Detection of bacteria affected by roasted burdock tea powder and fructooligosaccharide in human faecal culture.

BACKGROUND

Burdock root is rich in gut fermentable fructan (inulin). This study aimed to clarify the effects of processed foods containing burdock on the gut microbiota by inoculating faecal slurries into cultures containing roasted burdock tea powder.

METHODS AND

RESULTS

Human faecal slurries (n = 5) were inoculated into cultures containing 4% (w/v) roasted burdock tea powder that washed with 85% (v/v) ethanol (WBT), 0.4% fructooligosaccharide (FO), or both WBT and FO (BF). After 24 h of anaerobic incubation, lactate and acetate levels significantly increased in the BF and WBT cultures. Putrefactive compounds, such as ammonia and indole, were suppressed in BF and WBT cultures. Analysis of 16S rDNA (V3-V4 region) amplicon sequencing revealed that WBT increased the abundance of Bifidobacterium and Faecalibacterium spp. more than twofold; however, the effect varied among individuals. The amplicon sequences were used to predict metabolic functions using Tax4Fun and the Kyoto Encyclopedia of Genes and Genomes database. Histidine biosynthesis was suggested to be promoted in WBT cultures.

CONCLUSION

This in vitro study provides novel insights into the gut microbiota, typical WBT-responsible gut indigenous bacteria, such as Bifidobacterium and Faecalibacterium spp., and fermentable dietary fibre. Overall, these findings show the potential applications of burdock.