MICROWAVE BLANCHING OF SLICED POTATOES DIPPED IN SALINE SOLUTIONS TO PREVENT ENZYMATIC BROWNING

Response surface methodology was applied to investigate the way in which variables such as time of treatment, sodium or calcium chloride concentrations and lactic acid concentration affect the microwave blanching of potato slices dipped in these solutions. Two three factor-five-level, second order central composite designs were developed to analyze the considered variables. Results showed that, with reference to polyphenoloxidase inactivation, the blanching in calcium chloride-lactic acid solution was more effective than the blanching in sodium chloride-lactic acid solution. Color measurements showed that, in the applied operative conditions, the best results were obtained by short blanching in sodium chloride-lactic acid solution at high lactic acid concentration and low NaCl concentration and by short blanching in calcium chloride-lactic acid at low lactic acid concentration or low calcium chloride concentration.