Volume 38,Issue 2,2022 Table of Contents

1 Selenium-enriched Red Yeast Rice Improves Lipid Metabolism and Intestinal Flora in Mice Fed A High-fat Diet

ZHANG Yaping , YUAN Yahong , YUE Tianli

2022, 38(2):1-11. DOI: 10.13982/j.mfst.1673-9078.2022.2.0609

[Abstract](338) [HTML](357) [PDF 2.19 M](580)

Abstract:
The effects of selenium-enriched red yeast rice on lipid metabolism and intestinal flora in mice fed a high-fat diet were investigated. Forty-eight C57BL/6J mice were divided randomly into six groups (n=8 each): a common diet group; high-fat diet group; low-, medium-, and high-dose selenium-enriched red yeast rice group; and red yeast rice group. After gavage for 8 weeks, the serum total triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C) contents were determined. The liver tissue and fat status were examined using a microscope, and intestinal flora were analyzed using 16S rRNA high-throughput sequencing. Compared to the high-fat diet group, the high-dose selenium-enriched red yeast rice group showed significantly improved blood lipid levels, liver fat accumulation, and intestinal flora. Serum triglyceride, total cholesterol, and LDL-C levels were significantly reduced by 26.97%, 24.43%, and 49.03%, respectively, and high-density lipoprotein cholesterol levels were significantly increased by 95.71%. Additionally, the species richness and diversity of the intestinal flora were significantly increased, and the structure of the intestinal flora was significantly improved. The relative abundance of Firmicutes (positively correlated with blood lipid levels) was decreased by 39.26%, and those of Verrucomicrobia and Akkermansia (negatively correlated with blood lipid levels) were increased by 36.09% and 36.93%, respectively. Compared with that in the red yeast rice group, the LDL-C level in the high-dose selenium-enriched red yeast rice group was significantly reduced by 42.31%. Moreover, the relative abundance of Firmicutes was reduced by 26.10%, and those of Verrucomicrobia and Akkermansia were increased by 46.59% and 44.01%, respectively. This study showed that compared with red yeast rice, selenium-enriched red yeast rice markedly ameliorates lipid metabolism disorder and the intestinal flora imbalance induced by a high-fat diet in mice.

2 Compound Tea Lowers Lipid Levels by Promoting Organic Acid Metabolism

ZHOU Caibi , WEN Zhirui , MU Ren , PAN Xiujuan , WANG Chuanming , YANG Zaibo , ZHOU Xiaolu

2022, 38(2):12-27. DOI: 10.13982/j.mfst.1673-9078.2022.2.0621

[Abstract](246) [HTML](255) [PDF 6.44 M](439)

Abstract:
The lipid-lowering effects of compound tea were investigated to determine the mechanism underlying its action and provide theoretical support for the development and application of this compound tea. Specific pathogen-free male Kunming mice were randomly divided into four groups: a model control group (NK), positive control group (YK), blank control group (CK), and compound tea treatment group (DH), with 10 mice in each group. After 30 days of intragastric administration of compound tea, the body weight, liver coefficient, liver morphology, and liver metabolism of organic acids were analyzed in mice with hyperlipidemia. The weight of mice in the NK group was significantly increased compared to that of the mice in the CK group, whereas the weight gain and liver-to-body ratio of mice in the DH group exhibited no significant difference. Fifty-two differential organic acid metabolites were detected. Compared to the CK group, b-ureaisobutyric acid and n-acetyl-aspartyl-glutamate in the DH group were significantly upregulated, whereas creatine and 14 other organic acids were significantly downregulated. In the YK group, 13 organic acids, including argininosuccinic acid, were upregulated, whereas 17 organic acids, including chlorogenic acid, were downregulated. Compound tea had a better ability to regulate blood lipids compared with the YK (positive control, Xuezhikang). This may be because compound tea can regulate the metabolism of organic acids, such as chlorogenic acid, and their associated metabolic pathways, as well as ameliorate dyslipidemia induced by a high-fat diet in mice, thereby reducing body weight and blood lipid levels.

3 Betaine Increasing Expression Levels of Antioxidase in LO2 Cells

ZHANG Mengmeng , XIN Xuan , LAI Furao , WU Hui

2022, 38(2):28-35. DOI: 10.13982/j.mfst.1673-9078.2022.2.0590

[Abstract](261) [HTML](160) [PDF 742.94 K](455)

Abstract:
The present study investigated the effect of betaine (BET) on the mRNA levels of superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) in human normal hepatocyte LO2 cells and the mechanism. The mRNA levels of antioxidases and indicators involving Nrf2-Keap1-ARE pathway were detected by real-time fluorescence quantitative method, western blot and enzyme-linked immunosorbent assay. The mRNA levels of SOD, GPX and CAT in LO2 cells were significantly increased by 1.08, 0.51 and 0.88 times, respectively, after 12 h treatment with different concentrations of BET (p<0.05). After 250 μmol/L of BET treatment, the protein level of Nrf2, which can bind to the ARE region in the nucleus, and the total Nrf2 protein in cells were significantly increased by 1.21 and 0.80 fold, respectively (p<0.05).After treatment with brucopicol, the effect of BET on the mRNA levels of three antioxidant enzymes was completely abolished. Further analysis showed that BET did not significantly increase the mRNA and phosphorylation levels of Nrf2, but decreased the mRNA and protein content of Keap1 by 38.21% and 49.15%, respectively (p<0.05). These results indicate that BET activates the Nrf2-Keap1-ARE pathway by decreasing the level of Keap1, and thus enhances the expression of antioxidant enzymes.

4 Protective Effect of Flavonoids from Young Fruit of Golden Pomelo on Oxidative Damage of Erythrocyte Induced by AAPH

NA Yunong , CHEN Naiyi , ZHANG Huanyou , WANG Qin , XIAO Gengsheng , LIU Huifan

2022, 38(2):36-45. DOI: 10.13982/j.mfst.1673-9078.2022.2.0576

[Abstract](232) [HTML](194) [PDF 1.50 M](530)

Abstract:
In this study, microwave-assisted ultrasonic were used to extracted flavonoids from golden pomelo, after purified by AB-8 macroporous resin and preparative liquid chromatography, the components of PF were identified by liquid chromatography-mass spectrometry (LC-MS). The results showed that PF contained 35 components, among which the contents of cascaroside A, stachydrine, 2-O-caffeinated arbutin and betaine were 15.57%, 1.6%, 1.15% and 0.13%, respectively. In the model of erythrocyte hemolysis induced by AAPH, the hemolysis rate of the experimental group was 31.63% after high concentration treatment of PF, which was significantly lower than that of the AAPH group (52.79%). In the enzymatic antioxidant system, the enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), after high concentration treatment, were 241.04 U/L, 93.29 U/L and 72.93 U/L, respectively, which were lower than those in AAPH group. In the non-enzymatic antioxidant system, the contents of glutathione (GSH) and malondialdehyde (MDA) after high concentration of PF treatment were 1233.94 μmol/L, 27.39 nmol/L, respectively, and the activity of lactate dehydrogenase (LDH) was 314.75 U/L, and all showed a does response. The result shows that PF can inhibit AAPH induced oxidative stress mostly by scavenging free radicals through non-enzymatic system, which provides a certain research basis for the development of natural products of young pomelo.

5 Antioxidant Effect of Peptides of Wild Apricot from Yiwu County in Xinjiang in Aging Mouse Model

JIANG Li , LU Yue , Maidenamu•Ablimiti , SHANG Xueke , XU Hezhixiang , YANG Xiaojun

2022, 38(2):46-55. DOI: 10.13982/j.mfst.1673-9078.2022.2.0505

[Abstract](201) [HTML](181) [PDF 605.48 K](345)

Abstract:
In this study, enzymatic hydrolysis was used to extract the peptides in wild apricot from Yiwu County of Xinjiang, and its antioxidant effect was examined in aging mouse model. Through single factor experiments, the effects of enzyme-substrate ratio, material-to-liquid ratio, extraction time, pH and enzymatic hydrolysis temperature on hydrolysis degree were examined, and the extraction process for the wild apricot peptide was optimized through combining single factor and orthogonal experiments. Taking the extract as the raw material, D-galactose was used to establish an aging mouse model, and the mice were divided into the blank control group, the low-, medium-, and high-dose wild apricot peptide groups (50, 75 or 100 mg/kg), the aging model group and the Vc positive control group. After 30 days of continuous intragastric administration, the GSH-Px activity, SOD activity and MDA content in the serum, liver tissue and brain tissue homogenates were determined. The optimal conditions for extracting wild apricot peptides by enzymatic hydrolysis were as follows: enzyme-substrate ratio, 4%; enzymolysis time, 120 min; pH, 8; enzymolysis temperature, 65 ℃; material-liquid ratio, 1:25. The hydrolysis degree and peptide yield were 35.73 % and 7.22%, respectively. Compared with the model group, the medium-dose and high-dose peptide groups could significantly increase the activities of T-SOD and GSH-Px in mouse serum, liver tissue and brain tissue (p<0.05), and reduce the content of MDA (p<0.05). Among which, the serum contents of serum T-SOD, MDA and GSH-Px were 177.24 U/mL, 9.05 nmol/mL and 261.59 U/mL. Respectively, in high dose groups, were similar to those of the blank control group. The results showed that the peptides from the wild apricot in Yiwu County of Xinjiang exhibited good anti-oxidant effects in the aging mouse model.

6 Immune Function and Food Safety Evaluation of Soybean Isoflavone Composite Capsule

LIU Ling , WANG Meng , SONG Zijuan , SHAN Yuanyuan

2022, 38(2):56-63. DOI: 10.13982/j.mfst.1673-9078.2022.2.0639

[Abstract](189) [HTML](274) [PDF 464.96 K](444)

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The immune enhancement effect and safety of soybean isoflavone compound capsules (SIC) were evaluated. Mice were intragastrically administered SIC at doses of 340, 670 and 1000 mg/kg•bw for 30 days, in accordance with 30-, 20-, and 10-fold the recommended dosage for humans, respectively. Immune function was evaluated by measuring the organ/body weight ratio, cellular immunity, humoral immunity, mononuclear macrophage phagocytosis index, and natural killer cell activity. The degree of paw swelling, optical density difference of lymphocyte proliferation, and number of hemolytic plaques in the high-dose SIC intervention group were suppressed by 34.87% (p<0.05), 36.07% (p<0.05), and 15.85% (p<0.05), respectively, compared to the control group, and serum hemolysin levels were increased by 12.66% (p<0.01). Cellular and humoral immune functions were enhanced by SIC. The safety of SIC was evaluated through acute toxicity testing, the Ames test, mouse bone marrow cell micronucleus testing, and mouse sperm abnormality testing. During the 30-day observation period, there were no effects on the body weight, food intake, food utilization rate, hematological indexes, hematological biochemical indices, or organ coefficient in the experimental rats treated with the different doses of SIC. The acute toxicity in rats was greater than 19.76 g/kg•bw, and the no-observed-adverse-effect level was greater than 3.33 g/kg•bw. These results demonstrate that SIC has no acute toxicity or genotoxicity and effectively enhances immunity.

7 Transcriptomic Analysis of the Effects of Ultrasound Induction on Peanut Sprout and the Mining of Genes Involved in Phenylpropanoid Biosynthesis

XIE Mengxi , YU Miao , LU Ming , FU Xin , ZHANG Liangchen , SHI Taiyuan

2022, 38(2):64-71. DOI: 10.13982/j.mfst.1673-9078.2022.2.0622

[Abstract](192) [HTML](186) [PDF 1.15 M](425)

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To analyze the differences in genetic and metabolic pathways during germination in peanuts, peanut varieties were pre-screened to identify those with resveratrol enrichment for further evaluation. Germinated peanuts subjected to induction with ultrasound (CS) were used as the experimental group, and uninduced germinated peanuts (KB) were used as the control group. A total of 1104 differentially expressed genes (DEGs) was obtained, including 521 upregulated genes and 583 downregulated genes. In the Gene Ontology enrichment analysis of the DEGs, functional analysis of the top 20 categories with obvious enrichment levels was performed. Twenty-one different cluster of orthologous group functional annotations were obtained, which primarily involved carbohydrate transportation and metabolism, post-translational modification, and protein conversion. There were 21 biosynthetic pathways in which DEGs were enriched in phenylpropanoids, which are the most significant pathways for Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The KEGG database showed that the genes arahy.Tifrunner.gnm1.ann1.DXZI51, arahy.Tifrunner.gnm1.ann1.VGN2GE, and arahy.Tifrunner.gnm1.ann1.Y23DM6 are involved in phenylpropanoid biosynthesis. These results indicate that ultrasound induction can regulate the expression of genes related to phenylpropanoid biosynthetic pathways in germinating peanuts, and transcriptomic changes can be determined at the molecular level in peanut buds induced by ultrasound.

8 Proliferation and Tolerance Capability of Lactobacillus bulgaricus and Lactobacillus plantarum Regulated by the Resistant Starch from Arenga pinnata

LI Mengyun , REN Minhong , LIU Yuansen , ZHANG Lu , MEI Jiangyang , FU Zhen

2022, 38(2):72-78. DOI: 10.13982/j.mfst.1673-9078.2022.2.0255

[Abstract](181) [HTML](276) [PDF 459.82 K](394)

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In this study, the starch from Arenga pinnata was used as the raw material to prepare Arenga pinnata resistant starch (APRS). In vitro fermentation was performed to investigate the effects of different concentrations of APRS (0.1%, 0.2%, 0.5%, 1%, 1.5%) on the proliferation and tolerance capability in the adverse gastrointestinal environment of Lactobacillus bulgaricus (LB) and Lactobacillus plantarum (LP) were studied. The results showed that when the APRS concentration gradually increased to 0.2%, the OD600 nm of LB reached the maximum (0.91); when the APRS concentration gradually increased to 0.5%, the OD600 nm of LP reached the maximum (0.94). However, with the continuous increase of APRS content, the concentration of probiotics solution decreased significantly. Therefore, APRS at a low concentration (0.1%~0.5%) could promote on the growth of LB and LP; but APRS at a high concentration (1%~1.5%) was not conducive to on the growth of LB and LP. Compared with glucose (GLU), APRS could enhance the tolerance capability of LB and LP to an acidic environment, high concentration of bile acid salts and gastric fluid environment (p<0.05). APRS promoted and inhibited the proliferation of probiotics at a low and high concentration, respectively, thereby enhancing their tolerance in the gastrointestinal environment. The potential prebiotic effect of APRS can provide a theoretical reference for further development of APRS.

9 Immobilization of Alginate Lyase from Microbulbifer sp. with Tannic Functionalized Fe3O4 Magnetic Nanoparticles

JIAO Xiaojia , WU Liyang , CHEN Yanhong , JIANG Zedong , NI Hui , LI Qingbiao , ZHU Yanbing

2022, 38(2):79-86. DOI: 10.13982/j.mfst.1673-9078.2022.2.0533

[Abstract](259) [HTML](158) [PDF 628.63 K](455)

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The immobilization conditions of alginate lyase from Microbulbifer sp. were explored in this study. Tannic acid functionalized magnetic nanoparticles (TA-MNPs) were used as the immobilized carrier to optimize the immobilization conditions of alginate lyase by determining the specific activity and activity recovery of the immobilized enzyme. Then the immobilized enzyme was characterized by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). When the carrier amount was determined to be 10 mg, the optimized immobilization conditions for the alginate lyase were determined as follows: glutaraldehyde concentration 1.00%, cross-linking time 2 h, immobilization temperature 5 ℃, immobilization time 8 h, immobilization pH 8.00, and enzyme dosage 1.20 U. The immobilization effect was the best under these conditions with the specific activity and activity recovery of 36.56 U/g and 30.55%, respectively. The results of FTIR showed that the alginate lyase was successfully immobilized on the surface of TA-MNPs. The results of TEM showed that TA-MNPs had good dispersion and were regular spherical. After immobilization by TA-MNPs, the immobilized enzyme showed the obvious aggregation and little change in particle size. Compared with the free alginate lyase, the immobilized enzyme enhanced thermal stability, pH stability, and storage stability. Optimization of the immobilization conditions of Microbulbifer sp. alginatelyase laid a good foundation for the preparation and application of the immobilized enzyme.

10 Synergistic Inhibition and Mechanism of Mulberry Fruit, Passion Fruit, Pomelo and Pitaya Fruit Compound Juiceon α-glucosidase Inhibition

DONG Yuhao , CHEN Chun , FU Xiong

2022, 38(2):87-93. DOI: 10.13982/j.mfst.1673-9078.2022.2.0584

[Abstract](298) [HTML](291) [PDF 830.19 K](550)

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In order to study the synergistic effect of juice on bioactivity in compound system, mulberry fruit, passion fruit, pomelo and pitaya fruit with rich active substances were selected as materials. The four single juices were mixed based on polyphenol contents, and their antioxidant and hypoglycemic activities were examined. The results showed that the oxygen radical absorbance capacity of compound juice showed no significant improvement. The inhibitory activities on α-glucosidase were significantly enhanced, specifically, the IC50 values of compound juice were between 0.16~0.25 mg GAE/mL, both less than those of single juice (0.30~0.49 mg GAE/mL). The combination index values were all less than 0.9, among which the value of pomelo and mulberry fruit-passion fruit-pitaya fruit showed the lowest value of 0.57. The inhibition kinetics research indicated that mulberry fruit juice exhibited non-competitive inhibition type on α-glucosidase, while the other three juices were mixed inhibition type. Moreover, the lowest inhibition constant was 22.2 mg/mL in mulberry fruit juice. Generally, this research demonstrated that the combination of fruit juice had synergistic effect on enhancing α-glucosidase inhibition activity. Furthermore, the mulberry fruit juice with great activity was suggested to be used as the non- competitive inhibition material in compound juice.

11 Comparison of the Physicochemical Properties of Dietary Fiber from Lychee Pomace Treated with Different Desugarization Methods

LI Yina , YU Yuanshan , LI Lu , WU Jijun , XIAO Gengsheng , ZOU Bo

2022, 38(2):94-103. DOI: 10.13982/j.mfst.1673-9078.2022.2.0439

[Abstract](274) [HTML](288) [PDF 1.80 M](535)

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This study investigated the effects of three different pretreatments (alcohol wash, water wash and fermentation with yeast) on the desugarization of lychee pomace and the physicochemical properties of dietary fiber. The results showed that the contents of total sugar, fructose, and glucose in the lychee pomace were 11.13%, 4.89% and 4.33% (m/m), respectively. All the three desugarization methods could effectively remove the reducing sugar from the lychee pomace. Among them, the loss rate of lychee pomace in the alcohol-washing group and water-washing group exceeded 60%, which in turn decreased the yields of soluble dietary fiber (SDF) and insoluble dietary fiber (IDF). When the desugarization rate of lychee pomace of the yeast-fermentation group reached 91.24%, with the loss rate of lychee pomace being only 36.07%, the IDF yield decreasing by 3.34%, and the SDF yield increasing slightly (the difference was insignificant, p>0.05). Compared with the undesugarized, the water-holding capacity, water-binding capacity and swelling capacity of the total dietary fiber (TDF) in the alcohol-washing group increased by 1.53 g/g, 1.19 g/g and 0.70 g/g, respectively, whilst the hydration properties of the water-washing group and yeast-fermentation group decreased (p>0.05). The three desugarization methods all significantly improved the compression index and cation exchange capacity (CEC) of TDF, and the CEC of the TDF in the yeast-fermentation was the highest (0.67 mmoL/g). In summary, the fermentation with yeast can be used as a suitable desugarization method used before the extraction of dietary fiber from lychee pomace.

12 Analysis of Differences in Lipid Oxidation and Gel Properties of Porcine Myofibrillar Protein during Frozen Storage Period

YU Ligang , SUN Wenyan , FAN Sanhong , LI Qian , YANG Yukun , GUO Caixia

2022, 38(2):104-109. DOI: 10.13982/j.mfst.1673-9078.2022.2.0594

[Abstract](201) [HTML](281) [PDF 489.72 K](442)

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In this study, lipid oxidation and the gel properties (solubility, gel retention, gel whiteness, and strength) of myofibrillar protein were investigated during frozen storage of raw pork at -18 ℃ (0, 1, 4, 8, 12 weeks). The results indicated that TBARS value increased from 0.07 mg/kg protein to 0.22 mg/kg protein after 12 weeks of frozen storage. Compared with fresh raw pork, solubility, gel whiteness, gel retention and strength of myofibrillar protein decreased from 56.08% to 35.92%, 59.71 to 26.53, 46.67% to 33.57%, 0.25 to 0.14, respectively. Additionally, a correlation analysis and linear discriminant analysis between frozen time and the above indicators indicated that lipid oxidation would lead to a decrease in the gel properties of myofibrillar protein, and the decrease in solubility of porcine myofibrillar protein might be the main reason for the decrease of gel retention, gel whiteness and gel strength. Therefore, the decrease of gel properties of myofibrillar protein could be improved by controlling lipid oxidation during frozen storage of raw pork.

13 Effect of Fat Content on Color Stability of Marbling Steaks Stored under High Oxygen Modified Atmosphere Packaging

LIU Wenxuan , LUO Xin , YANG Xiaoyin , ZHANG Yimin , ZHU Lixian , MAO Yanwei , LIANG Rongrong , MA Weimin , YANG Zhengang

2022, 38(2):110-118. DOI: 10.13982/j.mfst.1673-9078.2022.2.0529

[Abstract](148) [HTML](256) [PDF 1.50 M](382)

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In order to explore the color stability of marbling beef stored under high oxygen modified atmosphere packaging (HiOx-MAP, 80% O2+20% CO2), the marbling steaks with different fat contents, grade A1 and A3, were selected. The steaks were packaged under HiOx-MAP. At each point (0, 5 and 10 d), the index was determined. The results showed the increased lipid oxidation, the decreased total reducing ability (TRA) and the higher MMb accumulation in both marbling grades steaks with the storage time prolonged (p<0.05). The color of both two marbling grades did not show significant changes after 5 days of storage, but A3 grade showed darker browning and higher lipid oxidation than A1 grade. The a* values decreased to 17.43, but it decreased to 12.22 in A3 grade. And the TBARS value reached to 1.82 mg MDA/kg in A3, but it was just 1.09 mg MDA/kg in A1, which was much lower than A3. And also, the MMb% exceeded 40% in A3 steaks which showed totally brown and was not acceptable to consumers. Therefore, the lipid oxidation degree of marbling steaks with higher fat content were much greater under HiOx-MAP, which promoted the browning of meat color. So, the ste aks of higher marbling grades with higher fat content can maintain the good color stability only for several days under HiOx-MAP. So, it should be paid more attention to these kinds of high marbling steaks in the production when HiOx-MAP is applied.

14 Comparative Analysis of Physicochemical Properties and Sensory Quality of Beef under Different Storage Conditions

WANG Ying , LI Qian , ZHU Yingchun

2022, 38(2):119-127. DOI: 10.13982/j.mfst.1673-9078.2022.2.0514

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In order to analyze the changes in the physicochemical properties and sensory quality of beef by different packaging methods and at storage temperatures, the longissimus dorsi muscle of beef in this experiment was stored at an ice temperature (-1.5±0.1) ℃ and low temperature (2±1) ℃ with air-packaging (AP) and vacuum packaging (VP), and modified atmosphere packaging (MAP). MAP included gases at two different ratios: MAP1 contained 78.8% O2, 18.8% CO2 and 2.4% N2, and MAP2 contained 60% CO2 and 40% N2. The changes in the beef indices of different treatment groups during storages such as cooking loss, juice loss rate, color parameters, metmyoglobin (MetMb), total volatile base-nitrogen (TVB-N), lipid oxidation and sensory quality were measured and analyzed. The results showed that the cooking loss of AP reached the maximum on the 15th day (28.93% and 27.03% for the storages at 2 ℃ and -1.5 ℃, respectively). The MetMb content of the MAP1 group was always higher than those of the other treatment groups, reaching the maximum value on the 10th day (54.39% and 48.69% for the storages at 2 ℃ and -1.5 ℃, respectively). The TBARS value increased with the extension of storage. The TBARS value of MAP1 was significantly higher than those of VP and MAP2 (p<0.05). The TBARS value of MAP1 on the 15th day was higher than 0.7 mg MAD/kg. The TVB-N values of MAP2 and VP on the 15th day were lower than the limit threshold (15 mg/100 g). According to the obtained sensory scores, the shelf life of MAP2 was determined to be 25 days, which was longer than those of other treatment groups. In summary, the quality of beef stored at the ice temperature was better than that under refrigeration, and MAP2 (60% CO2 and 40% N2) can make beef having better storage quality. This experiment provides data support for the application of the beef preservation method in actual production.

15 Effects of Amino Acids on Structures, Morphologies and Heat-induced Phase Transformation of Starches

XU Huixian , ZHU Zhiyi , WEI Huiying , LAI Xiaoning , ZHONG Hangyu , LIU Hongsheng , JIA Xiaojiang

2022, 38(2):128-142. DOI: 10.13982/j.mfst.1673-9078.2022.2.0599

[Abstract](254) [HTML](199) [PDF 4.35 M](590)

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In this work, corn starch was used as model material and the effects of amino acids on its morphology structure and phase transformations were systematically studied with a combination of traditional characterization techniques and molecular dynamics simulation. The results showed that the pH values were significantly changed from 7.13 to 3.27 and 9.72 by addition of acid glutamic acid and alkaline lysine, respectively. The amorphous areas of starch granules were damaged when treated by the strong acidic or alkaline condition of non-neutral amino acid solutions, which resulted in the rougher granule appearance and an increased in relatively crystalline content. In the blending system of amino acid/starch, the hydrogen bond interactions between starch molecules and amino acid molecules were gradually enhanced with an increased content of amino acid. The gelatinization of starch was inhibited by three amino acids at different contents. The peak gelatinization temperature of starch was increased by 3.71 ℃, 6.00 ℃ and 5.58 ℃ by 10% glycine, lysine and glutamate, respectively. Moreover, molecular dynamics simulation showed that the number of water molecules interacting with starch molecules through hydrogen bonding was reduced by amino acid molecules via affecting the distribution of water molecules around starch molecules, which induced a more stable structure of starch and further inhibited starch swelling and gelatinization.

16 Development of Longan-Goji-Jujube Nutritional Meal Replacement Powder and Its Regulatory Effects on Intestinal Microbiota in vitro

HUANG Fei , ZHOU Wenjun , YI Yang , ZHANG Mingwei , ZHANG Ruifen , LIU Lei , JIA Xuchao , CHEN Yanxia , CHI Jianwei

2022, 38(2):143-154. DOI: 10.13982/j.mfst.1673-9078.2022.2.0611

[Abstract](210) [HTML](257) [PDF 608.87 K](386)

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Dried longan, dried goji, and dried jujube were used as raw materials to develop a nutritional meal replacement powder that could regulate the intestinal flora. The process of crushing these raw materials was optimized and evaluated using an orthogonal experimental design. Other nutritional ingredients were added using a mixture design. Next, fluidity, stability, and sensory scores were used as testing indicators to determine the optimal formulation of the longan-goji-jujube nutritional meal replacement powder. In addition, the effect of the nutritional meal replacement powder on the intestinal flora was evaluated. The results showed that the optimal processing of the compound fruit powder was as follows: using whey protein as a supplemental material, the mass ratio of raw material to supplemental material was 1:1.5, and the freezing ultrafine grinding time was 150 s. The ratio of the 3 raw materials was dried longan: dried goji: dried jujube=3.59:4.60:1. The nutritional meal replaement powder was developed based on the proportion of the mixture design. The optimal proportion of longan-goji-jujube nutritional meal replacement powder was determined using a mixture design as follows: 50% compound fruit powder, 5% whole milk powder, 5% plant fat powder, 10% puffed rice powder, and 30% maltodextrin powder. The obtained longan-goji-jujube nutritional meal replacement powder showed good stability, sensory scores, and nutritional balance. The longan-goji-jujube nutritional meal replacement powder significantly promoted the growth of members from Lactobacillus, Bifidobacterium, and Bacteroides and Akkermansia muciniphila, as well as the production of short-chain fatty acids, particularly acetic acid and butyric acid. Thus, the longan-goji-jujube nutritional meal replacement powder showed regulatory effects on the intestinal microbiota in vitro.

17 Quality Analysis of Huangjincha Congou Black Tea Based on Variable Temperature Fermentation Technology

HUANG Hao , YU Penghui , ZHAO Xi , ZHONG Ni , ZHENG Hongfa , XIAO Lizheng

2022, 38(2):155-163. DOI: 10.13982/j.mfst.1673-9078.2022.2.0951

[Abstract](160) [HTML](194) [PDF 3.40 M](553)

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Baojing Huangjincha 1 was used as the raw material to produce congou black tea, and the effects of fermentation at variable temperatures (40 ℃ in the first stage and 30 ℃ in the second stage) on the quality of congou black tea were investigated. The results showed that the color of congou black tea fermented at variable temperatures was dark brown and moist, the taste was sweet, mellow, and fresh, the sweetness was long-lasting, the soup was red and bright, and the leaf bottom was red and even. Compared to fermentation at a constant temperature, the color of the tea soup changed significantly from bright red to dull red, the taste developed from sweet alcohol to pure and sweet, and the leaf bottom gradually became dark and tarnished (turned from bright red to reddish brown); these effects became more prominent as the fermentation time in the first stage (40 ℃) was extended. Compared to variable-temperature fermentation, the content of amino acids and tea polyphenols showed the greatest decrease after 3 h of constant-temperature fermentation at 40 ℃, and changes in the tea polyphenol, amino acid, and soluble sugar contents were generally the same as that observed after fermentation for 4 h at 30 ℃ and a constant temperature. The final content of theaflavins (0.39%) after variable-temperature fermentation was higher than that obtained after fermentation at constant temperatures (30 ℃ and 40 ℃). Based on the results of sensory evaluation and content of quality components in each treatment, variable-temperature fermentation (40 ℃, 1 h+30 ℃, 2 h) is optimal for processing congou black tea with a sweet, mellow, and fresh taste.

18 Comprehensive Quality Evaluation of Different Wheat Middlings by Principal Component Analysis and Cluster Analysis

SUI Yong , SHI Jianbin , CAI Sha , XIONG Tian , WANG Shaohua , MEI Xin

2022, 38(2):164-171. DOI: 10.13982/j.mfst.1673-9078.2022.2.0284

[Abstract](180) [HTML](281) [PDF 507.14 K](426)

Abstract:
In order to obtain high-quality wheat middlings for food use, principal component analysis and clustering analysis were used to analyze and screen different varieties of wheat middlings. The nutritional quality, color, gluten characteristics and gelatinization properties of 12 different varieties of wheat middlings and 2 different grades of wheat flour were determined. The main indexes for quality evaluation of different varieties of wheat middlings were screened and classified by principal component analysis and cluster analysis. The results showed that among the quality characteristics of different wheat middling flours, the coefficients of variation (CVs) of the lipids, ash, gluten index, peak viscosity, trough viscosity, final viscosity, breakdown and setback values were relatively high (all>20%). By principal component analysis, 4 more representative principal component factors were extracted, the cumulative variance contribution rates reached 84.182%. Analysis, calculation and ranking were conducted according to the comprehensive evaluation function, developed based on principal component analysis, the top three of the comprehensive ranking were DF1XF1-under, DF1XF1-upper and refined wheat flour, respectively. The cluster analysis divided the different varieties of wheat middling samples into 4 categories, and DF1XF1-under flour, DF1XF1-upper flour and refined wheat flour belonged to the same category, which was consistent with the results of the principal component analysis. Among the 12 varieties of wheat middling flour, DF1XF1-under and DF1XF1-upper had the best quality, whilst 7M-under, 8M-upper and 2T-under had the worst quality. Comprehensive evaluation of the quality characteristics of wheat middling flour based on principal component analysis and cluster analysis can provide a reference for its high-value utilization in foods.

19 Ultra-high-pressure Pretreatment Reduces Biogenic Amines in Fermented Ruditapes philippinarum Sauce While Improving Its Quality

HUANG Yating , RUAN Zheng , LI Dandan , LI Biansheng , QIAN Jiang

2022, 38(2):172-179. DOI: 10.13982/j.mfst.1673-9078.2022.2.0240

[Abstract](155) [HTML](153) [PDF 783.62 K](423)

Abstract:
In this study, Ruditapes philippinarum with/without a pretreatment by ultra-high-pressure sterilization or heat sterilization was hydrolyzed preliminarily with protease and then rapidly fermented with Pediococcus pentosus at 35 ℃ for 36 h. The results showed that during the fermentation process, the total acid content of the fermented Ruditapes philippinarum sauce increased gradually, with its pH value decreasing gradually and the amino acid nitrogen content increasing gradually. The content of amino acid nitrogen of the heat pretreated group increased slowly. At the 36th h, the content of amino acid nitrogen of the control group, ultra-high-pressure pretreated group and heat pretreated group was 0.68, 0.68 and 0.42 g/100 mL. The contents of total volatile basic nitrogen (TVB-N), putrescine and cadaverine in the fermented Ruditapes philippinarum sauce could be reduced by ultra-high-pressure pretreatment. At the 36th h, the contents of TVB-N of the control group, ultra-high-pressure pretreated group and heat pretreated group were 79.43, 65.15 and 43.73 g/100 mL, with their cadaverine contents as 140.96, 0.83 and 0.79 mg/L, respectively. The putrescine content of the control group was 0.64 mg/L, whilst those of the ultra-high-pressure pretreated group and the heat pretreated group were lower than the detection limit. Compared with the heat pretreated group, the ultra-high-pressure pretreated group could make the special flavor of the fermented Ruditapes philippinarum sauce unchanged. The total sensory evaluation scores of the control group, ultra-high-pressure pretreated group and heat pretreated group were 13.20, 18.20 and 15.60, respectively. Therefore, ultra-high-pressure sterilization can be used as a pretreatment for Ruditapes philippinarum fermentation. This approach can reduce the contents of TVB-N, putrescine and cadaverine, improve the sensory score and ensure the safety of the fermented Ruditapes philippinarum sauce. Compared with the heat pretreatment, ultra-high-pressure pretreatment can ensure that the original special flavor and fermentation outcome of the fermented sauce remained unchanged.

20 Optimization of Extraction Process of Active Components from Ganoderma lucidum by Low-temperature Continuous Phase Transition

HU Liuyun , LIU Cencen , CHEN Hongzhang , LIU Guo , WEN Linfeng , ZHANG Jun , CAO Yong , CHEN Cong

2022, 38(2):180-189. DOI: 10.13982/j.mfst.1673-9078.2022.2.0381

[Abstract](221) [HTML](217) [PDF 488.92 K](576)

Abstract:
In this study, the bioactive components of Ganoderma lucidum were extracted by low-temperature continuous phase transition extraction technology. The yields of the extracted solids, total sugars and total triterpenes from Ganoderma lucidum were taken as the main indices to study the effects of factors such as extraction temperature, extraction time, extraction solvent and solvent concentration on the bioactive components extracted by low-temperature continuous phase transition from Ganoderma lucidum. The extraction conditions for the bioactive components in Ganoderma lucidum were optimized by orthogonal experiments, and the molecular weight distribution of the total polysaccharides in the water extract obtained under such optimal conditions was analyzed by GPC (gel penetration chromatography). The experimental results showed that the optimal conditions for low-temperature continuous phase transition extraction of bioactive components from Ganoderma lucidum were: water extraction temperature, 100 ℃; desorption l temperature, 78 ℃; water extraction solvent flow rate, 30 L/h; total extraction time, 5 h; Ganoderma lucidum residues after water extraction were extracted using alcohol; ethanol extraction temperature, 85 ℃; desorption temperature, 68 ℃; ethanol extraction solvent flow rate, 28 L/h; total extraction time, 4 h. The yields of total solids, total sugars and total triterpenes extracted by low-temperature continuous phase transition from Ganoderma lucidum were 7.56 g/100 g, 1.14 g/100 g and 1.17 g/100 g, respectively, which were 15.60%, 23.91% and 333.33%, respectively, higher than those by traditional water extraction. According to the GPC spectrum of the water extract, it was found that the low-temperature continuous phase transition extraction led to two more components than the traditional process. The yield and number of the bioactive components extracted by the low-temperature continuous phase transition extraction process were significantly increased compared to the traditional process, which is suitable for large-scale industrial production. This study provides certain theoretical support for deep processing of Ganoderma lucidum.

21 Preparation of Flaxseed Oil Starch Powder Oil and Its Properties

LUO Mingchang , ZHU Baoyan , WU Chenbei , FENG Yinong , HUANG Qiang

2022, 38(2):190-196. DOI: 10.13982/j.mfst.1673-9078.2022.2.1197

[Abstract](266) [HTML](288) [PDF 4.37 M](497)

Abstract:
Flaxseed oil oxidizes easily and deteriorates in air because of its high unsaturated fatty acid content, leading to the deterioration of its sensory qualities. Powder oil technology not only greatly increases the ability of oil to resist degradation in harsh environments, but also reduces or conceals the unpleasant taste and odor of oil. In this study, V-type crystalline starches were prepared using normal maize and waxy maize starch as raw materials using the anti-solvent method, and powder oil was prepared by dry heating with various proportions of flaxseed oil. The effects of complex temperatures on the physical and chemical properties of powder oil were investigated. The oil-absorption capacity of V-type starch (1.54 g/g) was superior to that of commercial porous starch (1.08 g/g). Dynamic light scattering and X-ray diffraction analyses showed that the size and relative crystallinity of the powder oil prepared from V-type starch decreased gradually, indicating that the hydrophobic cavities in V-type starch were involved in oil adsorption. Laser confocal microscopy results showed that the diffusion rate of oil accelerated as the temperature was increased, and the degrees of complexity were higher at higher temperatures. The peak value at 1060/1022 cm-1 increased from 0.81 to 1.07 as the complex temperature was increased, indicating an increase in the short-range molecular order of anti-solvent normal maize starch. This study revealed that V-type starch can be used as an embedding material that shows high biocompatibility and a simple green processing ability, providing a foundation for the processing and utilization of powder oil.

22 Comparison on Eating Quality among Mushroom Yogurt Melts Added with Different Particle Sizes of Agaricus bisporus Powders

CHEN Cong , CHENG Shilun , YE Shuang , SHI Defang , FAN Xiuzhi , YIN Chaomin , YAO Fen , SHEN Wangyang , GAO Hong

2022, 38(2):197-205. DOI: 10.13982/j.mfst.1673-9078.2022.2.0537

[Abstract](157) [HTML](296) [PDF 957.89 K](339)

Abstract:
In this study, different particle size of Agaricus bisporus powders were added in yogurt to prepare freeze-dried mushroom yogurt melts. The effects of different particle size (20-mesh, 60-mesh, 100-mesh, ultra-fine powders) of Agaricus bisporus powders on the eating quality of yogurt melts were investigated. The results showed that the color of the products became darker and the concentration of volatile flavor components increased, when the powders were added. Meanwhile, the hydration capacity and texture characteristics changed obviously. Concerning the particle size effect, with the decrease of the particle size of Agaricus bisporus powder added, the color of the products became brighter and whiter, and the content of volatile flavor components increased gradually. Remarkably, the hydration capacity and sensory evaluation increased firstly and then decreased while the rehydration time, toughness, hardness and roughness showed the opposite trend. It was worth noting that the addition of ultra-fine powder of Agaricus bisporus could significantly improve the color of yogurt melts, but it had a negative effect on the taste of the final products. Therefore, when the Agaricus bisporus powders added were 100-mesh powders, the eating quality of the product was the best, the hydration capacity was 2.82 g/g, the rehydration time was 51.38 s, the toughness (distance) was 0.20 mm, the maximum puncture hardness was 1083.00 g and the roughness was 26.40. The addition of 100-mesh Agaricus bisporus powders is suitable for the preparation of mushroom yogurt melts, which can keep the eating quality of the products well. The study could provide important reference for the development and comprehensive utilization of special food related to Agaricus bisporus.

23 Different Methods for Extracting Oleoresin from Amomum Tsao-ko and Its Composition Analysis

LIN Yi , HUANG Mei , WU Guiping , XU Fei , HE Juncai , YOU Shengjun , GAO Penghui , LIU Linna , DUAN Mengya , HOU Meifang , GU Fenglin

2022, 38(2):206-217. DOI: 10.13982/j.mfst.1673-9078.2022.2.0524

[Abstract](242) [HTML](245) [PDF 1.40 M](470)

Abstract:
In this study, smoked Amomum tsao-ko (XGCG) was used as the raw material, and the thermal reflux method at different extraction temperatures (RA, Rb, RC), ultrasonic-assisted extraction method (C), microwave-assisted extraction method (W), ultrasonic-microwave-assisted extraction method (CW) were used to extract oleoresin from Amomum tsao-ko for the qualitative and quantitative analyses of its components and content by gas chromatography time of flight mass spectrometry (GC-TOF-MS). The results showed that the yield of oleoresin and the content of 1,8-eucalyptus oleanol obtained by different extraction methods were different. The yields of the XGCG oleoresins and the content of 1,8-cineole extracted by different methods varied and were in the orders of CWCW>RB>RA>W>C, respectively. A total of 100 aromatic compounds were identified in XGCG oleoresin. 58, 50, 47, 56, 54 and 55 kinds of XGCG oleoresins were extracted by RA, Rb, RC, C, W and CW, respectively. The total relative contents of XGCG oleoresins extracted by different extraction methods were 88.28%, 81.77%, 87.45%, 73.71%, 55.65% and 63.06%, respectively. Among them, the proportion of 1,8-eucalyptol, citronellol, 2-methyl-3-phenylpropanal, and nerol acetate contents varied with the extraction methods. Therefore, among the different oleoresin extraction methods, the Amomum tsao-ko oleoresin extracted by the RA method was 3.93%, with 58 types of oleoresin and 88.28% of the total oleoresin content, respectively. Although the yield of oleoresin was not the highest, the type and total content of volatile components were the highest, indicating that the RA method is more suitable for the extraction of flavoring substances. This also provides a theoretical basis for the development of value-added products of Amomum tsao-ko and the upgrading of deep processing industry.

24 Alcohol Extraction Process and Quality Analysis of Residual Oil from Perilla Cake Meal

HU Dongya , ZHANG Zhijun , CAO Qianhui , LI Huizhen , ZHANG Yousheng , ZHANG Yongrong

2022, 38(2):218-223. DOI: 10.13982/j.mfst.1673-9078.2022.2.0632

[Abstract](170) [HTML](167) [PDF 514.97 K](479)

Abstract:
We used 95% ethanol to extract residual oils in perilla cake meal to reduce residues and contamination by toxic organic solvents, as well as to obtain low-fat, high-protein perilla cake meal. Univariate analysis was performed to determine the optimal extraction temperature, number of extractions, liquid-solid ratio, and extraction duration. The processing conditions optimized through orthogonal experimental design were as follows: extraction temperature, 75℃; 5 extractions; liquid-solid ratio, 3.5:1; and time, 3 h. Using this process, the extraction rate of residual oil from perilla cake meal was 96.04%, oil content of perilla cake meal was reduced to 0.51%, and protein enrichment rate was increased to 57.90%. The physical and chemical properties of perilla seed pressed oil, perilla cake meal ethanol extract, and petroleum ether extract were compared. The three oils met national standards with respect to acidity, peroxide content, iodine content, and saponification. Among them, the acidity and peroxide content of petroleum ether extract oil were relatively high, with maxima of 3.65 (KOH)/(mg/g) and 5.96 (mmol/kg), respectively, followed by those for ethanol extract oil and low-temperature pressed oil (3.30 (KOH)/(mg/g) and 5.22 (mmol/kg), respectively). There was no significant difference in the iodine content, and the degree of saponification of the extract oil was greater than that of the low-temperature pressed oil. Gas chromatography analysis showed that the relative content of linolenic acid and proportion of unsaturated fatty acids in total fatty acids in ethanol extract oil were 59.60% and 89.31%, respectively, which are slightly lower than those observed for low-temperature pressed oil (61.09% and 90.33%, respectively) and higher than those observed for petroleum ether extract oil (57.29% and 86.10%, respectively). Overall, the quality of ethanol extract oil is higher than that of petroleum ether extract oil and slightly lower than that of low temperature pressed oil.

25 Comparison of Hepatopancreas Flavor Qualities of Mud Crabs (Scylla paramamosain) in Different Producing Areas

LU Yufeng , WANG Futian , NIE Yongtao , YANG Bing , JIANG Shaotong , LIN Lin , LU Jianfeng

2022, 38(2):224-235. DOI: 10.13982/j.mfst.1673-9078.2022.2.0538

[Abstract](163) [HTML](240) [PDF 503.95 K](375)

Abstract:
The sensory evaluation, taste activity value (TAV), E-nose and volatile compounds analysis were used to compare the flavor qualities among the hepatopancreas of mud crab from Bohai Sea, East China Sea and South China Sea. The results showed that the sensory score of the hepatopancreas of male and female mud crabs from East China Sea was greater than that of two others. TAV analysis indicated that the sweet and umami tastes of hepatopancreas were better, and Glu (umami), Ala (sweet), and Arg (bitter/sweet) were the predominant free amino acids that contributed to pleasant flavors. Meanwhile, the amino acids contents of sweet and umami tastes in the hepatopancreas of male and female mud crabs from East China Sea were similar to those from Bohai Sea, which were higher than those from South China Sea. The principal component analysis showed that the sum of the first and second principal components of hepatopancreas from three sources of mud crabs was all higher than 90%, and there was a great difference in their flavors. Moreover, volatile compound analysis showed that 41, 45, 46 kinds of volatile flavor compounds in the hepatopancreas of male crabs from three districts were identified, while 45, 40, 43 kind of volatile flavor compounds in the hepatopancreas of female crabs were detected respectively. Aldehydes were the main flavor source of the hepatopancreas of mud crabs. The hepatopancreas of male and female mud crabs from East China Sea containing 1-Decene-3-one and 2-Pentylfuran showed a unique flavor. To sum up, the hepatopancreas of male and female mud crabs from East China Sea displayed relatively better flavor quality.

26 Comparison of Nutritional Composition and Flavor of Sturgeon Meat (Acipenser sturio Linnaeus) Treated by Different Cooking Methods

PENG Haichuan , QIAN Qin , MU Yunlong , ZHANG Yingjie , LI Hui , ZHANG Yin

2022, 38(2):236-244. DOI: 10.13982/j.mfst.1673-9078.2022.2.0585

[Abstract](223) [HTML](163) [PDF 510.47 K](417)

Abstract:
To explore the effect of cooking methods on protein nutrition and flavor ingredients of sturgeon meat (Acipenser sturio Linnaeus), the meat from artificial breeding sturgeon was taken as raw material, the effects of steaming and frying on the contents of basic nutrients, amino acids, protein, flavor compounds, amino acid index (AAS, EAAI) and protein efficiency ratio (PER) of sturgeon meat were compared. The results indicated that steaming and frying reduced the water content of raw sturgeon meat by 56.41% and 43.73%, respectively; steaming and frying decreased the fat content (in dry matter) of sturgeon meat by 19.78% and 17.47%, respectively; steaming and frying increased the dry ash content of sturgeon meat by 25.80% and 20.85%, respectively; the dry protein content in both steamed and fried sturgeon meat were increased by 10.37% and 26.27%, respectively. The amino acid index and PER of sturgeon meat were higher than those of the steamed. Compared with the raw sturgeon meat, the essential amino acid content, amino acid index and PER of sturgeon meat were increased by frying, and higher than those of the steamed group. Solid phase microextraction and gas chromatography-mass spectrometry assays identified27, 28 and 27 volatile flavor compounds from raw, steamed and fried sturgeon meat, respectively. The flavor compounds are aldehydes, hydrocarbons, alcohols and others. In brief, the protein nutritional value and flavor ingredient content of sturgeon meat can be increased by frying and steaming.

27 Analysis and Identification of Main Chemical Components in Ethanol Extract of Ramie Seeds Based on UPLC-Orbitrap-HRMS Technology

XIONG Yingzi , ZHAO Zhen , CHENG Jing , LI Jiayin , LUO Lei , LI Pao , LI Maiquan , LIU Xia

2022, 38(2):245-255. DOI: 10.13982/j.mfst.1673-9078.2022.2.0542

[Abstract](208) [HTML](364) [PDF 1.10 M](380)

Abstract:
The main chemical composition of the ethanol extract from ramie seeds were analyzed and identified using ultra performance liquid chcromatography-orbitrap-high resolution mass spectrometer (UPLC-Orbitrap-HRMS). UPLC conditions: Agilent 5TC-C18 chromatographic column (4.6 mm×250 mm, 5 μm), the mobile phase gradient elution with 0.2% formic acid water solution and acetonitrile. HRMS conditions: electrospray ion source (ESI), ion trap mass analyzer (orbitrap), spray voltage 3500 V (positive ion mode). The mass spectrum information was analyzed by mass spectrometry data of standards, MsBank mzCloud mass spectrometry databases and relevant literature. Twenty compounds were identified from the ethanol extract of ramie seeds. In which, there are ten flavonoids, including proanthocyanidin dimer, rutin, isoquercitrin/hyperioside, kaempferol-3-O-β-D-rutin, quercetin-3-O-β-D-xyloside, kaempferol-3-O-β-D- glucoside/kaempferol-3-O-β-D-galactoside, querceitrin, quercetin, kaempferol and afzelin. The flavonoids in the ethanol extract of ramie seeds are mainly flavonoid aglycones with antioxidant activity, indicating that ramie seeds have potential antioxidant activity. This study provides a scientific basis for the development and utilization of ramie seed.

28 The Drying Characteristics and Aroma Changes of Orange Peel at Different Drying Temperatures

XU Kejing , HUANG Ke , LIANG Miao , YANG Jinchu , LIU Qianjin , ZHAO Shengchen , DU Jia , XI Gaolei , ZHANG Junsong

2022, 38(2):256-265. DOI: 10.13982/j.mfst.1673-9078.2022.2.0435

[Abstract](212) [HTML](349) [PDF 800.71 K](552)

Abstract:
In order to study the drying characteristics and changes in volatile aroma components of orange peel at different drying temperatures, orange peel was used as the rawmaterial for examining the change in its moisture content and the changing trend of its drying rate. The optimal model of the drying kinetics of orange peel was determined, and the effect of drying temperature on the volatile aroma components of orange peel was also investigated. The results showed that the drying process of orange peel was mainly a process with a declining drying rate. The higher the drying temperature, the shorter the drying time. The Page model could better describe the drying process of orange peel. With the increase of temperature, the effective coefficient of moisture of orange peel gradually increased from 9.35×10-8 m2/s to 30.17×10-8 m2/s, with the drying activation energy as17.37 kJ/mol. After being dried, the color and volatile aroma components of orange peel changed significantly, and the color difference value increased with the increase of drying temperature. Among them, the color difference at 30 ℃ was 10.53, and the color difference at 90 ℃ was 36.84. The total amount of volatile aroma components and the content of limonene showed a gradual upward trend with the increase of drying temperature. When the drying temperature increases from 30 ℃ to 90 ℃, the total amount of volatile aroma components increases from 4.67 mg/g to 26.88 mg/g, the content of limonene increased from 1.98 mg/g to 22.75 mg/g. Therefore, this study provides important data support for the development of the orange peel reprocessing industry.

29 Detection of Sparfloxacin in Pork by Enzyme Linked Immunosorbent Assay

XING Guangxu , ZHAO Dong , SUN Xuefeng , WEN Liuding , ZHANG Yingshuo , ZHANG Gaiping

2022, 38(2):266-271. DOI: 10.13982/j.mfst.1673-9078.2022.2.0527

[Abstract](172) [HTML](153) [PDF 517.78 K](403)

Abstract:
To establish a method for detecting sparfloxacin (SPFX) residues in pork, which has the characteristics of high specificity, low background, and no need for sample pretreatment, an indirect competitive enzyme-linked immunosorbent and a specific anti-spafloxacin monoclonal antibody were prepared in this paper. The results showed that the antibody had almost no cross-reactivity with flumequine (11.99%), fleroxacin (11.14%), enrofloxacin (4.60%), and ciprofloxacin (0.31%). This method measured drug residues in pork with SPFX, and the intra-detection coefficient of variation was less than 5.68%, and the inter-detection coefficient of variation was less than 5.51%. The average recovery rates between and within the test were 102%~106% and 101%~104%, respectively. The IC50 of this antibody against SPFX is 31 μg/L, and almost no antibody has four structurally related compounds and other compounds. The results of high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) further confirmed the reliability and accuracy of the rapid detection of SPFX in pork by icELISA. This study shows that the icELISA method to detect SPFX residues in pork is a reliable, simple, and low-cost method.

30 IQ-Check Salmonella II Kit-based Method for the Detection of Salmonella in Foods

AN Lin , YU Wen , CUI Shenghui

2022, 38(2):272-277. DOI: 10.13982/j.mfst.1673-9078.2022.2.0491

[Abstract](111) [HTML](200) [PDF 360.07 K](276)

Abstract:
The IQ-Check Salmonella II kit-based method was evaluated through the detection of standard strains and artificially contaminated Salmonella in foods. In this study, the kit method was used to detect 50 Salmonella strains with different serotypes and 50 non-Salmonella strains, and the sensitivity and specificity of this method were analyzed. By detecting the artificially contaminated Salmonella in food samples (including liquid milk, infant formula milk powder, meat and meat products), the consistency of the kit method and the GB 4789.4-2016 method was evaluated. The experimental results showed that when the concentration of Salmonella was 103 CFU/mL or above, all 50 strains of Salmonella could be detected by the kit method, and the average detection limit of Salmonella with different serotypes was 6.98×102 CFU/mL. The results of the kit method for 50 non-Salmonella strains were all negative, indicating that the kit method showed good specificity. The positive detection rates of the kit method and the GB method for the artificially contaminated Salmonella in food samples were 98.77% (161/163) and 96.32% (157/163), respectively. The relative accuracy was 96%, 99%, 97%, and the overall accuracy was 97.33%; the relative sensitivity was 96.22%, 100%, 100%, and the overall sensitivity was 98.73%.The relative specificity was 95.74%, 98.15%, 92.86%, and the overall specificity was 95.80%. The consistency analysis was carried out according to ISO 16140, and the results showed that there was no statistically significant difference between the two methods. The results showed that the kit method had the characteristics of high sensitivity and strong specificity, and was highly consistent with the GB method in the detection of artificially contaminated food samples. The kit method is worthy of popularization and application in the rapid detection of Salmonella in food.

31 Synergistic Inhibitory Effect of Clove Oil and Lauric Acid on Staphylococcus aureus

TAN Wanjing , ZHANG Xiaowei , BAI Hong , LI Xiaofeng , YU Yigang , XIAO Xinglong

2022, 38(2):278-285. DOI: 10.13982/j.mfst.1673-9078.2022.2.0312

[Abstract](164) [HTML](231) [PDF 569.50 K](429)

Abstract:
The inhibitory effects of three plant essential oils, clove oil, thyme oil, peppermint oil, as well as medium-chain fatty acid, lauric acid, on Staphylococcus aureus were investigated. The combination of clove oil and lauric acid with a synergistic inhibitory effect on Staphylococcus aureus was selected. The effects of such a combination on the growth and cell membrane permeability of Staphylococcus aureus were studied. The combination was used to prepare an antimicrobial preservative solution, which was applied to preserve fresh rice noodles. The results showed that the minimum inhibitory concentrations of clove oil, peppermint oil, thyme oil and lauric acid against Staphylococcus aureus was 2.00 μg/mL, 4.00 μg/mL, 7.50 μg/mL and 9.00 μg/mL, respectively. The combined use of clove oil and lauric acid exhibited a synergistic antimicrobial effect when the concentration was 1/4 MIC clove oil + 1/4 MIC lauric acid, leading to a fractional inhibitory concentration index (FICI) of 0.50. The synergistic action of clove oil and lauric acid damaged the cell membrane of Staphylococcus aureus and increased the permeability. The antimicrobial preservative solution had inhibitory effects on the total plate counts and Staphylococcus aureus in the fresh rice noodles, and exerted a positive impact on maintaining the quality of fresh rice noodles. During the72-h storage, the treatment group had a lower initial total plate counts (by at least 1.50 lg CFU/g), smaller number of Staphylococcus aureus (by 1.65 lg CFU/g), lower acidity value (by at least 0.8 °T), compared with those of the control group; The sensory evaluation score of the treatment group was higher than that of the control group. The results showed that the antimicrobial preservative solution made by the combination of clove oil and lauric acid might be an alternative compound preservative solution for fresh rice noodles.

32 Rapid Identification of Illegally Added Epimedium in Food Based on High-resolution Mass Spectrometry Library and Diagnostic Ratio of Characteristic Components

WU Wanqin , JIANG Feng , GAN Guoping , FAN Xiaolong , LIU Guojiao , WANG Bin , GAO Fang , ZHU Songsong , ZHANG Qiheng , SONG Zhe

2022, 38(2):286-294. DOI: 10.13982/j.mfst.1673-9078.2022.2.0515

[Abstract](186) [HTML](171) [PDF 611.78 K](483)

Abstract:
A method based on high-resolution mass spectrometry library and characteristic component diagnostic ratio was established for identifying illegally added epimedium in food. A high resolution mass spectrometry library of six characteristic components of epimedium was constructed by high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (HPLC-TOF-MS) for preliminary screening. Simulated wine, substitute tea and drink samples were prepared using Chinese medicinal materials of epimedium obtained from different origins and picking times. A liquid chromatography analysis method was established for the characteristic components of epimedium in three different matrices. The characteristic component peak area diagnostic ratios, DR1 (epimedin A/ epimedin B), DR3 (epimedin A/ icariin) and DR7 (epimedin B/ icariin), which were less affected by the origin, picking time and processing technology, with no significant differences among different matrix groups, were selected and combined to draw box plots. . Then, the non-abnormal value ranges of diagnostic ratios were determined to be 0.60~0.96, 0.26~0.64 and 0.35~0.91, respectively, which were used as identification indicators. The actual samples of prepared wine, substitute tea and drink were analysed. The prepared wine samples of one batch matched with the high-resolution mass spectrometry library of the six characteristic components of epimedium. The diagnostic ratios of the three characteristic components DR1, DR3 and DR7 were 0.73, 0.28 and 0.38, respectively, which were all within the specified range, inferring that epimedium-containing Chinese medicinal materials had been added to the prepared wine samples. The method is accurate, fast and stable, and can quickly identify the illegal addition of epimedium to food and provide technical support for cracking down on the illegally added epimedium in food.

33 Determination of Pyrrolizidine Alkaloids in Dendrobium officinale Kimura et Migo by UPLC-MS/MS

JIA Ning , ZENG Shaodong , CHEN Wuhai , GUO Hongbin , YE Jianzhi , LIN Ling , YANG Chunliang

2022, 38(2):295-304. DOI: 10.13982/j.mfst.1673-9078.2022.2.0600

[Abstract](185) [HTML](214) [PDF 87.85 M](607)

Abstract:
In order to determine the content of pyrrolizidine alkaloids (PAs) in Dendrobium officinale Kimura et Migo, an analytical method for the simultaneous determination of 16 kinds of unsaturated PAs in Dendrobium officinale Kimura et Migo by solid phase extraction combined with ultra performance liquid chromatography-tandem mass spectrometry was established in this study. Samples were extracted with 0.05 mol/L sulfuric acid methanol, purified and enriched by MCX solid-phase extraction cartridge. The mobile phases were methanol and 0.005 mol/L of ammonium formate - 0.1% of formic acid solution. The separation was performed on a Waters ACQUITY UPLC BEH C18 column with gradient elution. The electrospray positive ion and multi-reaction monitoring mode were used for acquisition, and matrix matching external standard method was used for quantification. The results showed that the linear range of 16 kinds of PAs in this method was 0.5~20 μg/L, and the correlation coefficients were all greater than 0.99. The limits of detection were 0.06~0.11 μg/kg, and the limits of quantification were 0.23~0.35 μg/kg. At the spiked levels of 0.5, 1.0 and 10 μg/kg, the average recoveries ranged from 75.38% to 110.27%, with the relative standard deviations ranging from 2.61% to 7.43%. This method was used to determine the PAs in 20 Dendrobium officinale Kimura et Migo samples commercially available. The results showed that 7-acetyllycopsamine was detected in 12 samples with the content ranging from 1.02~6.54 μg/kg. The method is simple, sensitive and accurate, and is suitable for rapid confirmation and quantitative analysis of PAS in Dendrobium officinale Kimura et Migo.

34 Colorimetric Enzyme-linked Aptamer Assay for Determination of Staphylococcal Enterotoxin A in Foods

LIN Xiangqun , YANG Guojiang , LU Chunxia , TAO Sihua , YAN Shengkun

2022, 38(2):305-312. DOI: 10.13982/j.mfst.1673-9078.2022.2.0556

[Abstract](166) [HTML](158) [PDF 1.23 M](367)

Abstract:
In this study, an enzyme-linked aptamer assay (ELAA) was developed for detection of staphylococcus enterotoxin A (SEA) based on sandwich-type format strategy. Several experimental conditions have been investigated, including the concentration of aptamer, BSA and streptavidin-horseradish peroxidase (SA-HRP), reactionsystem, blocking conditions, and incubation time between SEA and aptamer. The results showed that the optimal conditions for ELAA were as follows: aptamers concentration of 40 nmol/L; BSA concentration of 1%; blocking time of 4 h; SEA aptamer screening buffer was used as the reaction system; the dilution volume ratio of streptavidin-horseradish peroxidase (SA-HRP) was 1:40000; and the incubation time between SEA and aptamers was 30 min. Under the optimal conditions, the calibration curves for SEA showed good linearity in the range of 5~500 ng/mL with correlation coefficients (R) better than 0.996. The limit of detection (LOD) for SEA was 0.18 ng/mL. The recoveries of SEA in food samples were in the range of 91.22%~101.30%. There lative standard deviation (RSD) of intra-assay and inter-assay were in the range of 2.82%~7.50%. Subsequently, the proposed method was applied to measure SEA in real samples, and was validated using official standard method. A good correlation (R=0.994) was obtained between the results of the two methods. These results suggest that the proposed method had good sensitivity, accuracy and specificity. This study provides a simple, economical and high-throughput new rapid detection technology for SEA detection in food.

35 Development of Incomplete Biscuit Sorting System Based on Machine Vision

CHENG Zihua

2022, 38(2):313-318. DOI: 10.13982/j.mfst.1673-9078.2022.2.0372

[Abstract](224) [HTML](290) [PDF 2.02 M](480)

Abstract:
In order to reduce the picking intensity of the robot and improve the sorting efficiency, a method for identifying and sorting incomplete/broken biscuits is proposed in this study. Based on machine vision technology, the three-photo-comparison recognition algorithm was used to solve the problem of misrecognition of incomplete/broken biscuits due to only a part of the biscuits being photographed at the edge of the photographing area. The center coordinate position of the biscuit on the moving conveyor belt was obtained via the recognition algorithm. Comparisons were made to determine whether the difference in the center coordinate of the biscuit at the time interval t was equal to the distance traveled by the conveyor belt during time t, to confirm which biscuit images obtained by three shots were from the same biscuit and obtain the image feature data of this cookie. When the obtained biscuit image feature data were different from the visual feature parameters of the standard biscuit, it was identified as a defective product, and the center coordinates of the biscuit were outputted to the parallel robot for picking. In this study, the effectiveness of the program was verified experimentally and the factors that would affect the recognition rate of conversion are experimentally examined. Through experimental verification, it was found that the program was reliable, and the accuracy of identifying incomplete/broken biscuits remained at 100%. In addition, the height of the lenss had a small effect on the recognition accuracy rate, but exerted a greater effect on the recognizable radius (showing a linear relationship). After the speed of the conveyor belt increases to 19 mm/s, the recognition accuracy decreased linearly. When the light intensity reached 400 Lux, the recognition accuracy could be maintained at 100%. The method established in this study can well identify the incomplete/broken biscuit and provide technical support for online detection and sorting of biscuits in the future.

36 Gas Chromatography-mass Spectrometry for Analyzing TXIB Migration in Plastics in Contact with Chinese Baijiu

LIANG Xiaogang , HUANG Huanting , LONG Dan , LI Qinqin , WU Jianxia , LIN Lin

2022, 38(2):319-325. DOI: 10.13982/j.mfst.1673-9078.2022.2.0644

[Abstract](190) [HTML](254) [PDF 941.05 K](386)

Abstract:
Liquid-liquid extraction and gas chromatography-mass spectrometry (GC-MS) was used to establish a quantitative method for measuring the leaching of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB) in plastics in contact with Chinese Baijiu. Food simulants were used to prepare a simulated soaking solution for measuring the leaching of common plastic materials. N-Hexane was used as an extraction solvent. The volume of extraction solvent was 2 mL, and the shaking extraction time was 1 min. The extract was separated by HP-5 ms (30 m×0.25 mm×0.25 μm) capillary chromatography, analyzed by GC-MS with selective ion monitoring, and quantified using an external standard. The results show that this method can be used to rapidly measure the quantity of TXIB leached from plastic materials into Baijiu, which is reflected by the regression line correlation coefficient (r=0.9975), limit of quantification (0.02 mg/kg), recovery (106.60%~119.90%), and relative standard deviations (2.30%~6.50%). This method is rapid, sensitive, and accurate, and is suitable for evaluating TXIB leaching from plastics in contact with Baijiu.

37 Progress in the Application of Pulsed Electric Field in Food Industry

XIONG Qiang , DONG Zhiqin , ZHU Fangzhou

2022, 38(2):326-339. DOI: 10.13982/j.mfst.1673-9078.2022.2.0428

[Abstract](453) [HTML](527) [PDF 816.53 K](691)

Abstract:
Currently, food industrial processes mainly rely on traditional thermal treatment and chemical methods. These methods often have a negative impact on food quality and safety, and possess disadvantages such as high cost and environmental unfriendliness. The development of efficient and green food processing methods has become an urgent problem to be solved in the food industry. Pulsed electric field (PEF) technology is a physical method that uses electromagnetic pulses with high voltage amplitude for processing materials. As an emerging non-thermal processing technology, PEF technology has attracted extensive and profound discussions among scholars due to its unique advantages and the aim to apply it to the food industry. This article reviews the principle and application mechanism of PEF technology, including electroporation theory, electrohydrodynamics, plasma and electrochemical reactions and free radical activation hypotheses, and summarizes the applications of PEF in food industry. The review provides effective solutions for the food processing field, which is conducive to promoting the development and application of PEF technology in the field of food processing.

38 Progress on the Functional Activities of Mung Bean Peptides and Their Applications in Foods

AN Yu , FENG Yuchao , WANG Changyuan

2022, 38(2):340-346. DOI: 10.13982/j.mfst.1673-9078.2022.2.0516

[Abstract](411) [HTML](167) [PDF 371.92 K](782)

Abstract:
Peptides are bioactive small molecules, which have the characteristics of wide sources, high safety and high efficiency in trace. Mung bean is a traditional Chinese multi-grain legume with homology of medicine and food in China. It is a good source of proteins with a high protein content and multiple biological functions. Mung bean peptide had an amino acid composition similar to that of mung bean protein, but exhibited more diverse biological activities, such as antioxidant activity, immune activity, blood pressure-lowering effect. Mung bean peptide also had a strong metal chelating ability, which can improve its functional activity and the operation of metal ions in the body. Adding mung bean peptide to food can also give corresponding functional properties and play a certain role in the formation and maintenance of food quality. Therefore, mung bean peptide is a potential plant-derived bioactive peptide. In recent years, the domestic and international research on mung bean peptide is increasing gradually, but there is no extensive literature review. In this paper, the preparation, modification, functional activity of mung bean peptides and their applications in foods are summarized, and the existing problems and future research emphases are also pointed out. The aim is to provide realistic theoretical basis and intellectual support for mung bean peptide production, research and development of functional products, and their applications in food-related fields in the future.

39 Research Progress of Biodegradable Citric Acid and Its Influencing Factors

WANG Jinling , YAN Yuchen , LI Qiaoyue , ZHANG Fushun , LI Xin , LU Zhiquan

2022, 38(2):347-357. DOI: 10.13982/j.mfst.1673-9078.2022.2.0575

[Abstract](421) [HTML](341) [PDF 1.04 M](971)

Abstract:
Citric acid (CA) is a kind of natural organic acid, which has a high content in mature citric acid fruits such as lemon, passion fruit and red raspberry, resulting in sharp acidity of such fruits, and the palatability and sensory quality of processed products will be affected to varying degrees. Citric acid can be used by lactic acid bacteria to produce aromatic compounds such as diacetyl, acetoin and butanediol, and can also be transformed into multiple metabolites such as alcohol, acetaldehyde acid and succinic acid in yeast. The quality of citricacid type fruit processing products and flavor brought by different degradation pathways of citric acid have significant differences. In this paper, the pathways and metabolites of citric acid biodegradation by lactic acid bacteria and yeast were described in detail. The effects of pH and carbon source on citric acid biodegradation and the application of citric acid biodegradation in the processing of fruit juice and fruit wine were analyzed. The conditions limiting the use of lactic acid bacteria and yeast in citric acid biodegradation were pointed out, so as to provide theoretical basis and technical reference for the research and application of citric acid biodegradation.

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Volume 38,Issue 2,2022 Table of Contents