Objective To establish an analytical method for the determination of selenium content in beef and offal (beef heart, beef liver, beef lung) using microwave digestion-hydride atomic fluorescence spectrometry (HG-AFS). Methods Based on 2 factors, namely the feeding amount and feeding time of the cattle, 80 simmental bulls weighing around 500 kg (±10 kg) were selected and randomly divided into 4 groups: A, B, C and D. Groups A, B and C served as experimental groups, while group D was the control group, with 20 cattle in each group. Selenium in beef and offal samples was digested using a nitric acid-hydrogen peroxide (HNO₃-H₂O₂) microwave digestion method, with potassium borohydride as the reducing agent and 10% hydrochloric acid as the carrier stream, at a digestion temperature of 190 ℃. Results Selenium exhibited a good linear relationship within the mass concentration range of 0-20 ng/mL, with a correlation coefficient (r)>0.999. The average spike recovery rates (n=3) for samples A, B, C and D were 86.9%, 82.4%, 87.9% and 83.8%, respectively. Conclusion This study provides data support and a reference basis for the determination of selenium content in selenium-enriched cattle products and the development of selenium-enriched functional agriculture.

Objective To develop a method for analysis of 20 kinds of macrolides and lincomasides in mutton by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods Samples were initially extracted with acetonitrile, and the supernatant was concentrated to near dryness. The residues were further extracted with 50% methanol, and the 2 extracts were combined and diluted with a weak alkaline buffer solution (pH 8.0). The mixture was then concentrated and purified using an HLB solid-phase extraction cartridge. A methanol/5 mmol/L ammonium acetate solution (1:1, V:V) was used for final dilution. Detection was performed in positive ion multiple reaction monitoring mode. A matrix-matched standard curve was prepared for quantification. Chromatographic and mass spectrometry parameters were optimized for the 20 kinds of target compounds, while the effects of different mobile phases, extraction solvents, and purification methods on extraction efficiency and purification quality were thoroughly investigated. Results The 20 kinds of macrolides and lincomasides demonstrated excellent linearity within their respective ranges, with correlation coefficients (r²) exceeding 0.999. Recoveries ranged from 64.7% to 94.2%, the relative standard deviation was between 3.8% and 11.0%. Conclusion The developed method is sensitive, accurate, and suitable for the simultaneous detection of 20 kinds of macrolides and lincomasides in mutton.

Objective To process, annotate and analyze the genomic data of the high temperature resistant Bacillus amyloliticus BA-DES4 by biological software and databases, and to functionally annotate the strain characteristics at the gene level. Methods Metabolic signaling pathways were analyzed by metabolic signaling pathways kyoto encyclopedia of genes and genomes (KEGG) and gene ontology (GO), clusters of orthologous groups of proteins (COG), non-redundant protein (NR) database, etc., which were compared with the predicted gene sequences to obtain the gene function annotation table. The protein sequences of the predicted genes were compared with COG, KEGG and GO databases for BLASTP analysis, to realize the prediction of gene annotation information and function prediction. Results The database analysis showed that the number of bases was 4188731, and the GC content accounted for 46.18%. There were 4445 protein genes, with a total length of 3696380 bp. Functional annotation of genomic protein coding genes showed that the highest proportion of COG-annotated genes was for G (carbohydrate transport and metabolism), followed by K (transcription), which indicated that protein genes encoded in the COG database were mainly involved in the basic cellular function. The GO annotation revealed that the predominant gene types and genes were classified under biological processes. The carbohydrate-active enzymes (CAZy) annotation identified hydrolytic enzymes as the most prevalent category. The KEGG annotation showed that carbohydrate metabolism accounted for the highest number of genes. In the environmental information category, information transduction emerged as the most significant percentage. In the high-temperature resistant Bacillus amyloliticus BA-DES4, 11 genes were found to encode cellulases, with β-glucosidase and endoglucanase being the genes encoding enzymes. Conclusion In this study, the genomic data of Bacillus amyloliticus BA-DES4 is processed, annotated and analysed in order to further explore the research potential of the strain, to better investigate the regulatory mechanism of cellulose production in Bacillus amyloliticus BA-DES4 and to provide a theoretical basis for subsequent experiments.

Objective To optimize the fermentation process with fresh Capsicum annuum L. as raw materials using Lactiplantibacillus plantarum L. and analyze the quality of fermented Capsicum annuum L. under the optimized conditions. Methods Using single factor and orthogonal experiments, the fermentation parameter of fermented Capsicum annuum L. inoculated with lactic acid bacteria were optimized and verified for the optimized fermentation condition. The changes of total acid, reducing sugar, nitrite content, and volatile substances were studied during the fermentation process of Capsicum annuum L. under the condition of the optimal parameters. By comparative analysis, the quality characteristics of strongly fermented Capsicum annuum L. were obtained. Results Under the condition of optimized fermentation parameters (fermentation temperature 35 ℃; fermentation time 10 d; lactic acid bacteria addition 4%; salt addition 4%), fermented Capsicum annuum L. showed sensory scores of 83.00±0.16, pH 3.38±0.02, total acid content of (15.55±0.24) g/kg, L^* of 36.76±0.82, a^* of 22.45±0.65, b^* of 4.04±0.43, and soluble solid substance of (13.07±0.03)%. Lactic acid and malic acid were the main organic acids of fermented Capsicum annuum L., and their contents were (1.9611±0.0800) mg/mL and (1.8600±0.1000) mg/mL, respectively. The flavor substances mainly included acids, esters, ketones, alcohols, and hydrocarbons. Among them, acids accounted for 65.45% of the relative content of total flavor substances. Conclusion Fermentation with lactic acid bacterium strain can enhance brightly fresh redness, crisp, rich aroma, suitable acidity, uniform texture and excellent taste, which are widely accepted by consumers.

Objective To understand the contamination level of glycidyl esters (GE) in edible vegetable oils and to evaluate the dietary exposure risk of GE in Shanghai residents. Methods Based on the monitoring data of GE in edible vegetable oil sold in Shanghai in 2024, combined with the vegetable oil consumption data of Shanghai residents in 2024, the GE exposure of Shanghai residents via vegetable oil was calculated by simple distribution assessment method, and the margin of exposure (MOE) method was used to assess the health risk. Results The detection rate of GE in 178 edible vegetable oils was 94.4%, with an average content of 360.8 μg/kg and a maximum value of 5470.0 μg/kg. According to the EU regulations on the limit values of GE in vegetable oils, it was found that the exceeding standard rate of GE in vegetable oil was 5.6%. The mean content of GE in rice oil (1169.3 μg/kg) was the highest, followed by camellia seed oil (657.8 μg/kg) and corn oil (499.0 μg/kg). The mean daily exposure and 95th percentile exposure of GE from edible vegetable oils in Shanghai residents aged ≥3 years old were 0.208 and 0.497 μg/kg bw, the MOE values were 11538 and 4829, respectively, and P₉₅ MOE was less than 10000. The mean MOE value of GE exposure through vegetable oil in residents aged 3 to 17 years old was less than 10000. The P₉₅ MOE values of GE exposure through vegetable oil in 4 different age groups were all less than 10000. Conclusion The health risk of GE intake via edible vegetable oil in Shanghai residents is generally at an acceptable level. However, the health risks of GE exposure for individuals aged 3 to 17 year old and those with high consumption of vegetable oil still need to be focused.

Objective To compare the taste characteristics, physical and chemical indicators of preserved mustards samples in market, and statistically analyze the correlation between taste quality and physical and chemical indicators. Methods The 22 samples of preserved mustards from Zhejiang, Sichuan and Hunan were collected, and the taste characteristics of preserved mustards were analyzed by artificial sensory evaluation and electronic tongue, the physical and chemical indicators such as moisture content, total acid, amino acid nitrogen, trichloroacetic acid (TCA) soluble peptides, nitrite, and reducing sugar content were analyzed. Results The saltiness and umami of preserved mustards were prominent, and the acidity intensity of different preserved mustards varied greatly. Umami was significantly negatively correlated with sourness and saltiness (P<0.01), and significantly negatively correlated with bitter aftertaste (P<0.05). Water content had a great influence on the taste quality of preserved mustards, and was significantly positively correlated with the taste (P<0.05). The salt content was significantly negatively correlated with the total acid content (P<0.01). Conclusion The taste characteristics and physical and chemical indexes of different preserved mustards samples are very different, and some preserved mustards have high salt content, so it is necessary to establish quality standards; the taste quality and physical and chemical indexes of preserved mustards from different origins does not show obvious regional characteristics; there is a negative correlation between the indexes of carbohydrate fermentation products and protein fermentation products in preserved mustards.

Objective To investigate the uric acid-lowering effects of compound postbiotic powder in hyperuricemia. Methods In vitro experiments verified that the metabiotic powder had 2 kinds of effects: Inhibiting xanthine oxidase (XOD) activity and degrading uric acid, and then establishing a rat hyperuricemia model, and giving postbiotic powder treatment, respectively, the changes in body weight, joint growth, serum uric acid (UA) content, serum XOD activity, liver and kidney function, and total cholesterol (TC) in blood lipids, triglyceride (TG) level were compared. Results The sample significantly reduced the serum UA content, serum urea nitrogen (BUN), creatinine (Cr) and TC levels in rats with hyperuricemia. It could effectively reduce the activities of serum XOD, aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Conclusion Postbiotic powder has the effect of lowering uric acid, and also has a certain therapeutic effect on liver and kidney injury and dyslipidemia caused by hyperuricemia, and the therapeutic effect is positively correlated with the intake of postbiotic powder.

Objective To elucidate the effects of flower of Changshan-huyou on the aroma profile of black tea. Methods This study employed solid phase microextraction-gas chromatography-tandem mass spectrometry (SPME-GC-MS) to differentially analyze the aroma components of flower of Changshan-huyou, Jiukeng black tea, and the derived Changshan-huyou scented tea. Results A total of 186 volatile compounds were identified in this paper, with 92, 78 and 67 kinds of volatile compounds detected in flower of Changshan-huyou, Jiukeng black tea and Changshan-huyou scented tea, respectively. The volatile composition of flower of Changshan-huyou was mainly characterised by alcohols and alkenes, whereas the volatile profiles of Jiukeng black tea and Changshan-huyou scented tea were mainly alcohol-rich. Nerolidol and linalool were found to be the predominant aroma components in Changshan-huyou scented tea, imparting a pronounced flora, fruity aroma and sweetness. Comparative analysis revealed an increase in alcohols and a concomitant decrease in alkenes in Changshan-huyou scented tea compared to flower of Changshan-huyou. Conversely, an increase in alkenes and a decrease in aldehydes were observed in Changshan-huyou scented tea compared to Jiukeng black tea. In addition, 32 kinds of unique compounds were identified in Changshan-huyou scented tea, which may be due to its unique processing techniques and the specific varieties of raw materials used. Conclusion The results of this research not only substantiate the aroma signature of Changshan-huyou scented tea, but also provide insights into its quality enhancement, paving the way for standardised production and innovative development strategies.

Objective To optimize the extraction process of Chaenomeles sinensis polyphenols and study their antioxidant activity. Methods The extraction process of Chaenomeles sinensis polyphenols was optimized through single factor and orthogonal experiments; the in vitro experiments were simultaneously conducted to investigate the total reducing ability, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, and hydroxyl radical scavenging ability of Chaenomeles sinensis polyphenols. Results The optimal process for extracting polyphenols from Chaenomeles sinensis was: Ethanol volume fraction of 60%, solid-liquid ratio of 1:25 (g/mL), ultrasonic temperature of 55 ℃ and ultrasonic time of 90 min. Under these conditions, the polyphenol extraction amount was 2.22 mg/g; at a sample concentration of 1.0 mg/mL, the total reducing ability, DPPH radical scavenging rate and hydroxyl radical scavenging rate of Chaenomeles sinensis polyphenols were determined to be 2.41±0.02, 89.33%±0.24%, and 81.30%±1.27%, respectively, all higher than vitamin C at the same concentration (2.29±0.08, 86.05%±0.39%, 80.94%±0.41%), indicating that Chaenomeles sinensis polyphenols had good antioxidant activity and promising application prospects. Conclusion This study provides a reference for further research and application of polyphenols in Chaenomeles sinensis, offers new ideas for the diversified and high-value utilization of Chaenomeles sinensis resources, and provides theoretical basis for the deep processing of Chaenomeles sinensis resources and rational dietary selection.

Objective To optimize the fermentation condition of Enterococcus faecium with the capability of high-yield biogenic amine production by response surface design. Methods Based on the previous single factor experiment results, response surface methodology was used to investigate the interaction among 3 factors with different levels, namely culture temperature (10, 15, 20 ℃), initial pH (5.0, 5.5, 6.0), and sodium chloride addition (4.5%, 5.5%, 6.5%), on the production of biogenic amines by Enterococcus faecium. The fermentation condition for controlling the production of tyramine and phenethylamine by Enterococcus faecium were optimized. Results The results showed that the regression equations for the production of tyramine and phenethylamine at 48 h were obtained with R²=0.9866, adjusted R²=0.9693 for tyramine and R²=0.9875, adjusted R²=0.9714 for phenethylamine, the order of affecting the production of casein and phenethylamine was culture temperature>NaCl addition>initial pH.. The optimal fermentation condition to control the tyramine production of Enterococcus faecium was initial pH of 6.0, incubation temperature of 10.9 ℃, and NaCl addition level of 4.5%. The optimal fermentation condition to control the phenylethylamine production was initial pH of 5.34, incubation temperature of 13.8 ℃, NaCl addition level of 5.8%. Conclusion The results provide references for the effective control of the biogenic amine production of Enterococcus faecium growing in fermented food such as fermented meat products.