Despite being a promising butyrate carrier, butyrylated starch remains poorly understood in terms of the correlation between starch structure and fermentation characteristics. Herein, three butyrylated starches derived from different botanical sources were prepared with a similar degree of substitution. Raman microscopy and water contact angle analysis suggested that a relatively large proportion of butyl group substitutions occurred within the interior of butyrylated waxy maize starch (B-WMS) granules. In vitro digestion results showed that branch points provided butyl groups with a specific protection from enzymatic hydrolysis, whereas butyl groups significantly increased the resistant starch content of butyrylated starch. Moreover, the porous morphology with less distributed butyl groups on the granular surface contributed to a faster fermentation rate in B-WMS. The current study reveals the influence of botanical origin on butyl group distribution, which in turn plays a pivotal role in regulating the intestinal digestion and colonic fermentation of butyrylated starch.
Keywords: Botanical origin; butyl group distribution; butyrylated starch; in vitro digestion; in vitro fermentation.