To improve the utility of walnut meal protein, influences of ultrasonication on the
kinetic and thermodynamic constraints of enzyme (trypsin) hydrolysis were assessed
using a multi‐frequency counter current S‐type ultrasound machine. Results revealed
that both the ultrasonication treatment and control hydrolysis obeyed the first‐order
kinetics within the study constraints. After 90 min hydrolysis time, the uppermost
percentage conversion rate (57.5%) of substrate to product and the percentage increase
(25.42%) in hydrolyzed protein concentration were obtained at 323 K and
10% substrate concentration, respectively. The Michaelis constant (KM) in ultrasonic
enzymolysis declined by 58.66% over the control. The reaction rate coefficient (k) for
the proteolysis improved by 84.75%, 52.43%, 48.25%, and 37.79% at 219, 303, 313,
and 323 K, correspondingly. Generally, the bond energy (Ea), enthalpy change (ΔH),
entropy change (ΔS), and Gibbs free energy (ΔG) were reduced by the ultrasound
pretreatment with 36.61%, 28.05%, 18.22%, and 5.24%, respectively.