Moisture loss and oil uptake during deep fat frying of “Kroštula” dough

The mechanism of moisture transfer by diffusion and uptake of frying oil was studied during deep fat frying of "Krostula" dough with an initial moisture content of 0.4358 kg/kg (db). The experimental data were found to fit well to a first-order exponential model for moisture transfer (with a regression coefficient of 0.99). The effective moisture diffusivity of Krostula dough was determined for two periods of moisture loss (intensive in first 60 s and constant after 60 s of frying). In the frying range 0-60 s at temperatures of 160, 170, 180 and 190±1 °C, the effective moisture diffusivity values were 5.837, 6.607, 8.472 and 9.728×10^sup -9^ m^sup 2^/s, from which the activation energy (30 kJ/mol) was calculated by using an Arrhenius-type equation. The effective oil diffusivity values of Krostula dough in the frying time range 0-210 s at temperatures of 160, 170, 180 and 190±1 °C were 0.932, 1.135, 1.094 and 1.054×10^sup -9^ m^sup 2^/s, from which the activation energy (5.5 kJ/mol) was calculated by using an Arrhenius-type equation.[PUBLICATION ABSTRACT]