“…The microwave heat generation term per unit volume can be written as Where, f = frequency, = dielectric constant, = food factor loss, = Average electric field intensity. The surface of product being heated by microwave energy has typically convection phenomenon-either natural or forced convection, Where, T = load surface temperature, z = normal to surface, h = convective heat transfer coefficient, m w = evaporation rate, = latent heat vaporization, = Stefan boltzman constant, = radiative surface emissivity of load, = radiant heat flow rate per unit surface area, =surface absorptivity A Fick's second law of diffusion was taken into consideration for evaluation of moisture transport in food material during the analysis of falling rate period, which is given by [9,10] Where, M = free moisture content, kg water/kg dry matter; t= time, sec; x =diffusion path or length, cm; and D = moisture diffusivity, cm 2 s -1 A considerable variation in diffusivity with the method of slopes technique is used for the estimation of effective moisture diffusivity of thin infinite onion slab at varying moisture content under different drying conditions. For a thin infinite slab being dried from only one side, the following assumptions were made:…”