Ohmic blanching of Tetsukabuto pumpkin: Effects on peroxidase inactivation kinetics and color changes

The present work aimed to evaluate the application of an alternative technology for food blanching, the ohmic heating process, and compare it to conventional blanching of hybrid Tetsukabuto pumpkin. The influence of both treatments on the inactivation kinetics of peroxidase and on color changes of pumpkins was investigated. Different kinetic models were evaluated, and the Weibull distribution model showed the best fit to the experimental data. It was verified that ohmic heating accelerated the enzymatic inactivation process; for a reduction higher than 90% in peroxidase initial activity it took 2 min of ohmic blanching, while conventional blanching took 4 min to achieve the same degree of inactivation. Also, no significant differences (p > 0.05) between ohmic and conventional treatments were observed on the color of the samples. The overall results indicated that ohmic technology was efficient to promote the inactivation of undesirable enzymes and to maintain the food color.