Enzymatic Digestion of Fish Scraps in Bench Scale Production

Abstract

Enzymatic digestion of fish scraps by a cominercially available B. Subtilis proteolytic enzyme was investigated in bench scale production. Raw scraps of croaker and horse mackerel were slurried with an equal weight of water, and to the mixture 10% of salt was added in order to prevent decomposition during the enzymatic digestion at 50-55°C for 48hr. Continious mechanical stirring resulted in a great decrease in necessary amount of the proteolytic enzyme. When the temperature of the mixture after the enzymatic digestion was lowered to 1-3°C, fish oil came to the surface of the mixture and solidified, and fish bones precipitated at the bottom on standing. Then the oil could be separated very easily from the aqueous layer. Undisolved fish bones in the digested juice could be separated by passing through a fine mesh screen. As the refined enzymatic digest thus obiained still have unpleasant flavor, further treatment is necessary to utilize it as seasonings.