Experimental investigation and statistical validation of mathematical models for hot air drying traits of carrot.

The purpose of this investigation is to analyze the influence of sample shapes or geometry and dryer temperature on drying kinetics of carrot. Three different geometrical shapes including rectangular slab, circular discs and cubical samples, at temperatures of 70 °C, 80 °C and 90 °C, respectively, are dehydrated through hot air convection drying and regression analysis is executed to adjust the outcomes to 4 thin layer drying models. The models were validated by parameters- R2 (0.957-0.999), RMSE (0.0066-0.093), AIC (-209 to -54.6 for Henderson and Pabis model, -74.8 to -11.8 for Wang and Singh model, -91.47 to -22.7 for Newton model and -140 to -46.6 for Page model), BIC (-206 to -54 for Henderson and Pabis model, -72.4 to -10.76 for Wang and Singh model, -90.3 to -20.28 for Newton model and -138 to -43.92 for Page model) and residual errors (-0.03 to 0.03). The statistical analysis indicated that Henderson and Pabis model is best suited for the drying purpose. Fick's second law of diffusion is applied to compute values of effective moisture diffusivity, which was maximum for circular disc samples in all the cases and rose with an increase in dryer temperature. It varied in the range of 3.02 × 10-8 m2/s to 1.86 × 10-6 m2/s whereas the values of activation energies varied from 68.512 kj/mol to 74.256 kj/mol. The results obtained from this study reveals the experimentally determined drying properties of carrot in order to infer that circular disc shapes possess the ability to optimize the drying process in industries.