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

To address the pressing dual challenge of meeting global protein demand while mitigating environmental impacts, the food sector must transition to a circular bioeconomy. In this context, this review comprehensively examines the valorization of plant and animal byproducts, emphasizing how the recovery and application of their inherent bioactive and functional compounds can transform waste into high-value resources. Plant processing residues, such as fruit peels and pomace, and animal residues, such as blood and bones, are increasingly recognized as untapped sources of functional ingredients. These by-products yield bioactive compounds with health benefits. Simultaneously, the same or different compounds serve as structural building blocks, offering valuable technological properties. They improve water-holding capacity, texture, and emulsion stability in both traditional meats and plant-based analogs. 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.