Resumen de Kinetic modeling of high-pressure induced inactivation of polyphenol oxidase in sugarcane juice (Saccharum officinarum)

Pandraju Sreedevi, Lakshmi E Jayachandran, Pavuluri Srinivasa Rao

• Polyphenol oxidase (PPO) is the main enzyme in sugarcane juice associated with rapid browning and degradation of organoleptic properties. High-pressure processing (HPP) (300?600?MPa) of sugarcane juice in combination with moderate temperatures (30?60?°C) for different processing times (10?25?min) has shown promising results in minimizing PPO activity while preserving the juice's freshness. RESULTS A maximum PPO inactivation of 98% was achieved at 600?MPa/60?°C/25?min, while the corresponding value for thermal treatment at 0.1?MPa/60?°C was only 66%. The nonlinearity in the inactivation data was well described by the Weibull distribution model with a high adjusted R2 and reduced ?2 values at all levels of pressure and temperature. The PPO inactivation data were fitted at shape parameter, ? = 1 (log linear) and ? ? 1. A refitted Weibull model was used to predict kinetic parameters such as the inactivation rate constants (k), activation energy (Ea) and activation volume (Va), which govern PPO inactivation in HPP-treated sugarcane juice. A secondary kinetic model was formulated to predict the k values as a function of pressure (P) and temperature (T), incorporating Ea and Va. CONCLUSIONS Combined high-pressure and temperature processing has been considered a reliable alternative to conventional heat treatment for inhibiting PPO activity in sugarcane juice. While the isothermal inactivation of PPO followed first-order kinetics, inclusion of high pressure resulted in a strong deviation from log linear kinetics. Identification of suitable kinetic models describing these inactivation processes is expected to aid product development and process control of high-pressure processed sugarcane juice. ? 2018 Society of Chemical Industry