Recent understanding of resistant starch type 5 (RS5) and its role in modulating gut microbiota

Resistant starch type 5, characterized by its V-type complexes with guest molecules, has emerged as promising prebiotic for gut microbiota modulation. This review systematically summarized recent advances in resistant starch type 5's structural properties, preparation methods, and gut microbial interactions. Its unique V-type crystalline structure, particularly V_II-type complexes with higher thermal stability (melting point: 115-130 °C), enhances resistance to enzymatic digestion. Both in vitro and in vivo studies support their superior production of total short-chain fatty acids up to ∼300 %, primally including acetate, propionate, and butyrate, as well as the enrichment of beneficial taxa such as Bifidobacterium (up to 1.5-3-fold) and Lactobacillus (up to 2-fold). However, mechanisms underlying its microbial modulation and structural evolution during fermentation remain unclear, and human trials are scarce. Future research should prioritize standardized protocols for cross-study comparisons, mechanistic exploration of resistant starch type 5-gut microbe interactions, and clinical validation to optimize its application in functional foods.