Abstract: In this paper,heat pretreatment method and ultrasonic pretreatment method of pig bone before enzymatic hydrolysis,and the process of papain and trypsin bienzymatic hydrolyzing pig bone were studied.The result indicated that the optimum conditions of pig bone heat pretreatment are 90 ℃ and 10 min.The optimum conditions of pig bone ultrasonic pretreatment are as follows:total sonication time 10 min,ultrasonic power 400 W.After the heat pretreatment of the pig bone before enzymolysis,the hydrolysis rate and recycle rate of nitrogen respectively increased by 30.84% and 10.99%.After the ultrasonic pretreatment,the hydrolysis rate and recycle rate of nitrogen respectively raised 84.57%,66.45%.Therefore,the ultrasonic pretreatment was obviously better than heat pretreatment.The optimum bienzymatic hydrolysis conditions were determined as follows:substrate concentration 15%,E/S 6000U/g,enzymolysis time 4h,temperature 50 ℃,pH value 7.5,papain added amount:trypsin added amount1:1.When pig bone is pretreated by ultrasonic wave and hydrolyzed by bienzymes under these conditions,the hydrolysis rate is 25.99%,and recycle rate of nitrogen is 66.35%.

Key words: pig bone, flavour components, enzymolysis technology