To obtain high quality co-precipitated dual proteins with desirable functional properties and enhanced nutritional value, this study systematically evaluated the effects of varying dissolution pH levels (2.0, 3.0, 9.0, 10.0, and 11.0) on the nutritional and physicochemical properties of pea-grass carp dual protein (Co). Parameters including optimal precipitation pH, proximate composition, particle size, Zeta potential, protein subunit composition, amino acid profile, and digestibility were analyzed. Results indicated that the optimal precipitation pH for Co was 5.0. All Co samples prepared by the pH cycling method were identified as high-quality proteins, containing major heterologous protein subunits and a full spectrum of amino acids, with methionine content significantly higher than that of pea protein alone. Physicochemical analyses revealed that alkaline-processed Co samples (Co9, Co10, and Co11) exhibited higher α-helix and lower β-sheet ratios compared to acid-processed ones (Co2, Co3). SDS-PAGE results demonstrated that the alkaline method facilitated the enrichment of readily digestible protein fractions. Alkaline-processed Co also showed smaller particle sizes and higher absolute Zeta potential values. Nutritional profiling indicated that Co10 had a crude protein content of 86.98%, an essential-to-total amino acid ratio of 40%, and in vitro protein digestibility and corrected amino acid score of 86.16% and 1.04, respectively. These attributes support the commercial potential of Co10. In conclusion, the alkaline pH cycling method represents a promising approach for preparing pea–grass carp dual protein with superior nutritional benefits.

To investigate the microbial community structure and flavor quality of traditional Tibetan fermented milk, high-throughput sequencing and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME–GC–MS) were used to analyze the microbial diversity and volatile flavor components in traditional Tibetan fermented milk. The types and contents of organic acids were determined by liquid chromatography. The results showed that the main dominant bacterial flora in traditional Tibetan fermented milk products were Lactobacillus, Streptococcus, and Lactococcus, etc., while the main dominant fungal flora were Saccharomyces, Kluyveromyces, and Geotrichum, etc. Six organic acids were identified, including acetic acid, citric acid, lactic acid and so on, among which, lactic acid was the most abundant (6989.02 mg/L), followed by acetic acid (1047.25 mg/L). A total of 35 volatile flavor compounds were detected in the fermented milk, with esters accounting for the highest proportion (43.98%), followed by alcohols (28.98%) and acids (16.00%). The composition and concentration of volatile flavor compounds in fermented milk exhibited notable regional variations. Fermented milk from Shigatse was distinguished by pronounced fruity aromas, particularly pineapple and banana, complemented by creamy notes, which together contributed to a rich and complex flavor profile. By contrast, fermented milk from Nagqu was characterized by strong creamy aromas, nutty undertones, and a balanced sweet–sour taste, whereas fermented milk from Ali demonstrated a predominance of more intense fruity aromas. Spearman’s correlation analysis based on key odor–active compounds (odor activity value, OAV>1) revealed distinct associations between microbial taxa and flavor compounds. The bacterial genera most strongly correlated with key flavor compounds were primarily Lactobacillus, Acetobacter and Leuconostoc, while the fungal genera most closely linked to flavor development included Apiotrichum, Dipodascaceae and Pichia. This study elucidated the correlation between microbial community structure and the formation of aroma compounds in traditional Tibetan fermented milk, providing a theoretical foundation for the standardized production, targeted flavor regulation, and development of functional strains for traditional dairy products.

To develop composite probiotic fermented foods rich in γ-aminobutyric acid (GABA), this study systematically investigated the screening, biological characteristics, and probiotic potential of GABA-producing lactic acid bacteria from Badu sour bamboo shoots via methods including rapid indicator screening, 16S rDNA sequence analysis, phylogenetic analysis, and simulated gastrointestinal tract tests. Results showed that, a strain of Lactiplantibacillus plantarum SS5 with high GABA production capacity was successfully isolated. The strain exhibited a GABA synthesis activity of 0.27 mg/(h∙g _{wet cells}) through the conversion of L-glutamic acid. The strain SS5 was capable of growing within a temperature range of 20~40 ℃, with an optimal growth temperature of 30 ℃ and an optimal pH range of 6.0~7.5. Notably, the addition of 100 g/L NaCl to the MRS medium significantly inhibited its growth. Although strain SS5 exhibited certain tolerance to oxygen, microaerophilic conditions were found to be more conducive to its growth. Batch culture experiments showed that strain SS5 entered a rapid growth phase between 8~12 h post-inoculation and reached the stationary phase at 36 h. After treatment with acidic solutions, simulated gastric juice, bile salts, and simulated intestinal fluid, the survival rates of strain SS5 cells under simulated fasting conditions were determined to be 44.27%±1.19%, 70.61%±0.30%, 99.44%±0.66%, and 93.29%±0.83% respectively, and the corresponding relative specific growth rates were calculated as 127.72%±12.32%, 206.01%±5.24%, 97.28%±8.45%, and 98.61%±7.17% respectively. When using skimmed milk to simulate feeding conditions, the survival rates were determined to be 73.61%±0.52%, 74.53%±1.09%, 94.99%±0.64%, and 96.70%±0.44% respectively, and the corresponding relative specific growth rates were calculated as 150.62%±9.68%, 98.01%±2.30%, 95.77%±5.63%, and 89.61%±2.48% respectively. The results indicated that L. plantarum SS5 possessed robust GABA synthesis capabilities, excellent tolerance to gastrointestinal transit, and remarkable growth recovery potential, thereby demonstrating promising prospects for its application in the development of GABA-enriched composite probiotic fermented foods.

To investigate indigenous non-Saccharomyces yeast strains with high β-D-glucosidase activity and desirable fermentation characteristics, this study evaluated the enzymatic activity and environmental tolerance of non-Saccharomyces strains isolated from the eastern foothills of Helan Mountain. Selected strains were identified using molecular biological methods and combined with Saccharomyces cerevisiae to simulate grape juice fermentation. Microbial community dynamics were monitored during fermentation, and key oenological parameters, including sugar content, total acidity, pH, and alcohol degree, were analyzed. Aroma compounds were detected using gas chromatography-mass spectrometry (GC-MS), and data were further examined using cluster analysis (CA) and principal component analysis (PCA). It was found that four strains exhibiting high β-D-glucosidase activity and strong environmental resilience—RICNA-GM003, RICNA-GM005, RICNA-GM006, and RICNA-GM008—were identified as Hanseniaspora. Compared with pure S. cerevisiae fermentation, the use of Hanseniaspora significantly extended the fermentation cycle, improved sugar utilization, reduced alcohol levels, altered the aroma profile of the simulated wine, increased the concentrations of esters and ketones, and enhanced aroma intensity and complexity, especially in fruity and floral notes. Among the experimental groups, RICNA-GM003 combined with S. cerevisiae (RICNA-GM003+Sc) showed the longest fermentation duration, the strongest colonization ability, the most complex aroma profile, and the best overall fermentation performance. Indigenous Hanseniaspora yeasts demonstrated great potential for enhancing wine aroma complexity through mixed-culture fermentation. This study provides a foundation for developing local yeast resources and promotes wine style diversification and quality improvement.

To overcome the restricted bioactivity of konjac glucomannan (KGM) caused by its high molecular weight, KGM-degrading bacteria were isolated from konjac cultivation soil, diseased konjac tubers, and liquor fermentation systems. The probiotic potential of these strains was assessed based on acid and bile salt tolerance, resistance to simulated gastrointestinal fluids, and safety evaluations. It was found that all four isolated strains exhibited excellent KGM-degrading capability, along with high tolerance to acidic conditions, bile salts, and simulated digestive fluids, a safe profile, antibiotic sensitivity, antibacterial activity, and strong adhesion capability to human colon cancer Caco-2 cells. Through morphological and 16S rDNA analyses, strain JQ4 was identified as Bacillus halotolerans, whereas strains JZ6 and JZ8 were classified as Bacillus paralicheniforms, and RF8 was confirmed as Bacillus licheniforms. Notably, Bacillus licheniformis RF8 exhibited β-mannanase activity of 49.92±0.06 U/mL, demonstrated survival rates of 96.57%±0.27% and 82.22%±0.48% after 3 h in simulated gastric fluid (pH2.0) and 6 h in simulated intestinal fluid (pH8.0), respectively, and showed a high adhesion capability to human colon cancer Caco-2 cells of 362.76±4.31 CFU/cell. In conclusion, four Bacillus strains with both efficient KGM-degrading capacity and promising probiotic characteristics were successfully obtained. These findings provide valuable microbial resources and a theoretical foundation for the development of functional oligosaccharides and novel probiotic formulations.

In this study, Baoding Qishan yam was used as the raw material, and Lactiplantibacillus plantarum was inoculated for fermentation. With the viable count in yam powder and sensory evaluation score as indicators, the optimal fermentation parameters for fermented yam were investigated via single-factor experiments and response surface optimization experiments on fermentation process parameters. Subsequently, fermented yam was powdered by freeze-drying, spray-drying, microwave drying, and hot-air drying. The quality of probiotic yam powder prepared by the four drying methods was evaluated based on moisture content, bulk density, polysaccharide content, total polyphenol content, total flavonoid content, viable count, and starch digestibility, so as to select the most suitable method for drying and powdering of fermented yam. The results showed that the optimal preparation process for fermented yam was determined as follows: Inoculum size of 2%, fermentation time of 48 h, and fermentation temperature of 37 ℃. Under these conditions, the highest viable count and the highest sensory evaluation score in fermented yam were achieved, which were 9.07 lg (CFU/mL) and 91.36 points, respectively. Probiotic fermentation could significantly increase the contents of polysaccharides, total polyphenols, total flavonoids, and resistant starch (RS) in yam powder (P<0.05), while significantly (P<0.05) reduced the content of rapidly digestible starch (RDS). The quality of yam powder prepared by freeze-drying was the best, followed by that prepared by spray-drying. Although yam powder prepared by microwave drying had the highest total polyphenol and total flavonoid contents, it severely reduced the polysaccharide content in yam. Microwave drying and hot-air drying, while drying the samples, killed a large number of probiotics in yam powder, thus reducing the quality of the final product. These results suggested that probiotic-fermented yam could significantly improve the quality of yam, and among the four drying methods, freeze-drying and spray-drying were more suitable for the preparation of probiotic yam powder compared with microwave drying and hot-air drying.

This study aimed to investigate the effects of different concentrations (0, 0.06, 0.08, 0.10, 0.12, 0.14, 0.16 g/mL) of corn starch (CS) on the 3D printing accuracy of tremella polysaccharide-egg white protein (TFP-EWP) composite gels, as well as the influence of varying microwave vacuum freeze-drying times (0, 20, 40, 60, 80, 100, 120 and 140 min) on the solidification properties of the printed products. TFP-EWP-CS gels with different CS concentrations were used as the raw material, and the printing accuracy of the products was characterized. Microwave vacuum freeze-drying was applied as the drying method, and the products were systematically evaluated for moisture content, drying rate, geometric shape, texture, color difference, and moisture distribution. The results indicated that at a CS concentration of 0.12 g/mL, the 3D printing deviation of the TFP-EWP-CS composite gel was the lowest, with a deviation value of 0.75%. As the drying time increased, the proportion of free water significantly decreased, while some weakly bound water converted to free water and subsequently evaporated, leading to a decline in both moisture content and drying rate. During the processing times of 20, 40, 60 and 80 min, the shape of the printed products remained relatively stable, with a solidification fidelity greater than 90%; However, both the diameter and height significantly decreased (P<0.05). Surface cracking was observed at 100 min of drying. As drying time increased, the hardness, adhesiveness, and chewiness of the products significantly enhanced, while the microwave vacuum freeze-drying treatment increased the whiteness and reduced the yellowness of the products (P<0.05). In conclusion, this study provides valuable references for optimizing the drying process of TFP-EWP-CS composite gel printing products.

Objective: This study aimed to develop a functional beverage using turnip (Brassica rapa) and sea buckthorn (Hippophae rhamnoides), which were traditional medicinal and edible plants, and to investigate its ameliorative effect and potential mechanisms against hypoxia-induced injury. Methods: The formulation of the turnip-sea buckthorn compound beverage was optimized using single-factor experiments and response surface methodology. After optimization, mouse models of normobaric hypoxia and sodium nitrite poisoning were established. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and the level of malondialdehyde (MDA) in heart, brain, and lung tissues were measured. Hematoxylin-eosin (HE) staining and Western blot analysis were performed to assess the expression levels of hypoxia-inducible factor-1α (HIF-1α) and interleukin-6 (IL-6). Results: The optimal formulation was determined to be 22.0% sea buckthorn juice, 1.0% turnip extract, 7.5% high-fructose syrup, and 0.1% citric acid, which yielded a sensory score of 80.5±1.3. The physicochemical indices (including soluble solids at 8.00%, total sugar at 9.12%, and total acid at 3.31 g/L) all complied with relevant national standards. In animal studies, administration of the low-, medium-, and high-dose groups (8.45, 16.90, and 33.80 g/kg·d, respectively) resulted in a significant extension of survival time under normobaric hypoxia by 19.92%, 19.31%, and 18.97% (P<0.05), respectively. Concurrently, the beverage treatment enhanced the activities of antioxidant enzymes (SOD, CAT, and GSH-Px) while reducing the MDA content in the heart, brain, and lung tissues. Western blot analysis further revealed that the compound beverage ameliorated oxidative stress and modulated the energy metabolism pathway via the suppression of HIF-1α protein expression and IL-6 release. Conclusion: The optimized turnip-sea buckthorn compound beverage effectively improved hypoxia tolerance. The underlying mechanism may be associated with the enhancement of antioxidant capacity and inhibition of the HIF-1α/IL-6 inflammatory pathway. These findings provide a theoretical basis for the development of functional foods aimed at mitigating hypoxia-induced damage.

This study isolated and characterized bioactive peptides with dipeptidyl peptidase-IV (DPP-IV) inhibitory activity from walnut protein hydrolysates. The hydrolysis process was optimized using response surface methodology with alkaline protease, yielding optimal conditions as follows: Substrate concentration 2.23% (w/v), enzyme dose 9100 U/g, and hydrolysis time 180 min. Under these conditions, the degree of hydrolysis reached 25.47%, and the DPP-IV inhibition rate was 77.85%. The hydrolysate was further separated, purified, and characterized. The fraction with molecular weight <3 kDa (U1) demonstrated the strongest DPP-IV inhibitory activity (IC₅₀=2.81 mg/mL). Subsequent purification of U1 by Sephadex C-25 column chromatography yielded two sub-fractions (F1 and F2), with F2 exhibiting superior activity. A total of 6557 peptides were identified, and five potential hypoglycemic peptides were screened via in silico approaches. Among these, the peptide KFPF showed the highest DPP-IV inhibitory activity (IC₅₀=0.26 mg/mL). Molecular docking simulations revealed that KFPF binds to DPP-IV via six hydrogen bonds and ten hydrophobic interactions. In vitro assays indicated that KFPF acts as a competitive inhibitor. Furthermore, secondary structure analysis by infrared spectroscopy suggested a high content of β-turn (82.03%) and α-helix (15.18%), implying a possible correlation between these structural features and DPP-IV inhibition. These findings demonstrated that KFPF derived from walnut protein has potential as a functional dietary component for blood glucose management.

To promote the high-value utilization of wheat bran, soluble dietary fiber (SDF) was extracted using an enzyme-acid synergistic method. A combination of single-factor and orthogonal experimental designs was used to optimize the extraction process. Subsequently, the functional properties of the SDF, were systematically evaluated, including its water-holding, oil-holding and swelling capacities, as well as its binding capacities for cholate, nitrite, and glucose. Moreover, this study employed an in vitro simulated digestion model to analyze its regulatory effect on digestive resistance and its impact on starch digestion behavior. Guided by these findings, the SDF served as the core functional ingredient for a high-fiber beverage, with formulation optimization via single-factor and orthogonal testing, validation, and a 14-day storage stability assessment. The results showed the optimal extraction parameters of SDF to be pH2.0, 100 ℃, and 2 h, yielding 18.40%±0.78%. The obtained SDF exhibited water-holding, oil-holding, and swelling capacities of 7.35 g/g, 5.40 g/g, and 5.89 mL/g, respectively; The binding rates for sodium glycocholate and sodium taurocholate were determined to be 15.85% and 18.14%, respectively; The nitrite and glucose binding capacities reached 43.80 μg/g and 0.9 mmol/g, respectively. Moreover, the SDF effectively delayed glucose diffusion by 88%, inhibited starch gelatinization, increased resistant starch (RS) content by 20%, and maintained its structural stability under simulated gastrointestinal conditions. The beverage optimization results indicated that the optimal formulation comprised a 1:1.5 (v/v) tea liquid to water ratio, supplemented with 8% (m/v) xylitol, 0.06% (m/v) citric acid, and 0.25% (m/v) SDF. In validation test, this formulation achieved a sensory evaluation score of 93±0.21 points. After 14 days of storage, the sedimentation rate remained below 5%, and the pH stayed stable, ranging from 3.52 to 3.91, indicating that the beverage exhibited excellent sensory property and storage stability. This study not only provided validated process parameters and technical support for the industrial production of wheat bran SDF, but also elucidated its functional properties in regulating glucose and lipid metabolism as well as modifying starch digestion characteristics. These findings demonstrate that the potential of wheat bran SDF as a functional food ingredient for regulating blood glucose and modulating glucose-lipid metabolism.