Antioxidant properties of casein-phosphopeptides

Caseinphosphopeptides (CPP) have been associated with binding of bivalent ions and enhanced solubility of many important minerals, such as calcium and iron. Less is known of the affinity of these bioactive peptides to prevent oxidation reactions through possible primary or secondary antioxidant mechanisms. A CPP preparation derived from spray-dried whole tryptic digests of bovine casein contained unidentified peptides with molecular weights less than 6 KDa and an affinity to sequester Fe2+. Associated with this activity, the CPP also effectively suppressed Fenton reaction-induced site-specific and non site-specific deoxyribose oxidation. In addition, CPP was effective at reducing 2,2′-azobis(2amidinopropane) dihydrochloride; (AAPH-) and Fe2+-induced liposomal peroxidation and showed direct scavenging affinity for the hydrophilic 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid; (ABTS) radical. It can be concluded that CPP derived from bovine casein has both primary and secondary antioxidant properties that specifically involve direct free radical scavenging and sequestering of potential metal prooxidants.