Impact of selenium-enriched fermentation on nutritional composition, antioxidant capacity, flavor profile and metabolomic profile of Actinidia arguta powder

Actinidia arguta is a nutrient-rich fruit with potential for functional food development, yet its processing by-products remain underutilized. In this study, we examined the effects of fermentation combined with selenium enrichment on the nutritional composition, antioxidant capacity, flavor, and metabolomic profile of Actinidia arguta powder. Selenium-enriched fermentation produced 99.93% organic selenium, primarily in the forms of selenomethionine, selenocysteine, and methylselenocysteine. This process significantly enhanced antioxidant activity and favorably modulated by improving the bioavailability and organic Se conversion, thereby increasing its nutritional functionality. Furthermore, 40 volatile compounds were identified, with fermentation promoting the formation of fruity, floral, and milky aroma notes, while Se-enriched fermentation further introduced terpenoid-associated pine-like aromas. Non-targeted metabolomics revealed 32 differential metabolites mainly associated with amino acid and nucleotide metabolism. Pathway enrichment analysis indicated significant alterations in amino acid metabolism, purine metabolism, and glutathione metabolism. These metabolic shifts were closely associated with increased polyphenols, polysaccharides, and antioxidant enzyme activities. Overall, fermentation combined with Se biotransformation remodels the metabolic network of A. arguta powder, enhancing its flavor quality, nutritional value, and antioxidant functionality. This study provides a sustainable strategy for upgrading Actinidia arguta by-products into high-value functional food ingredients.