The Effect of Gum Based Edible Coating on the Infrared Drying Performance of Apricot Slices

Edible coating applied to fruit slices prior to drying is a technology that can improve the nutritional and sensory qualities of dehydrated products. One of the best ways to reduce the drying time is to provide heat by infrared (IR) radiation. In this study, the effects of polysaccharide based coating (xanthan and Balangu seed gums) on the IR drying kinetics of apricot slices were investigated. In addition, the effects of IR dryer system parameters including IR power (150, 250 and 375 W) and distance of apricot slices from lamp surface (5, 7.5 and 10 cm) on drying time and effective moisture diffusivity (Deff) were investigated. Also, experimental moisture ratio (MR) data were fitted to 7 various empirical thin-layer models (Quadratic, Page, Newton, Midilli, Logarithmic, Verma and Two term). The average drying time of uncoated apricot slices, coated by xanthan gum and coated by Balangu seed gum were 73.11, 81.04 and 83.74 min, respectively. The average effective moisture diffusivity increased from 1.48×10-9 m2/s to 5.56×10-9 m2/s with increasing lamp power from 150 W to 375 W, while it was decreased from 4.28×10-9 m2/s to 2.26×10-9 m2/s with increasing the distance of slices from 5 to 10 cm. The results indicate that Page model is appropriate in describing drying characteristics of apricot slices under the various coating pretreatment and IR drying conditions (r>0.988).