Brewers’ spent grain protein: A promising functional ingredient for innovative food applications

Abstract

The global food system is confronted with major challenges including food waste and food insecurity, driving the urgent need to find alternative sustainable food sources. At the same time, the brewing industry faces growing economic and environmental pressure to reduce both energy consumption and waste generation. Brewers’ spent grain (BSG), the dominant by-product of the brewing industry, represents a promising resource due to its widespread availability and rich content of proteins and bioactive compounds. The incorporation of BSG-derived ingredients can enhance the nutritional profile of food products and may contribute to the reduction of diet-related disease risk and associated mortality. Nevertheless, further research and technological innovation are needed to broaden its applications in food manufacturing. This review provides a comprehensive overview of the physicochemical, functional and bioactive properties of BSG protein, as well as its digestibility and role in functional food development, thereby providing valuable insights for brewing by-product valorisation and identifying directions for future research.