Potential prebiotic effects of nonabsorptive components of Keemun and Dianhong black tea: an in vitro study

Black tea is a healthy and popular tea beverage. However, its main bioactive compounds (theaflavins and thearubigins) are not easily absorbed. The aim of this study was to investigate the modulation of intestinal microbiota by the nonabsorptive components of Keemun black tea (KBT) and Dianhong black tea (DBT), and fructooligosaccharide (FOS) was selected for use in the control group. KBT, DBT, and FOS significantly increased total short-chain acid production. Specifically, FOS treatment predominantly increased the production of acetic acids and black tea treatments increased the production of acetic, propionic, and butyric acids at similar rates. Moreover, FOS exerted a strong bifidogenic effect after 24 h of fermentation; KBT and DBT increased the abundance of the beneficial genus Bacteroides and Roseburia. In summary, the nonabsorptive components of KBT and DBT could serve as novel prebiotics, the underlying mechanisms of which are quite different from those of FOS.