Enhancement on enzymolysis of pigskin with ultrasonic assistance

The fur is hard to decompose during the fermentation process of diseased swine carcasses. In order to enhance the enzymolysis of pigskin, the ultrasonic was proposed to use during the process of the enzymatic hydrolysis. The response surface optimization experiments were carried out with the DH (degree of hydrolysis) as the response value and the optimum conditions for enzymatic hydrolysis were determined. Based the optimum conditions, orthogonal experiments were carried out with ultrasonic frequency, power and time as variables, and optimal ultrasonic parameters were obtained. Without the assistance of ultrasonic, the descending order of influence factors on DH was, temperature＞SC(Substrate concentration)＞RES(The ratio of enzyme to substrate)＞pH. Moreover, the DH value is of 10.42% under the following optimal conditions: RES is of 16,006 U/g, the temperature is of 48.92°C, the SC is of 59.76 g/L and pH is of 10.43. Frequency has the greatest effect on DH, followed by power, and finally time. The optimum hydrolysis time is of 5 h, and the DH is of 22.94% were obtained under the following optimum ultrasonic pretreatment conditions: frequency combination is of (20,40,40), power is of 600 W and time is of 25 min. Comparing with the group without ultrasonic pretreatment, the DH for the ultrasonic assistance increased by 4%, the hydrolysis time was shorten by 3 h, and the total amino acids increased by 15.98%.