Deciphering the colonic fermentation characteristics of agavin and digestion-resistant maltodextrin in a simulated batch fermentation system

Gut microbial fermentation of soluble dietary fibers promotes general and substrate-specific health benefits. In this study, the fermentation characteristics of two soluble branched-dietary fibers, namely, agavin (a type of agave fructans) and digestion-resistant maltodextrin (RD) were investigated against cellulose, using a simulated colonic fermenter apparatus employing a mixed culture of swine fecal bacteria. After 48 h of complete fermentation period, the microbial composition was different among all groups, where Bifidobacterium spp. and Lactobacillus spp. dominated the agavin treatment, while the members of the families Lachnospiraceae and Prevotellaceae dominated the RD treatment. Agavin treatment exhibited a clearly segregated two-phased prolonged fermentation trend compared to RD treatment as manifested by the fermentation rates. Further, the highest short-chain fatty acids production even at the end of the fermentation cycle, acidic pH, and the negligible concentration of ammonia accumulation demonstrated favorable fermentation attributes of agavin compared to RD. Therefore, agavin might be an effective and desirable substrate for the colonic microbiota than RD with reference to the expressed microbial taxa and fermentation attributes. This study revealed a notable significance of the structural differences of fermentable fibers on the subsequent fermentation characteristics. • Agavin showcased a higher relative abundance of genus Bifidobacterium and Lactobacillus. • Digestion-resistant maltodextrin influenced a higher abundance of members of families Lachnospiraceae and Prevotellaceae. • Agavin exhibited favorable temporal variations in the total short-chain fatty acids production, pH and ammonia production. • Agavin is an effective and desirable substrate for the colonic microbiota than cellulose and digestion-resistant maltodextrin.