FACTORS AFFECTING THE OIL CONTENT OF POTATO CHIPS AND THE APPLICATION OF NEAR INFRARED REFLECTANCE TO ONLINE MOISTURE AND OIL CONTENT MEASUREMENTS (DEHYDRATION)

In the first part of this study, tubers from the cultivar Norchip were separated into five specific gravity categories: 1.065, 1.075, 1.085, 1.095 and 1.105. Tubers from each specific gravity were sliced as regular style chips at thicknesses of 0.127 cm, 0.152 cm and 0.178 cm, and wavy style chips at thicknesses of 0.152 cm and 0.191 cm. Sliced tubers were fried at 162.8(DEGREES)C, 176.7(DEGREES)C and 190.6(DEGREES)C, the frying time varying in order to maintain a final moisture content of 1.50 (+OR-) 0.25% for all samples.;The factors affecting the oil content of both regular and wavy style potato chips were specific gravity, slice thickness and fryer temperature. Frying time was a contributing factor for wavy style potato chips, but not regular style potato chips. Adjusting for the effect of frying time influenced the effects of other factors. Polynomial response surfaces were developed for the oil content of both styles of potato chips.;The second study involved drying slices prior to frying by microwave oven, tray dehydrator and vacuum oven. Tubers of the cultivar Superior were divided into two specific gravity categories (1.070 and 1.080), sliced and dried to 75 and 50% of their initial moisture content before frying. Oil contents, moisture contents, Agtron E-5-F Ratio color values, PC/SFA color scores, and the sensory assessment of differences in crispness, oiliness, color and flavor of the control and treated samples were determined. Drying to a moisture content of 50% prior to frying resulted in a decrease in oil content of 26 to 34% for all dehydration processes. Color improvement over control samples were noted for some of the dehydrated samples.;A Datatech BSP-4000 Moisture Monitoring and Control System equipped with both an oil and moisture sensor was tested for calibration and prediction of moisture and oil contents of potato chips. The calibration of the moisture and oil sensors resulted in correlation coefficients of 0.901 and 0.883, respectively. The NIR predicted moisture content was correlated with the actual moisture content of the samples (R = 0.879, s.e.p. = 0.664), but the oil content of the samples was not predicted by the NIR instrument.