The moisture transfer mechanism by diffusion and uptake of frying oil was studied during deep fat frying of papads with an initial moisture content (IMC) 24.8% dry basis (db). The experimental data were found to fit well to a first order exponential model for moisture transfer (with a regression coefficient 0.99). The apparent moisture diffusivity of papad in the frying time range of 0-20 s at temperatures of 165, 175, 180 and 185 +/- 1 degreesC were 2.83, 3.65, 3.87 and 5.03 x 10(-9) m(2) s(-1), from which the activation energy (45 kJ mol(-1)) was calculated by using Arrhenius type equation. The optimum experimental frying parameters for maximum diametrical expansion (46.4%) were noted to be: oil temperature 185 +/- 1 degreesC, moisture 1.2%db, oil absorption (47.3%db), density 377 kg m(-3) for frying time of 20 s. (C) 2003 Elsevier Ltd. All rights reserved.