Effects of environmental temperature and relative humidity on the rehydration of dried pistachios

Abstract

In this study, the environmental air temperature and relative humidity effects were investigated through rehydration on the dried and roasted Siirt Pistachios (S_PS) and Antep pistachios (A_PS) with an experimental and computational approach. Therefore, an experimental apparatus was set-up in lab conditions. A series of experiments were conducted to evaluate the water activity and weight change as a function of the relative humidity and temperature of ambient air. The experimental results show that there is a combined effect of relative humidity and temperature on the increase in the weight change and water activity (aw). The shell of pistachio is a good hygroscopic material despite its hard texture. The roasted pistachios are less prone to absorb moisture compared to the unroasted pistachios. Beside this experimental study, an intelligent modeling called “artificial neural network” model was used for prediction of the increase in the weight of different types of pistachios.