Continuous Ohmic Heating Assisted Isothermal Treatment of Standardized Pineapple Juice: Its Effect on Bromelain Inactivation, Vitamin C Degradation, and Their Kinetic Modeling

ABSTRACT Continuous ohmic heating (COH) is an electro‐resistance heating and an efficient emerging tool for fruit juice processing. The current work investigated the effect of COH parameters like electric field strength (EFS: 30–40 V/cm), temperature (70°C–90°C), and isothermal holding (0–60 s) on bromelain activity and vitamin C in standardized pineapple juice (22°Brix/Acid). The accuracy factor ( A f ), bias factor ( B f ), statistical parameters, and Akaike information criteria (AIC) were used to compare different kinetic models like first order, Weibull distribution, and logistic model and to choose the best‐fit kinetic model for bromelain inactivation and vitamin C degradation. The results showed that COH parameters significantly affected bromelain activity and vitamin C. A minimum bromelain residual activity and vitamin C content in the COH‐treated juice were 1.2% ± 0.4% and 38.2% ± 2.6%, respectively, when treated at 90°C, 40 V/cm for 60 s. The Weibull distribution model ( R 2 > 0.99; RMSE < 0.0293; ∆ i ≤ 2) described bromelain inactivation kinetics better than other models, while the first order model ( R 2 > 0.84; RMSE < 0.057; ∆ i = 0) was best suited for vitamin C degradation kinetics. The A f and B f for respective models of bromelain inactivation and vitamin C degradation were closer to the simulation line (closer to 1), suggesting the accuracy of these models in predicting. Thus, the Weibull and first‐order models are good tools for predicting bromelain inactivation and vitamin C degradation in COH‐treated standardized pineapple juice.