Functional properties of brewer’s spent grain protein isolate: The missing piece in the plant protein portfolio

Abstract: There is currently a gap in the market for highly functional plant-based protein isolates, with a nutritional profile that can compete with animal-based proteins. The development of more sustainable food systems is also a global topic of interest, in particular the upcycling of food processing side-streams. Brewer’s spent grain (BSG) is the major by-product of the brewing industry, with millions of tonnes produced each year. High in protein, BSG could serve as an ideal raw material for sustainable protein isolate production. This study outlines the nutritional and functional characteristics of a novel BSG protein isolate, EverPro, and compares these characteristics to two of the most commonly used plant protein isolates, pea and soy. All three isolates in this study have similar protein contents, however, there is a large variation regarding functionality and nutrition. EverPro displays the highest protein solubility, as well as a high foaming capacity and low sedimentation behaviour in dispersion. EverPro also showed minimal gelling behaviour during heating, unlike the pea and soy isolates. Regarding nutrition, EverPro meets or exceeds the requirement of each essential amino acids per gram protein, with the exception of lysine, while the pea and soy protein isolates are deficient in methionine and cysteine. When compared to some of the most widely studied and accepted plant protein isolates, EverPro shows potential for use in a wide range of products, in particular beverage applications, due to its high functionality and protein quality, allowing an increased level of sustainably produced protein in the global diet.