Optimization of process parameters for hybrid drying of apple

Abstract

The processing parameters viz. thickness of fruit slices, osmotic solution concentration and temperature during dehydration are considered most important for determining the drying kinetics and quality of final product. Hence, the present study was designed with the objective to optimize the processing conditions of hybrid drying involved ultrasound, osmotic followed by convective dehydration of apple. Data for the optimization were analyzed by using Response Surface Methodology. The experimental design involved sucrose concentration (30-70°B), thickness of apple rings (3.00–5.00 mm) and ultrasonicated time (0-60 min) and the response variables were solids gain and water loss. Results showed that maximum water loss and solid gain obtained at optimal conditions of 30 min ultrasonicated osmotic treatment at 50°B and thickness of 4.5 mm apple rings. The study concluded that application of ultrasound improved the product quality through 30-40 per cent reduction in dehydration time.