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 V_I-type and V_II-type crystallites were investigated in the present study. Compared to V_I-type complexes, fermentation of V_II-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 V_II-type complexes promoted a greater relative abundance of SCFAs-producing bacteria in the fecal microbiota than did V_I-type complexes. Our results show that the more stable V_II-type complexes are utilized more effectively than V_I-type complexes, which can be attributed to the bacteria binding more readily to V_II-type than to V_I-type complexes. Therefore, V_II-type complexes were considered to deliver better health benefits than V_I-type complexes due to their greater potential for producing SCFAs and stimulating beneficial gut microbial activity in the colon.