Gelatin was extracted from salmon skin by acid leaching and water extraction.Ultraviolet spectrum with the maximum absorption wavelength was 233 nm,and amino acid composition testified that the extract conformed to the characteristics of gelatin.The gelatin extract rate was 60.46%,and the gelatin content in the extract was 83.92%.Papain was used for enzyme hydrolysis of gelatin to become collagen peptides which were low molecular weight.The effects of hydrolysis time,amount of enzyme,substrate concentration...