Bifidogenic property of enzymatically synthesized water-insoluble alpha-glucans with different alpha-1,6 branching ratio

Bifidobacteria uses insoluble resistant starch (RS) fractions as prebiotics in the colon, consequently improving human intestinal health. In this study, various alpha-1,6 linkage ratios of insoluble alpha-glucans were synthesized by amylosucrase from Neisseria polysaccharea and glycogen branching enzyme from Rhodothermus obamensis to investigate the effect of branching patterns on Bifidogenic property. Different ratios (0%-4%) of alpha-1,6 branched insoluble alpha-glucans with alpha-1,4 linked backbones were effectively synthesized. Additionally, the proportions of RS fraction in the synthesized alpha-glucans were 69.5%-81.9% after the cooking process, which are higher amounts than amylomaize VII (36.8%). As various Bifidobacteria used the insoluble branched alpha-glucans, the structure with 2.5% of 1,6 linkage showed the highest consumption yield, more than 70%, among all tested strains. Therefore, the insoluble alpha-glucans with different alpha-1,6 linkage ratios can be applied as prebiotic ingredients to modulate the Bifidobacterium species to enhance colon health and related outcomes.