Research Progress on Bioactive Peptides From Diverse Sources: Preparation, Structure-Activity Relationship, and Applications.

Bioactive peptides (BAPs) derived from animal, plant, and microbial proteins have attracted considerable interest because of their potential antioxidant, antihypertensive, antimicrobial, and immunomodulatory activities. However, differences in protein matrix structure, amino acid composition, and non-protein components influence peptide release, structural characteristics, activity, and food-use potential. This review summarizes recent progress in the preparation, structure-activity relationships, and applications of BAPs from diverse sources, with particular emphasis on biomimetic enzymatic hydrolysis and microbial fermentation. The two approaches are compared in terms of substrate suitability, peptide release, downstream processing, sensory properties, scalability, and application scenarios. The review further discusses how molecular weight, amino acid composition, sequence arrangement, conformation, and post-translational modification may contribute to peptide activity, while emphasizing that source-level trends are not universal and require sequence- and assay-specific validation. Finally, current challenges related to gastrointestinal stability, bioaccessibility, safety, regulatory requirements, purification, cost, and commercialization are discussed, together with the potential and limitations of AI-assisted peptide discovery.