Undigested glycated lentil proteins modulate the gut microbiota profile but not the metabolites in vitro

Glycation enhances plant protein techno-functionality; however, digestibility and the equilibrium between peptides absorbed and those reaching the colon can be altered. This study evaluated how undigested glycated lentil proteins, potentially reaching the colon affect the gut microbiota using batch fermentation and the Simulator of Human Intestinal Microbiome Ecosystem (SHIME®). Lentil protein-fructose mixtures were incubated at 60 °C for 0, 24, or 48 h (conjugates labelled LP+Fr0, LP+Fr1, LP+Fr2). Maillard reaction markers increased by over 10-fold and in vitro protein digestibility decreased by 23.5 % after 48-h incubation. Short- and branched-chain fatty acids produced by 48 h-fermentation of the insoluble hydrolysates of conjugates were comparable. LP+Fr2 hydrolysates caused 42 % relative increase in Bacteroidetes in the proximal colon of Donor 1 whereas 26 % increase was observed with LP+Fr0 hydrolysates. Bacteria population profile in the colon sections was differentially modulated depending on the donor. Our findings show that the extent of glycation does not affect short- and branched-chain fatty acid levels produced in the colon, while the effect on microbiota population is dependent on host and colon section.