Production of angiotensin I-converting enzyme inhibitory peptides from defatted canola meal

To simplify the method of ACE-inhibitory peptide production, defatted canola meal was subjected to enzymatic proteolysis. Alcalase 2.4 L and protease M "Amano" were found to be the most efficient enzymes in releasing ACE-inhibitory peptides from canola proteins among 13 tested enzymes. The IC(50) values of canola protein hydrolysates ranged from 18.1 to 82.5 microg protein/mL. Differences in ACE-inhibitory activities of various protein hydrolysates reflected varied enzyme specificities. A positive correlation was determined between ACE-inhibitory activity and the degree of hydrolysis (r=0.5916, p<0.001). Ion-exchange chromatography of canola protein hydrolysate increased the protein content greater than 95% without loss of ACE-inhibitory activity. This fraction was resistant to the degradation of gastrointestinal enzyme and ACE during in vitro incubation and may be a useful ingredient in the formulation of hypotensive functional food products.