Zein, the main storage protein of corn, exhibits limited applications in the food industry due to its poor solubility. To enhance the solubility of zein and improve its functional properties, ultrasound-assisted Maillard reaction was performed to prepare zein-dextran (Dex) conjugates with zein and Dex as substrates in this study. The Maillard reaction conditions were optimized using response surface test based on single factor experiments. The effect of ultrasonic time on the structural and functional properties of Maillard reaction products was also investigated. The results showed that the optimal conditions for ultrasound-assisted Maillard reaction were as follows: ultrasonic power 250 W, ultrasonic temperature 65 ℃, ratio of sugar to protein 2:1 (w/w), protein concentration 2% (w/v), ultrasonic time 2 h, and degree of glycosylation 23.33%±0.58%. With an increase of ultrasonic time, the accumulation of intermediate products and the degree of browning significantly increased (P<0.05) and the blue shift of absorption peaks in the amide I, II, and III regions in Fourier-transform infrared spectra confirmed the successful preparation of zein-Dex conjugates. Scanning electron microscopy revealed the microstructure of zein before and after the Maillard reaction transformed from an initially smooth and flat surface to a honeycomb-like porous structure. The Maillard reaction induced the fluorescence quenching in both intrinsic and synchronous fluorescence spectra of zein and the increased intensity of characteristic absorption peaks of its ultraviolet absorption spectra. The results indicated that the Maillard reaction changed the molecular conformation of zein. At 2 hours of ultrasonic heating treatment, the solubility, emulsifying activity, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate were increased by 4.89-fold, 5.17-fold, and 3.17-fold, respectively (P<0.05). The reducing power was enhanced by 23% (P<0.05) and the foaming capacity was also improved to a certain extent (P<0.05). This study confirms that ultrasound-assisted Maillard reaction can effectively improve the solubility and functional properties of zein and provides a theoretical basis for its application in the food industry.

To address the problems of quality deterioration and taste decline associated with traditional high-temperature processing of ready-to-eat chicken liver, this study employed sous-vide technology to improve product quality. The effects of processing parameters on the quality characteristics and microstructure of chicken liver were systematically investigated. Particularly, the influence of different sous-vide durations (40, 45, 50, 55, and 60 min) at 80 °C on various quality indicators, including cooking loss, moisture content, water activity, color, pH, shear force, texture characteristics, electronic nose analysis, secondary structure, microstructure, and sensory attributes was examined. The results demonstrated that with increasing cooking time, the cooking loss and pH of chicken liver samples in the sous-vide group increased significantly, whereas the moisture content, water activity, and L^* and a^* values decreased significantly (P<0.05). The tenderness of the chicken liver initially decreased and then increased, whereas texture characteristics and sensory scores first increased and then decreased with extended processing time (P<0.05). Compared with the control group, the optimal processing time was determined to be 55 min, yielding the best overall quality. Fourier-transform infrared (FTIR) spectroscopy revealed that the secondary protein structure shifted from α-helix to β-sheet with longer processing times (P<0.05). Furthermore, an appropriate sous-vide duration (55 min) promoted a more orderly and compact reticular microstructure in the chicken liver. In conclusion, the optimal sous-vide process for ready-to-eat chicken liver, at 80 °C for 55 min. This paper provides certain technical support for the industrial production and quality improvement of low-temperature ready-to-eat chicken liver, and provides a new direction for the comprehensive utilization of livestock and poultry by-products.

This study systematically investigated the effects of different cooking-reheating combinations (steaming, roasting, frying coupled with water bath or microwave reheating) on the nutritional and oxidative profiles of chicken breast using orthogonal partial least squares discriminant analysis (OPLS-DA). Results demonstrated that frying significantly elevated thiobarbituric acid reactive substances (TBARS) levels compared to steaming and roasting (P<0.05), accompanied by reduced α-helix and increased β-sheet content in proteins. Fried samples exhibited lower vitamin E loss (12.90%~27.96%) and retained higher levels of key fatty acids, including C18:1n-9c, C18:2n-6c, C20:0, C18:3n-6, C18:3n-3, C22:0, C23:0, and C20:5n-3 (P<0.05). In contrast, steamed and roasted samples showed superior protein content, vitamin B₆ retention, and elevated levels of C12:0 and C20:1 fatty acids, alongside higher protein carbonyls and lower free sulfhydryl groups versus fried samples (P<0.05). Regarding reheating, microwave synergistic steam or roast reheated samples displayed significantly higher ratios of essential to total amino acids (EAA/TAA), essential to non-essential amino acids (EAA/NEAA), polyunsaturated to saturated fatty acids (PUFA/SFA), and greater retention of vitamins B₁, B₆, and E compared to water bath-reheated counterparts (P<0.05). Conversely, fried chicken breast retained higher nutritional quality when reheated via a water bath. Collectively, frying better preserves fatty acids and fat-soluble vitamins, while steaming and roasting favor protein integrity, water-soluble vitamins, and stable saturated/monounsaturated fatty acids. From the perspective of preserving key nutritional components, microwave reheating is recommended for steamed or roasted chicken breast, whereas water bath reheating optimizes fried samples. These findings elucidate the nutritional and oxidative dynamics during cooking-reheating processes, offering science-based insights that will enlighten and inform professionals about healthier dietary practices.

Objective: This study focused on the Lactiplantibacillus plantarum WCFS1 strain to investigate the structure–function relationship of its exopolysaccharide (EPS) biosynthesis gene clusters (cps), thereby laying the foundation for further research into strain-specific characteristics of lactic acid bacteria EPS. Methods: Mutant strains WCFS1∆cps1-3 and WCFS1∆cps4 were constructed using Cre-loxP homologous recombination and CRISPR/Cas9 techniques. The growth characteristics, EPS yield, and monosaccharide composition of the mutant strains were analyzed using the wild-type strain as a control. Transcriptomic analysis was performed to examine the functional roles of differentially expressed genes in the WCFS1∆cps1-3 mutant under three distinct culture conditions. Results: The WCFS1∆cps4 mutant exhibited a greater reduction in EPS yield, dropping to 62.2% of the wild-type level. This was accompanied by slow growth, with the time to reach the stationary phase delayed from 12 h to 32 h. However, biomass remained unaffected. The monosaccharide composition of EPS showed significant changes in the WCFS1∆cps1-3 mutant, with mannose content increasing markedly to 32.68% and galactose content decreasing significantly to 3.83%, while rhamnose was undetectable. The number of significantly differentially expressed genes in the WCFS1∆cps1-3 mutant compared to that in the wild-type strain under varying culture conditions accounted for only 5.1% (upregulated) and 6.8% (downregulated) of those observed under MRS culture conditions, with GO and KEGG analyses revealing substantial functional differences. Conclusion: The structure–function relationships of the cps clusters in the WCFS1 strain varied. The highly conserved cps4 cluster might regulate EPS yield to ensure normal bacterial growth. However, the cps1-3 cluster likely modulated the monosaccharide composition of EPS, conferring greater environmental adaptability to the strain.

This study aimed to enhance the utility of the wheat aleurone layer through solid-state fermentation using Agrocybe aegerita. The investigation monitored the dynamic changes in cellulase activities, including filter paper enzyme, endoglucanase, and β-glucosidase, as well as xylanase, laccase, feruloyl esterase, and amylase activities. The contents of reducing sugars, soluble pentosans, and total phenolics were also monitored throughout the fermentation process. The antioxidant capacity of the fermented aleurone layer was evaluated. The data revealed that filter paper enzyme and endoglucanase activities peaked on day 15, with values of 3.32 U/g and 5.93 U/g respectively, before gradually declining. In contrast, β-glucosidase and xylanase activities reached their peaks on day 18, with figures of 3.27 U/g and 10.00 U/g respectively. Compared to unfermented aleurone layer, the contents of reducing sugars, soluble pentosans, and free phenolics showed significant increases of 374.22%, 162.53%, and 34.90% respectively (P<0.05). The fermented substrate also exhibited improved DPPH·and ABTS⁺· scavenging capacities, with increases of 70.06% and 35.50%, respectively. These findings indicate that Agrocybe aegerita successfully established a stable mycelial network on the aleurone layer, efficiently utilizing carbon and nitrogen sources for growth. Moreover, SSF enhanced the antioxidant capacity of the wheat aleurone layer, providing theoretical insights into fungal fermentation-based modifications and high-value utilization of this by-product.

Urea was the main precursor substance of the carcinogenic ethyl carbamate in the production of Baijiu. In this study, urea-degrading microbiota was revealed in the fermented grains from different fermentation cellars of the same brewing enterprise, by Illumina NovaSeq high-throughput sequencing combined with bioinformatics and the correlation analysis between the microbiota and urea. The results showed that the urea content of six fermented grains ranged from 60.89 to 73.29 mg/kg, and significant negative relations between urea content and Brevibacterium (rho=−0.7591), Streptococcus (rho=−0.7969), Veillonella (rho=−0.8522), and Pseudomonas (rho=−0.8023) were observed by pearson correlation analysis. Furthermore, the function of bacterial microbiota in these fermented grains was mainly reflected in Metabolism, which occupied relative abundance of 80.59% by PICRUSt2 analysis. Notably, the relative abundances of carbohydrate metabolism and amino acid metabolism associated with urea degradation and urea cycle were 15.95% and 14.70%, respectively. Meanwhile, above four genera were positively correlated with urease (EC: 3.5.1.5), and the key enzymes including argininosuccinate synthetase (EC: 6.3.4.5), argininosuccinate lyase (EC: 4.3.2.1), and ornithine transcarbamylase (EC: 2.1.3.3) related to the urea cycle were negatively correlated with these genera by pearson correlation analysis, which showed potential of these genera for urea degradation. Based on this, a strain capable of effectively degrading urea was isolated from the fermented grains, and preliminarily identified as Brevibacterium linens by molecular biology, and the preserved strain has been registered in the China Typical Culture Repository. Taken together, unveiling the urea-degrading bacteria in fermented grains could provide a theoretical foundation for urea and ethyl carbamate reduction in Baijiu fermentation by bioaugmentation.

Mixed fermentation has exhibited great potential in improving flavor quality of wine and fruit wine. To reveal the competitive utilization of amino acids by different yeasts and their effects on key aroma production in mixed fermentation, this study used Saccharomyces cerevisiae and Hanseniaspora osmophila as research subjects, prepared simulated grape juice as the fermentation medium model. Single and mixed fermentations were conducted to assess fermentation activity, cell growth, amino acid consumption, and aroma production. Mixed fermentations included two modalities (simultaneous and sequential inoculation), each yeast was inoculated at a cell concentration of 2×10⁶ CFU/mL, and the inoculation ratio was 1:1. In sequential fermentation, H. osmophila was inoculated firstly, and S. cerevisiae was inoculated after 48 h. Results showed that both S. cerevisiae and H. osmophila preferentially consumed most amino acids, while the former exhibited higher uptake rates. In sequential fermentation, H. osmophila consumed key amino acids (alanine, aspartic acid, glutamic acid, threonine and serine) related to cell growth, which significantly reduced the maximum biomass of S. cerevisiae (−33%, P<0.05) subsequently inoculated, and induced fermentation delays. S. cerevisiae dominated amino acid utilization in simultaneous fermentation, leading to a similar production of aroma compounds compared to single S. cerevisiae fermentation. Aroma production in sequential fermentation was conditioned by amino acid competition between two yeasts. In sequential fermentation, early utilization of amino acids by H. osmophila induced the production of higher alcohol acetates (particularly 2-phenylethyl acetate, whose OAV was increased by 15-fold), and high productivity of fatty acid ethyl esters in S. cerevisiae was also retained. This study characterized the competitive utilization of amino acids and key aroma production in mixed fermentation, providing a scientific basis for improving fermentation stability and aroma-enhancing efficiency of mixed fermentation through exogenous supplementation of key amino acids.

To understand the microbial differences in traditional and industrial production of Northeast soybean paste and identify potential risk microorganisms, this study analyzed the microbial communities in Northeast soybean paste that are produced traditionally and commercially. The bacterial 16S rDNA V3-V4 region (338F/806R) and fungal ITS1 region (ITS1F/ITS2R) were amplified and sequenced using Illumina PE300 sequencer followed by bioinformatics analysis. The results revealed that in the traditionally produced soybean paste, the abundance of bacteria such as Lactobacillus, Tetragenococcus, and Bacillus, and fungi such as Aspergillus, Penicillium, Candida, and Trichosporon were relatively high. Among these, potential risk microorganisms such as Enterobacteriaceae and Staphylococcus were present. There were significant differences in the abundance of high-abundance bacteria like Leuconostoc and fungi like Sterigmatomyces and Fusarium between different soybean pastes that are family-produced. In commercially produced soybean paste, the high-abundance bacteria were Lactobacillus, while the predominant fungus was Aspergillus, albeit with a less diverse microbiota. The differences in microbial community and metabolic functions between traditional and commercial production processes were evident. Functional prediction analysis using PICRUSt2 revealed that traditional soybean paste had higher gene expressions in functions related to glycolysis, gluconeogenesis, glycerol metabolism, organic acid conversion, protein phosphorylation, purine metabolism, and acetaldehyde acid cycle. In contrast, commercial soybean pastes showed higher expressions in protein degradation and amino acid metabolism, which explains why traditional soybean paste has a better flavor, while industrial soybean paste has more stable flavor and shorter production cycle. Comparison with a self-constructed full-length 16S rDNA gene database of pathogens revealed that the biosafety of commercially produced soybean paste is better, while traditional soybean paste may contain more pathogens such as Vibrio vulnificus, Staphylococcus aureus, and Clostridium perfringens. This indicates that during the fermentation of traditional soybean paste, there may be a risk of insufficient control for anaerobic environment, raw material, or hygiene level in the processing stages, leading to the proliferation of toxin-producing strains. Commercial production have a significant advantage in controlling potential risk bacteria. This study provides scientific evidence for optimizing soybean paste production processes, improving product quality, and ensuring food safety.

Objective: The study aimed to develop a nutritionally rich Eucommia ulmoides leaf micro-powder shortbread biscuit with enhanced taste and unique flavor to cater to the demand in the health food market. Methods: Fuzzy mathematical comprehensive evaluation method and response surface test were used to optimise the biscuit formulation, and the optimal process formulation and baking conditions were determined using 100 g of low gluten flour as the benchmark. The superiority of the formulations was verified through multidimensional comparative analyses of sensory evaluation, textural properties, microstructure, nutrients, antioxidant capacity and volatile flavour substances. Results: Comparative analysis with a blank formulation (lacking Eucommia ulmoides leaf micro-powder) revealed that the optimized formulation exhibited significantly improved sensory evaluation, enhanced textural attributes including hardness, crispness, and chewiness, a notably higher porosity of 50.91%±0.71%, a reduced spreading ratio of 4.99±0.12, and decreased baking loss of 18.94%±0.23%. The nutrient composition analysis revealed an increase in total flavonoid content from 5.03±0.07 mg/mL to 6.61±0.03 mg/mL, total phenol content from 0.64±0.02 mg/g to 1.53±0.03 mg/g, and sodium cholate adsorption capacity from 16.06±0.48 mg/g to 21.17±0.53 mg/g. Furthermore, enhancements were observed in DPPH, ABTS⁺, hydroxyl radical scavenging, and ferric ion reduction capacities (P<0.05). The optimized biscuits exhibited elevated levels of volatile flavor compounds such as alcohols and ketones, contributing to a more balanced and harmonious flavor profile. Conclusion: Eucommia ulmoides leaf micro-powder can effectively enhance the textural properties, antioxidant properties and flavour of shortbread biscuits under the optimized process formulation and baking conditions.

To investigate the desirable purification process of ponkan Chenpi flavonoids (PCf) and their in vitro antioxidant and hypoglycemic activities, this study extracted PCf using ultrasound-assisted solvent extraction. Four types of macroporous resins were evaluated for their static adsorption-desorption efficiency toward PCf, and HPD-500 resin was identified as the optimal carrier. Single-factor experiments were subsequently conducted to optimize the purification parameters. The antioxidant activity of PCf (before and after purification) were assessed using DPPH radical scavenging rate, ABTS⁺ radical scavenging rate, and ferric ion reducing capacity. The α-glucosidase inhibitory activity was evaluated. Results demonstrated that HPD-500 resin achieved the highest purification efficiency for PCf under optimized conditions: 2 of pH, 80% ethanol concentration, sample loading flow rate of 4 mL/min, elution flow rate of 3 mL/min, and a sample-to-eluent volume ratio of 1:1.6. Post-purification, the reducing sugar content of PCf was significantly reduced, while the total flavonoid content increased (132.2±9.62 mg RE/g DW). Purified PCf exhibited stronger antioxidant and hypoglycemic activities, with 93.75%±0.82% of ABTS⁺ radical scavenging rate reaching, 77.42%±0.91% of DPPH radical scavenging rate, double ferric ion reducing capacity, and 66.84%±0.67% of α-glucosidase inhibitory rate. In summary, HPD-500 resin is suitable for the preliminary separation and purification of ponkan Chenpi flavonoids, and the purified substance demonstrates significant antioxidant activity and inhibitory effect of α-glucosidase, providing a valuable reference for the further development of ponkan Chenpi-based functional products.