evaluation and characterization of vacuum drying of date paste

the drying behavior and characteristics of date paste were studied at temperatures of 60, 70, and 80ºc as thin layer with sample thicknesses of 1, 1.5, and 2 cm in a laboratory scale vacuum chamber. modeling of drying kinetics of date paste was investigated based on the specific temperatures and sample thicknesses. the experimental moisture loss data were fitted to eight thin layer drying models available in the literature. the modified henderson-pabis, verma, and jena-das models showed better fitness to the experimental drying data compared to the other models. the effective moisture diffusivity ranged between 6.0854×10-8 and 4.868×10-7 m2 s-1. effective diffusivity increased with the increase in temperature and sample thickness. the temperature dependence of effective moisture diffusivity was expressed by an arrhenius type equation.