Enhancement of Bioactivity and Flavor Profiles of Tartary Buckwheat Through Kombucha Fermentation by Enrichment of Lactobacillus bulgaricus

ABSTRACT Tartary buckwheat (TB) products are receiving increasing attention due to their bioactive components and health‐promoting properties. However, current processing methods and derived products of TB remain limited in scope and diversity. In order to maximize the nutritional value of TB while maintaining a pleasant sensory profile, TB infused with pineapple at different ratios (0:1, 1:0, 1:1, 1:2, 1:3) was fermented by kombucha for 0, 2, 4, 6 days and the nutritive and sensory properties of the beverages were monitored. The fermentation process rapidly increased ( p < 0.05) the content of organic acids, bioactive components (rutin, gallic acid, folic acid), total phenol content, antioxidant capacity, and aroma compounds in the TB‐pineapple kombucha (TBPK) beverage after 2 days of fermentation. However, extended fermentation time (6 days) significantly decreased ( p < 0.05) the flavor profiles of TBPK beverages due to the rapid accumulation of total acids. TBPK3 (TB:PK = 1:3) fermented for two days obtained the highest sensory score while maintaining pronounced levels of bioactive compounds and antioxidant capacity. Results of GC–MS proved that TBPK3 produced abundant volatile compounds which “soften” the sharpness of the traditional kombucha beverage and formed the unique flavor characteristics of the TBPK3 beverage. Incorporation of Lactobacillus bulgaricus into TBPK3 further decreased its intensity of total acids while increasing the yields of esters and ketones with enhanced floral and fruity aromas. Results of this study may benefit the development of a novel TB beverage with enhanced bioactivity and flavor characteristics, and serve as a reference for the production of functional fermented beverages from other coarse cereals.