Submitted to: Journal of Food Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/15/2005
Publication Date: 10/15/2005
Citation: Samaranayake, C.P., Sastry, S.K., Zhang, H.Q. 2005. Pulsed ohmic heating: a novel technique for minimization of electrochemical reaction during processing. Journal of Food Science. 70(8):E460-E465. Interpretive Summary: Ohmic heating applies electricity to food to rapidly increase the temperature for either cooking or sterilization purposes. When electrical current flows through the food, it may cause electrochemical reactions to take place. These reactions degrade the quality of foods. Minimization of electrochemical reactions during ohmic heating would be desirable. Instead of using continuous sine wave electrical current, this study examines a pulsed ohmic heating technique where electrical current only flows for very brief time in microseconds to minimize electrochemical reactions. The results suggest that pulsed ohmic heating is capable of significantly (P<0.05) reducing the electrochemical reactions compared with conventional 60 Hz ohmic heating.
Technical Abstract: Minimization of electrochemical reactions during ohmic heating would be desirable. This study examines a pulsed ohmic heating technique to determine its effects on electrochemical reactions. Effects of pulse parameters, such as frequency, pulse width, and delay time were studied, in comparison with conventional (60 Hz, sine wave) ohmic heating using various electrode materials. Analyses of electrode corrosion, hydrogen gas generation and pH change of the heating media were performed. The results suggest that pulsed ohmic heating is capable of significantly (P<0.05) reducing the electrochemical reactions of stainless steel, titanium, and platinized-titanium electrodes, compared with conventional 60 Hz ohmic heating. The importance of allowing enough delay time for discharge of the electrical double layers after each pulse input is emphasized.