## Current Articles 2021, Volume 42,  Issue 20

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2021, 42(20): 0-0.
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2021, (20): 1-8.
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2021, 42(20): 1-13. doi: 10.13386/j.issn1002-0306.2021010155
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Objective: To explore the molecular mechanism of water extract and alcohol extract of ginseng and mulberry in treating osteoporosis by means of network pharmacology. Methods: The effects of water extract and alcohol extract of ginseng and mulberry on proliferation rate and testosterone secretion of mouse leydig cells (TM3), and the effects of water extract and alcohol extract of medicine pair on proliferation rate and alkaline phosphatase (ALP) activity of osteoblasts (MC3T3-E1) were observed. Collect chemical components, components and disease-related targets of ginseng and mulberry respectively through traditional Chinese medicine composition database TCMSP, GeneCards and OMIM. After the intersection of that, using STRING database to analyze protein interaction among key targets, and using DAVID database to analyze biological functions and pathways. The related results were mapped and analyzed by Cytoscape 3.7.0. Autodock software was used to perform molecular docking between potential pharmacodynamic substances and key targets. Results: Compared with the model control group, the cell proliferation rate of TM3 administration group was significantly higher than that of single drug, and it was concentration-dependent. The highest proliferation rate was found at the concentration of 200 μg/mL, which was 97.31% and 91.67% (P<0.01), and testosterone secretion was 3.48 and 3.06 ng/mL. Compared with the blank control group, the cell proliferation rate of MC3T3-E1 administration group increased significantly. The proliferation rate of cells at the concentration of 200 μg/mL was the highest in the group of water extract administration, and the proliferation rate was 155%. The highest cell proliferation rate was 142.8% at 100 μg/mL of alcohol extract. The results of ALP analysis showed that the drug had obvious increasing effect on both water extract group and alcohol extract group. In this study, 28 active components and 69 key targets were collected, and 257 biological process, 34 cell compound and 62 molecular function were collected by GO function enrichment. 109 pathways were collected from KEGG pathway enrichment. The results of molecular docking showed that the energy of potential pharmacodynamic substances docking with key targets IL6, ALB, MAPK8 and CASP3 was lower than 0 kcal/mol. Conclusion: This paper revealed the potential pharmacodynamic substances and targets of ginseng-mulberry medicine in the treatment of osteoporosis, which would lay a foundation for the development and follow-up research of ginseng-mulberry medicine.
2021, 42(20): 14-22. doi: 10.13386/j.issn1002-0306.2021050158
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Trace amine-associated receptors (TAARs) are a class of G-protein-coupled receptors, and with the exception of TAAR1, the remaining TAARs, like the olfactory receptors, are expressed in the olfactory epithelium and function to sense odorants. In recent years, the high expression of TAARs has been found in non-olfactory tissues, suggesting that TAARs may have important ectopic physiological functions. Recent studies have confirmed that endogenous and exogenous specific trace amines regulate a variety of physiological functions in non-olfactory tissues by acting on different TAARs, indicating that TAARs have the potential to become a new diagnostic and therapeutic target. This paper systematically introduces the expression of ectopic olfactory TAARs, endogenous and exogenous ligands, biogenic amines in food, ectopic olfactory TAARs-mediated signal pathways, and physiological and pathological functions. On the one hand, it provides new ideas for the future drug target development, physiological and pathological research, on the other hand, it also provides new research ideas for the biological activity of biogenic amines in food.
2021, 42(20): 23-31. doi: 10.13386/j.issn1002-0306.2020080247
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Effects of tea polyphenols (TP) on the quality of the steamed bun was studied, and its molecular action mechanism was preliminary analyzed. The effects of TP on the specific volume, texture, hardening rate and α-starch content of steamed bun were systematically observed. And the effects of TP on the iodine binding capacity, solubility, swelling power and thermal properties of starch were determined. And then the molecular dynamics (MD) was used to study the interaction between TP and starch molecules. The results showed that TP had a significant effect on the specific volume and texture. Besides, TP could decrease the hardening rate (from 195 to 138 g/h) and increased the α-starch content of the steamed bun; the addition of TP decreased the iodine binding capacity, increased the solubility (from 8.3% to 38.1%) and swelling power (from 11.4% to 13.8%), and decreased the gelatinization peak temperature (from 62.21 to 53.57 ℃) for promoting the gelatinization of starch and delaying the retrogradation of starch. Furthermore, TP could interact with starch by hydrogen bonds (highest occupancy hydrogen bonds 4GA_12@O2: EGCG_1@H18, ratio was 5.6%), and changed the spatial configuration of starch molecules, leading to the variation of the physicochemical properties of starch. The results indicated that TP could change the physicochemical and quality characteristics of starch, and had potential value as a new starch modifier.
2021, 42(20): 32-36. doi: 10.13386/j.issn1002-0306.2020120077
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The changes of solubility and immunoreactivity properties of Arah1, the main allergenic protein in peanut, were studied by immunological methods. The results showed that: Autoclaved treatment could significantly denaturate and decompose Ara h1 and peanut protein extracts, especially at 135 ℃; however, Ara h1 showed good thermal stability after 20 min treatment at 121 and 135 ℃, and the soluble protein content did not decrease significantly with the extension of treatment time; after being treated at 135 ℃ for 20 min or longer, main components of decomposition products were those protein fragments with molecular weight of 15 kDa or less. Autoclaving could significantly decrease the immunoreactivity of Ara h1, especially in the mixed system of protein extracts: After being treated at 135 ℃ for 20 and 60 min, the IgG immunoreactivity of Ara h1 was only 1/3 and 1/6 of that of control, respectively; in the mixed system, the IgG immunoreactivity of Ara h1 was only 2/9 and 1/9 of that of control under the same conditions.
2021, 42(20): 37-43. doi: 10.13386/j.issn1002-0306.2020120198
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This paper investigated the effects of water extraction and acid precipitation (WEAP), alkali extraction and acid precipitation (AEAP), and ultrasound-assisted alkali extraction and acid precipitation (UA-AEAP) on the functional properties and antioxidant activity of Ginkgo biloba proteins (GBPs). The functional properties of GBPs were evaluated through solubility, foaming capacity, foam stability, emulsifying capacity and emulsion stability. The DPPH radical scavenging ability, hydroxyl radical scavenging ability and chelated iron assays were employed to assess the effects of extraction methods on antioxidant activity of GBPs. The results showed that the yield and solubility of GBPs were significantly affected by the extraction methods. The UA-AEAP had the highest yield (11.36%±0.10%), and highest solubility in the pH range from 2 to 12. Foaming, foam stability and emulsification of GBPs were significantly influenced by the extraction methods(P<0.05), while the emulsion stability was not notably related to the extraction methods(P>0.05). The foaming, foam stability and emulsification of GBPs prepared by UA-AEAP were better than those of AEAP and WEAP. Moreover, the order of the chelating ferrous ionsability, scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical ability and scavenging hydroxyl radical ability were UA-AEAP>WEAP>AEAP. UA-AEAP was appropriate for the preparation of GBPs due to its higher yield, stronger antioxidant capacity and better functional properties.
2021, 42(20): 44-50. doi: 10.13386/j.issn1002-0306.2021010072
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Using the method of self-absorption salt tolerance identification, the influence of the different concentrations (0.10%、0.30%、0.60%、0.90%、1.20%) of NaCl stress on the components of Suaeda salsa during the different growth period was researched. The results showed that there were significant differences in the component content of Suaeda salsa in different growth stages. Among them, the salt in the seedling stage had the greatest influence on nitrite, with the highest content of nitrite being 7.09 mg/kg; the salt in the flowering stage had the greatest influence on the content of amino acid, with the content of highest, reached 134.26 μmol/g; in the result period, salt had the greatest impact on protein, with the content of highest being 19.36 mg/g. The content of water of Suaeda salsa was the highest in the seedling stage, which increased with the increase of salt stress, reaching the maximum under 1.20% NaCl treatment; ascorbic acid showed an overall decreasing trend with the increase of gradient salinity at different stages, and under low concentration (less than 0.60%) NaCl treatment, Suaeda salsa had the highest content of ascorbic acid in the seedling stage. With the content of total flavonoids as the optimization goal, the extraction technology of the total flavonoids of Suaeda salsa was optimized by high performance liquid chromatography (HPLC), and the optimal extraction conditions were obtained: ultrasonic power 500 W, ultrasonic temperature 70 °C, ultrasonic time 25 min, material-to-liquid ratio 1:60 g/mL; Under the treatment of 0.90% NaCl, the content of total flavonoid of Suaeda salsa in the flowering stage was the highest, reaching 3.68%. In summary, this study clarified that the soil salt range suitable for the development of high-quality and safe Suaeda salsa was 0.60%, which was used to provide technical support and theoretical basis for guiding the production and reasonable development of Suaeda salsa.
2021, 42(20): 51-60. doi: 10.13386/j.issn1002-0306.2021010091
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Water-soluble pectin was extracted from red-flesh guava peel and pulp by ultrasonic-assisted citric acid extraction. The functional group characteristics, monosaccharide composition, thermal stability, rheological properties, and microstructure of guava pectin were studied. The combination of guava peel pectin and pulp pectin with fat, cholesterol micelle, and cholate were studied in vitro. The esterification degree of guava peel pectin was 56.29%. The average molecular weight had two grades, which were 618.40 kDa (43.4%) and 93.90 kDa (56.6%) individually. Neutral sugar composition: 0.58%±0.02% rhamnose, 0.02%±0.01% petrolatose, 88.48%±0.07% arabinose, 0.78%±0.06% xylose, 0.07%±0.02% mannose, 0.40%±0.03% glucose, 9.68%±0.03% galactose. The esterification degree of guava pulp pectin was 48.57%, and the average molecular weight was 1168.00 kDa (11.0%), 120.30 kDa (53.9%) and 64.94 kDa (35.1%), individually. Neutral sugar composition: 0.47%±0.03% rhamnose, 0.03%±0.01% norvoose, 83.86%±0.04% arabinose, 0.76%±0.05% xylose, 0.08%±0.01% mannose, 0.43%±0.02% glucose, 14.37%±0.05% galactose. The particle size of peel pectin solution was significantly smaller than that of pulp pectin (P<0.05). Both kinds of pectin showed the characteristics of pseudoplastic fluid. At the same concentration, the apparent viscosity of pulp pectin solution was higher than that of peel pectin. There were differences between the two types of pectin, with more tentacle filaments at the edge of the peel pectin and deeper folds in the pulp pectin based on the results from the scanning electron microscope (SEM). The absorption of fat, binding amount of cholesterol micelle and cholic acid by pulp pectin were significantly better than that of peel pectin (P<0.05). These results indicated that both of them had lipid-lowering functions in vitro, and the effect of pulp pectin was better than that of peel pectin. The difference in biological activity resulted from the different molecular structure of the two.
2021, 42(20): 61-68. doi: 10.13386/j.issn1002-0306-2021010093
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2021, 42(20): 69-75. doi: 10.13386/j.issn1002-0306.2021010118
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In this paper, in order to clarify the effect of maturity on the quality of processed persimmon products and determine the suitable raw material maturity, the drying characteristics, texture, color, nutrition and sensory quality of processed persimmon slices were studied. The results showed that the higher the maturity, the lower the drying rate of persimmon at initial 5 h of dry stage. And the content of reducing sugar and soluble pectin of persimmon slices increased with the increase of maturity, while the content of VC, soluble tannin, hardness, and adhesion of dried persimmon slices decreased. While soluble tannin content of dried persimmon slices persimmon was 0.095% and 0.041% when maturity was Ⅲ, Ⅳ. L*, a* and b* after drying of persimmon firstly increased and then decreased to 30.33、9.77、17.50 with the increase of ripeness. The higher the maturity, the higher sensory score of dried persimmon slices. Comprehensively, maturity Ⅲ, Ⅳ persimmon were suitable for processing dried persimmon product, and quality of product using maturity Ⅳ was the best.
2021, 42(20): 76-85. doi: 10.13386/j.issn1002-0306.2021010122
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Almond kernel protein is rich in nutrition and it is an important plant protein resource. However, poor emulsification is a key problem that has always influenced its development and application. In order to improve its emulsifying properties, in this study, almond kernel protein isolate (API) was selected as the research object, the effect of Xanthan gum (XG) on the emulsifying properties of API was discussed. The results showed that the addition of XG could make the droplet diameter of the composite emulsion much smaller and more evenly distributed. When the addition of XG content was 0%~0.25%, the viscosity of the emulsion increased from 5.9 to 77.5 mPa·s, the surface tension decreased from 13.1 to 5.6 mN/m, the interface adsorption capacity was enhanced, and the absolute value of the emulsion position increased from 29.0 to 54.4 mV. Especially when the addition of XG was 0.2%, API-XG composite emulsion not only had better thermal stability and salt tolerance, but also had good stability in storage and freeze-thaw cycle. Such experimental research could effectively improve the emulsifying properties of API, and provide technical support for its application in food and chemical fields.
2021, 42(20): 86-93. doi: 10.13386/j.issn1002-0306.2021020002
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In order to develop black chokeberry juice beverage with healthy function and investigate its antioxidant activity, with the black chokeberry fruit as the main raw material, sucrose, citric acid and β- cyclodextrin were added, and sensory scores as the index. By single factor experiments and orthogonal experiment, the optimum formula of black chokeberry fruit juice beverage was determined as follows: The dosage of chokeberry extract juice was 60%, the dosage of 60% sucrose syrup was 10%, the dosage of 2% citric acid solution was 2.0%, and the dosage of 1% β-cyclodextrin was 3.0%. The sensory scores of the beverage prepared by this formula could reach 94.5 scores. The beverage prepared by the formula was rich in 16 kinds of amino acids, with a total amount of 374.79 μg/mL, it had the characteristic aroma of black chokeberry fruit, with bright and uniform color, harmonious and refreshing taste, and uniform texture. The results of antioxidant activity in vitro showed that the prepared black chokeberry beverage had good antioxidant capacity on DPPH radical scavenging rate, hydroxyl radical scavenging rate, ABTS+ radical scavenging capacity and total reducing capacity, which reached 36.42%, 32.58%, 0.54 mmol/L and 0.289, respectively. The results of this experiment would provide a theoretical basis for the development of black chokeberry functional beverage.
2021, 42(20): 94-99. doi: 10.13386/j.issn1002-0306.2021020031
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To improve the texture of red bean wheat noodles, 30 g red bean powder and 70 g wheat flour were mixed and added with 1 U Lipase, 4 U Glucose oxidase, 3 U transglutaminase and 3 U xylanase, respectively. The rheological properties of dough and texture properties of noodles were determined. The results showed that the addition of lipase, glucose oxidase and transglutaminase, increased the hardness of red bean wheat noodles, and the increase amplitude was 3588, 4183 and 6190 g, respectively. The chewiness increased by 1311, 1527 and 2673, respectively. The addition of xylanase decreased the hardness of red bean wheat noodles by 97.67 g, and the chewiness by 134.48 g. In summary, lipase, glucose oxidase and transglutaminase could improve the texture and quality of red bean wheat noodles. Among them, transglutaminase had the most remarkable effect on improving the texture quality of red bean wheat noodles.
2021, 42(20): 100-105. doi: 10.13386/j.issn1002-0306.2021020158
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In order to provide a theoretical basis for comprehensive utilization of mango byproducts, mango (Mangifera India L) kernel seeds were used as materials, the contents of polyphenol and flavonoid in mango of different varieties (Guiqi, Guifei, Tainong, Jinhuang, Yu and Ivory) mango kernel seeds and the antioxidant activity were studied. The contents of polyphenol and flavonoid in six varieties of mango kernel seeds were abundant. The highest contents of polyphenol and flavonoid in Yu were 4.31 and 1.07 mg/g. The respective polyphenol contents of Jinhuang, Tainong, Guiqi, Ivory, Guifei mango kernel seeds were 4.20, 4.10, 3.96, 3.86 and 3.82 mg/g. The respective flavonoid content of those was 0.95, 0.88, 0.92, 0.96 and 0.75 mg/g. The reasons of the differences of antioxidant activity of mango seeds were analyzed. The results showed that the scavenging rates of hydroxyl radical (·OH) and superoxide anion radical were the highest, which were 90.1% and 83.9%. Through correlation analysis found that the contents of polyphenol and flavonoid in different varieties mango kernel seeds were correlated with hydroxyl radical scavenging rate and superoxide anion radical scavenging rate significantly, respectively(P<0.05), and flavonoid had a greater influence on the antioxidant capacity of mango kernel seeds, and changes of flavonoid content might be an important factor leading to the difference of antioxidant capacity of different varieties of mango seeds.
2021, 42(20): 106-111. doi: 10.13386/j.issn1002-0306.2021030272
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After treated by microwave and ultrasound, the wheat bran was ground and sieved into three parts, coarse (280~450 μm), medium (154~180 μm) and fine (≤71 μm). Then the texture properties, rheological properties and free sulfhydryl content of whole-wheat dough were investigated. The relative enzyme activity and particle size distribution of wheat bran showed that ultrasonic treatment and microwave treatment could better improve the stabilization effect and crushing efficiency, and the effect of ultrasonic treatment group was better (P<0.05). The dough quality showed that with the decreasing of wheat bran particle size, the hardness and stickiness of microwave treatment group decreased, and the cohesion increased. The hardness and adhesiveness of ultrasonic treatment group were lower than those of microwave treatment group (P<0.05). Rheological analysis indicated that the elastic modulus and viscous modulus of the microwave group decreased as the particle size of bran decreased, and were smaller than those of ultrasound-treated group the microwave-treated group at the same particle size. The free sulfhydryl content decreased gradually with the decreasing of bran particle size, and the decreasing of free sulfhydryl content was greater in the ultrasonic treatment (P<0.05). Microwave, ultrasonic treatment and the reduction of wheat bran particle size could effectively improve the quality of dough. In addition, the effect of ultrasonic treatment on dough quality was more significant than that of the microwave treatment group.
2021, 42(20): 112-118. doi: 10.13386/j.issn1002-0306.2020120017
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In order to obtain an engineering strain of Aspergillus niger with high yield and purity of pectin methylesterase and improve the yield of pectin methylesterase, the pectin methylesterase gene pmeA was cloned from the pectinase-producing strain, and Aspergillus niger was transformed by agrobacterium-mediated method, the homozygous recombinant strain TH-2 (glaA::pmeA). The highest enzyme activity in the supernatant on the 9th day of fermentation in the basic fermentation medium reached 467.77 U/mL. At the same time, SDS-PAGE showed that the main background protein α-amylase disappeared, but the acid-stable α-amylase remained. Further the background protein acid-stable α-amylase encoding gene asaA in the recombinant strain TH-2 (glaA::pmeA) was knock out to obtain the homozygous recombinant strain TH-2 (glaA::pmeApyrGasaA). After the strain was cultured in a fermentation medium supplemented with 1% ammonium sulfate for 7 days, the main background proteins in the supernatant of the fermentation broth disappeared. However, compared with the homozygous recombinant strain TH-2 (glaA::pmeA), the expression of pectin methylesterase decreased, and the highest enzyme activity was 255.40 U/mL. The optimum temperature of the recombinant pectin methylesteraseis 50 ℃, the suitable temperature range was 40~80 ℃, it could still maintain more than 70% of its enzyme activity at 80 ℃, the suitable pH range was 3.0~5.0, the optimum pH was 4.0. Finally, an engineering strain of Aspergillus niger with high yield and high purity pectin methylesterase was obtained.
2021, 42(20): 119-125. doi: 10.13386/j.issn1002-0306.2021010246
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2021, 42(20): 126-133. doi: 10.13386/j.issn1002-0306.2021020025
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Microorganisms were isolated and purified from the fresh fruit of Changbai Mountain. The yeasts strains of degradable organic acids were screened and obtained. The acid reducing characteristics and tolerance were studied, and the biological identification was carried out. The results showed that five strains with acid reducing effect were selected from the fruits of Lonicera edulis. The acid reducing rates of B5 for malic acid, citric acid and tartaric acid were 42.60%±0.85%, 18.28%±0.80% and 13.09%±0.61% respectively. The strain B5 was identified as Zygosasaccharomyces bisporus by morphological observation, physiological and biochemical tests and 26S rDNA identification. The tolerance concentrations of strain B5 to glucose and SO2 were 250 g/L and 400 mg/L, respectively, and its alcohol tolerance was 18% vol. The results of this experiment can provide a reference for the biological deacidification of fruit wine products.
2021, 42(20): 134-139. doi: 10.13386/j.issn1002-0306.2021020035
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A rice wine koji collected from Nanning of Guangxi province and Xiaogan of Hubei province were used to sequence its 16S rRNA V3~V4 region based on Illumina Miseq high-throughput sequencing technology, combined with bioinformatics and multivariate statistical methods to analysis the bacterial diversity of rice wine koji in the two regions, while the bacterial taxa phenotypes were predicted. Results showed that, the Shannon index of the bacterial taxa in the rice wine koji from Nanning area was significantly lower than that of the Xiaogan area(P<0.05). Principal coordinate analysis based on weighted UniFrac distances showed a clear separation trend between the samples from the 2 regions in spatial arrangement. Multivariate analysis of variance indicated that the bacterial community structures of the rice wine koji in the 2 regions were significantly different(P<0.05). The bacterial taxa of rice wine koji in Nanning area were mainly Lactobacillus with an average relative abundance of 62.03%, while Weissella was predominant in the Xiaogan area with an average relative abundance of 50.14%. Phenotypic prediction showed that rice wine koji from Nanning area exhibited a significantly higher(P<0.01) abundance of gram-positive bacteria, while a significantly lower(P<0.01) abundance of oxidative stress tolerance, biofilm formation, gram negative, pathogenic potential and facultative anaerobic characteristics. It could be concluded that there were some differences in the bacterial taxa of rice wine koji from different regions.
2021, 42(20): 140-148. doi: 10.13386/j.issn1002-0306.2021020061
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Objective: To screen lactic acid bacteria (LAB) with anti-Helicobacter pylori activity and great probiotic properties from fermented food, dairy products and infant feces. Method: A total of 39 LAB-like strains with stable curd state were screened from 175 samples. 9 Strains with anti-H. pylori activity were initially isolated by agar diffusion assay and H. pylori urease activity test and identified by 16S rDNA sequence analysis. Subsequently, the acid and bile tolerance, antibiotic resistance, antibacterial activity, cell surface hydrophobicity, and cell auto-aggregation of the selected LAB strains were determined. Results: Two probiotic strains with anti-Helicobacter pylori activity were screened: Lactobacillus helveticus GQ1702 and Lactobacillus plantarum D1, and their cell culture supernatants exhibited anti-H. pylori activity equivalent to the anti-H. pylori activity of 0.038 and 0.034 mg/mL metronidazole, respectively. The survival rates of GQ1702 and D1 were above 70% after incubation at pH3 for 3 h, the survival rates of GQ1702 and D1 after incubation at 0.3% bile salt were 0.47% and 1.08%, respectively. Cell surface hydrophobicities of GQ1702 and D1 were 25.10% and 11.79%, respectively. The self-agglutination rate reached 75.53% and 68.61% respectively after 24 hours. The auto-aggregation percentages of GQ1702 and D1 were 61.18% and 57.25%, respectively, after 24 hours. The two LAB strains were not resistant to chloramphenicol, penicillin, erythromycin, ampicillin, or cefazolin, and exhibited antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, E. coli O157:H7, and Salmonella typhimurium. Conclusion: Lactobacillus helveticus GQ1702 and Lactobacillus plantarum D1 with anti-Helicobacter pylori activity were obtained in this experiment, which could provide a source of strains for development and research of functional dairy products.
2021, 42(20): 149-156. doi: 10.13386/j.issn1002-0306.2021040128
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Objective: To explore the mitigation effects of fermented wax gourd microorganisms and mouse intestinal flora on Staphylococcus aureus. Methods: The ICR mice were randomly divided into the control group (CT), smelly wax gourd group (SW), Staphylococcus aureus group (SA) and Staphylococcus aureus + smelly wax gourd group (SA+SW) according to gender. 16S rDNA high-throughput sequencing was used to analyze the dominant flora of the mouse intestines, the differences in flora, the changes of probiotics in the mouse intestines, and the correlation between the intestinal flora and short-chain fatty acids. Results: Whether male or female mice, fermented wax gourd could change the structure of the intestinal flora of mice infected with Staphylococcus aureus to make it closer to the CT group. Compared with the CT group, the relative abundance of Lactobacillus sp. in the SW group of male and female mice decreased from 32.51% and 44.34% to 7.56% and 6.86%, respectively. The Lactobacillus sp. in the SA group also decreased to 15.68% and 11.02%.The relative abundance of Lactobacillus sp. in SA+SW group rose to 25.30% and 39.16%. The change trend of Bacteroides sp. and Lactobacillus sp. was the same. Clostridium sp. and Muribaculum sp. of male and female mice. The relative abundance increased in the SW group, while the relative abundance decreased in the SA+SW group; compared with the control group, males infected with Staphylococcus aureus. The abundance of probiotics producing bacteria in the mouse intestine decreased from 51.37% to 13.56%, and the SA+SW group recovered to 43.61%. Fermented wax gourd acts on mice infected with Staphylococcus aureus to increase the synthesis of SCFAs and reduce the body's inflammatory response. Conclusion: Fermented wax gourd could improve the intestinal flora, thereby effectively alleviating the effect of Staphylococcus aureus on the intestines of mice.
2021, 42(20): 157-163. doi: 10.13386/j.issn1002-0306.2021010094
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The insoluble dietary fiber (HIDF) was extracted from Polygonatum sibiricum residue by response surface methodology. Firstly, the effects of solid-liquid ratio, papain concentration, papain hydrolysis time, α-amylase concentration and α-amylase hydrolysis time on the extraction rate of HIDF were discussed by single factor experiments, the extraction process parameters were optimized by response surface methodology (Box-Behnken). Finally, infrared spectrum analysis, X-ray diffraction and scanning electron microscope observation were carried out, the functional properties were determined. The results showed that the optimum extraction conditions were as follows: Solid-liquid ratio 1:20 mL/g, papain concentration 0.13%, papain enzymolysis time 1.9 h, α-amylase concentration 0.29%, α-amylase hydrolysis time 2 h, the content of HIDF was 52.184%. The hydraulic holding capacity, oil holding capacity and swelling capacity of HIDF were 5.99±0.05 g/g, 3.965±0.04 g/g and 4.565±0.05 mL/g, respectively. Therefore, HIDF extracted from Polygonatum sibiricum residue had good physical and chemical properties and was suitable for processing into functional food, which provided a reference for improving the utilization rate of Polygonatum sibiricum residue and further excavating its nutritional value.
2021, 42(20): 164-172. doi: 10.13386/j.issn1002-0306.2021020004
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Using grape and mulberry as raw materials, the optimal fermentation technology of compound fruit vinegar from grape and mulberry by alcohol fermentation and acetic acid fermentation was studied. The ethanol concentration, fermentation temperature, pH and inoculum amount of acetic acid bacteria were used for single factor experiments. The fermentation process of grape mulberry compound fruit vinegar was optimized by response surface methodology with acid production as response value. The results indicated that the optimum fermentation conditions were as follows: Initial ethanol concentration 7.4%, pH5.0, inoculum amount 9.8%, temperature 32 ℃. Under these conditions, the maximum acid yield of fruit vinegar was 5.38 g/100 mL. At the same time, the electronic nose technology was used to detect the different fermentation periods of grape mulberry compound fruit vinegar, which were the fruit juice period before alcohol fermentation, acetic acid fermentation period and fermentation completion period. Combined with principal component analysis (PDA), loading analysis and linear discriminant analysis (LDA), it was determined that the main flavor components of grape mulberry compound fruit vinegar were nitrogen oxides, nitrogen oxides and nitrogen oxides. The order of odor concentration in different fermentation stages was as follows: Finished fruit vinegar>mid fermentation stage>fruit juice. It showed that the electronic nose could accurately distinguish grape mulberry compound fruit vinegar products in different fermentation periods.
2021, 42(20): 173-182. doi: 10.13386/j.issn1002-0306.2021030083
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In order to develop a submerged fermentation medium for high-yield extracellular polysaccharides (EPS) of Tremella fuciformis spore, to improve its fermentation yield and achieve large-scale production applications, this study used a single factor method to explore the effects of different sources of carbon and nitrogen sources and nutrient elements on the yield of Tremella polysaccharides. Through the Plackett-Burman and Box-Behnken response surface design to obtain the high-yield EPS fermentation medium and fermentation conditions, and verified the optimization results in a 50 L fermentation tank. The results showed that the fermentation medium of Tremella spores with high production of extracellular polysaccharides was: Glucose 35 g/L, NaCl 0.6 g/L, compound nitrogen source (yeast extracts:corn steep dry powder=1:1) 3.6 g/L, MgSO4 0.5 g/L, KH2PO4 1 g/L; Optimal fermentation conditions were: 27 ℃, pH5, fermentation for 6 days, inoculation amount 3%(v/v) and shaker speed 150 r/min. After optimization, the yield of extracellular polysaccharide from Tremella spore was 214.45 mg/100 mL, with 8.56 times of that before optimization. In the 50 L fermentation tank, the polysaccharide yield was 258.78 mg/100 mL with 21.03% higher than the shake flask experiment. This optimization of the fermentation process significantly promoted the production of extracellular polysaccharides from Tremella spore, which would provide a theoretical support for its large-scale industrial production.
2021, 42(20): 183-190. doi: 10.13386/j.issn1002-0306.2021030121
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In this study, hot water and steam blanching were used to pretreat peach. The effects of two blanching treatments on microstructure, enzymatic browning and related qualities of peach were studied for determining the suitable blanching condition. The results showed that the effects of two treatments on peach were similar with the increase of blanching time (0~80 s) in general, the surface microstructure collapsed, PPO and POD inactivated, texture declined, the browning degree and VC content decreased, total phenol content and antioxidant activity increased. Correlation and cluster analysis showed that PPO, POD, hardness, browning degree and VC were extremely significant correlated. And the total phenol, DPPH· scavenging capacity and FRAP were extremely significantly correlated. The changes in physicochemical quality of hot water and steam blanching for 40 s were similar, and showed a high correlation. The quality changes of hot water and steam blanching for 60 s and 80 s were highly correlated. Overall, steam blanching maintained the better quality of peach compared with hot water treatment. When blanching for 80 s, steam blanching could effectively inactivate PPO and POD and maintain preferable tissue structure, and it showed better color quality and higher VC content than those of hot water treatment. Hence, steam blanching for 80 s was the best blanching condition for preserved peach processing.
2021, 42(20): 191-198. doi: 10.13386/j.issn1002-0306.2021030221
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In this study, Inonotus hispidus was used as a raw material, extraction rate of polysaccharide was used as the index, the single factor experiments and Box Behnken experiment design were used to study the preparation process of Inonotus hispidus polysaccharide (IHP) by ultrasound and microwave synergistic extraction, and the effects of several extraction methods on the extraction percentage of IHP and the bile acid binding capacity in vitro were compared and analyzed. The results showed that, the optimal process parameters for the extraction of IHP were: Material-to-water ratio 1:33 g:mL, microwave time 50 s, microwave power 500 W, ultrasonic time 51 min, ultrasonic power 200 W, the extraction percentage of polysaccharide under this condition was 85.61%. Compared with ultrasonic assisted extraction and hot water extraction, the extraction rate increased by 24.87% and 36.38%, respectively. The IHP had significant binding ability to sodium taurocholate and sodium glycocholate, which was positively correlated with the dosage of polysaccharide, and the binding ability of IHP to sodium taurocholate was higher than sodium glycocholate. And under the same mass concentration conditions, the binding ability of polysaccharides prepared by the three extraction methods to bile salts was ultrasonic and microwave synergistic extraction>ultrasonic assisted extraction>hot water extraction, and the binding rates for sodium glycocholate and sodium taurocholate were 30.93% and 32.13%, respectively. This study showed that the ultrasonic and microwave synergistic extraction method could significantly improve the extraction effect of IHP and the ability to bind cholate in vitro, and would provide a theoretical basis for the preparation and development and utilization of highly active IHP.
2021, 42(20): 199-206. doi: 10.13386/j.issn1002-0306.2021030301
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The starch extraction process was optimized by response surface Box-Behnken analysis with cowpea seed as raw material. The morphology, structure and physicochemical properties were characterized. Five factors and three levels of response surface analysis were used to determine the optimal parameters of cowpea starch extraction process: 420 mL NaOH solution, soaking time 17 h, ethanol 74 mL, oscillating speed 167 r/min, oscillating time 70 min. Under these conditions, the theoretical extraction rate was 62.13%. The extracted cowpea starch ash content was 0.17%, protein content was 0.87%, lipid content was 0.25%, cellulose content was 1.59%, solubility was 0.73%, swelling degree was 1.85 g/g. Scanning electron microscope images showed that cowpea starch granules were spherical or ellipsoid, and most of the granules were distributed in the range of 9~13 μm. Fourier transform infrared spectroscopy and X-ray diffraction analysis showed that cowpea starch had strong crystal structure and relative crystallinity, and showed typical C-type crystalline starch morphology. Thermodynamic analysis showed that the initial gelatinization temperature (To) was 73.86 ℃, the peak temperature (Tp) was 80.59 ℃, and the end temperature (Tc) was 88.53 ℃. The results showed that cowpea starch had a tight spatial structure and strong anti-gelatinization properties, and would have a great development potential in the field of food texture improvers.
2021, 42(20): 207-213. doi: 10.13386/j.issn1002-0306.2021020200
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In order to analyze the response law of internal stress and strain to extrusion of Lingwu jujube during the picking process and provide theoretical basis for the design of picking robot, in the paper universal mechanical testing machine was used to compress the whole fruit horizontally and vertically under five different extrusion rates of 15, 20, 25, 30 and 35 mm/min, and then fit the force deformation curve. The stiffness and fracture force of jujube were obtained. The two lateral extrusion rates of 15 and 35 mm/min were simulated by finite element method, and the finite element model was established. The results showed that the mechanical properties of Lingwu jujube were anisotropic and the lateral compressive capacity was stronger when it was squeezed. Under transverse compression, the whole fruit fracture load was 214.34 ~ 266.53 N, the elastic modulus was 14.90~17.05 MPa and the relative deformation was 20.70%~22.67%. During longitudinal compression, the whole fruit fracture load was 132.52~185.40 N, the modulus of elasticity was 4.59~6.07 MPa, and the relative deformation was 13.72%~17.25%. The stress and strain of the stress point was the largest in pulp, and extended along the equator to the surrounding fruit core, and decreased gradually. The difference between the simulation value and the experimental value of the finite element model with compression rate of 15 mm/min was 14.98%, and the deviation of 35 mm/min was 11.06%. It was feasible to apply the finite element method to the simulation of Longwu jujube extrusion.
2021, 42(20): 214-222. doi: 10.13386/j.issn1002-0306.2021020041
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To understand the contamination level and composition characteristics of per- and polyfluoroalkyl substances (PFASs) in animal food (aquatic food, egg food, meat food) produced in a typical area of Hubei province, and to evaluate the exposure risk of local standard man consuming PFASs from animal food, taking the animal food (aquatic food, egg food, meat food, dairy product) consumed by residents in a typical area of Hubei province as the research object, the pretreatment method (alkali digestion and solid phase extraction with small column purification) combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established. The concentrations of 14 kinds of PFASs in animal food were determined. The exposure risk of local adult men to PFASs from food of animal origin was assessed by referring to the consumption of various kinds of food, standard human body weight and the dose value of European Food Safety Authority in the fifth China total dietary survey. The results showed that the recoveries of 14 kinds of PFASs were in the range of 81%~120%. And the relative standard deviations (RSD) were in the range of 2.71%~12.28%. The correlation coefficient (R2) was greater than 0.994 in the concentration range of 0.1~20 ng/g. The limit of detection was 0.003 ng/g, and the limit of quantification was 0.01 ng/g. PFASs contamination was widespread in animal food in Hubei Province. The detection rate of 5 kinds of PFASs in aquatic food reached 100%, and the total PFASs concentration in aquatic food ranged from 0.381 to 75.114 ng/g, with an average of 8.655 ng/kg. The detection rate of 6 kinds of PFASs in egg foods reached 100%, and the total PFASs content in egg foods ranged from 1.090 to 7.581 ng/g, with an average of 4.163 ng/g. The detection rate of 1 kinds of PFASs in meat samples reached 100%. The total PFASs content in local meat products ranged from 0.306 to 2.512 ng/g, with an average of 0.742 ng/g. In addition, the concentration level and residual characteristics of PFASs in different kinds of animal foods were different. This was the median concentration of ∑PFASS in aquatic products: silver carp (11.680 ng/g)>Channa argus (2.156 ng/g)>crucian carp (1.766 ng/g)>bream (1.216 ng/g)>grass carp (0.754 ng/g). This was the median concentration of ∑PFASs in eggs: chicken eggs (6.049 ng/g)> duck eggs (2.514 ng/g). This was the median concentration of ∑PFASs in meat: beef (0.765 ng/g)>duck meat(0.665 ng/g)>chicken (0.547 ng/g) >pork (0.535 ng/g). From the perspective of dairy products, the median of ∑PFASs in yogurt was 0.138 ng/g. It was estimated that the harm index of PFOS in aquatic food and egg food was greater than 1 for a local standard person. These were potentially harmful to the local population.
2021, 42(20): 223-228. doi: 10.13386/j.issn1002-0306.2020030404
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In this study, Fe3O4@ZrO2 magnetic nanoparticles which were synthesized successfully were used as carrier for the highly selective enrichment of phosphopeptides from tryptic digest product of casein . Using N/P (molar ratio) of CPP and magnetic nanoparticles adsorbance as evaluating indicators, the influence of five variables which were the hydrolysis degree of casein, adsorption pH, adsorption time, adsorption temperature, and the initial concentration of phosphopeptides, on the ability of Fe3O4@ZrO2 magnetic nanoparticles to isolate and enrich phosphopeptides was analyzed. The technical parameters of CPP enrichment were optimized. Results showed that, the optimized conditions of CPP enrichment were as below: Casein hydrolysis degree 22%, adsorption pH4.5, adsorption temperature 30 ℃, adsorption time 50 min, the initial concentration of phosphopeptides 50 mg/mL. Finally, under these conditions, the N/P (molar ratio) of CPP was 4.87, and the adsorbance of Fe3O4@ZrO2 magnetic nanoparticles was 94.37. The bound CPP were eluted using NaOH (pH13) and the elution rate was 95% at least. Experiment results demonstrate that ZrO2 coated-magnetic microspheres showed the excellent potential for selective enrichment of CPP, which would play an important role in the production of high quality and purity CPP.
2021, 42(20): 229-241. doi: 10.13386/j.issn1002-0306.2020120272
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The essential oil and water extract of Zanthoxylum bungeanum pericarp were produced by steam distillation method. The aroma compounds of essential oil were analyzed by direct injection and the volatiles in water extract of Zanthoxylum bungeanum pericarp were isolated by solvent-assisted flavor evaporation (SAFE). Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were employed to identify the volatile compounds and aroma-active compounds. Results showed that a total of 99 and 153 volatile compounds were identified in the essential oil and water extract, respectively. The lactones and acids were only detected in the water extract. Linalool, D-limonene, terpene, and terpinen-4-ol had the highest concentration in the essential oil and water extract of the green Zanthoxylum bungeanum. Linalool, D-limonene, linalyl acetate, α-myrcene had the highest concentration in the essential oil and water extract of the red Zanthoxylum bungeanum. The total concentration of esters in the essential oil and water extract of red Zanthoxylum bungeanum were higher than that in green Zanthoxylum bungeanum. Sensory evaluation showed the green, sanshoamides-like, and fatty aromas of the essential oil were stronger than those of the water extract, while the sweet, acidic and hala (grease corruption-like) notes of the water extract were stronger than those of the essential oil. In addition, 57 and 68 aroma-active compounds were identified by GC-O in essential oil and water extract, respectively. And the contributions of aroma-active compounds to the aroma profiles were performed by partial least squares regression analysis (PLSR) further. PLSR results showed 29 aroma compounds had significant contribution to aroma profiles of Zanthoxylum bungeanum pericarp essential oil and water extract.
2021, 42(20): 242-247. doi: 10.13386/j.issn1002-0306.2021010064
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The content of mercury in Dictyophora was determined by automatic mercury analyzer and atomic fluorescence spectrometer. The main sources of uncertainty were analyzed and the main uncertainty components were calculated by establishing mathematical model, and the synthetic uncertainty and extended uncertainty were obtained, and the uncertainties results were compared. Results showed that, the expanded uncertainties of these two methods were 0.006 and 0.002 mg/kg(k=2), when the determination results of mercury were 0.050 mg/kg.This study might provide a guideline for uncertainty evaluation for determining mercury in edible fungus by automatic mercury analyzer and atomic fluorescence spectrometry.
2021, 42(20): 248-254. doi: 10.13386/j.issn1002-0306.2021010077
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A method for the determination of ofloxacin, pefloxacin, norfloxacin and lomefloxacin in flatfish by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established. Accoding to SN/T 1751.2-2007 Determination of Multi-residues of Quinolones in Food of Animal Origin for Import and Export-Part 2: LC-MS/MS Method, a mathematical model for uncertainty evaluation was established and the sources of uncertainty were analysed. The expanded uncertainty was 1.04, 1.09, 1.34 and 0.99 μg/kg(k=2) for ofloxacin, pefloxacin, norfloxacin and lomefloxacin of contents of 9.26, 10.08, 9.73 and 9.57 μg/kg in flatfish, respectively. As a result, the fitting of the standard curve, the high performance liquid chromatography-tandem mass spectrometry and the preparation of standard solution were the main sources of uncertainty.
2021, 42(20): 255-260. doi: 10.13386/j.issn1002-0306.2021010089
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Flaxseed oil was prepared from 40 kinds of flaxseed of different region in Qinghai by soxhlet extraction. And the volatile profiles were analyzed by headspace sampling combined with GC-MS method. In order to obtain the best solid phase microextraction conditions and GC-MS condition, the stirring rate, extraction temperature, equilibrium time, extraction time, desorption time and heating program were optimized. The results indicated that when using DVB/CAR/PDMS fiber, the optimum extraction conditions of the volatile compounds were: 20 min equilibrium time, 40 min adsorption time at 80 ℃ , stirring intensity of 400 r/min, and 5 min desorption time. Under this extraction condition, a total of 58 volatile components of 40 kinds of flaxseeds oil in Qinghai could be detected, including 12 aldehydes, 8 acids, 9 alcohols, 2 ketones, 5 esters, 13 hydrocarbon compounds, 3 heterocycles and 6 other types, which achieved a good chromatographic separation. According to cluster analysis, aldehydes were the main volatile components that distinguished flaxseed oil samples, which would provide a theoretical basis for the quality identification and development of flaxseed oil.
2021, 42(20): 261-267. doi: 10.13386/j.issn1002-0306.2021010109
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A HPLC method for simultaneous determination of astaxanthin, lutein, cantharidin, zeaxanthin and β-carotene in eggs and chicken was developed. The results showed a good linear relationship in the range of 0.5~100 μg/mL for five carotenes, and the coefficients of determination were all above 0.996. The limits of detection of the method were between 0.10 and 0.20 mg/kg, with the limits of quantitation were between 0.33 and 0.66 mg/kg. At the spiked levels of 1, 10 and 20 mg/kg, the recoveries of eggs and chicken samples were 71.6%~112.9% and 88.6%~119.7%, respectively, with RSD≤7.2%. The method is rapid, simple, accurate and reproducible. It is suitable for the detection of five kinds of carotenoids in complex matrix samples such as eggs and chicken. It is of great significance for the market supervision of eggs and chicken.
2021, 42(20): 268-278. doi: 10.13386/j.issn1002-0306.2021010156
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The method for simultaneous determination of 25 sulfonamides residues in beef was established by one-step automatic extraction and purification technology of QuEChERS combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with 1% acetonitrile acetate, C18, PSA and anhydrous magnesium sulfate were used as purification adsorbents, and the one-step QuEChERS automatic pretreatment equipment was used for extraction, purification and centrifugation. The analytes were separated by a reversed phase C18 column and eluted with 0.2% formic acid methanol and 0.2% formic acid water (containing 2 mmol/L ammonium acetate). The beef sample was analyzed under the multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI+) and quantify by external standard. The results showed that good linearities were obtained for the 25 sulfonamides in 0.1~20 μg/L with the linear correlation coefficients more than 0.990. The limits of detection (LOD) and the limits of quantification (LOQ) for sulfonamides were 0.1~3 μg/kg and 1~10 μg/kg, respectively. The recoveries at three levels were in the range of 70.14%~116.93%. The repeatability expressed as relative standard deviations (RSD) was ranged from 0.95% to 13.74%(n=5). The method was simple, rapid, accurate and reliable, and could be used to detect the residues of sulfonamides in beef.
2021, 42(20): 279-285. doi: 10.13386/j.issn1002-0306.2021020021
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In order to explore the nutritional worth in various cultivars of hibiscus(Hibiscus mutabilis L.), the component and content of amino acids in 18 cultivars of hibiscus were analyzed in this research. The results showed that plentiful kinds of free amino acids (17 kinds) were detected in these 18 cultivars of hibiscus. The total amount of amino acids was 7.36~13.28 mg·g−1. The content of essential amino acids was 1.92~3.42 mg·g−1, which accounted for 22.33%~37.51% of the total amino acids, the component of amino acid in ‘MDH’ was closest to the proportion of amino acids needed for human being, indicating that it had greatest edible quality, taste amino acids were rich and accounted for 43.82%~66.72% of total amino acids, among which umami amino acids showed the highest content, ‘JXZ’ had the highest taste amino acid content. The content of medicinal amino acids in Hibiscus mutabilis L. was relatively high, accounting for 58.73%~71.61% of total amino acids, ‘JXZ’ had the most medicinal amino acids. To sum up, the variety of amino acids in Hibiscus mutabilis L. was complete, and there were certain differences in content. It had great edible and medicinal development and utilization value. Among them, the development prospects of ‘MDH’ and ‘JXZ’ were the best.
2021, 42(20): 286-293. doi: 10.13386/j.issn1002-0306.2021020236
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A method of precolumn fluorescence derivatization of fipronil sulfoxide (a metabolite of fipronil) was established and applied in the residue detection of chicken eggs. The main optimized parameters of precolumn fluorescence derivatization were as follows: catalyzer for condensation: EDC/DMAP; reaction solvent: dichloromethane; ratio of fipronil sulfoxide to fluorescence derivatization reagent: 1/8; reaction temperature: 45 ℃ (water bath); reaction time: 75 min. The target product of the fluorescence derivatization reaction was (N-(3-cyano-1-(2, 6-dichloro-4-(trifluoromethyl)phenyl)-4-((trifluoromethyl)thio)-1H-pyrazol-5-yl)-4-(2-(9-ethyl-9H-carbazol-3-yl)-1H-phenanthro[9, 10-d]imidazol-1-yl)butanamide (DX1), with high fluorescence intensity when excited. The main conditions for HPLC-FLD of DX1 were as following: C18 chromatographic column; isocratic elution; mobile phase: acetonitrile/water (80/20, v/v), flow rate: 1.0 mL/min, wavelength of the exciting light: 310 nm, emission wavelength: 404 nm, injection volume: 20 μL, column temperature: 40 ℃. Under the above-mentioned conditions, the limit of detection (LOD) and limit of quantitation (LOQ) were 0.033 and 0.092 μg/L respectively. Meanwhile, the extraction and determination method for the residual fipronil sulfoxide in chicken eggs were further developed with a LOD of 0.052 µg/kg and a LOQ of 0.132 µg/kg, whose RSDs of the retention time and peak area of precision, stability and reproducibility were respectively less than 0.04% and 2.7%. What's more, the operation of the HPLC-FLD detection could be completed in 20 min. The method had good sensitivity, accuracy and reliability, and could be used to the determination of residual fipronil sulfoxide in eggs.
2021, 42(20): 294-300. doi: 10.13386/j.issn1002-0306.2021010068
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The effects of melatonin treatment on physiological characteristics and quality of passion fruits during post harharvest storage were valuated. The passion fruits were dipped in 0, 0.05, 0.10, 0.20 mmol/L melatonin (MT) solution for 1 hour, then put in crisper and stored at room temperature (25±1 ℃), the parameters of firmness, color, soluble solid, soluble sugar and other indexes were analyzed. The results showed that more than 77% of the passion fruits in the CK group had rotted on the 12th day of storage, the mass loss rate and decay rate of melatonin treatment group were 8.22%~12.81% and 22.22%~38.89%, which were significantly lower than those of CK group (P<0.05), the melatonin treatment groups kept a good quality and the contents of soluble solids, titratable acid and soluble sugar were significantly higher than CK group (P<0.05). On the 16th day, all the fruits in CK group had rotted, the firmness of passion fruits treated with 0.20 mmol/L melatonin was 9.95 kg/cm2, which was significantly higher than that in the other two melatonin groups (P<0.05), and the weight loss rate was only 15.52%, which was significantly lower than that in the other two treatment groups (P<0.05), while other quality parameters had no significant differences between the other two treatment groups. In conclusion, 0.05, 0.10 and 0.20 mmol/L melatonin treatments could prolong the storage time of passion fruits and maintain the quality at a high level, while 0.20 mmol/L melatonin treatment had the best effect.
2021, 42(20): 301-308. doi: 10.13386/j.issn1002-0306.2021010090
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To prolong the shelf life of roasted squid fillets, different preservatives including potassium sorbate, nisin and poly-lysine were utilized through 37 ℃ accelerated experiments to investigate its effect on quality of roasted squid fillets during seven days storage. Changes of TVB-N content, total microbial colony, microstructure, pH and color were evaluated. Sensory evaluation was also used to study the effects of different preservatives on the storage quality of roasted flake. Results showed that on the 7th day of storage, compared with grilled squid slices treated by potassium sorbate and ε-polylysine group and untreated group, the content of TVB-N in the grilled squid slices treated by nisin decreased by 2.35, 8.123 and 9.612 mg·100 g−1 respectively. The total number of colonies in control group and potassium sorbate treatment group exceeded the national standard at the 5th day, which was 4.59 and 4.48 lg CFU·mL−1. The total number of colonies in ε-polylysine treatment group exceeded the national standard at the 6th day, with the content of 5.08 lg CFU·mL−1. The total number of bacterial colonies in the nisin treated group did not exceed the national standard during storage. The color, texture and sensory scores of grilled squid treated with different preservatives were significantly different (P<0.05). Compared with ε-polylysine and potassium sorbate, nisin could effectively inhibit the increase of the content of TVB-N and the total number of colonies, slow down the changes of texture and color of the grilled squid, and maintain the grilled squid with good sensory properties, which was more beneficial to the storage of the grilled squid.
2021, 42(20): 309-319. doi: 10.13386/j.issn1002-0306.2021020051
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In this paper, largemouth bass was used as raw material to study the effects of different cooling rates (liquid nitrogen quick freezing (1.81 ℃), freezing liquid quick freezing (0.15 ℃), flat plate quick freezing (0.14 ℃)) in freezing storage (0, 1, 2, 4, 12, 24 weeks), the influence of the physical and chemical properties of largemouth bass protein, by measuring the salt-soluble protein, sulfhydryl group, carbonyl group, Ca2+-ATPase activity content, surface hydrophobicity, endogenous fluorescence spectrum and protein composition changes in the fish meat, and using double factor variance and correlation analysis study quick-freezing method and storage time to investigate the degeneration of fish protein after freezing. The results showed that with the passage of frozen storage time, the value of salt-soluble protein showed a downward trend: The plate group and liquid nitrogen group had the lowest and the highest at the end of the frozen storage, respectively; the activity values of sulfhydryl and Ca2+-ATPase both increased first and then decreased. The endogenous fluorescence intensity of fibrin increased, resulting in a blue shift phenomenon, and the value of myofibrillar protein carbonyl and surface hydrophobicity increased significantly (P<0.05). The results of SDS-PAGE electrophoresis showed that myofibrillar protein was degraded during the freezing period, while the liquid nitrogen group had a faster cooling rate and a slower degree of protein degradation, while the plate group was the opposite. The volume of ice crystals formed by quick freezing of liquid nitrogen was similar to the distribution of water in the raw material, which was conducive to storage. Compared with liquid nitrogen quick freezing, the time for the formation of the maximum ice crystal zone in the quick freezing of liquid nitrogen was longer than that of liquid nitrogen quick freezing and shorter than that of flat quick freezing, and there was not much difference between the two. The correlation analysis between the two-factor variance and the indicators showed that the quick freezing method had a significant effect on the active sulfhydryl group and the maximum fluorescence intensity of myofibril protein (P<0.05). The freezing time was the main factor affecting the protein of the sea bass. The oxidative modification of amino acid side chain groups in myofibrillar protein was the main factor causing the degradation or aggregation of protein.
2021, 42(20): 320-327. doi: 10.13386/j.issn1002-0306.2021020161
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The quality of blueberry juice after 54 days storage treated by thermal sterilization(80 ℃, 10 min) and ultra-high pressure (UHP) sterilization (550 MPa, 10 min) were compared and the shelf life were predicted. The results showed that two kinds of products stored among 4, 27 and 37 ℃ were not detected microorganism at the end of the shelf life, indicating that two sterilizations were thorough. The pH and soluble solids contents of blueberry juice had little change during the storage time. The VC contents and total phenolic contents of blueberry juice at UHP sterilization were higher than thermal sterilization at the end of storage time. Based on the change of sensory scores of blueberry juice, the quality deterioration kinetic model and shelf life predictive modeling in the range of 4~37 ℃ were established by using kinetic model and Arrhenius equation. The determination coefficients R2 of predictive modeling were higher than 0.95 and most of relative errors between the predicted and actual values were less than 10%. Therefore, the established model could quickly and reliably predict the remaining shelf life of blueberry juice.
2021, 42(20): 328-333. doi: 10.13386/j.issn1002-0306.2020090128
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Objective: To evaluate the effects of sclerotium and solid fermentation products of Inonotus obliquus on inflammation and oxidative stress in diabetic rats. Methods: The type 2 diabetic rat model were induced by high-glucose-fat diet together with STZ in this study, body weight, oral glucose tolerance test was performed, serum IL-6, IL-1β, TNF-α, SOD and MDA levels were measured using the enzyme-linked immunosorbent assay (ELISA). Results: Compared with the model group, body weight was significantly improved by I. obliquus group (IO 3.08 g/kg, IO 6.16 g/kg), the water extract of I. obliquus group (WIO 0.4 g/kg), the water extract of solid fermentation products of I. obliquus group (WSFIO 0.8 g/kg). Glucose tolerance were significantly improved by solid fermentation products of I. obliquus group (SFIO 1.3 g/kg, SFIO 2.6 g/kg). The IL-1β level were significantly reduced by WIO (0.4, 0.8 g/kg) and WSFIO (0.4 g/kg). The TNF-α level were significantly reduced by IO (3.08, 6.16 g/kg), WIO (0.4 g/kg), SFIO (1.3, 2.6 g/kg) and WSFIO (0.8 g/kg). The level of SOD and MDA were significantly advanced and decreased respectively by all the medicated group. Conclusion: Solid fermentation products of I. obliquus showed antioxidative and anti-inflammatory effects in diabetic rats. The direct administration of I. obliquus powder, solid fermentation products or water extract of both two had different effects on various indicators. In general, it was feasible to replace solid fermentation products with feral I. obliquus to ameliorate inflammation and oxidative stress in type 2 diabetes.
2021, 42(20): 334-341. doi: 10.13386/j.issn1002-0306.2020120263
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Objective: To isolate and screen the bioactive oligopeptides which can promote bone formation from square siphon worm. Methods: Oligopeptides were prepared by enzymatic hydrolysis and membrane separation, and peptide sequences were identified by HPLC-MS/MS. The online database was used to predict drug formation, and the zebrafish model was used to evaluate the effect of promoting bone formation. Results: A total of 10 low molecular weight peptides were given. Two potential candidate peptides were obtained by zebrafish bone development models. Their amino acid sequences were GFAGDDAPR and GLGGLSPEK, which named GSP1 and GSP2. Molecular weights of two potential candidate peptides were 905.04 and 857.06 Da. Two potential candidate peptides could significantly promote the osteogenesis of juvenile zebrafish. Compared with the blank group, when Juvenile of AB zebrafish were treated with GSP1 solution (1~50 μg/mL), the area of integral optical density and green fluorescence increased in the skull of juvenile fish. When the concentration of GSP1 was 5 μg/mL, it had the best effect of promoting bone development. Compared with the blank group, when the juvenile of AB zebrafish were treated with GSP2 solution (1~50 μg/mL) , the area of integral optical density and green fluorescence increased in the skull of juvenile fish. When the concentration of GSP2 was 50 μg/mL, it had the best effect of promoting bone development. Conclusion: The oligopeptides less than 1000 Da were expected to be candidate drugs for promoting bone formation.
2021, 42(20): 342-347. doi: 10.13386/j.issn1002-0306.2020120264
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Objective: To investigate the effect of Dendrobium nobile Lindl extract on improvement of constipation and intestinal Lactobacillus diversity of mice. Methods: The mice with constipation induced by in compound diphenoxylate were given the high-dose (300 mg/kg), middle-dose (100 mg/kg), low-dose (30 mg/kg) of Dendrobium nobile Lindl extract, respectively. The defecation function and intestinal propulsive rate in mice were observed. Using Lactobacillus-specific primer and the microbial genomic DNA extracted from the fecal samples, the ARDRA analysis of Lactobacillus diversity was accomplished after PCR amplification and enzyme digestion. Results: After intragastric administration, the defecation time of the first black stool decreased significantly (P<0.01). The number of fecal particles was increased, and the fecal water content increased significantly (P<0.01). The intestinal propulsive rate increased significantly in the middle-dose group and the high-dose group (P<0.05). The diversity of Lactobacillus increased after intragastric administration by Dendrobium nobile Lindl extract, and the evenness of Lactobacillus in the intestine was more stable in the high-dose group. Conclusion: It showed that Dendrobium nobile extract had an improvement effect on the symptoms of constipation by increasing the fecal water content, promoting the intestinal peristalsis and regulating the diversity of intestinal Lactobacillus in mice.
2021, 42(20): 348-354. doi: 10.13386/j.issn1002-0306.2021020011
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The antioxidant activity and protective effect of quercetin from seabuckthorn meal were studied in vitro. The antioxidant activities of quercetin in seabuckthorn were studied by 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH·) superoxide anion (${\rm{O}}_2^- \cdot$), 2, 2-diazo-bis (3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt (ABTS+·) and high iron ion reduction (FRAP). The aging model of mice was established by subcutaneous injection of D-galactose into the neck. The mice were treated with quercetin of seabuckthorn meal at different doses (100, 250, 500 mg/kg) by gavage. The eyeball blood was taken to measure the activities of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and malondialdehyde (MDA) in serum; the heart, kidney and liver were taken as hematoxylin eosin staining (HE) to observe the pathological state of the cells. The results showed that quercetin from seabuckthorn meal had good scavenging ability on DPPH·, ${\rm{O}}_2^- \cdot$ and ABTS+·. Compared with the model group, the content of MDA in the low dose group of quercetin of seabuckthorn meal decreased significantly (P<0.05), the activities of T-AOC, GSH-Px and SOD in the serum of mice in the medium and high dose groups increased significantly (P<0.05), and the content of MDA decreased significantly (P<0.05). From the pathological section, with the increase of quercetin dosage in seabuckthorn meal, the myocardial fibers arranged orderly and the transverse lines were clear; the morphology of renal sacs and glomeruli gradually became normal, the number of renal tubules increased and arranged closely; the number of hepatocytes increased, the cell morphology was complete, and the sinus space gradually became significant. Therefore, quercetin from seabuckthorn meal could improve the activity of antioxidant enzymes and the content of reducing substances in aging model mice, reduce the content of lipid peroxide, so as to improve the antioxidant capacity of aging model mice, and had a better protective effect on aging model mice.
2021, 42(20): 355-364. doi: 10.13386/j.issn1002-0306.2021020190
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Purpose: This study aimed to investigate the effect of 2’-fucosyllactose (2’-FL) on the proliferation, adhesion to intestinal cells and anti-inflammatory ability of lactic acid bacteria and bifidobacterial. Methods: 2’-FL was used to study if the strains could utilize it for promoting proliferation or improving adhesion, by determining the biomass, acid production and variations in adhesion capacity. Then finding out the potential anti-inflammatory strains among the strains whose colonization ability was enhanced by 2’-FL, by a lipopolysaccharide (LPS)-induced macrophage RAW264.7 inflammatory model. Finally, 2’-FL and the combinations of 2’-FL and the potential anti-inflammatory strains were used to investigate their effects on the inflammation. Results: Among the thirty experimental strains, 2’-FL could promote the proliferation of Bifidobacterium bifidum (FL-276.1, FL-228.1) and improve the adhesion of lactic acid bacteria (ML-1, FN515, FN518, FN249, ML329) and bifidobacterial (FL-276.1) to Caco-2 cells. Bifidobacterium bifidum FL-276.1, Bifidobacterium bifidum FL-228.1 and Lactobacillus rhamnosus FN518 could significantly reduce the secretion of NO, TNF-α, IL-6 and IL-1β in the inflammatory model. Meanwhile, 2’-FL alone significantly reduced the secretion of NO, IL-6 and IL-1β. The combination of 2’-FL and the above three strains had a synergistic anti-inflammatory effect, which showed a strain-specific trait. Particularly, strain FL-276.1 combined with 2’-FL exerted the best anti-inflammatory effect. Conclusions: 2’-FL could promote the colonization and anti-inflammatory activity of certain lactic acid bacteria and bifidobacterial, which showed a strain-specific trait. It might provide alternative choice for the prevention of necrotizing enterocolitis (NEC) in preterm infants.
2021, 42(20): 365-371. doi: 10.13386/j.issn1002-0306.2021020224
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To study the nutritional properties of altay sheep buttock fat and its solvent extraction fractions, 60 male mice were selected and divided randomly into 5 groups, using 2 ℃ fractionation products (2 ℃ group), 12 ℃ fractionation products (12 ℃ group), altay sheep buttock fat (BF), rapeseed oil (RO), normal saline (CK) to gavage (1.5 mL/10 g) them, killing them at day 20 and day 40, respectively and the relevant indexes were measured. The results showed that: 20 days after gavage, except for the CK group, there was no significant different in the content of acetic acid, butyric acid and valeric acid in the cecum of mice (P>0.05). The cecal propionic acid content of the BF group and the cecal isovaleric acid content of the 2 and 12 ℃ groups were significantly higher than those of the RO group (P<0.05). The length of colon villi and the depth of colonic crypts in the 12 ℃ and BF groups were significantly lower than those of the RO group (P<0.05). 40 days after the gavage, the contents of cecal propionic acid, butyric acid and valeric acid in the 2 ℃ group and the cecal acetic acid, propionic acid and butyric acid in the 12 ℃ group were significantly higher than those of the RO group (P<0.05). The colonic crypt depth and villi length in the 12 ℃ and BF groups were significantly lower than those of the RO group (P<0.05). It showed that under this intake level, altay sheep buttock fat at 2 ℃ was more conducive to maintaining the relative stability of the short-chain fatty acid content in the cecum of mice than raw fat and rapeseed oil, and had less damage to the colon.
2021, 42(20): 372-376. doi: 10.13386/j.issn1002-0306.2021030351
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The objective of this study was to explore the anti-aging effects of peptide from Antarctic krill on the skin of Kunming mice. The mice were randomly set as follows: Normal control group, model control group, group of Antarctic krill peptide (P-1), group of Antarctic krill peptide (P-2). Then characteristics and biochemical criterion analyzing were measured after mice were executed. The results showed that the skin of animals in P-1 and P-2 groups was similar to that of animals in model control group, showing elastic light wrinkled. Compared with the model group, the P-1 and P-2 groups significantly reduced water loss (P<0.01), significantly decreased levels of GAG, collagen breakdown of photoaging skin and lipid loss (P<0.05); the P-1 and P-2 groups significantly enhanced activity of T-SOD, CAT, GSH-Px and decreased levels of MDA in serum (P<0.05). This study showed that peptide from Antarctic Krill could protect skin against UV irradiation-induced photodamage. It provided a theoretical basis for the application of peptide from Antarctic Krill in the field of cosmetics.
2021, 42(20): 377-383. doi: 10.13386/j.issn1002-0306.2020070074
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Maturity, as an essential evaluation index of fruit quality, is closely related to the harvest, storage, processing, transportation, sales and other links of fruit, and is also one of the key factors affecting its output and quality. In this paper, the research status of fruit maturity detection using near-infrared spectroscopy and hyperspectral imaging technology in the recent ten years are reviewed. Starting from qualitative identification of fruit maturity and quantitative prediction of maturity parameters, the effects of spectral instrument working band, spectral acquisition mode, spectral sampling area, maturity characterization factor, single maturity parameter, and multiple maturity index on the accuracy and stability of the final detection model were analyzed in detail. Finally, the development trend of near-infrared spectroscopy and hyperspectral imaging technology in fruit maturity detection has been prospected in order to provide a scientific basis and technical reference for related research work.
2021, 42(20): 384-390. doi: 10.13386/j.issn1002-0306.2020080107
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Ulva lactuca polyphenols are secondary metabolites of green algae and have been experimentally proven to exert diverse biological activities. The content and biological activity of polyphenol extracted from U. lactuca depends not only on the growth environment and climatic conditions, but also on the extraction method and operation steps. This review aims to provide an overview of the extraction method, composition, and antioxidant, antibacterial, cholesterol lowering, anti-inflammatory as well as in vitro anti-cancer activities of polyphenol from U. lactuca. The application prospect of U. lactuca polyphenols in food and medicine field is also covered.
2021, 42(20): 391-399. doi: 10.13386/j.issn1002-0306.2020080184
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Milk is an ideal protein supplement, 80% of which is casein. Casein, as the main allergen in milk, seriously affects the nutritional supplement choice of patients with milk allergy. Studies have shown that the structural characteristics of casein play a vital role in its allergenicity. To deeply explore the relationship between its structural characteristics and allergenicity, it is necessary to use appropriate purification methods to obtain high-purity casein. From the two perspectives of the preliminary separation of micellar casein and the purification of casein components, this article focuses on the research progress of the purification of bovine casein, and describes the structural characteristics of bovine casein and its influence on allergenicity. It provides theoretical and technical support for the study of using protein modification technology to reduce or eliminate the allergenicity of casein.
2021, 42(20): 400-407. doi: 10.13386/j.issn1002-0306.2020080278
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Buckwheat is a kind of pseudocereal with high protein content and well-balanced amino acids. It is a source of high-quality protein. Buckwheat protein not only has high nutritional value, but also has a variety of health benefits such as lowering cholesterol, lowering blood pressure, and lowering blood sugar. So it has development value in functional food and other fields and has broad application prospects. In this paper, the advantages and disadvantages of the different methods for the extraction of buckwheat protein are described, and the current research status of buckwheat protein's structural characteristics, food functional properties, physiological activities and applications are presented. The research of buckwheat protein was prospected, hoping to provide basis for the development and utilization of buckwheat protein and the further processing of related products.
2021, 42(20): 408-414. doi: 10.13386/j.issn1002-0306.2020080281
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Edible fermented extract is a kind of product which is available for human consumption. Edible fermented extract is made from animal, plant, edible fungus and other raw materials with or without auxiliary materials, fermented by microorganism and with specific biological active ingredient. With the improvement of people's diet, edible fermented extract has been studied deeply by food scholars because of its multi-functional characteristics. Though research progress of edible fermented extract has been made, the understanding of the edible fermented extract is still not comprehensive. This review introduces the fermentation mechanism, microbial composition and function of edible fermented extract, summarizes the potential function and the existing problems of the edible ferment products. The purpose is to provide certain theoretical basis for promoting the development of edible ferment industry.
2021, 42(20): 415-423. doi: 10.13386/j.issn1002-0306.2020090087
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Milk and dairy products are one of the indispensable foods for human beings. The harmful substances such as agricultural and veterinary drug residues, mycotoxins, illegally added substances and other pollutants pose a serious threat to consumers' health and safety, and also hinder the development of the dairy industry. Surface enhanced raman spectroscopy (SERS) as an emerging detection method is expected to meet the current high-throughput and high-sensitivity detection needs of milk and dairy products. This article mainly summarizes the research progress of SERS method in milk detection, including the preparation of metal nano-detection probes and SERS solid-phase platform, the application of molecular recognition technologies such as antibodies and aptamers, the combination of nucleic acid amplification technology and microfluidic technology with SERS. Finally, the research and development direction and application prospects of SERS in dairy products are summarized and prospected.
2021, 42(20): 424-430. doi: 10.13386/j.issn1002-0306.2020090095
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Emulsifying properties are one of the most important functional properties of meat protein. It plays a significant role in the quality and value of meat products. The solubility, particle size, sulfhydryl distribution and surface hydrophobicity of meat protein have important influences on its emulsifying properties. Different physicochemical methods can improve the emulsifying properties of meat protein by changing the structure and aggregation degree of the protein. In this work, several promising methods in improvement on emulsifying properties of meat protein were reviewed, including physical and chemical methods such as high-pressure homogenization, high hydrostatic pressure, ultrasound, microwave, cold plasma, glycosylation and isoelectric solubilization/precipitation. Furthermore, the mechanism and appropriate conditions of different methods are discussed. The objective for this review is to provide reference for the improvement on emulsifying properties of meat protein and the development of emulsified meat products.
2021, 42(20): 431-439. doi: 10.13386/j.issn1002-0306.2020090103
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In the process of food fermentation, the change of microbial community has an important influence on the quality and safety of fermented food. In food fermentation, using modern biotechnology to analyze the types and characteristics of microorganisms, as well as studying the interaction between microorganisms to develop the application of compound microbial inoculums, can give food diversified flavor and improve the stability of industrial production. In this paper, recent domestic and foreign research relating to the design and process optimization of compound microbial inoculums, and application in the fermentation of traditional foods and aquatic products are summarized. The development prospect of food fermentation in fermentation foods are forecasted.
2021, 42(20): 440-448. doi: 10.13386/j.issn1002-0306.2020090106
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As a nutritious, healthy, delicious and portable meat product, meat jerky was favored by many consumers. Jerky includes beef jerky, mutton jerky, pork jerky, horse jerky, poultry jerky, goose jerky and other poultry jerky, fish jerky, frog jerky and other aquatic jerky, snake jerky, rabbit jerky and other types jerky. This article reviews the research status of different kinds of meat jerky, explains the factors that cause the spoilage of meat jerky, and the preservation techniques commonly used in meat jerky and other meat products. In this paper, the research status and preservation technology of different meat jerky are summarized, and the methods of improving the flavor and taste of dried meat, stabilizing the quality and prolonging the shelf life of dried meat are analyzed. The research content of this paper would have reference significance for the improvement of the quality of meat jerky in the market, the research of new varieties of meat jerky and the development of new storage methods, and also promote the development of meat products industry to a certain extent.
2021, 42(20): 449-455. doi: 10.13386/j.issn1002-0306.2020100136
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Food safety is a major concern for human. Various detection methods for foodborne pathogenic bacteria have become the focus of studies nowadays. Although polymerase chain reaction (PCR), as the most wildly used detection methods for pathogen, has overcome the shortcomings of time-consuming traditional method, the need for accurate temperature control greatly limits its application in field testing. Recombinase polymerase amplification (RPA), as a new isothermal amplification method, has developed rapidly in recent ten years. This method has broken up the barrier of PCR, getting rid of thermal cycle and expensive instruments, which is more suitable for insufficient resources on-site detection. In this manuscript, the mechanism of RPA and the probe design method are provided. Besides, the application of RPA in detecting foodborne pathogenic bacteria is reviewed. The hot topics of RPA development and the prospect of RPA technology development in the future are summarized.