Comparative analysis of nutritional and flavor compound alterations in Cordyceps militaris juice fermented by single or mixed Lactobacillus strains.

Cordyceps militaris (CM) is a precious edible and medicinal mushroom known for its bioactive components, which can potentially be enhanced through microbial fermentation. This study conducted a comparative analysis of nutritional and flavor compound changes in CM juice (CMJ) fermented by single or mixed Lactobacillus strains. Results showed that all Lactobacillus strains (L. plantarum DZ001, L. plantarum DZ003, L. salivarius DZ011, and L.fermentum DZ005) could grow well in CMJ, especially L.plantarum DZ001 and L.salivarius DZ011. However, the growth of mixed Lactobacillus strains was relatively delayed. Consistent with these growth patterns, both single- and mixed-strains fermentations significantly reduced pH and increased acidity. In addition, fermentation enhanced the nutritional value of CMJ to a certain extent, as indicated by increasing peptide and flavonoid content while maintaining total polyphenol level. E-nose and HS-SPME-GC-MS analysis further revealed that all of these fermentations significantly upregulated most of the flavor volatiles, which were mainly characterized as sweet, fruity, and green. Sensory evaluation also confirmed the analysis results of flavor volatiles. Notably, L. fermentum DZ005 or mixed-strain fermentations containing L.fermentum DZ005 had the greatest impact on flavor. These findings provide valuable theoretical guidance for developing fermented beverages from Cordyceps militaris.