Evaluation of the Fermentation Characteristics of Prebiotic-Containing Granola and Short-Chain Fatty Acid Production in an In Vitro Gut Microbiota Model.

Abstract

Mammalian gut microbiota is essential for host metabolism and immune function and produces short-chain fatty acids (SCFAs) via fermentation of dietary fibers and prebiotic materials. In this study, we aimed to investigate the effects of prebiotic-containing granola on SCFA production and gut microbiota composition using an in vitro pig feces anaerobic fermentation model. Six prebiotic materials (inulin, resistant starch, fructooligosaccharides, galactooligosaccharides, cacao mass, and barley) were added to granola, and their fermentation characteristics were evaluated. SCFA analysis revealed that prebiotic materials significantly increased the total SCFA production after 48 h, with inulin, fructooligosaccharide, and galactooligosaccharide showing the highest production. Bacterial growth was enhanced in multiple genera; however, the growth varied with different prebiotics. Previous studies have suggested the presence of responders and non-responders to individual prebiotics, emphasizing the need to combine diverse prebiotics to overcome such variations. Prebiotic-containing granola, but not prebiotic material, significantly increased the abundances of <i>Blautia</i> and <i>Prevotella</i> bacteria. Additionally, prebiotic-containing granola significantly increased the abundance of all bacteria more than granola alone. Base granola only exhibited high fermentability, whereas prebiotic-containing granola modulated the gut microbiota populations and enhanced SCFA production. These findings highlight the benefits of combining prebiotics with granola, suggesting that dietary interventions alter the gut microbiota composition and metabolism. Our results provide valuable insights and can contribute to future human trials of the investigated compounds.