Effects of selenium enrichment on the nutritional components, metabolites, and flavor volatiles of fermented Cordyceps militaris juice

Selenium (Se) enrichment changes the nutritional composition and secondary metabolites of Cordyceps militaris (CM), but its effect on the fermentation process of CM is still unclear. This research revealed the effects of Se enrichment on the nutritional and metabolic characteristics of Cordyceps militaris juice (CMJ) fermented by Lactobacillus DZ001 (API). The results indicated that Se enrichment significantly enhanced the growth and metabolic activity of API. Furthermore, Se enrichment showed a higher initial carbohydrate content and significantly increased the total peptide content in CMJ, while it reduced the degradation of polyphenols and ascorbic acid, indicating that Se mediated the antioxidant protection. In addition, the amino acid and fatty acid contents increased significantly, but the compositional diversity did not change. Untargeted metabolomics further revealed Se-induced upregulation of differential metabolites, which were related to pathways such as ascorbic acid and linoleic acid metabolism. Volatile metabolomics showed that Se enrichment considerably increased the content of terpenes, alcohols and esters in flavor metabolites, and significantly improved flavor diversity. Sensory evaluation confirmed that Se enrichment can improve the sensory properties of fermented CMJ. These results highlight the role of Se in improving nutritional components and enhancing flavor, making Se-CMJ a promising nutritional flavored beverage. • Se enrichment promoted lactic acid bacteria growth and peptide accumulation. • Se-CMJ maintained higher levels of polyphenols and ascorbic acid during fermentation. • Total amino acids and fatty acids significantly increased in Se-enriched CMJ. • Terpenes, esters, and alcohols were enriched, improving the flavor complexity of CMJ.