Castro et al. (2004) determined the ascorbic acid degradation kinetics in strawberry pulp under ohmic and conventional heating. The ascorbic acid degradation kinetics for temperatures ranging from 60 to 97 °C was not affected by low values of electric field (<20 V cm−1). Studies performed by Lima et al. (1999) also demonstrated that the nature of the heating, either ohmic or conventional, did not significantly affect the degradation of AA in orange juice. In contrast, in the

present study, high voltages promoted greater AA degradation during the ohmic heating when compared to the conventional heating. A similar analysis can be done for the total vitamin C degradation. As observed in Table 4 and Table 6, the VTC degradation of experiments with low voltage gradients was smaller than the degradation of the experiments Cyclopamine manufacturer with conventional heating. Furthermore, high voltage gradients caused higher total vitamin C degradation. This behavior can be explained by the increase of electrochemical reactions during high voltage gradient operations which release ions into the liquid that catalyze

the oxidation of ascorbic acid. Qihua et al. Y-27632 price (1993) observed that during ohmic heating of orange juice, bubbles were produced quickly in high voltage gradient operations as a consequence of electrochemical reactions. Assiry et al. (2003) compared the ascorbic acid degradation kinetics in a buffer solution of pH 3.5 using conventional and ohmic heating. The kinetics of degradation can be described adequately by a first order model for both conventional and ohmic treatments, Celastrol but unlike conventional heating, the temperature dependence of degradation for some ohmic treatments cannot be represented by the Arrhenius relation. Electrode reactions, electrolysis of the solution, as well as reactions between electrode materials and the electrolysis products

may all influence the reaction mechanism and the kinetic parameters. These researchers observed a brown color to the buffer solution, indicating the presence of ferric chloride. Insoluble brown deposits were also observed on the electrode surfaces, indicating the possible formation of iron(III) oxide or ferric chloride. The results obtained in present study confirm the importance of using either inert coatings on electrodes and sensors or high frequency electric currents to control electrochemical reactions. Further studies of the ohmic heating process should be conducted to achieve a better understanding of the mechanisms involved in the ascorbic acid degradation in the presence of oxygen and metallic ions. In addition, other parameters should be evaluated to compare both heating technologies.