Carbohydrates: How structural features influence digestion-fermentation kinetic parameters

Carbohydrates are the principal energy source for humans and livestock, but their structures affect digestion and fermentation differently in the gut. Despite their importance, a comprehensive understanding of mechanisms linking specific structural hierarchies to the kinetics of digestion and fermentation remains fragmented. This review posits that the digestion and fermentation kinetics of carbohydrates are primarily regulated by their intrinsic hierarchical structural features, spanning from molecular architecture and crystalline polymorphism to granule morphology. Specifically, we synthesize published work on structural factors affecting starch digestion and non-digestible carbohydrate structures. Key structural attributes, such as molecular weight and relative crystallinity, are highlighted for their consistent roles in modulating enzymatic accessibility and microbial degradation. Ultimately, elucidating the kinetic patterns of carbohydrate digestion and absorption is essential for refining nutritional models, highlighting the need for future research on the carbohydrate digestion and fermentation kinetics of mixed-nutrient interactions to achieve precision nutrition.