Bioactive peptides derived from bovine whey proteins: opioid and ace-inhibitory peptides

Abstract

Regulatory peptides can be released by enzymatic proteolysis of food proteins and may act as potential physiological modulators of metabolism during the intestinal digestion of the diet. The possible regulatory effects of peptides relate to nutrient uptake, immune defence, opioid and antihypertensive activities. Milk proteins, especially caseins, are an important source of these bioactive peptides. During recent years, major whey protein components, α-lactalbumin and β-lactoglobulin, were also shown to contain bioactive sequences. Peptides showing opioid and angiotensin I-converting enzyme (ACE) inhibitory activity were found in α-lactalbumin and β-lactoglobulin. Opioid peptides, α-lactorphin and β-lactorphin, were liberated during in vitro proteolysis of bovine whey proteins, and pharmacological activity was observed at micromolar concentrations. Whey hydrolysates showed ACE-inhibitory activity after proteolysis with different digestive enzymes, and several active peptides were identified. The results demonstrated the existence of several biologically active whey-derived peptides and hydrolysates. The findings of the study can be exploited in the development of foods with special health claims (e.g. treatment of hypertension) as well as in identifying new applications in food.