Valorization of brewing by-products as protein resources: Extraction, structural insights, functional properties, and...

Distiller's grains (DGS), a rich protein byproduct of brewing, is mainly used as animal feed due to the challenges in protein extraction techniques and the lack of clarity regarding the potential applications. The insufficient development of DGS limits its high-value utilization. Therefore, this work aims to comprehensively review the latest progress in DGS protein separation, elaborate on their structural and functional characteristics, and emphasize potential applications and future research directions. The extraction and application of DGS proteins mainly focus on the total protein as well as specific fractions such as prolamins and glutelins. DGS proteins can be extracted through a series of techniques, including conventional chemical, enzymatic, and physical-assisted methods, which have a significant impact on their structural and functional properties. Their unique functional characteristics have made DGS proteins key components in the fields of bulk food ingredients, drug delivery systems, and bioactive peptide research. In addition, based on their excellent hydrophobicity and assembly properties, the potential of DGS proteins as biodegradable food-grade films is attracting increasing research attention. Future research should innovate extraction methods and identify influential applications to address the problem of protein scarcity in food processing and enhance the value of proteins.