Esterification of high amylose starch with short chain fatty acids modulates degradation by Bifidobacterium spp.

Large bowel luminal short chain fatty acids (SCFA) are protective against gut diseases such as colorectal cancer, Crohn's disease and ulcerative colitis. High amylose maize starches acylated with acetic, propionic or butyric were previously shown to deliver SCFA to the gut and increase gut SCFA. This study examines the ability of five Bifidobacterium spp. (B. longum, B. breve, B. infantis, B. adolescentis and B. bifidum), Ruminococcus bromii and Faecalibacterium prausnitzii to degrade starches acylated with SCFA. Release of SCFA from modified starches was not observed, suggesting no preferential hydrolysis of the SCFA ester bond over the glycosidic bond. Acetylated and propionated starches are more readily degraded than either the base or butyrated starches in tested cultures. These observed differences may depend on modification to the starch structure. These structural differences alter the kinetics of starch digestion, irrespective of bacterial type, which may impact current approaches of prebiotic selection.