Pea proteins : from their function in the seed to their use in animal nutrition

Abstract

Pea is a protein-rich crop of European origin of particular interest for use in animal nutrition (monogastrics). The main function of proteins in the seed is to constitute a reserve of nitrogen and amino-acids. As a result, these proteins have developed certain characteristics : they are very compact in nature and resistant to hydrolysis before germination. In animal nutrition, pea protein digestibility is variable, and generally lower than soya protein (control diets). Protein digestibility can be limited at different steps of digestion : at the step of hydrolysis by digestive enzymes, during the absorption of hydrolysis products, or by a reaction of animals to the diets, that could result in an increase in endogenous proteins loss. Different hypotheses have been proposed to explain the limitation of pea protein digestibility : trypsin inhibitors, lectins, fibres, the particular structure of proteins and their antigenic nature. The application of various technological treatments may have positive (protein denaturation, inhibitors inactivation, loss of cellular structures) or negative effects (reticulation, insolubilisation) on pea protein digestibility.