Abstract:The collagen peptide from albacore tuna skins had been extracted by alkali，heating，and compound enzyme，collectively. Taking the degree of hydrolysis，nitrogen recovery and molecular weight as index，the opti－ mal conditions of enzymolysis were ascertained on the basis of single factor experiments and orthogonal array design. The results showed that，whole process could be divided into three steps：the first step was alkali treat ment，the albacore tuna skins were washed with 0.1 mol/L Ca（OH）2 and fresh water for several times；the second step was heating treatment，the skins were being heated to 90 ℃ and lasted for 30 min；and the last step was compound enzyme treatment，the alcalase，neutral protease，and flavourzyme were added into the reaction system，and eventually，the optimal hydrolysis conditions were determined as follows：the ratio of compound en－ zyme to skin was 1 ∶ 200 （g/g），the ratio of skin to water was 1 ∶ 2.5 （g/mL），the temperature was 55 ℃，the pH was 9.0-6.5，and the time was 4 h，resulting in the generation of hydrolysate with average hydrolysis degree， up to 30 %；and the optimal decoloration conditions were as follows，activated carbon addition content 2 %，pH nat－ ural， temperature 70 ℃，time 30 min . The collagen peptide was analysed and detected through HPLC，showing that under 3 kD molecular weight of accounted for more than 85 % after concentrating and spray drying.