<i>In Vivo</i>and<i>in Vitro</i>Digestibility of Soybean, Lupine, and Rapeseed Meal Proteins after Various Technological Processes

Abstract

Anti-nutritional factors and technological processes may modify the nutritional quality of plant proteins. Heated rapeseed meal, soybean, and lupine proteins dried by various processes were used to compare in vivo methods of nutritional quality measurement such as protein efficiency ratio and true digestibility (TD) to in vitro methods such as pH-stat giving degree of hydrolysis (DH) and digestion cell giving nitrogen digestibility (ND). Combined methods taking into account amino acid score were as follows: PDCAAS (protein digestibility-corrected amino acid score) derived from TD, NDCAAS (nitrogen digestibility-corrected amino acid score), and DHCAAS (degree of hydrolysis-corrected amino acid score). Correlations (p < 0.001) were 0.81 (TD vs DH) and 0.88 (TD vs ND). PDCAAS was significantly (p < 0.001) correlated with DHCAAS or NDCAAS (r = 0.92 and 0.98, respectively). Time-consuming and expensive TD determination could be supplanted by both in vitro methods; DHCAAS and NDCAAS could replace PDCAAS. Keywords: Plant proteins; nutritional protein value determination; in vivo methods; in vitro methods; combined methods; correlation between several methods