Effective moisture diffusivity determination and mathematical modelling of the drying curves of the olive-waste cake

Olive cake is an important agro industrial by-product with the dried cake being the input material of many applications areas. In this research, the drying kinetics of olive cake during convective dehydration at five temperatures (50, 60, 70, 80 and 90 degrees C) was investigated. Several empirical mathematical models were selected to describe experimental drying kinetics data, namely, Page, Modified Page, Henderson and Pabis, Modified Henderson and Pabis, Two-Terms, Logarithmic and Weibull. Air temperature showed a significant effect on drying rates. Based on the statistical tests results (sum squared errors, chi-square and correlation coefficients), the Modified Henderson and Pabis equation is the most suitable model to describe the experimental drying curves. Effective moisture diffusivity of olive cake was in the range of 2.03x10(-9)-1.71x10(-9) m(2) s(-1). An activation energy value of 12.43 kJ mol(-1) was determined. The findings allow the successful simulation of olive cake drying between 50 and 90 degrees C.