Health Benefits of High Protein and Dietary Fiber Dry-Fractioned Brewery Spent Grain Fines

The use of organic byproducts, such as brewery spent grain (BSG), a major byproduct of the beer-brewing industry, has increased in recent years. BSG is rich in fiber, proteins, polyphenols, vitamins, and minerals, as all these compounds remain untapped during the brewing process and is considered a potential source of bioactive molecules with potential health benefits. In this study, two BSG types, regular and a fines fraction, were evaluated. Proximate, amino acid, and dietary fiber analyses were performed to compare the characteristics of both BSG types. Protein increased from 19.4% in regular BSG to 26.9% in BSG fines, while total dietary fiber was reduced from 46.4% to 34.4% in BSG fines. An experimental murine study was conducted where both BSG types were incorporated into a high fat diet formulation at a concentration of 40% to determine whether consumption of these byproducts can provide potential health benefits. A decrease in weight, systemic levels of leptin, and liver fat were observed in mice with BSG incorporated in their diets. Changes in the gut microbiome with an increase in Firmicutes and Bacteroidota and a decrease in Actinobacteria phylum were also observed. Our results indicate that dry fractionation is a feasible technology to increase protein content of BSG and that BSG byproducts in diet may have potential health benefits.