Modeling Apparent Density of Potato Strips Pretreated with Ultrasound and Drying During Deep-Fat Frying

The aim of this study was to investigate the effect of ultrasound and drying pretreatments on apparent density as well as modeling apparent density during deep-fat frying of potato slices. Ultrasound pretreatment was performed at 28 and 40 kHz for 15 min and drying pretreatment were conducted at 80°C for 8 and 15 min. Then, the frying process was done at 150, 170 and 190°C for 60, 120, 180 and 240 seconds. In order to model apparent density, experimental data were fitted with six empirical models proposed in this study. The results showed that apparent density of various samples decreased during deep-fat frying. In samples pretreated with ultrasound (28 and 40 kHz), the process time for 180 or 240 s, significantly reduced the apparent density compared to control samples. However, in samples pretreated with pre-drying (8 and 15 min), the decrease in apparent density was not statistically significant in comparison with control samples for the same process time. Furthermore, by increasing the temperature from 150 to 190°C, the reduction in apparent density increased. In addition, applied models were well fitted to experimental data with high R2 and low RMSE. Also, through multiple regression analysis, models with high R2 were proposed that are applicable to the different conditions in terms of time and temperature of the deep-fat frying process.