Increased Crystallite Stability Enhances Gut Microbial Fermentability of Type 5 Resistant Starch

The amylolytic susceptibility of starch–lipid complexes with different forms of crystallites has been studied extensively, but the fermentation properties of these complexes remain little understood. Hence, the in vitro fecal fermentation properties of starch–lipid complexes with VI-type and VII-type crystallites were investigated in the present study. Compared to VI-type complexes, fermentation of VII-type complexes caused more severe disruption to the crystallites and resulted in greater acid, reducing sugar, and short-chain fatty acids (SCFAs) production. Moreover, fermentation of VII-type complexes promoted a greater relative abundance of SCFAs-producing bacteria in the fecal microbiota than did VI-type complexes. Our results show that the more stable VII-type complexes are utilized more effectively than VI-type complexes, which can be attributed to the bacteria binding more readily to VII-type than to VI-type complexes. Therefore, VII-type complexes were considered to deliver better health benefits than VI-type complexes due to their greater potential for producing SCFAs and stimulating beneficial gut microbial activity in the colon.