Abstract:Probiotics exert multiple beneficial effects on human health and have been widely applied in fields such as food and medicine. Their efficacy is highly dependent on the specific microbial community composition in the products. Therefore, rapid and accurate identification technologies for community composition play a crucial supporting role in product quality assurance, efficacy control, and market supervision and management. According to technical principles, the author classifies existing identification methods into three categories: culture-based methods, single-cell analysis technologies, and molecular biology technologies. The author elaborates on the principles and specific analytical contents (such as viable count and community diversity analysis) of each category of technologies. Meanwhile, the author points out the challenges currently faced by these technologies and provides prospects for future research directions, aiming to offer a reference for the quality control of probiotic products and the development of related fields.

Abstract:Natural starch has attracted much attention due to its low cost, biodegradability, renewability, and easy availability of raw materials. However, its poor water solubility, mechanical stability, and freeze-thaw stability limit its application scope. After modification treatment, the transmittance of starch significantly increases, and the apparent viscosity also increases. Moreover, the system exhibits significantly enhanced freeze-thaw stability, acid-base tolerance, and storage stability, showing more excellent processing and application performance. The author systematically describes the preparation strategies of modified starch, mainly from physical, chemical, enzymatic and composite modification methods, summarizes the influences of modification technology on the internal structure and physicochemical properties of starch, and introduces the application status of modified starch in various fields, laying a foundation for the development of more efficient and targeted modified starch technologies.

Abstract:Pullulan is an extracellular water-soluble polysaccharide synthesized by Aureobasidium. Due to its unique film-forming properties, biodegradability, and biocompatibility, pullulan has attracted considerable attention in the food industry. In recent years, pullulan has played an important role in areas such as food additives and food preservation. However, its industrial production faces challenges such as low yields and high production costs, which limit its widespread application in the food industry. The author reviews and summarizes the research progress in pullulan-producing strains, factors influencing biosynthesis, and regulatory mechanisms, providing insights for optimizing low-cost fermentation processes and enhancing the utilization of pullulan in the food industry.

Abstract:[Objective]This study aimed to screen composite enzyme formulations, optimize the enzymatic hydrolysis of chicken protein, and investigate the digestive characteristics of the resulting hydrolysates.[Method]Chicken slurry was hydrolyzed using two composite enzyme formulations: composite enzyme formulation 1, consisting of alkaline protease at a mass fraction of 2% and papain at a mass fraction of 2%; and composite enzyme formulation 2, consisting of papain at a mass fraction of 2% and flavourzyme at a mass fraction of 2%. Enzymatic hydrolysis was performed at 55 ℃ for 1.5 h. The degree of hydrolysis, peptide mass fraction, free amino acid composition, and volatile flavour compounds were determined. The hydrolysis efficiency, digestive characteristics, and physiological effects of the hydrolysates were comprehensively evaluated using in vitro simulated digestion and a mouse model.[Result]The degree of hydrolysis achieved with both composite enzyme formulations exceeded 56%, and peptides with a relative molecular mass below 500 accounted for more than 94% of the hydrolysates. The results of in vitro digestion experiments showed that the crude protein digestibility of composite enzyme group 2 was 87.48%, significantly higher than that of composite enzyme group 1 (P<0.05). The proportion of peptides with a relative molecular mass less than 500 in the digestion products of composite enzyme group 1 and composite enzyme group 2 was 92% and 90%, respectively. In the animal experiment, the crude protein apparent digestibility in mice fed the hydrolysate produced using composite enzyme formulation 2 reached 82.64%.[Conclusion]Both composite enzyme formulations effectively promoted chicken protein hydrolysis. Composite enzyme formulation 2 performed better in improving product digestibility, providing a feasible processing approach for the value-added utilization of chicken protein.

Abstract:[Objective]This study aims to evaluate the alleviating effects of Ligilactobacillus salivarius (L. salivarius)CCFM1398 and its postbiotics on orthodontic-induced bone resorption in rats.[Method]This study used MC3T3-E1 osteoblast model and the rat model of orthodontic-induced bone resorption to comprehensively evaluate the biological activity of L. salivarius CCFM1398 and its postbiotics in modulating alveolar bone resorption.[Result]L. salivarius CCFM1398 significantly induced the expression of osteoprotegerin (OPG) in MC3T3-E1 cells. This strain or its postbiotics significantly reduced the probing depth and gingival index score of the rat model of orthodontic-induced bone resorption. They ameliorated bone resorption by reducing the number of osteoclasts and relieved gingival inflammation by down-regulating the expression levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO).[Conclusion]L. salivarius CCFM1398 and its postbiotics can ameliorate orthodontic-induced bone resorption in rats. The findings provide a theoretical basis for the development of probiotic/postbiotic agents with bone resorption-modulating functions.

Abstract:[Objective]To investigate the regulatory mechanism of sodium chloride sodium chloride addition level on the microbial community in yak milk hard cheese.[Method]High-throughput sequencing technology was employed to analyze the evolution of microbial communities after the addition of sodium chloride at mass fractions of 1.0%, 1.3%, 1.8%, and 2.3% during the 0~6 month maturation period.[Result]As the sodium chloride addition mass fraction decreased, the Streptococcus in the cheese first increased and then decreased, which was accompanied by a slow increase in the relative abundance of Lactococcus, an upward trend in the relative abundance of Escherichia-Shigella, an overall downward trend in the relative abundance of Lactobacillus, and a rapid decreasing trend in the relative abundance of Weissella. In addition, the relative abundance of Acinetobacter, Chryseobacterium, and Pseudomonas first decreased and then increased. In the cheese with sodium chloride added at the mass fraction of 2.3%, Lactobacillus and Weissella were the characteristic differential bacterium genus, with their relative abundance being higher than that in other groups. In the cheese with sodium chloride added at the mass fraction of 1.0%, the characteristic differential bacterium genus were Lactococcus, Acinetobacter, Chryseobacterium, and Pseudomonas. Among them, the latter three genera showed evident increases in relative abundance compared with those in the cheese with sodium chloride added at the mass fraction of 2.3%. Their relative abundance was markedly lower in the cheese with sodium chloride added at the mass fraction of 1.3% than in the cheese with sodium chloride added at the mass fraction of 1.0%, and reached the lowest levels in the cheese with sodium chloride added at the mass fraction of 1.8%.[Conclusion]The safety and quality of low-salt yak milk hard cheese can be improved by optimizing starter cultures, controlling the quality of raw milk, moderately reducing the salt content, and inoculating appropriate beneficial bacteria.

Abstract:[Objective]This study aimed to investigate the distribution of Staphylococcus aureus (S. aureus) in prefabricated foods and the virulence genes and antibiotic resistance of isolated strains.[Method]S. aureus in commercial prefabricated foods sampled from Foshan City was detected according to the national standard GB 4789.10—2016. The virulence genes were detected by polymerase chain reaction (PCR). The antibiotic resistance and antibiotic resistance genes of isolated strains were characterized by the disk diffusion method and PCR.[Result]The average detection rate of S.aureus in samples of prefabricated foods was 13.1%, with meat products possessing the highest positive rate (24.3%). A total of 85.7% of positive samples had S. aureus contamination levels less than 1.0×10³ CFU/g. A total of 14 representative strains of S. aureus with high plasma coagulase activity were isolated from positive samples. Among the virulence genes, pvl had the highest detection rate (100.0%), followed by hla (78.6%), sea (71.4%), hlb (28.6%), and seb (14.3%), and 78.5% strains carried more than 3 virulence genes. Most strains were resistant to penicillin (78.6%), and 3 strains exhibited multi-drug resistance. The antibiotic resistance genes showed strong associations with the phenotypes, with mecA exhibited the highest detection rate of 21.4%.[Conclusion]S.aureus contamination in prefabricated foods presents mainly in meat products. Most of the isolated strains simultaneously carry multiple virulence genes, while a few strains exhibit multi-drug resistance. Therefore, it is of great importance for monitoring S. aureus in prefabricated foods.

Abstract:[Objective]This study aimed to investigate the synergistic ameliorative effects of an Ejiao-edible bird’s nest compound on the growth, development, and immune function of zinc-deficient pregnant mice and their offspring under stress.[Method]A pregnant mouse model of zinc deficiency was established and subjected to nutritional interventions with Ejiao, edible bird’s nest, and their compound. Body mass, serum zinc concentrations, and immunoglobulin levels in both pregnant mice and offspring were measured. Immunohistochemical analysis of the spleen was conducted.[Result]The compound effectively restored serum zinc homeostasis in both pregnant mice and offspring (with the serum zinc concentration reaching a maximum of 18.02 μmol/L in pregnant mice). It significantly increased the body mass gain rate of zinc-deficient pregnant mice to 46.77% and mitigated early growth retardation in the offspring. Regarding immunomodulation, the compound specifically reversed the severe deficit of serum immunoglobulin A in zinc-deficient offspring, increasing the mass concentration to over 1.20 mg/mL. Moreover, it significantly downregulated the abnormally elevated expression levels of NK cell and macrophage markers in the offspring’s spleen, thereby suppressing excessive inflammatory responses.[Conclusion]The Ejiao-edible bird’s nest compound synergistically ameliorates impairments in growth, development, and immune barrier function in zinc-deficient pregnant mice and offspring by reconstructing the zinc nutritional profile, enhancing mucosal immune reserves, and bidirectionally regulating the splenic immune microenvironment.

Abstract:[Objective]This study aimed to improve the quality and drying efficiency of hot air-dried mulberries.[Method]Mulberries were pretreated with different pressure levels (0~300 MPa). The effects on drying characteristics, water distribution, cellular structure, and active components were systematically investigated through low-field nuclear magnetic resonance (LF-NMR), microscopic structural observation, quantitative analysis of cell wall components, active compound determination, and principal component analysis of electronic nose data.[Result]The key pressure threshold was identified at 150 MPa. Under this condition, the free water ratio reached its peak (T₂₃ peak area accounted for 47.3%). Selective rupture of the cell wall-membrane system formed interconnected cavities, significantly increasing porosity. The mass fraction of cellulose gradually decreases as pressure increases, stabilizing at 250 MPa (10.28 mg/g). The protopectin kept degrading (down to 10.25 mg/g at 300 MPa), and that of soluble pectin gradually increased to 11.81 mg/g, indicating that pectin degradation induced by high pressure dominated structure changes in the cell wall. Ultra-high pressure pretreament resulted in a reduction of 38.5% in drying time and significantly improved the retention of active compounds (mass fraction of flavonoid: 1.01 mg/g; mass fraction of total phenols: 0.32 mg/g). Electronic nose analysis revealed the greatest flavor change occurred at 300 MPa.[Conclusion]Considering both quality and drying efficiency, 150 MPa was selected as the optimal pretreatment condition. It exerts the synergistic effects of cellular structural reorganization, water state transformation, and degradation of cell wall components in improving the drying process. This study provides a theoretical basis for the high-value processing of mulberries.

Abstract:[Objective]This study aimed to screen the Bifidobacterium animalis subsp. lactis (B. lactis) strains with unique advantages and probiotic properties from the intestinal tract of children.[Method]Fifty-six strains of B. lactis isolated from the intestinal tract of children in Nanyang City, Henan Province were used for the study. The strains were evaluated for their acid tolerance, bile salt tolerance, gastrointestinal fluid tolerance, growth characteristics, surface auto-aggregation ability, surface hydrophobicity, and antioxidant capacity.[Result]B. lactis MN16631 had strong acid and bile salt tolerance. It achieved the survival rates of 87.15% and 43.64% after being incubated in the simulated gastric fluid for 2 h and the simulated intestinal fluid for 4 h, respectively. B. lactis MN16631 showed the surface hydrophobicity of (56.69±1.96)% and the surface auto-aggregation rate of (84.28±2.41)% after 24 h. Furthermore, B. lactis MN16631 exhibited strong antioxidant activity. Its DPPH radical scavenging capacity was superior to that of commercial strains, while its hydroxyl radical scavenging capacity and superoxide anion radical scavenging capacities, as well as its ferric reducing capacity, were comparable to those of commercial strains.[Conclusion]B. lactis MN16631 is a strain with excellent probiotic properties and thus can be used as a strain resource for the research and development of functional foods for children and other populations.

Abstract:[Objective]This study explored the antioxidant activity and exercise fatigue-alleviating effect of Chlamydomonas reinhardtii-derived extracellular vesicles (CLEVs), aiming to provide a reference for the application of microalgae-derived extracellular vesicles in the field of sports nutrition.[Method]CLEVs were isolated by ultracentrifugation, and their antioxidant and anti-fatigue effects were evaluated through in vitro and in vivo experiments.[Result]CLEVs exhibited typical cup- or bowl-shaped morphology with an average particle size of (88.35±0.36) nm. CLEVs demonstrated concentration-dependent antioxidant activity in vitro and effectively scavenged DPPH and ABTS⁺ free radicals. In the H₂O₂-induced oxidative damage model, CLEVs increased the levels of superoxide dismutase (SOD) and reduced glutathione (GSH), decreased the levels of malondialdehyde (MDA), lactate dehydrogenase (LDH), creatine kinase (CK), and lactic acid (LA), and promoted glycogen storage. Animal experiments showed that CLEVs significantly prolonged the load swimming time to exhaustion and enhanced the antioxidant defense by upregulating the expression of Nrf2 and downregulating the expression of Keap1.[Conclusion]CLEVs could alleviate exercise fatigue by ameliorating oxidative stress, promoting energy metabolism, and activating the Nrf2/Keap1 signaling pathway, demonstrating potential application in sports nutrition and the development of anti-fatigue products.