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L. NELSON¹, A. Rao, and P. Olson. (1) Applications, Davisco Foods International, Inc., 11000 West 78th St., Suite 210, Eden Prairie, MN 55344

Hydrolyzed whey protein isolate (WPI) is a highly purified ingredient, hydrolyzed under controlled conditions to obtain unique functional and nutritional properties. The enzymatic hydrolysis process produces protein ingredients designed for nutritional, dietetic and medical foods. The hydrolysis of the WPI manufactured using ion-exchange technology produces antihypertensive (bioactive) peptides, which suppress angiotensin converting enzyme (ACE). ACE catalyses the degradation of angiotensin I into angiotensin II, a strong vasoconstrictor. Hypertension is considered to be the most important cause of human deaths in industrialized countries. The study of the physiological mechanisms responsible for hypertension has lead the pharmaceutical industry to propose ACE-inhibitory substances. The inhibitory effect of natural peptides has been related to their binding at the active site of ACE. While other manufacturers have produced hydrolyzed whey protein ingredients, laboratory tests have shown that Davisco's hydrolyzed WPIs provide uniquely effective peptides for the ACE-inhibiting activity. ACE-inhibitory activity values or IC₅₀ (concentration of protein hydrolysate material inhibiting 50% of ACE activity), as determined in vitro, are in the range of 0.30 to 0.50 mg/ml, compared to 0.96 to 1.3mg/ml for other commercially available whey protein hydrolysates. The enzymatic hydrolysis of WPI leads to a synergistic effect in terms of ACE-inhibitory potential of the hydrolysates obtained. It appears that the synergy could result from unique compositional characteristics brought by the ion-exchange process in combination with the use of specific enzymes. These characteristics are responsible for specific functional and sensory properties. The molecular weight distribution of the commercial hydrolysates is not only the result of the nature of the protein and of the specificity of the enzyme used, but is also strongly affected by the severity of the heat treatment applied for enzyme inactivation at the end of the reaction. The results are food additives to combat one of the nation's most destructive health problems.