Effects of Waxy Maize Starch and Malate-Debranched Waxy Maize Starch on Gut Microbiota of Humans In Vitro and Mice In Vivo

The gut microbiota plays a pivotal role in host health. Dietary components such as waxy maize starch (WMS) and malate-debranched WMS (MADBS) may serve as modulators of microbial composition and function. In this study, the effects of WMS and MADBS on murine gut microbiota in vivo and human fecal in vitro fermentation were investigated. The results of gut microbiota in mice revealed that WMS increased the abundance of <i>Muribaculaceae</i> and <i>Bifidobacterium</i>, while MADBS enriched <i>Ileibacterium</i>, <i>Muribaculaceae</i>, and <i>Dubosiella</i>. The in vitro fermentation model demonstrated that WMS increased the abundance of <i>Bifidobacterium</i>, <i>Lactobacillus</i>, <i>Megamonas</i>, and <i>Megasphaera</i>, whereas MADBS enhanced <i>Weissella</i>, <i>Lactobacillus</i>, and <i>Prevotella</i>. Both compounds decreased the levels of <i>Escherichia-Shigella</i>. Metabolically, compared to the control group, WMS improved the production of acetic, propionic, butyric, and valproic acids, while MADBS decreased the concentrations of all short-chain fatty acids (SCFAs). Compared to the control group, WMS reduced the production of CH₄, NH₃, and H₂S while increasing CO₂ yield. MADBS reduced the generation of CH₄, NH₃, H₂S, and CO₂. These findings suggest that WMS and MADBS can modulate the gut ecosystem by selectively promoting probiotics, inhibiting pathogens, and altering metabolic profiles.