Pea proteins : structure, extraction and functionalities

Plant proteins, and in particular those derived from legumes, offer interesting prospects in the context of a growing global demand for protein. Yellow pea proteins in particular have received particular attention since the early 2000s to meet the needs of both animal feed and human nutrition. They can represent an alternative to soy proteins, which are widely used for food applications that aim to replace products of animal origin. Yellow peas are grown in temperate and even continental regions. The seed contains around 25% protein, but is also rich in starch. Pea protein is therefore a co-product of the starch industry, and is available in the form of concentrates or isolates. For human consumption, the production of these proteins, reputed to be non-GMO and non-allergenic, is in line with market demand.

Compared with animal proteins such as milk or egg, pea proteins have poorer nutritional, functional and organoleptic qualities. These weaknesses can be explained by their amino acid composition, their heterogeneity of composition and structure, their poorer solubility and their characteristic "leguminous" taste, all of which are difficult to erase using current processes. Indeed, current extraction processes recover either a fraction of complex proteins (concentrates) or purer proteins (globulins in the form of isolates), which are generally not very soluble. Until now, for economic reasons, the industry has favored protein yield rather than advanced fractionation or the correct functionalization of these compounds. Nevertheless, the use of these proteins is spreading in various sectors of the food industry, notably as emulsifiers for sauces, ready-made meals, dairy products and ice creams, meat preparations and cold meats; and, as a protein supplement, for minced meat preparations, health foods, sports foods, bakery products, pastries and snacks. In addition, it seems possible to modulate the techno-functional (solubility, gelling, foaming and emulsifying power, etc.) and organoleptic aptitudes of these proteins, firstly through varietal selection, then through production processes, and finally when they are used in food products. The efforts made by industry and research to improve these properties are promising, and point to a wider use of these plant protein materials in human food.

In order to gain a better understanding of the properties of pea proteins for use in foods, this article successively presents the characteristics of the proteins in terms of structure and composition, the processes for preparing protein concentrates and isolates, their functional aptitudes and their exploitation in food applications.

A glossary and table of acronyms are provided at the end of the article.