The drying process of turnip and drying rate curves were investigated at different temperatures (55, 70 and 85Ã?°C)\nwith air flow rate of 1.5 m/s. Also effective diffusion coefficient and activation energy were calculated by using Arrhenius\nequation and Fickââ?¬â?¢s second law for infinite slab. The effective diffusivity varied between 5.471Ã?â??10-10 and 8.966Ã?â??10-10 in the\nrange of (55Ã?°C to 85Ã?°C). The value of activation energy was found to be 16.013 kJ/mol. The mathematical models (Newton,\nPage, Modified Page, Henderson and Pabis, Logarithmic, Two term, Two term exponential, Wang and Singh, Simplified Fickââ?¬â?¢s\ndiffusion, Modified Page ââ?¬â??II, Verma, Midilliââ?¬â??Kucuk, Hii, Law and Cloke, Approximation of diffusion, Modified Henderson\nand Pabis) were fitted to the experimental data. Sigmaplot v10.0 software was used to find the best model for evaluating the\nrate of moisture change. Decency of fit by these models was based on comparing the coefficient of determination (R2),\nreduced chi-square (?2), mean bias error (MBE) and root mean square error (RMSE) between the observed and predicted\nvariables. Among 15 evaluated models, Modified Henderson and Pabis in 85Ã?°C and Hii, Law and Cloke in 55Ã?°C and 70Ã?°C\nwith highest R2 and lowest MBE, ?2 and RMSE were selected to better estimate the drying curves.
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