Effect of high-pressure treatment prior to enzymatic hydrolysis on rheological, thermal, and antioxidant properties of lentil protein isolate

Abstract

The objective of the present work was to assess the effectiveness of high-pressure (HP) treatment on the enzymatic hydrolysis of lentil protein (LP) in order to improve functionality and antioxidant activity of hydrolysates. LP dispersions were subjected to HP treatment in the selected pressure levels (300, 450, and 600 MPa for 15 min) prior to hydrolysis with alcalase (0.5% and 1%, w/w). The postprocess samples were analyzed to assess the impact of pressure treatment on denaturation, the degree of hydrolysis (DH), and antioxidant activity of hydrolysate. HP treatment improved the %DH of the LPI (p ≤ 0.05). The HP-assisted alcalase hydrolysis imparted significant changes on the secondary structure of protein with a shift of amide I and amide II bands. The hydrolysis of LP was further confirmed by a significant drop on the enthalpy (ΔH) values in the DSC endothermic peaks and decreasing the steady shear viscosity. The pressurized protein hydrolysates attained an improvement in the foaming properties (≈1.5 times) and antioxidant activities (≈2 times) than the control hydrolysates. However, a detrimental effect was pronounced on the emulsifying activity and stability index, foam stability, and water holding capacity. These results could be useful for food industries to develop products using hydrolysates as protein supplements.