Effects of high pressure and microwave on pronase and α-chymotrypsin hydrolysis of β-lactoglobulin

The effects of hydrostatic high pressure, microwave irradiation, and conventional heating on hydrolysis of bovine β-lactoglobulin AB by pronase and α-chymotrypsin were studied. The high pressure treatments were performed between 100 and 300 MPa, the microwave irradiation was applied at different power conditions, pronase (30 W) and α-chymotrypsin (15 W). All enzymatic reactions were carried out during 10 and 20 min, at 40 °C. The initial rate of pronase and α-chymotrypsin hydrolysis of protein was increased by using either physical treatment during the enzymatic digestion. The microwave-assisted digestion by pronase was more effective than those performed under conventional heating. The only apparent microwave induced difference on protein digestion by α-chymotrypsin was in a lower relative concentration of peak eluting at 24.5 min, and the conversion of this fraction into final peaks eluting from 24.5 to 28.5 min (F1 fraction) after 20 min of incubation. Under high pressure, the β-lactoglobulin AB is completely hydrolyzed by pronase and α-chymotrypsin.