Inhibitory effects of legume seed extracts on fish proteinases

Proteinase inhibitor extracts were prepared from various legume seeds. Black cowpea and soybean seeds showed the highest inhibitory activity against viscera proteinases (p < 0.05). Optimal extraction was attained by shaking the defatted legume seed powder in distilled water (3 ml g−1) at ambient temperature for 1 h. Both extracts showed high thermal stability, but that from soybean was slightly less stable. The inhibitory activity of both extracts was retained over a broad pH range. The proteinase inhibitor extracts also reduced modori-inducing proteinase (MIP) activity. The sarcoplasmic MIP activities were more effectively inhibited than the myofibrillar-associated MIP activities.