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 <i>Prevotella</i> 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.