牛骨蛋白酶解工艺条件的优化

Protease Hydrolysis of Bovine Bone Power

以水解度和氮收率为指标,研究酶制剂种类、底物质量浓度、加酶量、酶解时间、pH值及酶解温度对牛骨酶解工艺的影响,并采用二次正交旋转组合设计进行工艺优化,得到最佳优化工艺条件:确定木瓜蛋白酶作为试验用酶、底物质量浓度1g/100mL、加酶量6000U/g、酶解温度60℃、pH6.5、酶解时间3h。在该条件下制备的酶解产物水解度可达26.27%。考虑到酶解后固形物的产率,选取底物质量浓度为5g/100mL进行工艺试验,根据回归方程可得水解度的理论值为18.33%。经反复实验证实,在5g/100mL的底物质量浓度条件下,牛骨酶解产物水解度可达16.5%～20%,氮收率可达84.5%～92%。

Pepsin, alkaline protease, trypsin, neutral protease and papain were used to hydrolyze bovine bone powder, respectively. According to the overall evaluation on degree of hydrolysis and nitrogen recovery of bovine bone powder and sensory quality of the resulting hydrolysate, papain was selected to prepare bovine bone hydrolysate. Single factor experiments were carried out to examine the effects of papain hydrolysis parameters including substrate concentration, enzyme amount, pH and hydrolysis time and temperature on degree of hydrolysis and nitrogen recovery of bovine bone powder. Based on this, a 4-variable, 5-level quadratic orthogonal rotation combination design involving 36 experiments was employed to investigate the optimal values of other 4 hydrolysis parameters except hydrolysis time. Results showed that the optimal hydrolysis of bovine bone powder with 6000 U/g papain for 3 h at 60 ℃, pH 6.5 and 1 g/100 mL substrate concentration resulted in a degree of hydrolysis of up to 26.27%. When the substrate concentration was adjusted to be 5 g/100 mL for the enhancement of solid content in bovine bone powder hydrolysate, a predicted value of degree of hydrolysis of 18.33% was obtained. Validation experiments gave an actual value range of 16.5% to 20% and a nitrogen recovery range of 84.5% to 92%.