Optimization of osmotic dehydration parameters of banana under pulsed microwave conditions by response surface methodology

Abstract

Microwave assisted osmotic dehydration (MWOD) conditions of banana were optimized using response surface methodology. In this study, the microwave energy was applied in pulsing form to adjust the intermittent temperature distribution and overheating problem at respective microwave power level. The experiments were conducted using a face-centered central composite design (FCCD) with four factors, viz. slice thickness (5-10 mm), sugar concentration (40-60oBrix), microwave power (100-1000W), and time (10-50 min) at three levels. Multiple regression analysis showed that all process factors significantly affects linearly on the water loss, solid gain, drying efficiency, and color difference at p<0.05. The optimum operating conditions were found to be slice thickness of 9.87mm, sugar concentration of 59.99oBrix, microwave power level of 100W, and osmosis time of 50 min. Under this operating condition, WL, SG, color difference and drying efficiency were 19.41%, 6.80%, 15.11 and 28.23 (MJ/kg), 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.