Selecting of lactic acid bacteria from traditionally fermented food and their application in functional raspberry fermented beverage

Fermentation of plant-based juices by lactic acid bacteria (LAB) is a effective way to improve their aroma and nutritional functions. This study was to select LAB for fermentation of raspberry, further investigating the functionality of fermented raspberry beverage (FRB). Lactobacillus plantarum X-37, Lactobacillus pentosus P-l, and Enterococcus faecalis W-9 were found to improve total phenolic content of FRB by at least 36.40 %. Meanwhile, L. plantarum R-1, S-4, and DF9 that improved flavor of FRB were also selected. The optimal strain combination for FRB was L. pentose P-1 and L. plantarum R-1, which could not only improved the content of total phenol to 3.34 g/ L, but also enhanced the contents of key aroma components such as phenethyl alcohol and geranyl acetone to 3.73 mg/L and 0.09 mg/L, respectively. Besides, the contents of undesirable aromas in FRB by this strain combination reduced significantly. The results of functional evaluation indicated the relative abundance of beneficial genera in FRB such as Bifidobacterium and Lactobacillus increased by more than 100 % while the abundance of harmful bacterial genera such as Klebsiella Dorea, and Collinsella decreased by more than 50 % compared with saline group (BG) after 48 h digestion. Besides, the contents of short chain fatty acid in FG were higher than those in control groups (FIG, UFG and BG). Therefore, this study indicated that fermentation with mixed LAB could enhance the aroma and functionality of raspberry beverage, which provide a theoretical basis for the application of LAB in the fermentation of raspberry beverage.