54F-4

M. KIM and Q. H. Zhang. Dept. of Food Science and Technology, Ohio State Univ., 2015 Fyffe Road, Columbus, OH 43210

Investigations of microbial inactivation and engineering aspect of Pulsed Electric Fields (PEF) have been done by many researchers. However, there is lack of literature on the effects of electrochemical reaction during PEF treatment. Electrochemical reaction in PEF chamber may cause partial electrolysis of food, electrode corrosion and electrode material migration into the food. Furthermore, it may result in shortened lifetime of electrode. The objective of this research was to reduce electrode corrosion and electrode material migration into the food by selecting corrosion resistant material as electrodes in PEF chamber. Four materials - titanium, platinized titanium, stainless steel, and boron carbide, were selected as electrodes and made to the same geometry. Citric acid buffer, pH 3.5 and electrical conductivity 0.22 S/cm, was treated through the OSU-5C pilot plant scale PEF system. The PEF process conditions were 28kV/cm field strength, 2µs pulse duration, 600pps repetition rate, 43µs total treatment time and 125L/hr flow rate. Recirculation system was operated due to detectable limit of metal traces in media. Temperature, electrical conductivity, pH and total volume of media were monitored and controlled during recirculation. Seven samples were collected during 4 hours of recirculation process. Electrode corrosion was measured by metal trace detection in media, Ti for titanium, Pt for platinized titanium, Fe for stainless steel, and B for boron carbide, using ICP-MS and changes of electrode surface morphologies using SEM. Concentrations of metal trace for four materials were increased proportionally respect to recirculation time. Titanium electrodes showed the most corrosion resistance. Boron carbide electrodes had the least corrosion resistance. Both amounts of migrated Ti and B in media were well below dietary exposure limits. The results of this study indicate the potential application of titanium as a durable electrode material in PEF processing.

Session 54F, Nonthermal Processing: General I
2:00 PM - 5:30 PM, Monday PM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana