Protein-polyphenol interactions and in vivo digestibility of buckwheat groat proteins

A rat model system, based on a diet with (Nb+) or without (Nb-) the inclusi on of 0.7% of a 2:1 (w/w) mixture of Bacitracin and Neomycin sulfate (Nebac itin) was used to elucidate interactions of polyphenols with proteins in bu ckwheat. The treatment with the antibiotic Nebacitin suppresses the microfl ora in the large intestine and is used to obtain an estimate of the digesti on occurring in the small intestine. Experimental buckwheat samples were ob tained in order to contain different levels of polyphenol and were subjecte d to different hydrothermal treatments. It was found that a considerable in teraction between polyphenols and proteins appeared during the hydrothermal treatment, and this interaction reduces the digestion of proteins through the small and large intestine. Microbial processes in the colon enhance the digestibility of protein, blocked by polyphenols in hydrothermally process ed buckwheat.