29D-1 |
Electrochemical corrosion of platinized-titanium electrodes during ohmic heating |
C. P. SAMARANAYAKE and S. K. Sastry. Dept. of Food, Agricultural & Biological Engineering, Ohio State Univ., 590 Woody Hayes Dr., 260 Agricultural Engineering Bldg., Columbus, OH 43210-1058 Electrochemical reactions, chemical reactions at electrode/solution interfaces induced by current, are common nuisances encountered in ohmic heating. The reactions associated with the interfaces are mainly the corrosion of electrodes and (partial) electrolysis of the heating medium. Effects of those reactions may involve food contamination, oxidative damage of nutrients, alteration of organoleptic properties, and loss of useful electrical energy. We examined the corrosion of platinized-titanium electrodes both in laboratory scale at pH=3.5, 5.0, & 6.5 and in pilot scale flow-through system (Power=39.8 kW) at pH=3.5, using 60 Hz sinusoidal alternating currents. The corrosion analysis was performed by high resolution Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). In the laboratory scale studies, the highest corrosion rate was observed at pH=3.5, but no signs of electrolysis at any of the pH. The extent of corrosion in the pilot scale study was evaluated with respect to a typical meal of 8 OZ, and compared with some published upper-level daily dietary exposure limits for Pt and Ti. The results indicate that, the levels of contaminants are far below the published guidelines; and therefore Ohmic heating may be performed without significant electrode corrosion with platinized-titanium electrodes, and might not have any adverse effects on the processed foods.
Session 29D, Food Engineering: Thermal processes
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