Frying of Potato Strips Pretreated by Ultrasound-Assisted Air-Drying

Abstract

Ultrasound is an emerging technology in various areas of food processing, preservation and safety. Due to its high dehydration efficiency, application of ultrasound prior to frying may hand in promising results in reducing oil uptake. The objective of this study was to examine the effect of ultrasound as well as the simultaneous effect of ultrasound and pre-drying on oil uptake of fried potato strips. Ultrasound pretreatments were performed at 28 and 40 kHz and drying pretreatments were conducted at 80C for 8 and 15 min. Then, frying process was carried out at 150, 170 and 190C. Results showed that, compared to control, oil uptake of samples pretreated with both ultrasound and drying significantly decreased (P < 0.05). It was concluded that at all the frying temperatures, samples pretreated with ultrasound had lower oil uptake in comparison with control samples. Practical Applications Deep-fat frying process is broadly used for both domestic and industrial purposes. High-power (low-frequency) ultrasound modifies food properties by inducing mechanical, physical and chemical or biochemical changes. Ultrasound techniques are relatively cheap, simple and energy saving. It has been demonstrated that decreasing the initial moisture content of raw material reduces oil uptake in the fried product. Regarding high dehydration efficiency of ultrasound, this study provides information on the possibility of using ultrasound-assisted air-drying as a pretreatment prior to frying, in order to investigate oil uptake of fried potato strips.