OPTIMIZATION OF PROCESS PARAMETERS DURING PULSED MICROWAVE OSMOTIC DEHYDRATION (PMOD) OF BANANA SLICES BY RESPONSE SURFACE METHODOLOGY

Abstract

The pulsed microwave osmotic dehydration (PMOD) of banana slices was carried out by immersing in sucrose solution. The experiments were conducted using a face-centered central composite design (FCCD) with four factors, viz. slice thickness (5-10 mm), sucrose concentration (40-60oBrix), microwave power (100-1000W), and time (10-50 min) at three levels to take into account the individual and interaction effects of the factors. The sample to solution ratio of 1:30 was kept constant throughout all of the experiments to minimize the cost of processing. Optimization of the process parameters for osmotic dehydration of banana slices was also obtained by response surface methodology. Multiple regression analysis showed that all process factors highly affect linearly on the water loss (WL), solid gain (SG), drying efficiency (DE), and color change (ΔE). Microwave power was found as the most significant factor during pulsed microwave osmotic dehydration (PMOD) of banana slices except for water loss (WL) in which osmosis time was found as the most influential factor (p<0.01). The optimum operating conditions were found to be slice thickness of 9.94 mm, sucrose concentration of 60oBrix, microwave power level of 100W, and time of osmosis of 50 min. Under this operating condition WL, SG and color change were 19.49 % (wb), 6.96% (wb) and 15.06, respectively. The predicted optimum values for independent variables were validated by performing several experiments and the simulated data were found in closeness to the experimental ones.