We have reported that peptides in enzymatic hydrolyzates of sardine meat can inhibit the activity of angiotensin I converting enzyme (ACE). In a next step, we set out to establish techniques to separate and purify the peptides with high activity and to remove odor and color which hinder the practical use. On the laboratory scale, after enzymatic hydrolyzation of sardine meat, the odor resulting from amines and the peptides which contributes to color were removed by treatment with activated carbon and aluminum silicate. Fatty acids, another odorous component, were removed by ODS fractionation. Thus, peptide fractions that strongly inhibited ACE were obtained. We set up an apparatus that gave reproducible separation by ODS fractionation. The apparatus was suitable for industrial use. We constructed a plant that could process about 30 times the volume handled on the laboratory scale. The pilot plant gave the same satisfactory results, showing the possibility of further scaling up. We then designed a system that could be used for industrial production at processing rate of 1 000 l/h. The physiologically active peptides obtained by us would be useful in a wide range of application as a food ingredient.