Influence of potato processing with ultrasound and microwave pretreatments on oil uptake during frying

The aim of this study was to investigate the effect of process conditions as well as ultrasound and microwave pretreatments on oil uptake during frying of potato slices. In this study, ultrasound pretreatment with two frequencies of 28 and 40 kHz and microwave pretreatment with two powers of 3 and 6 watts per gram was applied to the potato pieces. Then, the frying process was done at 150, 170 and 190°C for 1, 2, 3 and 4 min. The results showed that oil uptake is decreased or increased using the ultrasonic pretreatment depending on the process time and temperature. Oil uptake was reduced at the beginning of the process with low temperatures but was increased at the end of the process with high temperatures compared to controls. In addition, Microwave pretreatment significantly reduced oil uptake of the potato slices. Oil uptake was further reduced by increasing microwave power from 3 to 6 watts per gram. In addition, for predicting oil uptake with regard to the process conditions, six models including 2 models from the literature and 4 new models proposed in this study was examined. Considering the results of the fitted experimental data, ultrasound and microwave pretreatment increased and decreased the equilibrium oil content, respectively. Also, the ultrasound pretreatment reduced the oil uptake rate constant, but the microwave pretreatment increased it.