Abstract:

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%.

Key words: bovine bone, utilization, hydrolysis conditions, quadratic orthogonal rotation combination design