Modeling engineering characteristics of hazelnut kernel during infrared fluidized bed drying

Abstract

In this study, a laboratory scale infrared fluidized bed dryer was used to dry the hazelnut kernels. The drying experiments were performed under the following drying conditions: air temperatures of 45, 65 and 85 °C, air velocities of 1.30, 3.09 and 4.87 m/s and infrared powers of 500, 1000 and 1500 W. Maximum and minimum values of effective moisture diffusivity for hazelnut kernels were obtained 1.87 × 10−9 and 1.75 × 10−10 m2/s, respectively. Activation energy was obtained between 33.02 and 50.22 kJ/mol. Specific energy consumption of hazelnut kernels was obtained between 1.72 × 103 and 2.23 × 104 MJ/kg. Six mathematical models were used to predict the drying behavior of hazelnut samples. Among these models, the Midilli model sufficiently fitted the experimental drying data. The shrinkage values were obtained within the range of 0.10 and 0.24. The results obtained showed that the \({{L}^{*}},\)\({{a}^{*}},\)\({{b}^{*}}\) and \(\Delta E\) color values of the kernels were significantly affected (P < 0.05) by air temperature. The highest color changes were related to the air temperature of 85 °C at all air velocities and infrared powers. Maximum values of energy (103.57 N mm) and force (129.84 N) at initial rupture point was related to air temperatures of 85 °C and infrared powers of 1500 W. Minimum values of energy (16.47 N mm) and force (31.74 N) at initial rupture point was related to air temperatures of 45 °C and infrared powers of 500 W.