Effect of high-pressure treatment on trypsin hydrolysis and antioxidant activity of egg white proteins



High-pressure processing (HPP) is known to modify the functional properties of the proteins by changing its structure that can lead to protein denaturation, aggregation or gelation, depending on the protein system and the applied pressure. The potential to modify functional properties of protein and their products using HPP has been explored widely in last decade. In this study, the effect of HPP on the degree of trypsin hydrolysis (DTH) and antioxidant activity (AA) of egg white protein (EWP) and freeze-dried egg white powder (DEW) was evaluated. EWP and DEW were subjected to trypsin hydrolysis for up to 120 min, with and without HP treatments [pressure level (350–550 MPa) and treatment time (5–15 min)]. HP treatment caused substantial increase in DTH of EWP and DEW, increasing it from 2.78% (EWP control) and 2.20% (DEW control) to 11.3% (HP-treated EWP) and 8.41% (HP-treated DEW), respectively. HP treatment also had an emphatic effect on AA of EWP (concentration 10% w/v) with AA increasing from 9.34% for control EWP to 19.0% after 5-min HP treatment at 350 MPa and 25.00% after the same treatment at 550 MPa. Overall, HPP caused an increase in DTH and AA of EWP and DEW over the control. SDS-PAGE and differential scanning calorimetric studies confirmed the effect of HP on the hydrolysis of egg proteins.