Bioactive Peptides from Andean Crops: Lactic Acid Bacteria Fermentation, Complementary Proteolysis, and Biological Activities

Andean crops, including quinoa (Chenopodium quinoa), amaranth species including kiwicha (Amaranthus caudatus), chocho (Lupinus mutabilis), and cañihua (Chenopodium pallidicaule), constitute promising protein matrices for bioactive peptide generation by microbial fermentation and enzymatic proteolysis. These pseudocereals and legumes contain storage proteins, mainly 11S globulins and 2S albumins, enriched in lysine and sulfur-containing amino acids, and therefore provide suitable precursors for multifunctional peptides. In addition, secondary metabolites, such as quinoa saponins and chocho alkaloids, may influence proteolysis, peptide release, and peptide stability during fermentation. This review critically examines LAB fermentation as a food-grade strategy for bioactive peptide production from Andean crops. Evidence from enzymatic hydrolysis and simulated gastrointestinal digestion is included as complementary information and is discussed separately from fermentation-derived evidence. Reported activities include antioxidant, ACE-inhibitory, DPP-IV- and α-glucosidase-inhibitory, antimicrobial and anti-inflammatory activities. Particular attention is given to peptide generation, molecular-weight fractionation, peptidomic characterization, structure–activity relationships, simulated gastrointestinal digestion, and bioaccessibility. Most reported activities were measured in hydrolysates or molecular-weight fractions rather than in defined sequences, and individually validated peptides remain a minority. The strength of evidence differs markedly among crops: fermentation-derived data are more developed for quinoa and amaranth, whereas evidence for chocho and cañihua relies largely on enzymatic hydrolysis. Current limitations, including substrate variability, sensory acceptability, process standardization, peptide identification, bioavailability, and the lack of human validation studies, are also discussed. Andean crop proteins are promising precursors of functional peptide ingredients; however, peptide-specific bioavailability and human efficacy remain largely untested.