15D-37 |
Effect of ohmic pretreatment on oil uptake of potato slices during frying and subsequent cooling |
S. SALENGKE, Food, Agricultural, and Biological Engineering, The Ohio State University, 590 Woody Hayes Dr., Columbus, OH 43210 and S. K. Sastry. Current approaches to reduce oil contents of fried potato products has been related to the reduction of moisture evaporated during frying by treatments such as pre-fry drying. Although this method has been reported to be effective when initial moisture contents of samples were reduced by as much as 60%, some authors have cautioned that an excessive moisture removal during pre-fry drying might cause significant textural and aroma alterations. Recent studies have indicated that ohmic heating could cause structural changes which could be conducive to lowering oil absorption during frying and subsequent cooling. Therefore, it is worthwhile to study the effect of ohmic pretreatment on oil uptake of potato slices during frying and subsequent cooling. The objective of this study was aimed at investigating the effect of ohmic pretreatment on total oil uptake during frying and cooling of potato slices. In this experiment, a complete block experimental design was employed, with each potato tuber acting as a block. Accordingly, for each replication, samples for ohmically treated and untreated slices were obtained from the same tuber. The treated slices were heated by either directly sandwiching the slices between two electrodes or by heating them in a 0.11% salt solution. The treatments were carried out using an AC filed of 35.5 V/cm. The samples were deep-fat fried at 170oC in a bench-top fryer containing 2.5 liters of canola oil. Oil contents of the samples were determined using a 12-hour continuous solvent extraction method with hexane. Results from this study indicated that oil uptake was decreased by the ohmic pretreatment without involving a liquid medium, but the effect was not evident when the ohmic pretreatment was carried out in a liquid medium. The results obtained from this study indicated that an ohmic pretreatment could potentially reduce oil absorption during frying and subsequent cooling.
Session 15D, Food Engineering: Processing Technologies
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