The objective of this study was to evaluate the effect of microwave precooking on mass transfer during deep-fat frying of chicken nuggets. The effect of microwave power level, frying temperature and time On mass transfer in the breading coating and the core parts were determined. The results showed an interaction effect of these processing conditions on mass transfer. The most reduction in fat absorption was observed when samples were precooked at 6.7 W/g and fried 170 degrees C. The first order kinetic model fitted the moisture and fat transfer data well except for fat transfer in the core portion. The effective moisture diffusivity for the breading coating and core portion ranged between 6.39 x 10(-10) to 14.7 x 10(-10) m(2)/s and 1.77 x 10(-10) to 14.0 x 10(-10) m(2)/s, respectively, and the R values were between 0.86 and 0.99. Fat transfer rate constant in the breading region was between 0.04 and 40.96 s(-1) with R(2) from 0.67 to 0.97. Activation energy obtained from the Arrhenius plot for the effective moisture diffusivity ranged between 13.65 and 54.93 kJ/mol. (C) 2008 Published by Elsevier Ltd.