Kinetic modeling of polyphenoloxidase and peroxidase inactivation in pineapple (Ananas comosus L.) puree during high-pressure and thermal treatments

Thermal and high pressure inactivation kinetics of polyphenoloxidase (PPO) and peroxidase (POD) in pineapple puree were developed within the domain of 0.1-600 MPa, 30-70 degrees C and 0-20 min, in which, PPO was more resistant compared to POD. The inactivation orders (n) for PPO and POD during thermal treatment were 1.018 and 1.028, derived from nth order kinetic model; whereas n values for PPO and POD during high pressure domain (200-600 MPa/30-70 degrees C) were 0.991 and 0.995, respectively. Pressure and temperature acted in antagonistic manner on both the enzymes within 200-300 MPa; however, they became synergistic beyond 400 MPa. An empirical model considering the pressure dependency of activation energy and temperature dependency of activation volume was developed which adequately described the inactivation behavior of both enzymes. At 70 degrees C/20 min, high pressure like 600 MPa protected the bioactive components better in the sample than at 0.1 MPa. Industrial relevance: Preparation of stable pineapple puree includes the requisite of inactivating the browning enzymes like polyphenoloxidase (PPO) and peroxidase (POD), which are responsible for less market value of the product. A detailed kinetic evolution of these enzymes is obligatory for the design and optimization of process to be applied, as both the oxidoreductases react in different way depending on the source and experimental domain. The stability of these enzymes has been compared between thermal and high-pressure processes. The developed empirical model in this study will help in identifying the optimum condition targeted towards the inactivation of browning enzymes during high-pressure processing of pineapple puree with an extended shelf-life. (C) 2014 Elsevier Ltd. All rights reserved.