The Silent Revolution of Brewer's Spent Grain: Meat/Food Innovations Through Circularity, Resource Recovery, and Nutritional Synergy-A Review.

Brewer's spent grain enhances nutritional quality by increasing fiber and plant-based proteins and reducing the need for synthetic additives. Technologies such as extrusion and fermentation transform BSG into functional ingredients that improve texture and stability. A significant increase in antioxidant capacity was observed in enriched foods; for example, in burgers, BSG improved fiber and protein levels, while decreasing fat and calories without negatively affecting sensory acceptance. In sausages, substituting 5% of pork with BSG achieved acceptance similar to traditional formulations, and hybrid formulations with BSG maintained improved protein content while preserving texture. However, concentrations above 20% may negatively impact sensory and technological properties, by introducing undesirable flavors or altering texture. Thus, BSG is a promising source of high-value functional ingredients that contribute to the circular economy and healthier, sustainable foods. Nonetheless, more in vivo studies are needed to validate the health benefits, understand the interactions in complex matrices, assess the shelf life, and evaluate the long-term sensory perception. The "Silent Revolution" of BSG requires a multidisciplinary approach that integrates science, technology, sustainability, and effective communication with consumers.