Physiological Functions of Enzymatic Hydrolysates of Collagen or Keratin Contained in Livestock and Fish Waste

We studied the physiological functions of enzymatic hydrolysates of collagen or keratin contained in livestock and fish waste, for the purpose of determining optimal utilization of those wastes. The enzymatic hydrolysate of meat meal, a collagen-waste, showed strong angiotensin-I-converting enzyme (ACE) inhibiting activity (IC500.6–2.8 mg/ml). In contrast, the enzymatic hydrolysate of a mixture of horn and hoof, a keratin-waste, showed high antioxidative activity. Thus, collagen or keratin contained in livestock and fish waste may be convertible to useful products by enzymatic hydrolysis, providing new physiologically functional food materials.