The effect of drying methods and pretreatment on physico-chemical, energy consumption and thermodynamic analysis of "Hatay" genotype purple carrot slices

The aim of this study is to investigate the effects of drying temperatures and pretreatment on the physico-chemical, energy consumption and thermodynamic analyses of purple carrot slices drying processes. Slices were dried from 6.13 +/- 0.05 g moisture.g dry matter moisture(-1) value to 0.029 +/- 0.001 g moisture.g dry matter(-1) moisture value. The samples were dried in an oven at 50, 60, 70 and 80 degrees C at hybrid oven 350 W + 50 degrees C, 350 W + 60 degrees C, 350 W + 70 degrees C and 350 W + 80 degrees C. Among the models, the drying rates were best estimated by the Midilli-Kucuk (R2: 0.9996) model. The effective diffusion values were between 1.30 x 10(-7) and 1.27 x 10(-6) m(2) s(-1), and the activation energy values were between 7.96 and 25.61 kJ mol(-1). It has been determined that pretreatment and drying methods have different effects on the color values of the dried samples. While the highest energy consumption was determined in the drying process performed as 1.103 kWh, the least energy consumption was determined as 0.330 kWh. While the total evaporation energies of the control samples dried in the oven ranged between 14,039.20 and 14,231.70 kWh, the total evaporation energies of the pretreated samples were determined to vary between 14,175.50 and 14,352.00 kWh. It was determined that the total evaporation energies of the control samples dried in the hybrid oven varied between 14,143.30 and 14,360.10 kWh, while the evaporation energies of the pretreated samples varied between 14,197.50 and 14,234.60 kWh. Enthalpy (Delta H) values of drying processes were determined as 2601.67-2863.34 kJ mol(-1), entropy (Delta S) values as 351.15-369.44 kJ mol(-1) and Gibbs free energy (Delta G) values as 93,000.26-98,255.87 kJ mol(-1).