Starch–EGCG Complexes Improve Starch Fermentability, Acetate Production, and Alter Relations between Gut Microbiota and Starch Chain-Length Distributions

Epigallocatechin gallate (EGCG), a major catechin in green tea, was selected due to its dietary prevalence and potential synergistic functions with starch. Starch–EGCG complexes represent a form of type 5 resistant starch, but their effects on gut microbiota relative to starch chain-length distribution remain unclear. Using an in vitro fermentation model, we analyzed complexes derived from five starches. All complexes significantly enhanced gas and short-chain fatty acid (SCFA) production. Remarkably, the pea starch–EGCG complex yielded the highest acetate (32.26 mM), whereas chestnut and cassava starch–EGCG complexes generated notable amounts of propionate (3.37 mM) and butyrate (1.52 mM), respectively. These shifts were correlated with altered microbial composition. Notably, the corn starch–EGCG complex markedly increased Prevotella abundance (3.12% to 34.37%). A slowly fermentable starch fraction (peak DP ∼65) was identified and unaffected by EGCG. These findings suggest that starch–EGCG complexes differentially modulate microbial communities and SCFA profiles, highlighting their potential for tailored gut health interventions.