Oil uptake modeling during deep-fat frying of potato strips pretreated with ultrasound and drying

In this study، the effect of different pretreatments on oil uptake and sensory characteristics of fried potato slices was investigated and also oil uptake of the samples was modeled. Ultrasound pre-treatment was performed at 28 and 40 kHz for 15 min and drying pretreatments 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 the oil uptake، experimental data were fitted with six empirical models (2 models from published literature works and 4 models proposed in this study). The results showed that ultrasound-pretreated samples achieved the best result in decreasing oil uptake at the frying temperature of 150°C، compared to the control samples (rectangular slices with dimensions of 4×1. 2×1. 2 cm3) fried at similar frying time and temperature conditions; although the decrease was not statistically significant. Moreover، the samples pretreated with drying as well as combination of ultrasound and drying reduced oil uptake in comparison with the control samples. The decrease was significant in some samples and insignificant in some others. In addition، all the models used were well fitted to the experimental data. On the other hand، through multiple regression analysis، various models with high R2 were proposed to be applied at different circumstances of time and temperature during deep-fat frying process. Between different fried samples، in terms of sensory evaluation، no statistical significant difference was observed among the evaluated factors.