Antioxidant peptides from edible aquatic animals: Preparation method, mechanism of action, and structure-activity relationships

Peptides with strong antioxidant activity have been increasingly extracted from various edible aquatic animals, as natural substitutes for synthetic antioxidants. In this paper, a systematic review of the research progress on the enzymatic hydrolysis strategy and structure-activity relationship of antioxidant peptides from edible aquatic animals, especially marine animals, over the last decade was presented. The selection of enzymes varied markedly among organs and tissues. Tools and indicators used in the purification and identification process were clarified. The similarity and the difference in structure and antioxidant activity between vertebrate-derived peptides and invertebrate-derived peptides were discussed. The stability of antioxidant peptides was reviewed. Most peptides could maintain activity under mild conditions, but they hardly resisted gastrointestinal digestion. The poor ability of peptides to cross the small intestinal epithelium in prototype form brought a challenge for food and pharmaceutical applications.