Influence of Nonenzymatic Browning Reactions on the Digestibility and Gut Microbiota Fermentation of Starch and Protein

Cooking has dramatic effects on the digestion and fermentation of food components. The changes that occur to starch and protein during nonenzymatic browning (NEB) have garnered attention due to health concerns. Among these changes, Maillard reaction, caramelization, and oxidation have major effects on starch and protein digestibility, as well as gut microbiota fermentation. The purpose of this review is to discuss how NEB reactions influence the digestibility of starch and protein from food materials and how this might affect gut fermentation with an emphasis on the implications for human gut health. Different reactions that happen during NEB can alter starch and protein digestibility differently. Maillard reaction products (MRPs) can decrease starch digestibility directly by reacting with starch and indirectly by inhibiting amylolytic enzymes. MRPs have a dichotomous effect on the gut microbiome, where they simultaneously increase the production of the beneficial microbial metabolite, butyrate, while also enriching for detrimental sulfate-reducing bacteria. A greater understanding of the effects of NEB on protein and starch digestibility and gut microbiota fermentation holds promise for advancing the development of healthier cooking techniques, potentially leading to meaningful improvements in health-promoting foods.