Enzyme inactivation and its kinetics in a reduced-calorie sapodilla (Manilkara zapota L.) jam processed by thermal-assisted high hydrostatic pressure

The effect of high-pressure processing parameters within the domain of 300-600 MPa/25-65 degrees C/0-30 min was evaluated on polyphenol oxidase (PPO) and peroxidase (POD) inactivation in a reduced-calorie sapodilla jam. The residual activity of PPO and POD enzymes was significantly reduced (up to 57% for PPO and 43% for POD) by temperature followed by pressure and time, and all the process parameters showed a synergistic effect represented by contour plots. However, POD was more baroresistant than PPO. The rate constants obtained from the first-order kinetics applied to enzyme inactivation during isobaric-isothermal phase varied from 2.1 x 10(-3) min(-1) to 1.36 x 10(-2) min(-1) for PPO, and 2.0 x 10(-3) min(-1) to 7.8 x 10(-3) min(-1) for POD. Various other kinetic parameters viz. D value, D-P, N-D, z(T), z(P), activation energy, and activation volume were also obtained to compare the results. Also, the HPP jam samples were microbiologically safe. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

The study found that under high-pressure processing conditions, temperature had the most significant effect on the inactivation of polyphenol oxidase and peroxidase, followed by pressure and time. Peroxidase was more resistant to high pressure compared to polyphenol oxidase, and there was a synergistic effect among all process parameters.