Volume 38,Issue 7,2022 Table of Contents

1 Anti-inflammatory Effect of Pueraria lobata (Willd.) Ohwi and P. thomsonii Benth. Polysaccharides on LPS-Induced RAW264.7 Cells

ZHANG Zhuang , LI Qiong , HUANG Liping , CUI Yushun , LIU Ronghua , FENG Yulin , OUYANG Hui , ZHU Weifeng , YANG Shilin

2022, 38(7):1-10. DOI: 10.13982/j.mfst.1673-9078.2022.7.1267

[Abstract](344) [HTML](500) [PDF 3.73 M](561)

Abstract:
The anti-inflammatory effects of Pueraria crude polysaccharide (FGC), Pueraria crude polysaccharide (GGC), and Pueraria homogenized polysaccharide (FGJ) were compared in an LPS-induced RAW264.7 cell model. The effects of FGC, GGC, and FGJ on cell viability were detected using a CCK8 kit. Secretion of nitric oxide, TNF-α, and IL-6 in cells was detected using their corresponding kits. The expression levels of NF-κB and Nrf2/HO-1 pathway related proteins were detected using western blot, mRNA expression levels of TNF-α and IL-6 were detected by qPCR, and ROS production was detected using flow cytometry. The results showed that FGC, GGC, and FGJ had no toxicity to cells at concentrations of 10, 20, and 40 μg/mL (p>0.05). FGC and FGJ did not inhibit LPS-induced nitric oxide, TNF-α, and IL-6 secretion (p>0.05) at any concentration. At 40 μg/mL, GGC inhibited nitric oxide, TNF-α, and IL-6 levels by 38.46%, 52.90%, and 55.87%, respectively, which was able to inhibit intracellular ROS release. Inhibition rates reached 37.28%, 41.05%, and 54.09% at concentrations of 10, 20, and 40 μg/mL. The inhibition rates of iNOS, COX-2, p-p65, and p-IκBα were 29.27%, 95.04%, 27.18%, and 28.45% at 40 μg/mL, which was able to promote the expression of Nrf2 and HO-1 proteins. At 40 μg/mL, mRNA expression levels of IL-6 and TNF-α were significantly inhibited, with inhibition rates reaching 57.70% and 81.68%, respectively. The results showed that GGC had a more distinct anti-inflammatory activity than FGC and FGJ, and its anti-inflammatory effect was realized through the NF-κB and Nrf2/HO-1 pathways.

2 Crude Momordica Grosvenorii Extract Inhibites H2O2-induced ROS Production and Apoptosis in MIN6 Cells

LI Xiaojuan , LI Yuxue , ZHOU Luwei , WANG Juan

2022, 38(7):11-18. DOI: 10.13982/j.mfst.1673-9078.2022.7.1036

[Abstract](375) [HTML](231) [PDF 2.34 M](502)

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The study is to investigate the protective effect and mechanism of crude Momordica grosvenorii extract (MGE) against hydrogen peroxide (H2O2)-induced apoptosis and oxidative damage in MIN6 cells. An oxidative damage cell model was established by the induction by H2O2 at different concentrations, and the optimal induction concentration was selected according to cell viability. The cell viability was determined by the MTT assay. Flow cytometry was used to detect the level of reactive oxygen species (ROS) and apoptosis rates of cells. The apoptosis-related factors were detected by Western blot. The results showed that the crude MGE (0~200 μg/mL) showed little effect on the viability of MIN6 cells, thus, 200 μg/mL of the crude Momordica grosvenorii extract was chosen for subsequent experiments. The crude MGE at 200 μg/mL significantly reversed the decrease (p<0.05) in H2O2-induced cell viability. The results of flow cytometry showed that compared with the treatment with H2O2 alone, the crude MGE decreased significantly (p<0.05) the H2O2-induced increase in ROS level, and inhibited H2O2-induced apoptosis of MIN6 cells. Moreover, the Western blot results revealed that the crude MGE could partially reversed H2O2-induced decrease in the expression of PCNA and increase in the expression of Bax (p<0.05). In summary, the crude MGE could inhibit H2O2-induced ROS generation and apoptosis in MIN6 cells. The results of this study can provide an experimental basis for the development of Momordica grosvenorii into functional foods for the prevention and treatment of diabetes.

3 In vitro Digestion and Absorption of Ca, Fe and Zn in Morchella esculenta and Their Correlations with Their Existing Forms

XUE Shujing , YANG De , LU Qi , SHI Defang , YAO Fen , CHEN Jian , LI Lu

2022, 38(7):19-26. DOI: 10.13982/j.mfst.1673-9078.2022.7.0973

[Abstract](169) [HTML](215) [PDF 2.89 M](491)

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This study aimed to evaluate the digestion and absorption of Ca, Fe and Zn in Morchella esculenta. The bioaccessibilities and partition coefficients of Ca, Fe and Zn in the coarse powder and ultrafine powder from the caps of Morchella esculenta and the coarse powder and ultrafine powder from the stipes of Morchella esculenta were examined by using an in vitro digestion model and octanol absorption model. Correlation analysis was carried out with the dissolution amounts of different forms. The results showed that Morchella esculenta was a very good food source of Ca, Fe and Zn. The total contents of Ca, Fe and Zn in the caps of Morchella esculenta were 268.77, 467.71 and 757.84 µg/g, respectively, with the bioaccessibilities being 66.44%~75.09%, 38.33%~46.17% and 35.51%~40.53%, respectively. The total contents of Ca, Fe and Zn in the stipes of Morchella esculenta were 290.25, 1234.31 and 727.59 µg/g, respectively, with the bioaccessibilities being 68.81%~75.62%, 27.70%~37.86% and 37.25%~42.96%, respectively. The bioaccessibility and partition coefficient of Ca were correlated significantly with the contents of its soluble form, organic form, polysaccharide-binding form and protein-binding form. The bioaccessibility and partition coefficient of Fe were correlated significantly with its total content, and contents of its soluble form and organic form. But the correlations among the in vitro digestion, absorption and dissolution amounts of different forms were not observed for Zn. The research results provide certain theoretical support for the development of Morchella esculenta products and the intake of trace elements.

4 Protective Effect of Rice Bran Insoluble Dietary Fiber on Chronic Cadmium-exposed Mice

LIU Hao , XIA Yuhong , LIU Yehao , WU Yifan , WANG Yi , WANG Rong , JI Yanli

2022, 38(7):27-32. DOI: 10.13982/j.mfst.1673-9078.2022.7.1247

[Abstract](188) [HTML](224) [PDF 1.56 M](499)

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Escherichia coli were cultured in vitro to observe the effect of cadmium on bacterial growth as well as the adsorption of cadmium by rice bran insoluble dietary fiber (RBIDF) to investigate the protective effects of RBIDF on mice under chronic cadmium exposure. Mice were divided into the negative and positive control groups and RBIDF treatment group. After 8 weeks of feeding, cadmium levels in tissues, blood, and feces as well as fecal short chain fatty acids (SCFAs) were tested. DNA was extracted from intestinal flora in feces for high-throughput sequencing and fluorescence quantitative PCR detection. The results of the experiments showed that RBIDF can adsorb cadmium and protect the growth of E. coli. Cadmium content in blood, liver, small intestine, and feces of mice treated with RBIDF decreased by 66.67%, 57.67%, 27.15%, and 60.64%, respectively, when compared with that in the positive control group. The levels of the three types of SCFAs in feces increased by 1.30 times, 2.25 times, and 2.75 times, respectively. The total amount of intestinal bacteria in the RBIDF treatment group increased by 1.40 times. In addition, at the phylum level, the distribution of intestinal flora of the RBIDF treatment group was similar to that of the negative control group and was dominated by Bacteroidetes (68.75%), Firmicutes (23.67%), and Proteobacteria (6.82%). The positive control group was dominated by Bacteroidetes (55.71%), Firmicutes (33.25%), and Verrucomicrobia (5.62%). The results of this study suggest that RBIDF is able to adsorb cadmium to reduce cadmium concentration in the tissues and blood of mice, promote the recovery of intestinal flora in mice, and has a protective effect on chronic cadmium-exposed mice.

5 Laxative Effect of Black Jerusalem Artichoke Polysaccharide and Its Regulatory Effect on Intestinal Flora

JI Yanru , ZHANG Zhenghai , YANG Qingli , DONG Yan , TENG Chunbo , LI Guowei , SHI Jie , WEI Lianhui , PAN Jing , GAO Yuan

2022, 38(7):33-39. DOI: 10.13982/j.mfst.1673-9078.2022.7.1347

[Abstract](181) [HTML](279) [PDF 2.56 M](533)

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The effects of black Jerusalem artichoke polysaccharide on intestinal function and floral diversity in constipated mice were investigated in this study. KM mice were randomly divided into blank and model control groups, and black Jerusalem artichoke polysaccharide low (2.5 g/kg·bw), medium (5.0 g/kg·bw) and high (10.0 g/kg·bw) dose groups. The constipation mouse model was established by treating with diphenoxylate for 14 consecutive days and polysaccharide intervention was started from day 8. The number of defecation pellets within 6 h and intestinal ink propulsion rate were observed. The 16S rDNA gene sequences of intestinal flora were also analyzed using Illumina MiSeq high-throughput sequencing. The results indicated that compared with the model group, in the low, medium, and high dose groups, the number of melena increased by 48.21%, 98.21% and 78.57%, respectively, and the ink propulsion rate increased by 67.34%, 107.05% and 87.08%, respectively. Among groups, the medium dose group produced the best results. After intervention with the medium dose black Jerusalem artichoke polysaccharide, the diversity and richness of intestinal flora, as well as the ratio of Firmicutes/Bacteroides and the abundance of Proteobacteria increased significantly (p<0.05). The intervention also promoted the proliferation of the beneficial bacteria Lactobacillus and Faecalibaculum (p<0.05). Therefore, consumption of black Jerusalem artichoke polysaccharide in appropriate amounts may be helpful to reverse the disturbance of intestinal flora caused by constipation and to alleviate symptoms of constipation.

6 Antialcoholism Effects of Curcuma Botanical Beverage in KM Mice

CHEN Jiaming , JIAO Chunwei , LIANG Huijia , ZHONG Jing , XIE Yizhen

2022, 38(7):40-47. DOI: 10.13982/j.mfst.1673-9078.2022.7.1088

[Abstract](284) [HTML](270) [PDF 3.09 M](461)

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The antialcoholism effect and possible mechanism of curcuma botanical beverage in KM mice were investigated in this paper. After establishing the model of high concentration alcohol-induced intoxication in mice, the anti-alcoholism effect of curcuma botanical beverage were evaluated according to the behavior of anti-inebriation test in mice, the concentration of ethanol in blood, the content or activity of the key enzyme of ethanol metabolism in vivo, and the changes of gastrointestinal tissue. The results showed that the latency of drunkenness was 235.00 min, which was significantly longer than that in the model group (p<0.05). The time required to regain consciousness was 232.00 min, which was significantly shorter than that in the model group (p<0.05). The concentration of ethanol in the blood was 4.21 mg/mL, which was significantly lower than that of the model group (p<0.01). The activities of alcohol dehydrogenase and acetaldehyde dehydrogenase were 3.74 U/mg prot and 8.36 U/mg prot, respectively, which were significantly higher than those of the model group (p<0.05). The contents of coenzyme I and reduced coenzyme I were 0.08 nmol/mg prot and 0.39 U/mg prot, respectively. The ratio of NADH to NAD+ was significantly higher than that of model group (p<0.01). The contents of cytochrome P450 and glutathione peroxidase were 78.51 pg/mg and 1341.00 pg/mg, respectively, which were significantly higher than those in the model group (p<0.01). The results of stomach and intestinal tissue observation and pathological section showed that low and high dosage of curcuma botanical beverage could alleviate the injury of intestinal tract caused by ethanol and reduce the intestinal bleeding and edema. The above results indicated that curcuma botanical beverage has obvious anti-alcoholism effect on drunken mice. The mechanism may be related to enhancing the activities of key enzymes and antioxidant enzymes in the pathway of ethanol metabolism, speeding up the metabolism of ethanol in vivo, and protecting the liver and gastrointestinal tract.

7 Screening of Hypolipidemic Lacticaseibacillus rhamnosus and Exploration of Its Effect on High-fat Hamster Models

CAO Lan , BAI Yuqin , YU Ping , TANG Chun , JIAO Yanping , MIN Xiangbo

2022, 38(7):48-54. DOI: 10.13982/j.mfst.1673-9078.2022.7.1295

[Abstract](139) [HTML](211) [PDF 1.76 M](476)

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Screening was performed for a strain of Lactobacillus with strong cholesterol reduction ability from experimental strains isolated from the intestinal tract of healthy infants. The cholesterol reduction ability of the strains was measured using the o-phthalaldehyde colorimetric method, whereas triglyceride reduction ability was measured using the GPO-PAP method. The tolerance of the strains to acids and bile salts was also measured. Strains with strong cholesterol and triglyceride reduction functions were selected and confirmed using 16S rDNA. The hypolipidemic ability was studied by establishing a hyperlipidemic hamster model. Results showed that Lacticaseibacillus rhamnosus HCS01-013 had strong cholesterol and triglyceride reduction ability, with cholesterol degradation rate reaching 35.40% and triglyceride degradation rate reaching 44.32%. The survival rates after culturing in 0.3% and 1.5% bile salts for 17 h were 99.67% and 96.79%, respectively, and 88.76% and 71.34% after culturing in pH 3.0 and pH 2.0 for 17 h, respectively. After establishing the high-fat hamster model through a high-fat diet, hamsters were treated with different doses of probiotics. Regardless of dosage, triglyceride levels in the group fed with Lacticaseibacillus rhamnosus HCS01-013 was significantly lower than that of the model control group fed with normal saline. Lacticaseibacillus rhamnosus HCS01-013 has definite lipid lowering function and strong resistance to adverse environments, which provides a theoretical basis for related research for this strain and product development.

8 Application of Enzyme Preparation and Yeast Compound Bulking Agent in the Production of Fried Dough Sticks

XIAO Zheng , MO Shuxin , LEI Changmei , LIANG Xinyue , CHE Xinyi

2022, 38(7):55-62. DOI: 10.13982/j.mfst.1673-9078.2022.7.1046

[Abstract](281) [HTML](193) [PDF 2.02 M](523)

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In this study, fried dough sticks were taken as an example to explore the feasibility of using food enzymes and yeast as the bulking agents for traditional fried flour products. The effects of bulking agents for common flour products and the combination of food enzyme and yeast were evaluated based on the expansion rate, specific volume and sensory score. The fermentation process with the best combination was analyzed. The results showed that alum exhibited the greatest fluffy effect with the highest expansion rate as 8.73 times among the commonly used bulking agents for flour products under the same processing conditions. The yeast-based bulking agent was improved, and the yeast was compounded with protease, amylase, lipase, xylanase and glucose oxidase. The effect of amylase was the best. When the addition amount of amylase was 0.50 g/kg, the expansion rate of fried dough sticks reached 7.65 times. The analysis of the fermentation involving the amylase-yeast compound bulking agent showed that the optimal dough fermentation time was 2.5 h, and the carbohydrates in flour products were greatly degraded into reducing sugars (with a content of 5.25%). The new compound bulking agent was composed of food enzymes and microorganisms without added aluminum, which allows bulking while ensuring safety and healthiness.

9 Optimization of Yeast Lyophilization Protectant Based on Oat β-glucan

LI Zhen , JI Shengxin , LIANG Jingjing , SUO Biao , FAN Huiping , AI Zhilu

2022, 38(7):63-69. DOI: 10.13982/j.mfst.1673-9078.2022.7.1148

[Abstract](164) [HTML](444) [PDF 3.00 M](480)

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To improve the survival rate of freeze-dried yeast, Saccharomyces cerevisiae was selected as the research object, and the survival rate of the strain was the corresponding index. The main freeze-dried cryoprotector was oat β-glucan, which was combined with γ-poly-glutamic acid and mannitol. The single factor rotation test was used to determine the level of three factors and serve as the central point of response surface optimization test. The regression equation between the survival rate of yeast and the three factors was established by Central Composite response surface method. The effects of various factors on the response values were analyzed by response surface analysis, and the morphology of lyophilized yeast cells was observed by scanning electron microscope. The results showed that the best ratio of cryoprotectores was 6.56% oat β-glucan, 0.15% γ-poly-glutamic acid, 1.15% mannitol, and the mass ratio of bacteria to protective agent was 1:2. Under these conditions, the survival rate of cells could reach 90.69%, which was close to the theoretical predicted value of 89.86%. Compared with the yeast cells without adding cryoprotector, the yeast cells in the group with adding cryoprotector were full in morphology and complete in structure. The results of this study can provide data support for the freeze-drying protection and promotion of yeast.

10 Contribution of Sequence Structure to the Thermotolerance of Tyrosine Phenol Lyase

LI Xuewen , ZHENG Suiping

2022, 38(7):70-78. DOI: 10.13982/j.mfst.1673-9078.2022.7.0858

[Abstract](146) [HTML](205) [PDF 8.53 M](638)

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In order to understand the relationship between the thermostability of tyrosine phenol lyase (TPL) and its sequence, and to provide a reference for mutating the tyrosine phenol lyase to produce thermotolerant tyrosine phenol lyase, bioinformatics was used to analyze the thermostable tyrosine phenollyases, StTPL derived from Symbiobacterium toebii, FnTPL derived from Fusobacterium nucleatum, and mesophilic CfTPL derived from Citrobacter freundii. These lyases were compared in terms of phylogenetic tree, primary structure, secondary structure and tertiary structure. With the increase of the proline content in the primary structure of TPL, the optimal reaction temperature increased. The proline contents of StTPL, FnTPL and CfTPL were 5.02%, 3.70% and 2.85%, respectively. There were more β-sheets and turns in the secondary structure, which were 25.51%, 25.00%, and 23.91%, respectively. These characteristics were in line with the difference between thermostable enzymes and mesophilic enzymes reported in the literature. The comparison of the three-dimensional structures of StTPL, FnTPL and CfTPL revealed that the 310-313 residue region, residue 13, and 82-88 residue region had a poor superposition effect. The mutation of the 313 residue was conducive to the thermalstability of CfTPL. The mutation ofAla13, Glu83 and Thr407 residue was conducive to the thermalstability of StTPL. It is speculated that the above residue regions are related to thermalstability, which is also in line with the findings reported in the literature. In addition, the relevant bioinformatics analysis provides a preliminary reference for further understanding the hyperstability mechanism of hyperstable enzymes and screening and transforming new hyperstable enzymes.

11 Effects of Microbial Nitrosation Inhibitors on the Changes of Microbial Colony during the Fermentation and Maturation of Air Dried Sausage and Sensory Evaluation Analysis

CHEN Yuanyuan , FU Huijing , LUO Qiaozhi , REN Xiaoqing , MA Lizhen

2022, 38(7):79-89. DOI: 10.13982/j.mfst.1673-9078.2022.7.1164

[Abstract](156) [HTML](225) [PDF 5.13 M](743)

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In order to study the effects of microbial nitrosation inhibitors (MNI) on the dynamic changes of microbial community during the fermentation and maturation of air-dried sausage and sensory properties, four groups of air-dried sausages were designed: MNI group: MNI was added; MNIP group: MNI was added and PRO-MIX5 commercial starter (Staphylococcus xylose, Lactobacillus sake, Lactobacillus plantarum) were inoculated; FBFAP group: PRO-MIX5 commercial starter was inoculated while adding fermented beef flavorings and compound antioxidant; CK group: blank control group (CK). The results showed that in the fermentation stage, the number of lactic acid in the air-dried sausages of the four groups gradually increased, MNI group and MNIP group meat stuffing reached the fermentation end point at 15 h and 12.5 h respectively, that is, the pH decreased to 5.4~5.6, and the number of Lactic acid bacteria was 8.99 lg cfu/g and 8.91 abundance of lg cfu/g respectively, which was significantly higher than that in CK group (8.88 lg cfu/g at 22 h) (p<0.05). At the end of maturity, the relative Gram-negative spoilage microorganisms in MNI group was the lowest (19.35%), and the inhibition rates of Enterobacteriaceae and Pseudomonas were 30.43% and 27.22% respectively, second only to MNIP group 37.00% and 33.79%, which was better than CK group and FBFAP group. Comprehensive analysis shows that MNI can be used as a growth promoting factor to promote the growth of Lactobacillus in meat stuffing, the inhibitory effect of MNI on spoilage microorganisms was better than that of FBFAP. The addition of MNI alone or the synergistic effect of MNI and PRO-MIX5 can improve the microbial safety and sensory performance of air-dried sausages, indicating that MNI has a broad application prospect in improving the safety quality of air-dried sausages.

12 Optimization of Preparation of Fermented Milk by Bacillus coagulans

XIAO Lanfang , ZHAO Shan , LIU Dongmei , WU Hui

2022, 38(7):90-97. DOI: 10.13982/j.mfst.1673-9078.2022.7.1111

[Abstract](236) [HTML](261) [PDF 2.70 M](519)

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The production process of Bacillus coagulans fermented milk was optimized. The new fermented milk co-fermented with Bacillus coagulans 13002, Lactobacillus bulgaricus CGMCC 1.290 and Streptococcus thermophilus CGMCC 1.2741 was used as the research object. The single factor experiment was conducted with different strain compound ratio, strain inoculation amount and fermentative oligosaccharides addition amount. Sensory score was used as the response value. Box-behnken center combination was used to establish a mathematical model to study the optimal production process of fermented milk. The results showed that the optimal technological conditions of fermented milk were as follows: bacteria compound ratio (Bacillus coagulans: (Streptococcus thermophilus: Lactobacillus bulgaricus=1:1)) 3:1, oligosaccharides addition amount 1.50%, inoculation amount 1.50%. Under the optimized conditions, the average titrated acidity of fermented milk was determined to be 90.59, and the fitting rate with the acidity predicted by the model (93.25) was 97.15%, indicating that Bacillus coagulans fermented milk has certain competitive advantages, providing theoretical basis and expanding ideas for the development of new fermented milk.

13 High-throughput sequencing-based analysis of the succession of fungal communities during the storage of northeast japonica rice

LI Xinwei

2022, 38(7):98-106. DOI: 10.13982/j.mfst.1673-9078.2022.7.1064

[Abstract](222) [HTML](325) [PDF 3.49 M](458)

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To explore the succession of the fungal communities of the northeast japonica rice with different initial moistures under the conditions simulating those of the real storage ware house environment. The rice with a moisture content of 14.50%~15.50%, HW, and the rice with a moisture content of 13.50%~14.50%, LW, were sued for the simulated storage experiments. The results showed that the moisture contents of the HW rice and LW rice decreased from 15.50% to 15.09% and from 14.21% to 13.59%, respectively, in the first and second storage periods, and remained stable in the third storage period. According to the taxonomic analysis based on operational taxonomic units (OTUs), the fungal communities of the two types of rice underwent different successional changes. The fungal commnity of the HW rice exhibited obvious succession during each storage period, and Magnaporthe_grisea, Papiliotrema_aurea, Curvularia_inaequalis, Neosetophoma_samararum, Hannaella_sinensis became the final dominant species at the end of storage. The fungal community of the LW rice experienced obvious succession in the second storage, Curvularia_inaequalis, Hannaella_sinensis and Hannaella_zeae became the dominant species.

14 Isolation and Identification of Gas-producing Microorganisms from Bagging Red Braised Pork and Sauce Packs

ZHANG Yuanyuan , ZHU Yaodi , LI Miaoyun , ZHAO Lijun , LIU Shijie , ZHAO Gaiming , MA Yangyang , WANG Xinyi

2022, 38(7):107-112. DOI: 10.13982/j.mfst.1673-9078.2022.7.1095

[Abstract](167) [HTML](196) [PDF 2.85 M](497)

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In order to solve the problem of swelling and corruption of red braised pork and sauce packs, the microorganisms in swelling red braised pork, steak sauce and tomato sauce were isolated and identified, and through the gas production verification test and 16S rDNA identification, the main gas producing microorganisms that caused the product swelling were determined. The results showed that 9 strains of dominant bacteria, numbered 1-9, were isolated from 3 kinds of expanded bag products. Bacteria 1 and 5 were Gram-positive cocci, strain 1 was identified as Staphylococcus edaphicus, and strain 5 was Pediococcus pentosaceus; Strain 4 and strain 8 were Gram-negative bacteria, strain 4 was Citrobacter braakii, and strain 8 was Citrobacter freundii. Strains 2, strain 3, strain 6, strain 7 and strain 9 were Gram-positive bacteria, strain 2 was identified as Weissella cibaria, strain 3 was Bacillus velezensis, strain 6 was identified as Bacillus cereus, strain 7 was identified as Bacillus pacificus, and strain 9 was identified as Bacillus amyloliquefaciens. According to the verification test of gas production, Bacillus velezensis, Citrobacter braakii, Bacillus cereus, Bacillus pacificus and Citrobacter freundii were identified as gas-producing microorganisms, which were the main contaminating microorganisms that caused braised pork and sauce bags to swell. Comprehensive analysis showed that Bacillus was one of the main gas-producing microorganisms that caused swelling of packaged food. Effective control of the contamination of spores and bacillus is the key to solving the problem of food swelling.

15 The Bioinformatics Analysis of the Lipase LipA from Bacillus subtilis

LI Jingjing , LAI Xinjue , LI Xinyao , MA Junwei , YU Minyi , LUO Jiawei , CHEN Yinxi , YU Jieting , ZHENG Shaopeng , ZHENG Dunjin , CAO Shilin , CHEN Wanjuan

2022, 38(7):113-119. DOI: 10.13982/j.mfst.1673-9078.2022.7.1130

[Abstract](167) [HTML](222) [PDF 1.72 M](472)

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In this study, bioinformatics methods were applied to analyze the Bacillus subtilis lipase LipA, aiming to lay some theoretical foundation for the subsequent study of LipA. The primary structure, hydrophobicity, basic properties, secondary structure, special crimp helix, motif and PEST sequences rich in proline (p), glutamic acid (E), serine (s) and threonine (T) of LipA were predicted and analyzed by using a series of online websites or software, the homology modeling of the tertiary structure was carried out, and the surface potential, the accessibility distribution and the Ramachandran diagram were analyzed. Bacillus subtilis lipase LipA is a stable liposoluble protein composed of 212 amino acids. The regions with the strongest hydrophilicity and hydrophobicity were predicted to be Lys75~Asn81 and Val9~Leu17, and there is no stable dimer, trimer curling helix and non-PEST sequences. LipA was found to have three motifs that may participate in different biochemical reactions, as well as α/β proteins with five segments α-helix, six-segment β-sheets; LipA is predicted to be weak positive potential; The modeled three-dimensional structure is shown by accessibility and Ramachandran diagram to be reasonable and reliable. The subsequent molecular design and modification of Bacillus subtilis lipase LipA were provided with some theoretical basis in this study.

16 Inhibitory Effects of Ginger Juice on α-Glucosidase Activity

PAN Xueli , ZHAO Zhenjun , HU Xianchun

2022, 38(7):120-125. DOI: 10.13982/j.mfst.1673-9078.2022.7.0303

[Abstract](215) [HTML](207) [PDF 2.58 M](442)

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Enzyme kinetics and spectroscopic analyses were performed to determine the inhibitory effects of ginger juice on α-glucosidase activity and possible inhibitory substances involved were explored. The results showed that the inhibitory effect of Shandong ginger juice on α-glucosidase activity was the best, with an inhibition rate of 73.38%. The results of enzyme kinetics and Lineweaver-Burk double reciprocal analysis showed that the inhibitory effects of ginger juice on α-glucosidase activity were reversible and competitive. The inhibition rate of ginger juice on enzyme activity decreased to 46.5% of the initial inhibition rate after 3 days of storage at 5 ℃. Enzyme activity inhibition rates of stored ginger juice during heat treatment first increased before decreasing. Analysis of components separated by ultrafiltration showed that inhibition rate (67.16%) of the MW≥10 ku component in ginger juice was the highest among components. This indicates that the substances with enzyme inhibiting activity were mainly concentrated in the MW≥10 ku component of ginger juice. In the mixed system of ginger juice and α-glucosidase, the absorbance value of ginger juice components decreased significantly in the ultraviolet absorption spectrum of 240~280 nm, indicating that the components with inhibitory activity in ginger juice were distributed in this band. The results of this study provide a theoretical basis for further research on the hypoglycemic activity of ginger juice as well as the development of further processed products.

17 Comparison of Bacterial Communities and Physicochemical Properties in Yak Milk with Different Cold Storage Durations

SONG Xuemei , MA Anna , LIU Xuanyan , ZHANG Yan , QIU Ting , ZHANG Weibing

2022, 38(7):126-132. DOI: 10.13982/j.mfst.1673-9078.2022.7.1327

[Abstract](188) [HTML](234) [PDF 1.31 M](491)

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Refrigerated storage helps to ensure the quality of raw milk; however, it can also increase the risk of psychrophilic bacteria propagation. Therefore, investigation of bacterial communities of raw milk under different refrigeration durations is crucial to the sustainable development of the dairy industry. This study compared the characteristics of bacterial communities and physicochemical properties of yak milk stored at 4 ℃ for 24 h and 72 h through high-throughput sequencing and by using a milk composition analyzer. The results revealed that the two dominant bacteria in yak milk for both refrigeration durations were Lactococcus and Chryseobacterium, which together accounted for 59.5% and 67.51% of the relative abundance of bacteria in yak milk refrigerated for 24 h and 72 h, respectively. The relative abundances of Lactococcus and Chryseobacterium in yak milk were 22.74% and 3.56% higher, respectively, after 72 h of refrigeration than those in yak milk after 24 h of refrigeration. However, after 72 h of refrigeration, Streptococcus and Acinetobacter in yak milk showed a decreasing trend. The relative abundance of Pseudomonas in yak milk refrigerated for 24 h and 72 h was 1.69% and 1.78%, respectively. Casein and fat levels of yak milk refrigerated for 72 h were lower than those of yak milk refrigerated for 24 hours, and acidity increased to 14.66 ºΤ. Refrigeration for 72 h is helpful in controlling the reproduction of bacteria in yak milk to maintain milk quality. This study provides a theoretical basis for the storage of yak milk and processing of dairy products, such as cheese, to ensure quality and safety.

18 Structural Characteristics of Exopolysaccharide from Lactiplantibacillus plantarum NM18 of Koumiss in Inner Mongolia

LIU Mingchao , WANG Rongping , HE Yuxing , YANG Xiaofeng , YU Jinghe , Wuyundalai

2022, 38(7):133-142. DOI: 10.13982/j.mfst.1673-9078.2022.7.1349

[Abstract](146) [HTML](215) [PDF 4.63 M](711)

Abstract:
Exopolysaccharides (EPSs) are macromolecules with different sugar residues and are widely used in medicine, food, environment, and other fields. In this study, six components (EPS-1A, EPS-1B, EPS-2, EPS-3, EPS-4, and EPS-5) of the exopolysaccharides produced by Lactiplantibacillus plantarum NM18 were purified using ethanol precipitation, anion exchange method, and gel filtration chromatography, and their primary structures were identified. Components EPS-1A, EPS-1B, and EPS-2 comprised mannose, glucose, and galactose. Component EPS-3 comprised mannose, glucose, galactose, rhamnose, trehalose, and N-acetyl-D-glucosamine. Component EPS-4 comprised mannose, glucose, galactose, and N-Acetyl-D-glucosamine. Component EPS-5 comprised mannose, galactose, and N-acetyl-D-glucosamine, and contained trace amounts of fucose and allose. The methylation reaction of EPS-1A, EPS-1B, and EPS-2 combined with GC-MS analysis showed that EPS-1A and EPS-1B carbohydrate chains mainly comprised →3)-D-Glcp-(1→,→6)-D-Galp-(1→,→4)-D-Glcp-(1→ and →6)-D-Manp-(1→, with the terminus being Glcp-(1→. The EPS-2 carbohydrate chains mainly comprised →6)-D-Galp-(1→ and →6)-D-Manp-(1→, with the terminus being D-Glcp-(1→. Components EPS-1A, EPS-1B, and EPS-2 have a mixture of α and β type glycosidic bonds. In conclusion, this study provides theoretical basis for further study and application of the biological activity of exopolysaccharides produced by strain NM18

19 Post-haze and Protein Composition of Raw Sugarcane Juice

WANG Qi , MENG Lidan , TIAN Run , WANG Shupei , XIE Caifeng , HANG Fangxue , LI Kai

2022, 38(7):143-151. DOI: 10.13982/j.mfst.1673-9078.2022.7.1025

[Abstract](194) [HTML](197) [PDF 1.19 M](424)

Abstract:
Post-haze of raw sugarcane juice refers to the phenomenon that the clarified raw sugarcane juice undergoes changes in composition, increase of turbidity or precipitation during storage or commodity circulation. In this study, the basic composition as well as the molecular weight, type, amino acid composition and secondary structures of proteins of the sediment in sugarcane juice were studied by polyacrylamide gel electrophoresis, combined mass spectrometry, amino acid analysis and Fourier transform infrared spectroscopy. The experimental results showed that the main component in the sediment of the raw sugarcane juice was sugar (total sugar content 60.94%), followed by ash and protein (19.52% and 18.43%, respectively), and the content of total phenolics was only 0.62%. The molecular weight distribution of post-haze proteins was about 42 ku and lower than 20 ku, and 12 and 44 proteins were identified, respectively. Among them, the proteins with higher abundance are protein Z, PREDICTED: calmodulin-7 isoform X1, PREDICTED: calcium-dependent protein kinase 34 isoformX1, and hypothetical protein SORBIDRAFT_01g014740. The amino acid compositions of the post-haze proteins and the supernatant proteins were only marginally different, but their secondary structures differed significantly. Except that the content of random coil structure in the post-haze proteins was much higher than that of the supernatant protein, the α-helix and β-turn of post-haze proteins were lower than those of the supernatant protein by 33.43% and 22.42%, respectively, although the difference in the β-sheet was insignificant. In general, proteins with molecular weight slower than 42 ku, high hydrophobicity, low α-helix content and high random coil content more likely contributed to the post-haze of raw sugarcane juice.

20 Comparative Analysis of the Metabolites in Two Varieties of Pu-erh Tea

ZHOU Yongchen , LIU Ying , ZHENG Wenzhong , GAO Jun , ZHAO Yiming , CHA Fengguan , DING Haiqin , KONG Sheng , LYU Caiyou

2022, 38(7):152-159. DOI: 10.13982/j.mfst.1673-9078.2022.7.1060

[Abstract](209) [HTML](203) [PDF 4.71 M](736)

Abstract:
In this research, metabolomic techniques and tools were used to analyze two excellent varieties of Yunnan Pu-erh tea obtained through population breeding. The results showed that: A total of 798 metabolites were detected and quantified in cultivar 1 (Taoxingye), and 802 metabolites were detected and quantified in cultivar 3 (Yungui). There were 202 metabolites (SCMs) with significant changes between the two cultivars. The abundance of 108 SCMs in cultivar 1 (Taoxingye) was significantly lower than that in cultivar 3 (Yungui), with 94 increasing significantly. According to their quantities, these SCMS can usually be divided into flavonoids, phenolic acids, lipids, amino acids and their derivatives, lignans and coumarins, organic acids, alkaloids, nucleotides and their derivatives, tannins and other classes. In addition, differential metabolites were enriched in 49 KEGG pathways, and most of the identified differential metabolites exist in phenylpropanoid biosynthesis, phenylalanine metabolism, flavonoid biosynthesis (including flavone biosynthesis and flavonol biosynthesis), amino acid biosynthesis and other metabolic pathways. The results of these significantly different metabolites can be used to provide a theoretical basis and scientific guidance for monitoring tea adaptability and quality control of cultivar 1(Taoxingye) and cultivar 3(Yungui).

21 Trichoderma Harzianum Enhance Shelf Life Qualities of Netted Melon (Cucumis melo L. var. reticulatus Naud.)

LI Ting , WANG Ruiqi , ZHANG Xuemei , SHI Yue , ZHANG Jing , WANG Yubin , HAO Jinghong , ZHAO Xiaoyan , ZHANG Chao

2022, 38(7):160-168. DOI: 10.13982/j.mfst.1673-9078.2022.7.1174

[Abstract](142) [HTML](204) [PDF 2.99 M](420)

Abstract:
The effect of Trichoderma harzianum treatment on shelf life qualities of netted melon (Cucumis melo L. var. reticulatus Naud.) was evaluated. Trichoderma harzianum agent was applied to the root of the netted melon during the planting for 4 times (each time with a dose of 0.1 g/m2) with water as the control. The fruits were stored in 10 ℃ after harvest immediately. The sensory, color, taste, texture, and antioxidant capacity of samples were evaluated at 0, 5, 10 and 15 days of storage. The results showed that the pulp of melons treated by Trichoderma harzianum showed the uniform texture with lower fiber content, and the best taste period of fruits was 4 days longer than that of the control, and the soluble solid content and Vc content of fruits increased by 15.20%, and 64.58%, respectively. The ORAC value reached 667.80 (µmol/L)/100 g, which was 10.05% higher than that of the control. Moreover, Trichoderma harzianum treatment increased the hardness of peel by 1.75 times and delayed the softening of pulp which was more convenient for storage and transportation. Therefore, the application of Trichoderma harzianum during the planting of the melon improved the shelf-life qualities of the melon.

22 Effects of Different Packaging on Preservation of Postharvest Lotus Root

XIAO Yue , ZHU Zichun , DENG Yun , LIU Yongjun , LI Yongjun , ZHONG Yu

2022, 38(7):169-176. DOI: 10.13982/j.mfst.1673-9078.2022.7.1091

[Abstract](146) [HTML](201) [PDF 2.48 M](503)

Abstract:
Fresh lotus roots were used as experimental materials, PE open bag (PEO), PE sealed bag (PES), modified atmosphere bag (MA) and modified atmosphere humidity control bag (MA/MH) were used for packaging treatment, and the packaged lotus roots were stored at 4±0.5 ℃ and 90% RH. The weight loss, brightness, browning degree, hardness, respiration intensity, relative conductivity, malondialdehyde content (MDA), para-phenol oxidase activity and peroxidase activity of lotus root were measured every 4 days. The results showed that MA and MA/MH packaging could effectively reduce the weight loss rate, maintain hardness, inhibit the rise of relative conductivity, delay the peak of respiratory intensity of lotus roots. The preservation effect of PEO was worser than MA and MA/MH, and PES had the worst effect. The browning degree values of MA and MA/MH treated group were 31.53% and 45.91%, respectively, lower than that of PEO treated group after storage for 16 days. During storage, the para-phenol oxidase activity and peroxidase activity of MA, MA/MH treated group were decreased, and the contents of MDA in MA and MA/MH treated group were 60.91% and 45.87% of that in PEO treated group. In conclusion, MA and MA/MH packaging can enhance the stress resistance, keep the cell membrane structure intact and extend the shelf life of lotus root. Among the four different packages, the MA/MH packaging is the most suitable for the preservation of lotus root.

23 Comparison of the Effects of Different E-commerce Packagings on the Preservation of Litchi at Room Temperature

WU Meiting , CHEN Yulong , QI Yingwei , WANG Ling , LIU Hai , LUO Zheng , LUO Yudong

2022, 38(7):177-183. DOI: 10.13982/j.mfst.1673-9078.2022.7.1053

[Abstract](168) [HTML](187) [PDF 1.73 M](508)

Abstract:
The e-commerce packaging of fresh fruits and vegetables is very important for their preservation. In this study, litchi "Xianjinfeng" was used as the test material, the quality changes of the litchi packed in a new type of fresh-keeping paper cardboard box and the ordinary foam box at room temperature (28~29 ℃) were examined. The results showed that both packaging forms could delay the changes in total soluble solids (TSS) content, titratable acid (TA), soluble protein content and vitamin C content, and maintain better fruit flavor and nutrients, inhibit the increases of polyphenol oxidase (PPO) and peroxidase (POD) activities, and decreased the accumulation of malondialdehyde (MDA) in the process of logistics transportation. The comprehensive results showed that there were no significant differences in the contents of TSS, TA and vitamin C between the new type of carton packaging and the ordinary foam packaging during 0~2 days of storage, with the contents of TSS, TA and vitamin C for the new type of carton being 18.15 °Brix, 0.6% and 7.45 mg/100 g. Compared with the ordinary foam box (MDA content 0.07 μmol/g), the litchi in the new carton had a significantly lower MDA content (0.04 μmol/g), and the lipid membrane of litchi pericarp was damaged to a lesser extent. Therefore, the new type of carton can be used as the e-commerce logistics packaging material for short-term storage of litchi to replace the ordinary foam carton .The new packaging material has the preservative function and is environmentally friendly and available.

24 Preparation of Compound Biological Preservative for Agaricus bisporus and Its Application in Storage and Preservation

SHANG Lichao , WANG Wenliang , GONG Zhiqing , CUI Wenjia , JIA Fengjuan , ZHAO Fengchun , WANG Yansheng

2022, 38(7):184-196. DOI: 10.13982/j.mfst.1673-9078.2022.7.1090

[Abstract](165) [HTML](213) [PDF 5.10 M](598)

Abstract:
In order to develop new and safe compound biological preservative for Agaricus bisporus, 3 categories and 12 kinds of common biological preservative were selected through the optimal screening experiment, and the preservative with better protective effect on the whiteness, opening degree, texture, hair viscosity and smell of Agaricus bisporus was screened out. The effects of ascorbic acid (Vc), Nisin and carrageenan on the preservation of Agaricus bisporus after storage were investigated. After screening, it was found that Vc, Nisin and carrageenan had a good effect on delaying the Browning of Agaricus bisporus. Then the optimization results showed that the compound biological preservative prepared by Vc 0.80 g/L, Nisin 0.40 g/L and carrageenan 5.40 g/L had the best effect. The whiteness value at the end of storage was 21.32% higher than that of the negative control (CK). Compared with the control group, the compound biological preservative treatment significantly reduced the weight loss rate and decay rate of Agaricus bisporus during storage, inhibited the decline of hardness, delayed the enhancement of polyphenol oxidase (PPO) activity, accelerated the peak of total phenol content and promoted the accumulation of phenols, promoted the peak of ABTS cation free radical clearance, and effectively delayed the reduction of antioxidant capacity of Agaricus bisporus. The results showed that the Vc-Nisin-carrageenan compound biological preservative had a good protective effect on the storage quality of Agaricus bisporus. This study can provide reference and basis for developing new, safe and efficient compound biological preservative of Agaricus bisporus.

25 Degradation Kinetics Models of Phenolics in Dried Strawberry during Storage

HU Lili , NIU Liying , LI Dajing , ZHANG Zhongyuan , XIAO Lixia , LU Maolin

2022, 38(7):197-204. DOI: 10.13982/j.mfst.1673-9078.2022.7.1063

[Abstract](121) [HTML](192) [PDF 2.03 M](441)

Abstract:
Phenolic substances are important bioactive components in strawberries, which are unstable and easy to degrade. In order to explore the changing trend of the phenolic substances in dried strawberries during storage, the degradation kinetics of these compounds in the dried strawberries stored in different packages at 4, 20and 37 ℃ were examined. The results showed that the phenolic substances in dried strawberry were unstable to heat and light. With the increase of storage temperature, the degradation rate increased and the half-life decreased. At the same storage temperature, the degradation rate of the strawberries in vacuum light-proof packaging was the lowest, followed by those with vacuum light-transmitting packaging, non-vacuum light-proof packaging and non-vacuum light-transmitting packaging. The degradation of phenolic substances in the dried strawberries packaged with the four packagings all conformed to the first-order kinetic model, with their reaction activation energies as 22.45, 17.75, 18.91 and 17.42 kJ/mol, respectively. The correlation coefficients between the validated values of the strawberries in the four packaging materials obtained from the prediction model and the measured values, R2, were higher than 0.99, indicating the effectiveness of the model. The model can be used to predict the contents of phenolic substances stored at any temperature and the shelf life of dried strawberries. At the same time, the values of the thermodynamic parameters for the phenolic substances in the dried strawberries were calculated and analyzed, which provide a basis for explaining the degradation mechanism of phenolics.

26 Effects of Grain Size and High Addition of Highland Barley Powder on the Characteristics of Batter and Quality of Chiffon Cake

RUAN Zheng , LI Sai , LI Xuhan , ZHOU Yaxuan , LI Dandan , LI Biansheng

2022, 38(7):205-216. DOI: 10.13982/j.mfst.1673-9078.2022.7.1102

[Abstract](190) [HTML](195) [PDF 6.44 M](820)

Abstract:
In view of the unstable quality such as structural collapse caused by raw materials with high dietary fiber in cake preparation, highland barley powder with high dietary fiber content was selected as the raw material to explore the effects of particle size and high addition amount on the batter characteristics and cake quality of Chiffon cake. Take the wheat flour based Chiffon cake as control, the changes of specific gravity, bubble distribution, viscosity of batter and the specific volume, pore structure, texture and sensory quality of cake with different particle sizes (QKF80, QKF100 and QKF120) under different addition amounts (50%, 75% and 100%) of highland barley powder were studied. The results showed that the larger the grain size was, the higher dietary fiber contents and the stronger water and oil absorption capacity of highland barley powder had. With the increase of highland barley powder, the stability of batter decreased, the specific gravity and viscosity of batter increased, the specific volume and sensory quality of cake decreased, and the hardness, internal pores and degree of collapse increased. The highland barley powder with small grain size gave the batter appropriate viscosity, so that it could be stable in the absence of gluten protein. Under the three addition amounts of QKF120, the specific gravity range of batter was 0.33~0.36, the bubbles in the batter were evenly distributed, the specific volume of the cake was 4.8~5.2 mL/g, the internal pore structure was dense and uniform, and there was no significant difference in texture characteristics and sensory scores between the highland barley powder and wheat flour based cake. This study can provide theoretical basis and practical reference for the development of Chiffon cake with high content of highland barley powder.

27 Comparative Analysis of the Quality Components in Xinyang White Teas Collected and Processed in Different Seasons

MA Yuan , REN Xiaoying , MA Cunqiang , XU Chengcheng , MA Bingsong , WANG Zihao

2022, 38(7):217-224. DOI: 10.13982/j.mfst.1673-9078.2022.7.0898

[Abstract](193) [HTML](227) [PDF 2.86 M](529)

Abstract:
In this work, 8 kinds of catechins, 6 kinds of flavonoids, 2 kinds of phenolic acids, 3 kinds of purine alkaloids and other quality components contents in 18 kinds of Xinyang white teas processed from the fresh tea leaves of Spring, Summer and Autumn were analyzed by methods such as high performance liquid chromatography (HPLC). The quality components of the Xinyang white teas collected and processed in different seasons were compared and analyzed. Principal component analysis (PCA) and hierarchical clustering analysis (HCA) could classify Xinyang white tea samples into spring white tea, summer white tea and autumn white tea based on the processing seasons. Through the independent-samples t-test and one-way analysis of variance, the differences in the quality components (such as catechins, flavonoids and purine bases) of the Xinyang white teas collected and processed in different seasons were investigated. The results showed that there were significant (p<0.01) or extremely significant (p<0.001) differences in the quality components of the Xinyang white teas collected and processed in different seasons; The contents of (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG) and ellagic acid in the spring white tea (33.26, 59.30 and 2.81 mg/g, respectively) were extremely significantly (p<0.001) higher than those in the summer or autumn white teas. The contents of (-)-catechin gallate (CG), (-)-gallocatechin gallate (GCG), taxifolin, rutin, myricetin, kaempferol, quercetin and luteolin in the summer white tea (0.72, 4.40, 0.84, 2.40, 0.97, 0.21, 0.25 and 0.11 mg/g, respectively) were extremely significantly (p<0.001) higher than those in the autumn white tea. The contents of (+)-catechin (C), (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), gallic acid, caffeine and theobromine (4.98, 14.35, 27.02, 10.10, 36.85 and 1.53 mg/g) in the autumn white tea were extremely significantly (p<0.001) higher than those in the spring or summer white tea. This study revealed the quality characteristic of Xinyang white teas and the differences in the quality components of Xinyang white teas harvested and processed in spring, summer and autumn seasons. These results provide a scientific basis for the distinguishing white teas and other teas harvested and processed in different seasons.

28 Optimization of Extraction Process for Chestnut Starches and Analysis of Their Properties

ZHANG Zengjiang , WANG Zhu , ZHU Junchao , CHEN Ling , LI Xiaoxi , ZHENG Bo

2022, 38(7):225-231. DOI: 10.13982/j.mfst.1673-9078.2022.7.0986

[Abstract](218) [HTML](190) [PDF 1.91 M](498)

Abstract:
This research aimed to improve the extraction rate of starch from chestnut. Three extraction methods were screened, and the extraction parameters were optimized by response surface methodology to obtain the optimal extraction process. Furthermore, starches from different chestnut varieties were extracted by the optimal process, and their properties were compared and analyzed. The results showed that the enzymatic method (alcalase) could extract chestnut starch more efficiently than the surfactant method and the alkali method. The optimal extraction conditions were as follows: enzymatic hydrolysis time, 100 min; enzyme dosage, 0.22%; enzymatic hydrolysis temperature, 43 ℃. The optimal theoretical extraction rate and actual extraction rate were 96.73% and 96.61%, respectively, and the purity of starch was 99.28%. The comparison of the properties of the starches from the three chestnut varieties showed that the starch of Dongyuezaofeng had the highest solubility (2.13%) and the lowest swelling degree (11.52%), whilst that of Dafeng had the lowest solubility (0.67%) but the highest swelling degree (13.44%). After the same freeze-thaw cycles, the freeze-thaw stability of Dafeng starch was the worst (67.33%), whilst Youzhen and Dongyuezaofeng starches had the same and better stability (64.52% and 64.23%). The resistant starch contents of Dongyuezaofeng, Dafeng, and Youzhen starches were 60.88%, 74.44% and 60.70%, respectively, among which Dafeng starch had the highest resistant starch content (74.44%). This research can provide basicy data and a theoretical basis for the high-value application of chestnut starch.

29 The Gel Properties of White Shrimp and Antarctic Krill Mixed Shrimp Surimi

ZHANG Biao , LI Dongmei , GUO Xuan , XU Wei , ZHANG Yuying , LIN Junxin , SUN Peizi , YU Bo

2022, 38(7):232-239. DOI: 10.13982/j.mfst.1673-9078.2022.7.1070

[Abstract](159) [HTML](199) [PDF 2.55 M](493)

Abstract:
In order to improve the quality of Antarctic krill shrimp surimi, in this research, white shrimp and Antarctic krill were used as raw materials and mixed in different mass ratios (0:1, 1:1, 3:2, 7:3, 4:1). The effects of different ratios of white shrimp and Antarctic krill on the texture, water holding capacity, cooking loss, color, rheological properties and microstructure of the composite shrimp surimi gel were studied. The results showed that white shrimp and Antarctic krill ratio from 1:1 to 4:1, the hardness, gel strength and water holding capacity were increased by 18.28%, 168.64% and 5.55%, respectively, and the storage modulus (G') and loss modulus (G") were significantly increased. The whiteness and cooking loss were reduced by 4.92% and 22.81%, respectively. Scanning electron microscope results showed that with the increase in the proportion of white shrimp, the pores of the mixed shrimp surimi gel became uniform and compact. The gel properties of the mixed shrimp surimi prepared by mixing white shrimp and Antarctic krill at the ratio of 3:2 were improved. The present research provided theoretical support for the development of Antarctic krill shrimp surimi products.

30 Preparation Process Optimization of Barley Leaf Broccoli Yogurt

ZHENG Qing , WANG Gang , BIAN Xuefen , SHI Jiyu , HU Chengxuan , HUANG Zixia , WANG Chunji

2022, 38(7):240-246. DOI: 10.13982/j.mfst.1673-9078.2022.7.1072

[Abstract](166) [HTML](217) [PDF 2.36 M](504)

Abstract:
In order to increase the utilization of barley leaf and broccoli and increase the health value of yogurt, barley leaf broccoli yogurt was made with barley leaf, broccoli and skimmed milk powder as the main raw materials. In addition, the process and formula of barley broccoli acid are optimized by univariate test and orthogonal test, and the qualitative structure of yogurt under different processes and formulas was explored and analyzed. Finally, the antioxidant properties and acidity of barley leaf broccoli yogurt were studied. The results showed that the best formula of barley broccoli yogurt was as follows: Based on the reconstituted milk, barley juice 15%, broccoli juice 12%, sucrose 7%, starter inoculation amount 0.6%, fermentation time 6 h, and gelatin addition amount 0.1%. The final product retains the nutritional components of barley leaf broccoli, with uniform curd, no whey precipitation, light green wheat flavor, suitable acidity and sweetness, full color. The hardness of yogurt is 191.7 gf, the adhesion is 79.4 gf, and the cohesion is 0.39. At the same time, the antioxidant activity is greatly improved, and the acidity meets the national standard.

31 Modification Effect of Volvariella volvacea on Protein Structure of Beef

SHEN Shuangwei , QING Zhenglong , LIN Weiling , ZHANG Xianbin , LIU Xueming , LIN Yaosheng , TANG Daobang , WANG Xuping , CHENG Jingrong , ZHU Mingjun

2022, 38(7):247-255. DOI: 10.13982/j.mfst.1673-9078.2022.7.1084

[Abstract](168) [HTML](208) [PDF 2.47 M](499)

Abstract:
In this study, the physicochemical properties of beef paste and the solubility, structure, aggregation state, and rheological properties of myofibrillar protein were compared before and after Volvariella volvacea (Vv) powder (5%, m/m) treatment, in order to analyze the mechanism of straw mushroom on beef paste quality. The results showed that Vv effectively reduced the cooking loss rate of beef paste, but increased the pH value and volatile base nitrogen content of meat, and darkened the color of meat. Among them, the cooking loss of beef paste samples was the lowest (3.44%) after 48 h of treatment, which was 4.48 times lower than that of the control group. At the same time, with the extension of treatment time, protein solubility decreased first and then increased, the degree of carbonylation and conversion of sulfhydryl group to disulfide bond gradually increased, and the content of α-helix gradually unwound from 34.50% to 29.50%. After treatment, the degree of protein degradation and aggregation was increased, and the gel rheology was significantly improved. These results indicate that the endogenous components of Vv may affect the flavor and texture of meat products by promoting protein oxidation and hydrolysis. The above research results are helpful to analyze the influence mechanism of edible fungi on the quality of meat products, and provide theoretical basis for the application of Vv in the development of new flavor meat products.

32 Preparation of Citrus medica 'Fingered' Probiotic Gummies and Analysis of Its in Vitro Digestive Tolerance

TANG Ying , ZOU Bo , YU Yuanshan , LI Lu , XU Yujuan , XIAO Gengsheng , WU Jijun

2022, 38(7):256-263. DOI: 10.13982/j.mfst.1673-9078.2022.7.1089

[Abstract](233) [HTML](198) [PDF 5.78 M](476)

Abstract:
Gummies rich in fruits and probiotics are one of the important directions for the development of confectionery in the future. This study optimized the processing technology of bergamot probiotic gummies, and explored the effect of in vitro simulated gastrointestinal digestion environment on the survival rate of probiotics in gummies. The results showed that the hardness, elasticity, adhesiveness, and chewiness of bergamot gummies were closely related to the sensory quality of the gummies. The effect on the sensory quality of the gummies from strong to weak is the addition amount of bergamot pulp, blending temperature and blending time. The results of response surface analysis showed that the best process for probiotic gummies is: 12.5% of bergamot pulp, blending temperature 70 ℃, and blending time 4 min. Under this process condition, the sensory quality of gummies is the best, and the number of viable bacteria is 7.6 log CFU/g. The in vitro digestion test showed that Bacillus coagulans had good gastrointestinal tolerance, and the number of viable bacteria in artificial gastric fluid with pH 1.5~3.5 reached more than 6.01 log CFU/g; the number of viable bacteria was only decrease by 0.27 log CFU/g after 4 h digestion in artificial intestinal fluid. When the bile salt concentration was 1~4 g/L, the number of viable bacteria after 24 hours of digestion was above 6.24 log CFU/g; digested in gastric gummies at pH 3.0 for 2 h and then transferred to intestinal gummies for digestion 10 h, the number of viable bacteria only decreased by 0.28 log CFU/g. Taken together, the results provided a scientific basis for the development of fruit-flavored probiotic gummies.

33 Preliminary Study on the Techniques for the Yellowing Process of Yellow Tea High in γ-Aminobutyric Acid

ZHANG Mingming , FAN Qiye , LI Wencui , WANG Jiapeng , TANG Xiaolin

2022, 38(7):264-270. DOI: 10.13982/j.mfst.1673-9078.2022.7.1061

[Abstract](199) [HTML](208) [PDF 989.94 K](402)

Abstract:
Gamma-aminobutyric acid (GABA) has a significant blood pressure-lowering function, but its content in tea is extremely low (only 40~50 mg/100 g). In order to increase the content of GABA in yellow tea, this study examined the from the effects of the raw materials obtained from different seasons (spring and autumn), the yellowing process (wet yellowing process, dry yellowing process or wet-dry combined yellowing process), the facilities for yellowing (natural yellowing, mechanical yellowing, bamboo cage yellowing), and conditions of yellowing process (temperature and time) on the GABA content in yellow tea in the oxygen stress environment of the yellowing process. Based on the results of the sensory evaluation and the analysis of GABA content, a set of technical parameters for the yellowing process to increase the GABA content in yellow tea were obtained. The results showed that the yellowing process could effectively increase the content of GABA in tea leaves. Among them, the fresh leaves in spring were better raw materials than those obtained in autumn; Wet yellowing process was better than dry yellowing process and wet-dry combined yellowing process; bamboo cage yellowing and mechanical yellowing were better than natural yellowing; The yellowing conditions of 50 ℃ and 4 h were beneficial to the formation of a large quantity of GABA. In summary, using spring fresh leaves, wet yellowing process, fermentation machine for yellowing at 50 ℃ for 6 h could lead to the highest increase in the GABA content (up to 127.54 mg/100 g). The research results have provided a new way for the processing of functional yellow tea and an important reference for the future research, development and production of the GABA-rich yellow tea.

34 Comparison and Analysis of Volatile Components in Different Parts of Fruiting Body of Stropharia rugoso-annulata

LU Huan , SHANG Xiaodong , WANG Xiaoyan , WANG Chunhui , LIU Jianhui , CHEN Wanzhu , WANG Ruijuan , XU Ning

2022, 38(7):271-281. DOI: 10.13982/j.mfst.1673-9078.2022.7.1016

[Abstract](192) [HTML](191) [PDF 1.66 M](424)

Abstract:
The volatile components in pileus and stipe of the fruiting body of Stropharia rugoso-annulata were comparatively analyzed by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Principal component analysis (PCA) was also performed. The results showed that 50 compounds were identified from the pileus and stipe of the fruiting body of Stropharia rugoso-annulata. Among which, alcohols, esters and alkanes were mainly present in the pileus, accounting for 19.93%, 19.43% and 9.79%, respectively. Alcohols, esters and ketones were mainly detected in the stipe, accounting for 23.04%, 21.04% and 12.35%, respectively. Among the detected compounds, the relative percentages of 3,4-dihydroxy-2-methylpyridine-5-methanol, 4-piperidinol, bis(2-ethylhexyl) maleate, cyclohexane and (E)-3-nonen-2-onewere the highest, which played important roles in the formation of the aroma of Stropharia rugoso-annulata. The results of principal component analysis showed that alcohols were the main volatile components in the pileus and stipe of Stropharia rugoso-annulata, and there were significant differences in the volatile composition between the pileus and stipe. The results of this study provide a reference for the evaluation of the flavor and quality of Stropharia rugoso-annulata and breeding of high-quality Stropharia rugoso-annulata.

35 Comparative Analysis on the Quality of Preserved Mango and Dried Mango of Different Varieties

REN Erfang , LUO Chaodan , HUANG Yanting , FENG Chunmei , DENG Youzhan , LI Jianqiang

2022, 38(7):282-290. DOI: 10.13982/j.mfst.1673-9078.2022.7.0405

[Abstract](208) [HTML](176) [PDF 1.86 M](376)

Abstract:
The color, taste, odor, and volatile flavor compounds of four dried and preserved mango varieties (Jinhuang, Guiqi, Tainong, and Yumang) were examined using a colorimeter, an electronic tongue, an electronic nose, and gas chromatography-mass spectrometry. Preserved Jinhuang, Tainong, and Yumang mangoes retained their original color better than Guiqi mangoes, whereas in terms of flavor, dried Jinhuang, Tainong, Guiqi, and Yumang mangoes and preserved Guiqi mangoes were the best performers. Electronic nose analysis showed that preserved and dried Tainong mangoes retained the odor of the original fruit better than the others, followed by preserved and dried Yumang mangoes. The main volatile flavor components identified in fresh, preserved, and dried mangoes of the four varieties were alcohols, esters, ketones, alkanes, olefins, and aromatic hydrocarbons, among which olefin predominated. The relative olefin content of preserved and dried Yumang mangoes was higher than that of the others, at 81.09% and 77.52%, respectively. Preserved Jinhuang and Yumang mangoes and dried Jinhuang, Guiqi, and Yumang mangoes retained the volatile flavor components of the original fruit well. Considering the original flavor and quality of different varieties of preserved and dried mangoes, Yumang was the most suitable overall.

36 Taste Analysis of Protein Hydrolysates from Tilapia By-product

GAN Ruiqing , HE Yanfu , LI Yongcheng , LI Laihao , ZHAO Jingjing , SHEN Xuanri , LI Chuan

2022, 38(7):291-300. DOI: 10.13982/j.mfst.1673-9078.2022.7.1092

[Abstract](154) [HTML](196) [PDF 4.32 M](427)

Abstract:
In this paper, the source of taste-active compounds from tilapia by-products (skin, head, and bone) was investigated. Three types of by-products were hydrolyzed by neutrase, bromelain, flavorzyme, protamex, papain, and alcalase. The relationships between the degree of hydrolysis (DH), molecular weight (MW) distribution, precursor protein, and the characteristics of taste-active compounds were analyzed. The results showed that the highest degree of hydrolysis of the three tilapia by-products was obtained after hydrolysis with flavorzyme for 8 hours, which were 14.29%, 23.7% and 31.86% respectively. The by-products of papain hydrolysis showed significant bitter or sour taste, while the hydrolysate of fish head hydrolyzed by alkaline protease had umami taste, the fish bone hydrolyzed by bromelain had umami taste, and the fish skin hydrolyzed by neutral protease showed umami and sour taste, but the fish head showed bitter taste. By LC-MS/MS, collagen, myofibril proteins, and some sarcoplasmic proteins were important taste-active precursor of the potential taste peptides of tilapia by-products. The MW of most of these potential taste peptides was lower than 1500 u. The hydrophobic amino acid residues in peptides played an important role in the formation of the taste of tilapia by-products, in which methionine contributed to generate umami taste in the by-products hydrolysates.

37 Characteristic Volatile Aroma Components Analysis of Lotus Seed Paste Fillings Using HS-SPME-GC-MS/MS

LIANG Zijian , FANG Jiaqin , WU Jinyuan , DU Fangmin , FU Shuyong , GAO Xiangyang

2022, 38(7):301-308. DOI: 10.13982/j.mfst.1673-9078.2022.7.1458

[Abstract](189) [HTML](178) [PDF 2.30 M](447)

Abstract:
The volatile components of five kinds of lotus seed paste fillings were studied using HS-SPME-GC-MS/MS. A total of 29 volatile components were detected, including 2 alcohols (7.07%~9.72%), 7 aldehydes (18.38%~36.45%), 6 esters (9.97%~23.88%), 4 pyrazines (19.07%~29.38%), 3 alkanes (1.31%~5.29%), 2 furans (1.53%~4.88%), 2 ketones (2.78%~3.62%), 1 terpene (0%~10.82%), 1 thiophene (0.04%~0.31%), and 1 compound belonging to another class (11.11%~16.21%). Through PLS-DA modelling and analysis of variance, the main differential substances of different lotus seed paste fillings were furfural, E,E-2,4-decadienal, (±)-3-carene-2,5-dione, benzaldehyde, n-nonaldehyde, 2,6-dimethylpyrazine, 3-methylbenzaldehyde, and tetradecane. According to the relative odor activity value, the main volatile flavor compounds were identified as E,E-2,4-decadienal, ethyl octanoate, 2-acetylthiophene, n-nonaldehyde, hexanal, phenylethyl acetate, and phenyl ethanol in order of degree of contribution. Results of the analysis of the main differential volatile components and flavor contribution degree of different lotus seed paste fillings showed that the flavor of fillings were mainly influenced by the relative levels of E,E-2,4-decadienal, n-nonaldehyde, and benzaldehyde. The results of this study revealed the flavor profile of lotus seed paste fillings and provides a theoretical basis for its quality evaluation and standardized production.

38 Regulation of Vomit Toxin on Proliferation and Apoptosis Inducing Protein Expression of HK2 Cells

ZHANG Baigang , LI Jinliang , LIANG Hairong , HUANG Chenghui , XU Dongmei

2022, 38(7):309-315. DOI: 10.13982/j.mfst.1673-9078.2022.7.0996

[Abstract](159) [HTML](230) [PDF 3.31 M](373)

Abstract:
This paper investigated the effects of vomit toxin on inhibiting the proliferation and inducing the expression of apoptotic protein in HK2 cells. After different concentrations of vomit toxin acted on HK2 cells, the inhibitory effect of vomit toxin on cell proliferation was detected by MTT method, the changes of cell morphology were observed by fluorescence microscope, the changes of apoptosis rate were detected by flow cytometry, and the expression levels of apoptotic proteins Bax, Bcl-2, NF-KB, caspase-2, 3, 6, 8 and 9 were detected by Western blotting. The results showed that vomit toxin could significantly inhibit the proliferation of HK2 cells in a dose-response relationship, at the concentration of 15, 30, 40, 60 and 80 μmol/L, the inhibitory rates of vomit toxin on HK2 cells were 61.82%, 53.64%, 42.43%, 38.66% and 36.54%, respectively; The survival rates of HK2 cells treated with 30 μmol/L of vomit toxin for 0, 12, 24, 48, 72 and 96 hours were 99.84%, 80.51%, 60.25%, 52.22%, 62.50% and 71.34% respectively. The apoptosis rates of cells treated with 15, 40 and 80 μmol/L of vomit toxin for 24 hours were 2.30%, 30.20% and 53.50% respectively. The Western bloting results showed that vomit toxin upregulated Bax, Caspase-2, 3, 6, 8, 9 protein expression and inhibited the protein expression of bcl-2 and NF-KB. The results showed that vomit toxin significantly inhibited the proliferation of HK2 cells, caused apoptosis and regulated the expression of apoptotic protein.

39 Comprehensive Quality Evaluation of Asparagus from Different Production Areas by Principal Component Analysis and Cluster Analysis

TAN Yan , WANG Guoqing , CHEN GAN , WU Jinzhu , ZHOU Aimei

2022, 38(7):316-326. DOI: 10.13982/j.mfst.1673-9078.2022.7.1288

[Abstract](160) [HTML](201) [PDF 1.99 M](374)

Abstract:
The basic nutritional and functional components of asparagus from selected production areas were determined in this study. The locations included: Heze, Shandong (S1); Xuchang, Henan (S2); Mile, Yunnan (S3); Guiyang, Guizhou (S4); and Ji’an, Jiangxi (S5). A comprehensive evaluation was conducted for asparagus quality using correlation analysis, principal component analysis, and cluster analysis. The results showed that the 32 quality indicators were simplified into four principal components, and that the cumulative variance contribution rate was 100%. In conjunction with correlation analysis, 13 quality indicators were selected from the 32 indicators, namely potassium, lignin, total phenolic acid, zinc, narcissin, nicotiflorin, pectin, total saponins, caffeic acid, soluble protein, chlorophyll, phlorizin and kaempferol. Cluster analysis results showed that the five asparagus production areas could be divided into three categories, with overall quality ranked from best to worst as S1, S2, S5, S4, and S3. The production areas with similar rankings were placed in the same category, indicating that the results obtained by the two analysis methods were relatively consistent. This study provides a theoretical basis for the quality evaluation of asparagus from different production areas as well as the selection of core quality indicators.

40 Research Progress on Geographical Origin Traceability of Coffee Beans

TIAN Ling , ZHOU Haichao , ZHANG Ang , WU Hao , WU Fengqi

2022, 38(7):327-337. DOI: 10.13982/j.mfst.1673-9078.2022.7.0948

[Abstract](274) [HTML](284) [PDF 1.83 M](437)

Abstract:
Due to the relatively high economic value of coffee beans in the origin and their shortage of supply in the consumer market, coffee bean origin fraud is becoming more severe. Therefore, it is urgent to develop technologies and methods that can accurately trace the geographical origin of coffee beans. This review introduces the main origins of coffee beans in the world and analyzes 79 domestic and international research papers related to the geographical origin of coffee beans, and compares the advantages and disadvantages of metabolomics, multi-element fingerprinting, stable isotopes, terahertz magnetic spectroscopy and infrared spectroscopy combined with chemometric methods in the applications of tracing the origin of coffee beans. It was found that the combination of light stable isotopes with multi-element fingerprints can effectively trace the geographical origin of coffee beans. This method has high stability and accuracy, and requires relatively low cost for traceability. On this basis, the focus and development direction for the combined use of light stable isotope technique and multi-element fingerprints in the research field of coffee bean origin are prospected.

41 Polymer-based Delivery Systems for Probiotics: Carrier Type, Performance Evaluation and Application of New Technologies

JIA Guochao , CHEN Xiaofeng , ZHANG Jun , WANG Lan , ZHI Aimin , CHEN Wenbo , LI Jingjing

2022, 38(7):338-344. DOI: 10.13982/j.mfst.1673-9078.2022.7.1030

[Abstract](238) [HTML](281) [PDF 966.23 K](439)

Abstract:
Probiotics confer a variety of health benefits on the host, and can be used to prevent and treat gastrointestinal and non-gastrointestinal diseases, such as diarrhea, colon cancer, obesity, neurological diseases, diabetes, and inflammation. However, the survival rates of probiotics are affected by various environmental factors in the process of production, processing, storage and digestion. How to maintain the vitality and stability of probiotics to the maximum extent has become one of the current probiotic research hotspots. Biocompatible and degradable polymers can be used as delivery carriers for probiotics, which can effectively enhance the activities of probiotics, prolong storage time, reduce the loss of probiotics in the stomach, and even achieve targeted delivery to the colon and mucosa. This article reviews the types of current polymer carriers for probiotics encapsulation, and the evaluation methods for probiotic delivery systems. New techniques for preparing probiotic delivery systems are also discussed. The results show that combining properly the new delivery system technologies with diversified evaluation methods allows the establishment of probiotic delivery systems with high stability, functionality, safety, effectiveness, and targeting capability. These new delivery systems can achieve efficient delivery of probiotics, which will further promote the application of multifunctional probiotics in food or pharmaceutical fields.

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Volume 38,Issue 7,2022 Table of Contents