Drying kinetic modelling of Kalle-Ghuchi cultivar pistachio nut using different methods: solar, sun and shade drying

Drying is one of important stage of the postharvest processing of agriculture crops. In this study design, construction and evaluation of a solar dryer for pistachio processing was investigated. To measure and record air temperature and relative humidity at different places of dryer, a digital data logger device was fabricated and installed. To evaluating of drier, the parameters of drying time, moisture content variation during drying and drying rate were studied. Drying of pistachio in traditional methods exposed to direct sunlight, shade and solar drying were carried out at the ranges of air temperature of 19.91-33.11oC, 20.63-36.82oC and 32.30-54.20oC during 19, 48 and 13 h, respectively. The results illustrated that, Aghbashlo et al. and Diffusion approximation models were introduced as the best models for predicting drying behaviour of whole pistachio in solar drying and traditional drying (sun/shade) methods, respectively. Generally, the result indicated that solar drying method than other drying method was recommended to processing of Persian’s pistachio.