Bioactive Peptides from Animal By-Products: Production, Functional Evidence and Food Applications.

Animal-processing by-products contain collagen, myofibrillar proteins, blood proteins, whey proteins, and egg proteins that can be converted into peptide-rich food ingredients. Within a single application-oriented framework, this review integrates source heterogeneity, process control, peptide-profile characterization, tiered functional evidence, food-matrix performance, and regulatory substantiation. Evidence is evaluated for antioxidant, ACE-inhibitory, antimicrobial, DPP-IV-inhibitory, anti-inflammatory, mineral-binding, and taste-modulating functions, while distinguishing chemical assays, cell models, animal studies, human interventions, and tests in real-food matrices. Potential applications include functional foods, dietary supplements, natural preservation, flavor systems, texture modification, active packaging, and oral delivery. Translation remains limited by raw-material heterogeneity, batch variability, sensory defects, processing and gastrointestinal instability, uncertain bioavailability, incomplete safety assessment, and poorly defined regulatory claims. Future work should prioritize source traceability, peptide fingerprints, food-matrix validation, human exposure data, and scalable food-grade production. Compositionally defined peptide mixtures with reproducible functionality may be more practical than single highly purified sequences.