Selenium, a crucial trace element, has garnered significant attention in functional food development due to its effective conversion into organic forms. This study systematically investigated the selenium enrichment potential and metabolic regulation mechanisms of 50 lactic acid bacteria (LAB) strains from Xinjiang. Through sodium selenite tolerance tests, eight core strains with over 80% selenium enrichment were selected, with optimal enrichment conditions being a 37 °C temperature, 2% sodium chloride concentration, and pH of 6.0 in MRS medium. Functional tests demonstrated that selenium-enriched strains exhibited a significantly enhanced antioxidant capacity (demonstrated by DPPH and ABTS free radical scavenging activities) and improved gastrointestinal fluid tolerance, with strain No.41 showing the most outstanding performance. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX) revealed nanoscale selenium (1.34 keV) on cell surfaces. Further characterization showed that 68.94% of selenium was incorporated into selenoproteins, 7.61% into nucleic acids, and 7.02% into polysaccharides. Integrated metabolomic and proteomic studies have shown that selenium reduces the content of L-cysteine primarily by replacing sulfur and competing for key sites in cysteine-S-conjugate-β-lyase, S-adenosyl-L-cysteine hydrolase, and homocysteine synthase, ultimately leading to the synthesis of selenocysteine and selenomethionine. A correlation analysis between differential metabolites and proteins revealed selenium’s significant impacts on the metabolic networks of LAB, antioxidant mechanisms, energy metabolism, and membrane stability. This research provides new insights for developing selenium-enriched probiotics for functional dairy products and health supplements.

This work optimized the formulation of the traditional Kyrgyz layered pastry Katima to lower its high butter-derived lipid content. High-gluten flour served as the base raw material, with butter, yeast, salt, egg liquid, and raisins as auxiliary ingredients. Single-factor trials combined with Box–Behnken response surface methodology (RSM) were carried out, with overall sensory score as the primary evaluation index to screen critical formulation variables: butter, yeast, and salt exerted distinct linear and interactive effects on product acceptability. The validated optimal formula contained 12.67 g butter, 0.78 g instant active dry yeast, and 0.56 g edible salt per 100 g flour, yielding a mean sensory score of 95.03 and a 37.21% fat reduction relative to full-fat traditional Katima. Significant intergroup differences (p < 0.05) were observed in texture, surface color, and physicochemical profiles. Reduced-fat Katima exhibited elevated moisture, hardness, and chewiness, alongside markedly lower fat, peroxide and acid values, reflecting enhanced lipid oxidative stability. This study provides standardized technical parameters and a feasible upgrading strategy for industrialized production of healthy Xinjiang ethnic cereal pastries.

In this study, Apocynum venetum was employed as the raw material to optimize protein extraction and enzymatic hydrolysis processes for the preparation of highly active angiotensin-converting enzyme (ACE)-inhibitory peptides, achieving an ACE inhibition rate of 92.34%. Multispectral analyses and microstructural characterization demonstrated that enzymatic hydrolysis induced the unfolding of protein secondary structures, resulting in a looser and more porous morphology enriched with characteristic amino acids. A total of 2567 peptide sequences were identified by LC–MS/MS, among which 18 potential bioactive peptides were screened. Molecular docking analysis revealed that these peptides interact with the active site of ACE primarily through hydrogen bonding and hydrophobic interactions, with WLRDFL exhibiting the strongest binding affinity. This study systematically elucidates the structural characteristics and antihypertensive molecular mechanisms of ACE-inhibitory peptides derived from Apocynum venetum, providing both theoretical insights and experimental support for the development of natural antihypertensive functional foods and the high-value utilization of this plant.