Effect of Myoinositol Phosphate Esters on In Vitro and In Vivo Digestion of Protein

Abstract

Effects of phytate and its hydrolysis products (myo-inositol phophate esters) on protein digestion were investigated by in vitro and in viva procedures. Tri-, tetra-, penta-, and hexa-phosphate ester fractions, isolated from phytate hydrolysates, inhibited pepsin digestion of casein and bovine serum albumin in vitro. The inhibition ranged from 0% for the mono-and diphosphate esters to 9-14% with the hexdphosphate ester (phytate). The phosphate ester fractions did not significantly affect trypsin digestion of the proteins. In the in vivo study, rats were fed phytate and hydrolysates thereof (mixtures of the esters above) at levels of l-3.5% of the diet. Under the conditions of this study, neither phytate nor its hydrolysates significantly affected protein utilization or weight gain in rats.

Effect of dietary phytate and phytase on proteolytic digestion and growth regulation of broilers

“…These results are in agreement with in vitro studies that phytate significantly inhibited the peptic or tryptic digestion of proteins (Singh and Krikorian 1982;Knuckles et al 1985Knuckles et al , 1989Vaintraub and Bulmaga 1991;Caldwell 1992). However, limited in vivo research has been conducted in this area.…”

Myoinositol Phosphates: Analysis, Content in Foods and Effects in Nutrition

“…However, this was not reflected in vivo (162). It was later found that the presence of phytate inhibits the digestion of proteins and does not affect the hydrolysis of low molecular weight substrates (163).…”

Consequences of calcium interactions with phytate and phytase for poultry and pigs

“…This initial, rapid step is followed by a progressive protein-protein aggregation that may result in precipitation (Rajendran and Prakash, 1993). The crucial proposition is that phytate-bound protein is refractory to pepsin digestion (Camus and Laporte, 1976;Knuckles et al, 1985Knuckles et al, , 1989. Camus and Laporte (1976) attributed inhibition of pepsin digestion by phytate to the formation of insoluble protein-phytate complexes under acidic conditions.…”