This study characterized gelatins prepared by mild hydrolysis of freshwater fish-scale collagen. Among the selected types of protease (trypsin, neutral protease, papain, and alkaline protease), alkaline protease was proven to be the most effective enzyme for gelatin extraction by hydrolysis of fish-scale collagen. The optimum hydrolysis conditions were as follows: reaction time, 6 h; temperature, 50 °C; pH 9; and enzyme amount, 3 % (w/w). Under these optimum hydrolysis conditions, the gelatin yield reached 48.1 % (w/w). The gelatins prepared by alkaline protease hydrolysis show higher emulsion activity and lower emulsion stability indices than those prepared by water extraction.
Fish-scale gelatin Emulsion activity index Emulsion stability index Alkaline protease