Total solids content and degree of hydrolysis influence proteolytic inactivation kinetics following whey protein hydrolysate manufacture

The kinetics and thermodynamics of the thermal inactivation of Corolase PP in two different whey protein concentrate (WPC) hydrolysates with degree of hydrolysis (DH) values of ∼10 and 21%, and at different total solids (TS) levels (from 5 to 30% w/v), were studied. Inactivation studies were performed in the temperature range from 60 to 75 C, and residual enzyme activity was quantified using the azocasein assay. The inactivation kinetics followed a first-order model. Analysis of the activation energy, thermodynamic parameters, and D and z values, demonstrated that the inactivation of Corolase PP was dependent on solution TS. The intestinal enzyme preparation was more heat sensitive at low TS. Moreover, it was also found that the enzyme was more heat sensitive in solutions at higher DH.