Kinetic modeling for inactivation of polyphenoloxidase and peroxidase enzymes during ozonation of sugarcane juice

The inactivation of polyphenoloxidase (PPO) and peroxidase (POD) enzymes in sugarcane juice by ozone treatment was modeled in this kinetic study. The juice was exposed to three ozone doses per unit volume, 0.12, 0.28, and 0.45 mg min(-1) ml(-1) for exposure time varied in the range of 5 to 50 min. The result showed that, after 50 min of treatment, maximum PPO and POD inactivation of 83.24% and 86.03%, respectively, were achieved with ozone exposure dose of 0.45 mg min(-1) ml(-1). Among all attempted models, the inactivation kinetics of both the enzymes could be best modeled with Weibull model which provided adequate fitting of data with good agreement (adj R-2 > .96, accuracy factor similar to 1 and akaike increment = 0). Derived Weibull model equations based on relationship of scale parameter with ozone dose were introduced to describe residual activity as a function of ozone dose in addition to exposure time. Practical applications During long term storage, sugarcane juice is susceptible to rapid oxidation by browning enzymes. The approach of their inactivation is crucial for better storability with least deterioration in juice quality. Ozone treatment is attempted to achieve the effect through kinetic study and mathematical data modeling. The kinetic models are able to quantitate the inactivation effect by the treatment. Determination of kinetic parameters for enzyme inactivation is of paramount importance for the design and optimization of the process to achieve safe food product.