Plant Proteins and Bioactive Peptides: Distinguishing Nutritional Quality from Sequence-Dependent Bioactivity

Plant proteins represent both important nutritional resources and reservoirs of encrypted bioactive peptide sequences. However, protein nutritional quality and peptide bioactivity are distinct properties: a favorable indispensable amino acid profile or high digestibility does not necessarily predict the generation of biologically active peptides. This review examines plant-derived proteins and peptides with particular emphasis on the relationship between parent-protein composition, peptide release, sequence-dependent activity, analytical identification, and biological validation. The relevant peer-reviewed literature was critically evaluated, with detailed search and selection criteria. Major plant protein sources, peptide-generation strategies, purification and mass-spectrometric characterization approaches, and reported antioxidant, antimicrobial, antihypertensive, antidiabetic, anti-inflammatory, and other regulatory activities are discussed. Particular attention is given to experimentally validated peptide sequences and to the hierarchy of evidence from computational prediction and biochemical assays to cellular, animal, and human studies. Structure–activity relationships are interpreted cautiously, recognizing that peptide length, charge, hydrophobicity, and individual amino acid residues are contributory rather than independently predictive features. The review further integrates computational prediction with experimental validation and highlights gastrointestinal stability, intestinal transport, bioavailability, safety, scalability, and regulatory considerations as major translational challenges. This evidence-based framework distinguishes nutritional adequacy from peptide function and supports more rigorous development of plant-derived bioactive peptides for functional-food, nutraceutical, and related applications.