Ultrasound-assisted enzymatic hydrolysis kinetics of pea protein isolate and functional properties of hydrolysates

In this paper, pea protein isolate was hydrolyzed by ultrasonic-assisted enzymatic method. Kinetics of the protein hydrolyses using trypsin was established by measuring the degree of hydrolysis (DH) when varying ultrasound powder and treating time. Moreover, effects of enzyme variety and dosage on the degree of hydrolysis of pea protein isolate were also investigated. Results showed that trypsin was a more appropriate enzyme to hydrolyze pea protein isolate than others. The optimum conditions were as follows: ultrasonic power 450 W, ultrasonic time 20 min, pH 8. Under the conditions, the degree of hydrolysis ranged from 19.11 to 38.06% as trypsin concentrations increased from 0.5 to 3.5 U/g. Kinetics of the hydrolysis of pea protein isolate indicated a log-linear relation was established between the DH values at a definite time and the initial enzyme/substrate ratio. Functional properties of hydrolysates showed enzymatic treatment improved the solubility (more than 300%), foam capacity (more than 8.3 times) and emulsifying capacity of the hydrolysates (55.3 mm-2/g) as compared to the material (32.1 m-2/g) without modification. The above results suggested potential use of ultrasound-assisted enzymatic hydrolysis for modifying the functional properties of pea protein isolate and preparing bioactive peptides from pea protein isolate. ©, 2015, Chinese Institute of Food Science and Technology. All right reserved.