Characterization of strawberry purees fermented by Lactobacillus spp. based on nutrition and flavor profiles using LC-TOF/MS, HS-SPME-GC/MS and E-nose

This study aims to characterize the fermentation performance of Lactobacillus spp. in strawberry puree and expected to screen out the Lactobacillus that can improve the nutrition and flavor of strawberry puree. Results suggested that strawberry puree was a favorable substrate for Lactobacillus growth, all strains reached above 9.0 log CFU/mL after fermentation. L. plantarum 21802 and L. brevis 6239 presented excellent polyphenol bioconversion capacities, and significantly increased the total phenolic content and antioxidant activity of strawberry purees. However, L. plantarum 21802 increased the levels of protocatechuic acid (13.41%) and procyanidin B2 (38.04%), L. brevis 6239 increased gallic acid content (11.67%). Moreover, they promoted the production of alcohols, acids and ketones (increasing 36.11%, 44.0% and 121.83% by L. plantarum 21802, 57.98%, 8.85% and 43.34% by L. brevis 6239). Four key aroma compounds (OAV>1), namely 1-hexanol, linalool, DMMF and ethyl butanoate, also increased significantly. Although L. plantarum 21802 fermentation product had stronger flavor and higher odor satisfaction, it was less attractive than that fermented by L. brevies 6239 since high organic acids production. Overall, these two strains would be the potential Lactobacillus to enhance the nutrition and aroma of strawberry puree. The co-fermentation of them would be analyzed in the future since various metabolic profiles of them.