Effect of pretreatment on the drying kinetics of yacon slices
Dept. of Food Engineering, Daegu University
Dr. Jun Ho Lee
Yacon is a food with great potential for research because of its beneficial properties to human health, especially the prebiotic activity, which is ascribed to the high concentration of inulin and fructooligosaccharides in its composition. However, the high percentage of water renders this tuber extremely perishable, hindering transporting and processing. Pretreatment such as blanching and streaming prior to hot-air drying allows more efficient drying process with excellent physicochemical and sensorial characteristics. The assessment of the process kinetics and application of mathematical models to predict it provides information for the process design, increasing the use of yacon in the agro industry.
Hot-air drying of yacon samples was carried out to compare the influence of blanching and steaming as pre-treatments on the drying kinetics at temperatures of 50, 60, 70, and 80℃. The experimental curves of drying were adjusted to the diffusional model of Fick for a thin layer. The results provide evidence which pretreatments prior to drying affect moisture transport of these products. Water removal during drying of the yacon samples occurs in the falling-rate period and main factors affecting the drying of this sample as the pretreatment applied and temperature.