Brewers' spent grain: a review with an emphasis on food and health

Brewers' spent grain (BSG) is the most abundant by-product generated in the beer-brewing process. This material consists of the barley grain husks obtained as solid residue after the production of wort. BSG is rich in fibre and protein and, to date, the main use for the elimination of this by-product has been as an animal feed. However, because of its nutritional content, BSG is of interest for application and fortification of human food products, particularly in view of its low cost and availability in large amounts. In addition, the importance of BSG as an ingredient and potential source of health-promoting bioactive components is beginning to be recognised. The investigation of alternative uses of BSG is pertinent, not only from the perspective of the brewer who can benefit from valorisation of this by-product, but also from an environmental perspective as the recycling and re-use of industrial wastes and by-products has become increasingly important. This review presents the current knowledge on BSG, covering its production, composition and methods for the release of valuable components, and focuses on the potential health benefits attributed to its constituents and the use of this brewer by-product in food applications.