A Comparative Study on Drying and Coating of Osmotic Treated Apple Rings

In this study, the effect of edible coat (carboxy methyl cellulose) before osmotic dehydration and different drying methods on sensory and physical properties of dried apple (V. Golden delicious) rings was investigated. The coated and non-coated samples pretreated with 50% sucrose osmotic solution and dried in freeze drier (-40 to -50°C, 0.026-0.017 mbar, 24 hr), vacuum drier (70°C, 200 mbar, 8-10 hr), air dryer (60°C, 1.5 m/s, 2-3 hr). Sensory evolutions, Rehydration ratio (RR), color changes (?E), shear strength (SS), true density and shrinkage present of dried samples were determined. Effect of using edible coats before osmotic process was significant on the SS, RR and color changes. As the lowest shrinkage, color changes, RR, and highest SS were found in freeze dried apples. The air and vacuum dried samples had the highest RR and true density, respectively. The best sample in sensory evolutions was coated and freeze dried samples.