In order to integrate the natural biofilm of probiotics with microencapsulation technology in a synergistic manner, so as to construct a novel and synergistic probiotic protection strategy. This study aimed to select the optimal combination of bacterial strains from various prebiotic culture media based on their growth rate and ability to form biofilms. The selected strains were then used to prepare single-layer, double-layer, biofilm-like single-layer, and biofilm-like double-layer microcapsules. The protective effects of the freeze-dried microcapsules containing the selected strains on the viability of the probiotics under simulated gastrointestinal conditions and conditions of low temperature storage were investigated. The results showed that the highest growth and biofilm formation was achieved when Lactobacillus fermentum F7 and Bifidobacterium longum B22 were co-cultured in a medium containing 1.5% IMO at a 1:1 inoculation ratio. The particle size was determined to be in the range 2.29~2.45 mm for all four microcapsule types, and viable counts were recorded between 9.58~10.03 lg CFU/g. Stress tests showed that the biofilm-like bilayer microcapsules provided the strongest protection against the compound bacteria, with a survival rate of more than 93% after freeze-drying. Even after storage at −18 ℃ and 4 ℃ for 7 weeks, the viable counts were maintained above 10⁸ CFU/g in the biofilm-like bilayer microcapsules. This study lays the foundation for the development of freeze-dried biofilm-like composite probiotic microcapsules and suggests an effective protective strategy for probiotics under stressful conditions.

This study aimed to develop yak milk Emmental cheese enriched with conjugated linoleic acid (CLA) by incorporating high-CLA-converting lactic acid bacteria and to evaluate the resulting changes in cheese quality and lipid oxidation characteristics. The ripening environment of Emmental cheese was simulated to screen optimal bacterial strains for preparing a direct-to-vat set adjunct culture. Cheese with the adjunct culture served as the experimental group, while cheese without it served as the control group. At 1, 25, 50, 75, and 100 days of ripening, the microstructure, volatile compounds, lipolysis, and fatty acid composition of the cheeses were compared using sensory evaluation, scanning electron microscopy, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), Soxhlet extraction, and gas chromatography–mass spectrometry (GC-MS). Results showed that Lactobacillus fermentum S57 and Lactobacillus delbrueckii S60, with CLA conversion rates of 15.27% and 15.82%, respectively, were selected as the optimal strains. 2-Nonanone and ethyl lactate were identified as characteristic flavor compounds produced by the high-CLA-converting LAB in the experimental cheese. The casein micelles in the experimental group were finer and had larger gaps compared to those in the control group. As ripening progressed, the fat content in all cheese groups first increased and then decreased, remaining higher at 100 days than at the initial stage. Acid degree value (ADV) and thiobarbituric acid (TBA) value gradually increased with ripening time, and the TBA value of the experimental group remained below 0.5 mg/kg, without producing any off-flavor. The CLA conversion rates in cheeses made with L. fermentum S57 and L. delbrueckii S60 reached up to 6.09% and 7.06%, respectively, both higher than that of the control group. At 25, 50, and 100 days of ripening, significant differences (P<0.05) in the health promotion index were observed between the experimental and control groups, with the experimental group showing a higher level of health promotion. Therefore, the application of high-CLA-converting lactic acid bacteria in yak milk Emmental cheese improves cheese quality and enhances lipid oxidation profiles, indicating promising potential for development and application.

To enhance the quality of Cyperus esculentus L. and diversify its product range while promoting multi-level utilization within its industry, Cyperus esculentus L. meal obtained post-oil extraction was employed as the raw material to develop a probiotic beverage via enzymatic hydrolysis coupled with fermentation. The beverage's quality characteristics were subsequently evaluated. Initially, optimal enzymatic hydrolysis and fermentation conditions were determined based on reducing sugar content and viable probiotic counts as indicators, employing single-factor and orthogonal experimental designs. Changes in physicochemical properties, antioxidant activity, and volatile compound composition during fermentation were monitored. The results indicated that the optimum enzymatic hydrolysis parameters were a cellulase concentration of 4%, a hydrolysis time of 3 hours, a temperature of 55 ℃, and a pH of 5.5. A subsequent verification experiment yielded a reducing sugar content of 5.17 g/L under these optimal conditions. The optimal fermentation conditions were determined to be a temperature of 37 ℃, a duration of 36 hours, a solid-to-liquid ratio of 1:6 (w/v), and an inoculum size of 10% (v/v). A validation experiment using this optimal protocol resulted in a final viable probiotic count of 1.10×10⁹ CFU/mL. Lactic acid fermentation significantly decreased the beverage's pH, total sugar content, and fat content, while markedly increasing soluble dietary fiber content, total phenols, total flavonoids, and reducing sugar content (P<0.05). Consequently, antioxidant activity was significantly enhanced post-fermentation compared to pre-fermentation levels (P<0.05). Noticeable difference was observed in the volatile compound composition between the pre-fermentation and post-fermentation stages. The levels of nitrogen oxides, sulfides, and methyl compounds demonstrated a clear elevation after fermentation, the fermentation process contributed the distinctive flavor profile that was typical of lactic acid bacterial fermentation. The enzymatic hydrolysis coupled with fermentation process significantly improved the flavor profile of Cyperus esculentus L. meal and enhanced its nutritional properties, providing technical reference for the development of novel plant-based probiotic beverages.

This study applied solid-state fermentation with Monascus to black highland barley bran to enhance its utilization. The fermentation process was optimized by monitoring the antioxidant potency composite (APC) index. Comparative analysis of unfermented samples and those from the optimal fermentation time point was conducted using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to systematically profile volatile flavor compounds and untargeted metabolomes. The results demonstrated that the contents of total polyphenols and total flavonoids exhibited an initial increase followed by a decrease during fermentation. In contrast, compounds including 4-hydroxybenzoic acid, p-coumaric acid, luteolin, and its glycoside derivatives peaked in the unfermented samples and declined continuously thereafter. Levels of cis- and trans-ferulic acid, as well as protocatechuic acid, also showed an initial increase followed by a decrease. Based on the APC assessment, the optimum fermentation duration for black barley bran using Monascus was established at 5 days, achieving an APC of 98.45%. A total of 215 volatile compounds were identified. Fermentation led to significant increases in the relative contents of esters, ketones, alcohols, aldehydes, and phenols. A total of 2914 differential metabolites were identified in the untargeted metabolomics analysis (VIP≥1, FC≥2 or FC≤0.5, and P<0.05). Compared to the unfermented group, 1671 metabolites were significantly upregulated (P<0.05) in the 5-day fermentation group, with the most notable change observed in the content of 8-deoxyanthocyanin. KEGG pathway enrichment and correlation analyses indicated that fermentation effectively enhanced the flavor profile of black highland barley bran, providing a theoretical foundation for its development into functional foods.

This study investigated the regulatory effects of inoculation timing on the quality of navel orange wine in mixed-culture fermentation. Fermentation protocols were established using Saccharomyces cerevisiae and non-Saccharomyces cerevisiae under four modalities: Simultaneous co-inoculation, non-Saccharomyces cerevisiae pre-inoculation, non-Saccharomyces cerevisiae delayed inoculation, and Saccharomyces cerevisiae mono-culture fermentation. Characteristic components and antioxidant activity were systematically analyzed via gas chromatography-mass spectrometry and ultraviolet spectrophotometry. Results demonstrated significant quality modulation by inoculation timing. Mixed-culture fermentation generated 24 additional volatile compounds versus mono-culture. The pre-inoculation group exhibited peak levels of total alcohols at 1500.09 mg/L and total esters at 198.43 mg/L. Total phenolic content reached 753.93 mg GAE/L in the pre-inoculation group, while total flavonoids peaked at 138.30 mg RE/L under simultaneous inoculation. Antioxidant capacity was significantly enhanced in the pre-inoculation group, demonstrating IC₅₀ values of 0.0483 mg/mL for DPPH radical scavenging, 0.071 mg/mL for hydroxyl radical scavenging, and 0.152 mg/mL for ferricyanide reducing power. Sensory evaluation favored the delayed inoculation (DC) and simultaneous inoculation groups (SC), with respective composite scores of 82.13 and 80.13. In conclusion, inoculation timing critically governs flavor quality, functional components, and antioxidant attributes in mixed-culture fermented navel orange wine. Systematic comparison across fermentation modes elucidated yeast interaction mechanisms and quality formation patterns, providing theoretical and empirical foundations for process optimization. This research facilitates value enhancement in citrus wine products and fosters sustainable development in navel orange processing industries.

This study aimed to construct a novel aqueous two-phase system for the efficient separation of albumin components from sheep blood, followed by structural identification and functional characterization of the isolated sheep serum albumin. First, the optimal phase-separation system was screened from seven salts, and then a single-factor experiment combined with a Box-Behnken experimental design was used to determine the optimal process parameters for separating sheep blood albumin using an aqueous two-phase system. The isolated albumin was then characterized by using electrophoresis and spectroscopic techniques. Finally, the emulsification, foaming and gelling properties of albumin from different species were compared to evaluate its application potential in food. The results showed that the ethanol–sodium dihydrogen phosphate combination was the optimal aqueous two-phase system for albumin separation. Under the conditions of 3.8% (w/w) plasma loading, 27.6% (w/w) ethanol, 18.4% (w/w) sodium dihydrogen phosphate, and 2.6% (w/w) sodium chloride, efficient separation of sheep serum albumin was achieved within 30 minutes, yielding a recovery rate of 92.8% and a purity of 93.3%. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD) and fluorescence spectroscopy showed that the molecular weight of the separated sheep blood albumin was about 66 kDa, and the secondary and tertiary structures were consistent with standard albumin. Furthermore, the emulsifying stability, foam stability, and gel strength of the isolated sheep serum albumin were 3.3-, 2.4-, and 3.0-fold higher than those of egg albumin, respectively, demonstrating superior functional properties. This study provides a theoretical basis for the low-cost and high-efficiency recovery of sheep plasma albumin, while also offering critical insights for its advanced processing and potential applications in functional food products.

To simultaneously enrich polyphenols and β-glucan in Lactobacillus-fermented oats and enhance their activity in regulating glucose and lipid metabolism, single-factor experiments and response surface methodology (RSM) were employed to optimize fermentation conditions. Untargeted metabolomics was utilized to analyze the composition and relative abundance of polyphenols in fermented oats. Subsequently, the antioxidant activities of aqueous and ethanolic extracts from fermented oats, as well as their inhibitory effects on key enzymes involved in glucose and lipid metabolism, were evaluated. Furthermore, representative polyphenolic components identified in fermented oats were used as ligands for molecular docking to elucidate the molecular mechanisms underlying the inhibition of these key enzymes. The results demonstrated that fermentation with Lactobacillus kisonensis (JCM 15041) under optimal conditions (inoculum size: 2%, solid-to-liquid ratio: 1:6 g/mL, fermentation time: 6 h, temperature: 30 ℃) significantly increased the β-glucan content in oats by 61.54%, while enhancing the inhibition rates against α-amylase and α-glucosidase by 28.61% and 24.11%. Compared to unfermented oats, both the ethanolic and aqueous extracts of fermented oats exhibited significantly enhanced antioxidant activity (P<0.05) and inhibitory effects on key glucose and lipid metabolism enzymes (P<0.001). Untargeted metabolomics revealed a significant increase (P<0.01) in the abundance of cinnamic acid post-fermentation. Molecular docking using cinnamic acid as the ligand indicated its potential binding modes: Forming two hydrogen bonds (2.1 Å) with Lys-466 of α-amylase (binding energy: −4.59 kcal/mol), two hydrogen bonds (2.2 Å) with Phe-416 and Lys-418 of α-glucosidase (binding energy: −4.43 kcal/mol), and five hydrogen bonds (1.6 Å, 2.1 Å, 2.4 Å, 2.6 Å, and 2.8 Å) with Pro-430, Arg-457, and Glu-458 of pancreatic lipase (binding energy: −5.77 kcal/mol). These interactions suggested that cinnamic acid likely inhibits enzyme activity by affecting the substrate-binding domain and catalytic active site. In conclusion, this study established a Lactobacillus-fermentation process capable of significantly enriching oat polyphenols and β-glucan. The resulting fermented oat extracts possessed potent in vitro antioxidant activity and significant potential for regulating glucose and lipid metabolism.

This study aimed to optimize the ultrasound-assisted aqueous two-phase extraction (UATPE) process of Anemarrhena asphodeloides polysaccharide (AAPs), separate and purify the crude AAPs by different column chromatography techniques to obtain a uniform polysaccharide fraction (AAPs-1-SG), and characterize its structure. The effect of AAPs-1-SG on the viability of RAW264.7 cells was determined by the MTT method. The neutral red method was used to evaluate the effect of AAPs-1-SG on the phagocytic activity of RAW264.7 cells, and the effects of AAPs-1-SG on the levels of NO, IL-1β, IL-6 and TNF-α in RAW264.7 cells were investigated. The results showed that the process parameters of UATPE polysaccharide from Anemarrhena asphodeloides were obtained as follows: Ammonium sulfate mass fraction of 24%, ultrasonic power of 400 W, ethanol volume fraction of 45%, and solid-to-liquid ratio of 1:20 g/mL, and the yield of AAPs was 12.17%±0.25%. Ultraviolet spectral scanning revealed that AAPs-1-SG had no proteins or nucleic acids. FT-IR showed that AAPs-1-SG exhibited typical infrared absorption characteristics of polysaccharides and possessed α and β types glycosidic bonds. AAPs-1-SG was mainly composed of Glc, Ara, and Man, and its molecular weight was 11298 Da. Scanning electron microscopy and atomic force microscopy observed that AAPs-1-SG presented irregular sheet-like and porous structures. In addition, AAPs-1-SG could markedly increase the viability and phagocytic activity of RAW264.7 cells, and significantly improve the levels of NO, IL-1β, IL-6, and TNF-α (P<0.05), further revealing that AAPs-1-SG had better immunomodulatory activity. The findings can provide an important method for the efficient extraction of natural polysaccharides and also offer significant references for the development and utilization of AAPs.

To investigate the effects of different drying methods on the quality of Tanyang Gongfu black tea, five drying processes were employed in this study: Vacuum-freeze drying (FD), hot-air drying (HD), hot-air-vacuum-freeze combined drying (HFD), vacuum-freeze-hot-air combined drying (FHD), and microwave drying (MD). The five dried tea samples were compared by combining sensory evaluation, physicochemical component determination, aroma compound detection, and chemometric analysis. The results indicated that the Tanyang Gongfu black tea was characterized mainly by sweet floral aroma and sweet mellow taste. Among them, the FHD sample was characterized by a pure, sweet, refreshing taste and a pronounced sweet floral aroma, achieving the highest sensory score (90.90 points). Significant differences were observed in the quality components of the tea samples subjected to different drying methods. FD treatment was found to be conducive to increasing the thearubigins content (3.08%). The free amino acid (6.69%) and tea polyphenol (12.28%) contents in the FHD sample were significantly higher than those in the other groups (P<0.05). The highest water extract content (38.23%) was found in the HFD sample. Soluble sugars (44.34 mg/g) in the HD sample were found to contribute to its sweet mellow taste characteristic. Flavonoids were maximally retained (24.61 mg/g) in the MD sample. A total of 99 aroma compounds were detected in the five tea samples, mainly including aldehydes, esters, and alcohols. The FD sample possessed unique grassy and floral characteristics, mainly contributed by hexanal (OAV=33.51), linalool (OAV=75.45), and geraniol (OAV=239.77). The sweet and honey-like aroma characteristics of the HD sample were associated with the enrichment of isovaleraldehyde (OAV=254.73) and phenylacetaldehyde (OAV=41.44). Geraniol (OAV=210.22) was identified as the characteristic aroma compound for the FHD treatment. Geraniol (OAV=130.04) and isovaleraldehyde (OAV=122.23) were determined to be the main aroma-contributing components for HFD. Nonanal (OAV=71.89) was identified as the key aroma component for MD treatment. This study systematically elucidated the influence of different drying processes on the quality of Tanyang Gongfu black tea, providing a theoretical basis for optimizing black tea processing technology.

In this study, the process of preparing microcapsules using a vacuum freeze-drying technique, with gum arabic/maltodextrin as the wall and anthocyanins derived from grape-skin pomace as the core materials, was optimized. The stability of the microcapsules under various temperature, light, and oxygen conditions was investigated before and after encapsulation. Single-factor experiments were conducted using the encapsulation rate as the indicator to evaluate the effect of the core-to-wall ratio, gum arabic-to-maltodextrin ratio, embedding temperature, and embedding time on the encapsulation performance of anthocyanins. The optimal encapsulation process was refined using the response surface methodology. The results indicated that the optimal process parameters were a core-to-wall ratio of 1:3.3, a gum arabic-to-maltodextrin ratio of 1:3.3, an embedding temperature of 41 ℃, and an embedding duration of 30 min. The encapsulation efficiency of the microcapsules was 98.48%±0.03% under this process. The surface of the anthocyanin microcapsules exhibited amorphous, concave-convex, and wrinkled structures. Fourier-transform infrared spectroscopy and X-ray diffraction revealed that the anthocyanins could be encapsulated by gum arabic and maltodextrin, with an average encapsulated particle size of 1.0213 μm, a distribution index of 0.456, and an average potential of −13.70 mV. Investigating the effect of natural light, temperature, and oxygen on the stability of anthocyanins showed that the microencapsulated anthocyanins were more stable than their unencapsulated counterparts. In conclusion, the microcapsule preparation process is feasible and exhibits high encapsulation efficiency, which can effectively enhance the stability of anthocyanins. This study provides a theoretical basis and technical reference for the high-value utilization of grape-skin pomace by-products and the stabilization application of anthocyanins in the food industry.