The development of functional foods and dietary supplements based on food proteins and their bioactive peptides is currently a topic of great interest. Peptides can directly influence physiological systems and exert beneficial effects in humans. These peptides may act locally within the gastrointestinal tract or be absorbed from the intestinal mucosa and transported throughout the body. These properties make them attractive as alternative therapies to pharmacological drugs that are often limited in their clinical effectiveness, require lifelong adherence and carry the risk of side-effects (106).
The biological activity of bioactive peptides depends on their structure, formation and chemical characteristics. Peptides containing aromatic amino acids such as histidine, glutamic acid and tyrosine are known to exhibit antioxidant properties. These peptides are able to interact with pro-oxidant metal ions, scavenge free radicals and inhibit lipid peroxidation by the donation or trapping of electrons. Cystine, methionine and threonine-containing peptides have been shown to possess antimicrobial properties.
Food-derived peptides also offer the advantage of being perceived as “natural” and therefore more acceptable to consumers, than synthetic peptides. However, the peptides must be able to survive enzymatic digestion and to be absorbed in sufficient quantities in order to exert their effect.
In addition, the food-derived peptides must be sufficiently stable to resist degradation by endogenous peptidases in the digestive tract and thermal processing. The peptides must be readily separated from the other proteins in the food matrix using separation techniques such as SEC, IEF and HPLC with tandem mass spectrometry.