Define Influence of Polyphenols on Proteins?

You know that tannins are considered as anti-nutritional because their presence is usually accompanied by a reduced protein digestibility and a subsequent increase in the faecal nitrogen. Decreased protein digestibility may be due to the formation of 'protein-tannin complex', as well as, inhibition of proteolytic enzymes like lrypsin by polyphenols. Polyphenols have exhibited a highly significant and negative correlation with in vitro digestibility of proteins. However, this may have a beneficial effect in overweight or obesity, since tannins bind to endogenous proteins in the intestinal tract such as digestive enzymes like lipase and amylase and inhibit them, resulting in lower energy availability.