Shrinkage modeling during deep-fat frying of potato strips pretreated with ultrasound and osmotic dehydration

In this study, effect of ultrasound and osmotic dehydration pretreatments on shrinkage of fried potato strips was examined. Potato strips pretreated with ultrasound at 28 and 40 kHz frequencies and osmotic dehydration at salt solution concentrations of 2 and 4% were fried for 60, 120, 180 and 240 seconds at temperatures of 150, 170 and 190°C. Also, in order to control the optimal process conditions and improve the final quality of fried product, changes in the shrinkage were modeled in terms of frying time, oil content, dimensionless moisture content and apparent density. Ultrasound pretreatment at 28 and 40 kHz frequencies at 150°C led to a decrease in shrinkage compared to control samples. Application of osmotic dehydration and its combination with ultrasound pretreatment increased the shrinkage. In addition, experimental data were well fitted by proposed models in terms of frying time, oil content, dimensionless moisture content and apparent density parameters having high correlation coefficients.