Engineering and Applied Science Research (Nov 2023)
Drying of tamarind foam-mats using far-infrared radiation combined with a belt conveyor system: Drying kinetics, quality attributes, and mathematical modeling
Abstract
The study aimed to evaluate the effects of far-infrared radiation (FIR) power level and the thickness of tamarind foam-mats (TFMs) on changes in moisture content during the drying process. This process involved the use of far-infrared radiation, combined with a belt conveyor system (FIR+BCS), to dry the TFMs. Specific energy consumption (SEC) and quality attributes of tamarind powder, such as color and dissolution time, were examined. The study also investigated a mathematical model to describe the suitable drying characteristics of TFMs. In the experiment, cylindrical TFMs with a diameter of 5 cm and thicknesses of 3 and 6 mm were dried using FIR+BCS at FIR power levels of 400, 500, and 600 W until the moisture content of the TFMs was reduced to less than 13% w.b. Based on the experimental results, it was found that higher FIR power levels led to more rapid decreases in moisture content in TFMs, lower SEC, and quicker dissolution of tamarind powder in water, compared to lower FIR power levels. The 3 mm thick TFMs exhibited faster moisture content reduction, lower SEC, and more rapid dissolution of tamarind powder in water than the 6 mm thick ones. In addition, tamarind powder produced from 6 mm thick TFMs had higher lightness (L* value) and yellowness (b* value), but lower redness (a* value) than those of 3 mm thick TFMs. However, tamarind powder produced from TFMs with FIR power levels of 400, 500, and 600 W were not significantly different in color values (L*, a*, and b* values). Among the seven mathematical models, the Midilli et al. model satisfactorily described the drying kinetics of TFMs, with an R2 value of 0.993269, an RMSE of 0.005117, and a χ2 value of 0.000321. The effective moisture diffusivity values of TFMs ranged from 9.41×10-10 to 2.33×10-9 m2/s.
