Valorization of By-Products for Functional Ingredients in Meat and Meat Replacers: A Circular Bioeconomy Approach

The food industry faces the dual challenge of meeting a global protein demand projected for 11.2 billion people by 2100 while mitigating environmental impacts. This review explores the valorization of agri-food by-products within a circular bioeconomy, shifting from a linear "take-make-dispose" model to one prioritizing resource efficiency. Processing residues such as fruit peels, pomace, animal blood, and bones is increasingly recognized as an untapped source of functional ingredients. These by-products provide bioactive compounds—such as polyphenols, carotenoids, and peptides—that offer antioxidant and cardioprotective health benefits. Simultaneously, technological compounds such as dietary fibers, collagen, and hydrocolloids serve as structural building blocks. They improve water-holding capacity, texture, and emulsion stability in both traditional meats and plant-based analogues. While upcycling these materials reduces disposal costs and formulation expenses, challenges remain regarding compositional variability, regulatory barriers, and consumer perception of "waste-derived" ingredients. Ultimately, integrating advanced processing technologies such as enzymatic hydrolysis and fermentation is essential to building a resilient, sustainable, and circular global food system.