Wheat germ protein in functional foods: structure, processing, applications, and mechanistic insights

As a sustainable plant protein resource, wheat germ protein (WGP) has attracted increasing attention because of its high digestibility, balanced essential amino acid profile, and broad potential in functional food development. However, its industrial application remains limited by processing bottlenecks and an incomplete understanding of its structure-function relationships and molecular mechanisms of action. This review systematically summarizes the structural characteristics, digestion behavior, and functional properties of WGP, and further evaluates its incorporation into diverse food matrices, particularly bakery products, meat analogues, and other functional formulations. In addition, current evidence on the physiological activities of WGP and its derived bioactive peptides is critically examined, with emphasis on antioxidant, antihypertensive, immunomodulatory, neuroprotective, and metabolic regulatory effects, together with the signaling pathways involved. Available studies indicate that WGP-derived peptides exert health-promoting effects not only through activation of key pathways such as Nrf2 and AMPK, but also through modulation of systemic homeostasis via the gut-brain and gut-liver axes. Overall, this review highlights the need to move beyond conventional nutritional fortification toward a mechanism-oriented design strategy, and provides a theoretical basis for the development of next-generation functional foods and specialized medical nutrition products based on WGP.