Brewers’ spent grain as a functional ingredient in bakery, pasta, and cereal-based products

The food industry by-product causes a negative environmental impact and reduces resource efficiency and productivity. Although these by-products have been used only for animal feed purposes in the past, there is an emerging trend to use them in human food as well. Brewers’ spent grain (BSG) is a proper example of such industrial by-products; it constitutes about 85 % of the total by-products generated in the brewing industry. With high amounts of fiber and protein, BSG can serve as a formulation ingredient in human nutrition. Accordingly, many studies have tried to investigate the possibility of using it in different food products. Overall, BSG is a promising source of bioactive compounds with antioxidant, antidiabetic, anti-inflammatory, and antithrombotic properties. Enzymatic hydrolysis, fermentation, and extraction conditions can be optimized to enhance the functional attributes of BSG for food, pharmaceutical, and nutraceutical applications. This review elaborated on the possibility of using BSG within bakery, pasta, and cereal-based formulations and its effect on such products' quality and nutritional characteristics. In addition, the functional ingredients of BSG and their biological properties are briefly reviewed. The research results suggest that incorporating BSG into various bakery products can enhance their nutritional value, but the optimal level of addition varies depending on the specific product. Careful optimization is required to balance an improved nutritional profile and acceptable technological and sensory qualities. However, the challenge facing the high-scale utilization of BSG ingredients is the variability of raw material composition. Therefore, more study is needed to develop innovative technologies for integrated and comprehensive valorization of BSG.