Color changes and drying kinetics modeling of basil seed mucilage during infrared drying process

Abstract

The physicochemical properties and color of dried seed mucilage (gums) depend on the condition and method of drying. So, in this study, the effects of infrared (IR) dryer system parameters such as IR power (150, 250, and 375 W), distance of mucilage from lamp surface (4, 8, and 12 cm), mucilage thickness (0.5, 1.0, and 1.5 cm) on drying kinetics and color indexes (L*a*b*) of basil seed mucilage (BSM) were examined in an IR dryer system. IR drying kinetic of BSM was modeled using mathematical approach. Thus, experimental moisture ratio data were fitted to 8 various empirical models. It was found that Page model has the best fit to show the kinetic behavior and acceptably described the IR drying behavior of BSM with the highest correlation coefficient values and the lowest standard error values. The average effective moisture diffusivity (Deff) increased from 1.69 × 10−9 to 9.21 × 10−9 m2/s with increasing lamp power from 150 W to 375 W, while it was decreased from 7.93 × 10−9 to 2.65 × 10−9 m2/s and 7.81 × 10−9 to 1.82 × 10−9 m2/s 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. The increasing in IR radiation power has a positive influence on the lightness (increasing L* index) of dried BSM and it reduced color changes index (ΔE) from 13.04 to 11.51. The results showed that IR drying method has great industrial potential in saving processing time as well as energy with better maintenance of color and quality of dried BSM.