Objective To isolation and identification of caproate bacteria and metabolic analysis of mixed bacteria in cellar mud of strong-aroma white wine.Methods In this study, cellar mud from a winery in southern Sichuan was used as the research object. In the experiments of isolation and screening of caproacidobacteria in an anaerobic workstation, 120 experimental strains were finally obtained. These strains were screened using bacterial morphology analysis, gram staining, spore staining, physiological and biochemical tests, gas chromatography-mass spectrometry, and agarose gel electrophoresis of polymerase chain rreaction products. Results Followed enrichment and streaking screening, 8 target bacteria were selected and designated as SY1 to SY8. Further analysis identified SY4 as Clostridium kluyverii, SY1-SY3 as Bacillus Belesenii, and SY5-SY8 as Bacillus siamicus. Subsequent cultivation revealed that the fermentation products of these 8 strains contained caproic acid, a key organic acid component that significantly influences the flavor of liquor. The results demonstrated that these 8 strains were core producers of organic acids in the aromatic substance skeleton of strong-flavor liquor. Optimal fermentation conditions for SY4 were determined to be 34 °C, initial pH 6.0, ethanol concentration 2%, fermentation time 14 days, inoculation ratio 5%, with a caproic acid yield reaching up to 10.1 g/L. In co-culture fermentation experiments, the co-culture of Aspergillus fuchsinensis produced higher levels of volatile compounds compared to pure caproic acid-producing bacterial fermentation broth, including 10 kinds of alcohols, 21 kinds of esters, 9 kinds of acids and 3 kinds of aldehydes. Conclusion These findings not only provide a scientific basis for the screening of high-yield caproic acid-producing strains and the application of co-culture fermentation to enhance the flavor of strong-flavor liquor but also offer new insights into the research and development of volatile flavor compounds in liquor.

Objective To explore the change of quality characteristics of Yunnan plateau specialty fresh Capsicum annuum L. and establish its evaluation system. Methods The 35 quality indexes of 59 samples of Yunnan plateau fresh Capsicum annuum L. were selected to determine and analyze, and the differences among the quality indexes of different samples of Capsicum annuum L. were investigated. The quality of Yunnan plateau specialty fresh Capsicum annuum L. was comprehensively evaluated by principal component analysis (PCA) and cluster analysis (CA), and the evaluation model of Yunnan plateau specialty fresh Capsicum annuum L. quality was established. Results There were significant differences in quality indexes among samples of Capsicum annuum L. (P<0.05), and the coefficient of variation of the quality indexes were different, indicating that the plateau fresh Capsicum annuum L. presented varieties between different quality attributes. PCA showed that 5 principal components represented the 35 quality indicators Capsicum annuum L., making 89.005% cumulative contribution to the total variance. Based on the CA results, indicators such as spiciness, capsaicinoids, dietary fiber, protein, soluble solids, carotenoids, amino acids and organic acids could be used to comprehensively evaluate the quality of Yunnan plateau specialty fresh Capsicum annuum L.. Conclusion Among 59 different samples of Capsicum annuum L., ‘Ca38’ has the best quality. ‘Ca55’ has the worst quality. The comprehensive evaluation method of PCA and CA can provide reference for the quality evaluation of different Capsicum annuum L. varieties, and provide the oretical basis for the breeding of special plateau Capsicum annuum L., and the development and utilization of the germplasm resources of Yunnan plateau specialty Capsicum annuum L..

Objective To explore the antioxidant capacity and enzyme inhibition activity of strong fragrance natural spices. Methods The total phenolic content in spices was determined using the Folin-phenol colorimetric method. The antioxidant activity of spices was studied using the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt (ABTS) cation radical and total antioxidant activity as indicators. Using polyphenol oxidase (PPO) and peroxidase (POD) activities as indicators, the enzyme inhibitory activity of spices was studied. Results The results showed that there was a difference in the total phenolic content among strong fragrance spices, with the highest content in Eugenia caryophyllata. Among the spices, Syzygium aromaticum, Eugenia caryophyllata, Cinnamomum loureirii, Cinnamomum burmanni and Pimenta dioica exhibited strong DPPH free radical scavenging ability. Syzygium aromaticum, Eugenia caryophyllata and Cinnamomum burmanni had strong ability to scavenge ABTS cation free radicals. The 8 types of spices, including Syzygium aromaticum, Eugenia caryophyllata, Elettaria cardamomum, Cinnamomum loureirii, Artemisia dracunculus, Cinnamomum burmanni, Pimenta dioica and Cinnamomum cassia, had a certain total antioxidant capacity. Cinnamomum cassia had the strongest inhibitory activity on PPO enzyme, while Cinnamomum burmanni had the most significant inhibitory effect on POD enzyme. The total phenolic content in spices was significantly correlated with antioxidant activity and enzyme inhibition activity. The total phenolic content was negatively correlated with the median inhibition concentration (IC₅₀) value of DPPH free radical scavenging ability, ABTS cation radical scavenging ability and inhibition of POD activity, and positively correlated with total antioxidant capacity (P<0.05, P<0.01). Conclusion Eugenia caryophyllata, Syzygium aromaticum, Cinnamomum burmanni, Cinnamomum loureirii and Cinnamomum cassia have antioxidant and enzyme inhibitory activities, and are potential natural antioxidants and browning protectants, which have the prospect of developing into healthy, efficient and economical natural antioxidants, preservatives and color protection agents.

Objective To evaluate the safety of a composite beverage made from Ganoderma leucocontextum fermented Pu-erh tea compound beverage. Methods Using the Ganoderma leucocontextum fermented Pu-erh tea compound beverage as the study subject, based on preliminary experiments and related research, the dose was set at 10000 mg/(kg·bw). The classical limit method was employed, with healthy ICR mice selected as the experimental model, and the test substance was administered via oral gavage. The experiment strictly adhered to animal ethics and welfare principles, with precise control of environmental conditions including temperature, humidity and light cycles to ensure the accuracy and reliability of the data. Results After administration of the test substance, no signs of toxicity were observed in any of the ICR mice throughout the observation period. Their behavioral activity remained normal, with glossy fur and vigorous spirits. Regular precise measurements of mouse body weight showed no significant abnormalities in growth trends, and no deaths occurred. Statistical analysis revealed that the acute oral toxicity median lethal dose (LD₅₀) values for both male and female ICR mice were greater than 10000 mg/(kg·bw), with 95% confidence intervals also exceeding 10000 mg/(kg·bw). Conclusion Based on international acute toxicity dose classification standards, the Ganoderma leucocontextum fermented Pu-erh tea compound beverage is classified as practically non-toxic. This indicates that under the experimental conditions of this study, the acute oral intake safety of this composite beverage is high, providing critical safety data support for subsequent product development and market promotion.

Objective To systematically analyze the main chemical components and evaluate the quality of Siraitia grosvenorii fruits. Methods High performance liquid chromatography (HPLC) was employed to determine mogroside V, total sugar, vitamin C, moisture and water-soluble extracts in samples of different cultivars (Yongqing 1, Bolin 3, Nongyuan B6 and Qingpi 3), supplemented with additional tests for mogroside V content to enhance data integrity. After the data were standardized, multidimensional analysis including correlation analysis, principal component analysis, and hierarchical cluster analysis was conducted to assess fruit quality. Results Certain variations were observed in different indicators of Siraitia grosvenorii fruits, with coefficients of variation ranging between 5.28% and 35.38%. Several parameter groups exhibited statistically significant correlations at P<0.05 (significant) or P<0.01 (highly significant) levels. The 3 principal components were proposed in principal component analysis, and the contribution rate of cumulative variance was 91.13%. Through hierarchical cluster analysis (squared euclidean distance 11.5), the samples were categorized into 4 distinct groups. The Siraitia grosvenorii in groups Ⅰ and Ⅱ exhibited superior comprehensive performance, while those in group Ⅳ demonstrated relatively poorer overall quality. Conclusion The classification of Siraitia grosvenorii provides a data-driven reference for its cultivation, processing and application, thereby facilitating the enhancement of its quality and practical value.

Objective To establish a method for rapid detection of nutritional components in raw milk by milk composition analyzer. Methods This study used commercial raw milk as the test sample, and based on Fourier transform infrared spectroscopy (FTIR), it constructed a rapid detection method for 9 parameters such moisture, protein, fat, lactose, ash, non-fat milk solids, total dry matter, relative density and freezing point in raw milk. The precision and accuracy of the rapid detection method were evaluated by comparing it with the national standard detection results. Results The determination results of the milk composition analyzer were as follows: Moisture 86.00%-89.09%, protein 2.52%-4.51%, fat 2.65%-5.39%, lactose 3.81%-5.40%, ash 0.56%-0.80%, and non-fat milk solids 6.94%-9.81%. F-test and T-test were performed on 9 parameters including fat, lactose and non-fat milk solids. The maximum F-value was 9.00, less than 9.55, indicating no significant difference in precision for the 9 parameters. The maximum T-value was 20.82, less than 22.327, confirming no significant difference in accuracy for the 9 parameters. Both the milk composition analyzer method and the national standard method could accurately determine milk nutritional indicators. The results showed that the precision and accuracy of the established rapid detection method had no significant differences from those of the national standard method. Conclusion The rapid detection method for nutrient components in raw milk constructed in this study can be used for high-throughput and low-cost rapid screening of nutrient components in raw milk. National standard methods should be used as the benchmark for high-precision scenarios, supervision and admission, while daily monitoring should primarily rely on rapid detection results from milk composition analyzers.

Objective To comprehensively evaluate Lentinula edodes quality using texture profile analysis (TPA) and compare characteristics across different geographical origins. Methods Using Lentinula edodes from different origins as experimental materials, the TPA model of texture analyzer was used to study the main indicators that affect the texture quality of Lentinula edodes by statistical analysis methods, at the same time, the quality of Lentinula edodes was comprehensively evaluated in combination with the nutrients of Lentinula edodes. Results Statistical analysis showed that among the 7 kinds of index parameters of Lentinula edodes detected by the texture analyzer, principal component 1 mainly included 3 indicators: Chewing ability, adhesiveness and hardness, among which the hardness had the maximum range of correlation. The 3 important indicators of principal component 1-1 in Lentinula edodes were protein, arginine and Ca, among which Ca had the maximum range of correlations. Cluster analysis of 6 important indicators yielded 3 groups of Lentinula edodes. Among them, the third group, which had relatively high values in chewiness, stickiness, hardness, protein and arginine, had a better overall quality. Conclusion This study conductes a comprehensive analysis of the quality of Lentinula edodes based on the TPA method combined with nutrients. The results show that Lentinula edodes in Chengde are good quality and relatively high nutritional content, providing a scientific basis for the further development and utilization of Lentinula edodes.

Objective To investigate the effects of zeaxanthin (Zea) on apoptosis, oxidative stress, mitochondrial dysfunction and Akt/GSK3β pathway of SH-SY5Y cells induced by tunicamycin (TM). Methods The cells were divided into 4 groups: The control, TM-induced injury (5 μg/mL TM), Zea (5 μmol/L Zea) and injury plus protection group (5 μmol/L Zea pretreatment+5 μg/mL TM co-treatment). The intracellular reactive oxygen species level was detected by flow cytometry. Mitochondrial dysfunction was analyzed by Seahorse XF cell energy metabolism instrument. The expressions of apoptosis-related proteins Bcl-2 and Bax, oxidative stress-related proteins Nrf2, Akt, p-Akt, GSK3β and p-GSK3β were determined by Western Blot. Results Zea (5 μmol/L) exerted a protective effect against apoptosis, increased the expression of the anti-apoptotic protein Bcl-2 and decreased the pro-apoptotic protein Bax/Bcl-2 ratio; alleviated cellular oxidative stress, decreased TM-induced intracellular reactive oxygen species levels, and up-regulated the expression of the antioxidant protein nuclear factor E2-related factor (Nrf2); and increased the rate of oxygen consumption of the damaged cells, enhanced proton leakage capacity and spare respiratory capacity. Endoplasmic reticulum stress (ERS) decreased Akt activity, while down-regulating the phosphorylation level of its Ser473 site, which in turn weakened the phosphorylation level of the downstream GSK3β Ser9 site, leading to an increase in GSK3β activity, and Zea exerted a mitigating effect on TM-induced changes in this pathway. Conclusion Zea significantly alleviated TM-induced endoplasmic reticulum stress injury through multiple mechanisms, with potential applications in the prevention and treatment of Alzheimer’s disease in the early pathological process.

Objective To establish a method for determination of 17 kinds of amino acids in 3 kinds of animal blood tofu products (duck, pig, sheep) by ultra performance liquid chromatography with pre-column derivatization. Methods The samples were hydrolyzed in 6 mol/L HCl for 24 h at 110 ℃. Norvaline was used as the internal standard and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate was used as the derivatizing agent. The derivative products were separated using an Acquity UPLC™BEH C₁₈ chromatographic column (2.1 mm×150 mm, 1.8 μm), with a flow rate of 0.4 mL/min. The column temperature adopted the programmed temperature rise mode, and the detection wavelength was 260 nm. The quantification of amino acids was performed using an internal standard method. Results The calibration curves of 17 kinds of amino acids showed good linearity with correlation coefficients greater than 0.999. The limits of detection were 0.06-0.14 mg/g, the limits of quantitation were 0.19-0.45 mg/g. Recoveries were in range of 85.1%-108.8%, and the relative standard deviations were within 0.3%-6.7%. The established method was adopted to determine the 3 kinds of animal blood tofu sold online respectively. The 17 kinds of amino acids were found in all products. The content of total amino acids in duck, pig, sheep blood tofu was 63.82, 95.61, 93.52 mg/g. Conclusion The 17 kinds of amino acids can be separated completely within 22 min by use of this method. The established method has good repeatability and high accuracy, and is suitable for the 17 kinds of amino acids determination in animal blood tofu.

Meat products are essential for a balanced human diet due to their high protein content, vitamins, minerals and trace elements, and their flavor is a core attribute that determines their quality and consumer preference. Different types of meat products have distinctive flavor characteristics due to differences in processing techniques. The paper introduced 4 typical types of meat products: Cured meat products, soy sauce and marinated meat products, fermented meat products, smoked meat products, etc. Under the process of curing, soy sauce and marinade, fermentation, smoking, etc., their proteins, fats and microorganisms decomposed aldehydes, ketones, esters and other volatile flavors, to form a unique flavor profile. Based on these flavor formation characteristics, traditional flavor control technology through process optimization and spice compounding to achieve flavor improvement, and modern technology with the help of molecular analysis, microbial engineering and other means to achieve precise control, aimed to provide a reference for future research on the molecular mechanism of flavor formation of typical meat products, multi-omics linkage technology development and other fields, and to further promote the enhancement of the flavor and quality of meat products and sustainable development of the industry.