    A method for rapid screening and quantitative analysis of 22 kinds of illegally added compounds in health-promoting foods using ultra-performance liquid chromatography-quadrupole/electrostatic orbitrap high-resolution mass spectrometry was established. In this paper, the commonly marketed gut function-improving healthcare products (tablets and oral liquid matrices) were taken as the research objects. Samples were extracted with methanol by vortex oscillation and ultrasonic treatment, and separated on an Agilent ZORBAX Eclipse XDB-C18 column (2.1 mm×50 mm,1.8 μm) using 0.1% formic acid aqueous solution and methyl alcohole as the mobile phase for gradient elution. Mass spectrometry analyses adopted a positive ion scan and full MS/dd-MS2 mode, and a database was established based on the retention times of compounds, primary parent ions and secondary fragment ions information collected automatically for high-throughput qualitative screening and quantitative analyses with primary parent ions. The 22 kinds of chemical compounds were well separated within 6.5 minutes with the mass accuracy deviation less than 1.77×10-6. The results showed a good linear relationship for each target compound in the concentration range of 5 ng/mL~500 ng/mL (r2 >0.995). The limits of quantitation (LOQs) were 50 μg/kg. The recoveries were 82.11%~116.16% for tablet samples and 83.64%~117.21% for the oral liquid samples. This method is simple, rapid, sensitive and accurate, thus suitable for rapid screening and quantitative analysis of 22 kinds of illegally added compounds in gut function-improving healthcare products in tablet and oral liquid forms.
    37  Evaluation of Human Exposure to Food-borne Heterocyclic Aromatic Amines using UPLC-MS/MS
    YANG Wanqi ,  PENG Lijuan ,  WANG Ya’nan ,  LI Qing ,  CHEN Jiwang ,  WU Bo
    2023, 39(1):320-325. DOI: 10.13982/j.mfst.1673-9078.2023.1.0228
    [Abstract](8) [HTML](40) [PDF 949.21 K](56)
    Abstract:
    An accurate and highly sensitive assay was developed for the determination of sulfinamide adducts formed by heterocyclic aromatic amines (HAAs) and human serum albumin (HSA) after human ingestion and absorption, using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The aim of this study was to assess exposure to HAAs, and further investigate the related cancer risks. Using 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) as a research subject, the PhIP-HSA sulfinamide adduct was synthesized in vitro according to the metabolic pathway of the human body and was quantified using UPLC-MS/MS based on the detection of PhIP derived from its acid hydrolysis. The results showed that the recovery of HSA by the HiTrap Blue affinity columns was greater than 90%, and the hydrolysis efficiency of the PhIP-HSA sulfinamide adduct reached 96% under optimized conditions. There was a positive linear relationship between the PhIP-HSA sulfinamide adduct content and the signal intensity of PhIP, and the linear regression equation was y=1.011 7x+3.256 3, R²=0.998 7. The respective detection and quantitation limits for the PhIP-HSA sulfinamide adduct in plasma were as low as 5×10-3 fmol/mg HSA and 1.50×10-3 fmol/mg HSA. This method showed a high degree of sensitivity when determining PhIP-HSA sulfinamide adducts in human plasma, and proved to be a feasible method for the evaluation of exposure to HAAs in individuals who frequently eat cooked meat, as well as the associated cancer risks.
    38  Rapid Detection of Vibrio parahaemolyticus Based on Time-resolved Fluorescence Lateral Flow Immunoassay
    CAO Qingqing ,  ZHAO Lichao ,  FANG Xiang ,  ZHONG Qingping ,  LIAO Zhenlin ,  WANG Li
    2023, 39(1):326-334. DOI: 10.13982/j.mfst.1673-9078.2023.1.0249
    [Abstract](11) [HTML](34) [PDF 1.16 M](63)
    Abstract:
    Vibrio parahaemolyticus-induced food poisoning is frequently reported, highlighting the necessity to develop a simple, rapid, large-scale on-site detection method to ensure food safety and avoid financial losses. Time-resolved fluorescence lateral flow immunoassay (TRF-LFIA) was successfully developed for the rapid detection of Vibrio parahaemolyticus, using europium (III) nanoparticles (EuNPs) to label V. parahaemolyticus monoclonal antibodies, forming microsphere-antibody conjugations for use as specific immunofluorescent probes. The intensity of fluorescence signals emitted by the combination of the probes and the target pathogenic bacteria could be detected to achieve quantitative detection of the target pathogenic bacteria. The TRF-LFIA has a sensitivity of 8.2×102 CFU/mL, a visual detection limit of 1.2×104 CFU/mL, a linear range of 1.8×103~1.8×107 CFU/mL, a recovery rate range of 84.25%~105.13%, and a coefficient of the variation range of 2.56%~9.14%. There was no cross-reaction to the other seven major foodborne pathogenic strains. The TRF-LFIA established in this study has high sensitivity, allowing for simple and rapid operation, and good repeatability and specificity, providing a powerful detection tool for rapid on-site detection of V. parahaemolyticus.
    39  Optimization of the National Standard Method for Determining the Fluoroquinolones Residues in Chicken and Eggs Based on Laboratory Proficiency Testing Requirements
    TANG Ziheng ,  LIN Zening ,  CHEN Zimin ,  HUANG Chubiao ,  LAO Huajie ,  ZHAN Weiwei ,  LIU Wenzi ,  SHEN Xiangguang
    2023, 39(1):335-342. DOI: 10.13982/j.mfst.1673-9078.2023.1.0165
    [Abstract](123) [HTML](147) [PDF 634.18 K](401)
    Abstract:
    Based on the characteristics of the laboratory proficiency testing and verification, the liquid chromatography analysis in the two national standard methods of the No. 1025-14-2008 announcement and No. 781-6-2006 announcement from the Ministry of Agriculture of the People’s Republic of China are optimized. In combination with the thermal precipitation process, rapid determination of the fluoroquinolone residues in chicken and egg samples could be accomplished, which provides a quality verification reference for the results of the proficiency testing and verification following the procedure of the national standard method. The test samples of chicken or eggs were extracted according to the national standard method to obtain the standby liquid (with the volume of the egg standby liquid was fixed to 6 mL). 1 mL of the standby liquid was precisely withdrawn for solid phase extraction (SPE) purification, then, the protein was rapidly precipitated by adding 0.2 mL of acetonitrile, vortexing, and heating for 20 min in a water bath at 55 ℃. After centrifugation, the supernatant was collected for rapid determination of the drug residue by high performance liquid chromatography. When the rapid heat precipitation method was applied to chicken and egg samples, the recoveries were 81.08%~103.09% and 77.60%~102.94%, respectively. The remaining standby liquid was further purified in accordance with the national standard method, and the purification processes were slightly optimized as follows: only 3 mL of the standby liquid of egg was taken for SPE purification; whilst the standby liquid of chicken was firstly frozen, then thawed, and centrifuged at a high speed. The supernatant was collected for SPE purification. Overall, the optimized procedure is simple with improved recovery and repeatability, and can not only provide a quality verification reference for the results of proficiency testing and verification, but also allow daily rapid batch detection.
    40  Rapid and Quantitative Detection of Salmonella in Food by mini-MPN-qLAMP Based on ttr Gene
    ZHANG Xiaohong ,  ZHENG Lianbao ,  CHEN Weipin ,  WANG Weiying ,  HE Yunpeng ,  FANG Fang ,  HU Tong
    2023, 39(1):343-351. DOI: 10.13982/j.mfst.1673-9078.2023.1.0163
    [Abstract](130) [HTML](143) [PDF 757.47 K](406)
    Abstract:
    In this study, the 3-tube mini most probable number (mini-MPN) counting method was used to establish a fluorescence quantitative loop-mediated isothermal amplification (qLAMP) method for rapid and quantitative detection of food-borne Salmonella. According to the ttr gene sequence of Salmonella, the primers for qLAMP and quantitative polymerase chain reaction (qPCR) were designed, and in combination with the 5h BPW amplification and MPN counting, a rapid and quantitative detection method by mini-MPN-qLAMP for Salmonella was established, and the consistency between the analysis results obtained by different assays was compared using the Bland-Altman analysis. The mini-MPN-qLAMP method was validated using two artificially contaminated samples, The results showed that the established qLAMP method and the qPCR method had good specificity. The pure culture experiments revealed the detection limit of qLAMP of 500 CFU/mL. The Bland-Altman analysis revealed that in the quick-frozen black rice, the established mini-MPN-qLAMP method had a relatively high consistency with the mini-MPN-qPCR, the mini-MPN counting and plate counting method, with the R2 not lower than 0.994, and the detection limit being -0.44 lg MPN/mL. In quick-frozen chicken breast, the mini-MPN-qLAMP method had the highest consistency with the mini-MPN-qPCR, with the R2 being 0.990 and detection limit being -0.64 lg MPN/mL. The spoilage bacteria in the meat products could affect the mini-MPN counting and plate counting results, whilst the mini-MPN-qLAMP method could eliminate the interference of spoilage bacteria in meat products. Accordingly, the mini-MPN-qLAMP method established in this study is simple, easy to be used and accurate, thus can be used for rapid and quantitative detection of Salmonella in food.
    41  Thoughts on the Construction of Our Country’s Food Safety Traceability System under the Background of Normalized COVID-19 Epidemic Prevention and Control
    CHEN Xiangyu ,  GONG Jing ,  CHEN Junhong
    2023, 39(1):352-358. DOI: 10.13982/j.mfst.1673-9078.2023.1.1259
    [Abstract](154) [HTML](131) [PDF 446.46 K](524)
    Abstract:
    The sudden emergence of COVID-19 in 2019 and its constant repetition have brought great food safety challenges, in particular, cold-chain foods have become the priority and difficult point of current epidemic prevention and control. Under the background of normalized COVID-19 prevention and control, it’s a major topic concerning people's present livelihood how to improve the existing food safety traceability system to make it adapt better to the normalized epidemic prevention and control, while satifying consumers' demands for safe intake and high-quality consumption. Accordingly, this paper reviewed the current situation of our country’s food safety traceability system, and analyzed the existing problems in the system construction: the food safety traceability systems at all levels need to be integrated, the standards needed to be further improved, the construction of the ecological circle need to be accelerated, and the traceability system for imported cold-chain food need to be strengthened. These problems are even more pronounced in the normalization stage of COVID-19's prevention and control. In view of the above-mentioned problems, this paper proposes to establish a unified food traceability management platform, implement vigorously actions towards standard improvement, create a sustainably developing ecological circle, and establish a good environment for technological operation, in order to provide a decision-making reference for further strengthening the construction of China's food safety traceability system and ensuring food quality and safety under the background of normalized epidemic prevention and control.
    Journal introduce

    Editor in chief：李琳

    Inauguration：现代食品科技

    International standard number：ISSN 1673-9078

    Unified domestic issue：CN 44-1620/TS

    Domestic postal code：46-349

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