Effect of Infrared Drying on Drying Kinetics and Color Changes of Wild Sage Seed Mucilage

Abstract

In this study, the effects of infrared (IR) dryer system parameters such as IR power, the distance of mucilage from lamp surface, mucilage thickness on drying kinetics and, color indexes (L*, a*, b* and ΔE) of wild sage seed mucilage (WSSM) were investigated in an IR dryer system. Experimental moisture ratio (MR) data were fitted to 7 various empirical thin-layer models. It was found that the Page model has the best fit to show the kinetic behavior and acceptably described the IR drying behavior of WSSM with the lowest mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and standard error (SE) values and the highest correlation coefficient (r) value. The values of MSE, RMSE, and MAE for all experiments were in the range of 0.1×10-3-1.1×10-3, 1.04×10-2-3.25×10-2 and 8.7×10-3-27.1×10-3, respectively. The average effective moisture diffusivity (Deff) increased from 4.61×10-9 m2s-1 to 15.8×10-9 m2s-1 with increasing lamp power from 150 W to 375 W, while it was decreased from 14.4×10-9 m2s-1 to 5.16×10-9 m2s-1 and 13.2×10-9 m2s-1 to 4.31×10-9 m2s-1 with increasing the distance of mucilage from 4 to 12 cm and the reduction of mucilage thickness from 1.5 to 0.5 cm, respectively. Increasing in IR radiation power has a positive influence on the yellowness (increasing 19.78% in b* index) of dried WSSM. Also, it increased the color changes index (ΔE) from 16.05 to 17.59.

Keywords

• color indexes
• effective moisture diffusivity
• gum
• moisture ratio
• page model