Optimization of process parameters for osmotic dehydration of papaya cubes

Process temperature (30, 40 and 50 °C), syrup concentration (50, 60 and 70(o) Brix) and process time (4, 5 and 6 h) for osmotic dehydration of papaya (Carica papaya) cubes were optimized for the maximum water loss and optimum sugar gain by using response surface methodology. The peeled and pre-processed papaya cubes of 1 cm size were immersed in sugar syrup at constant temperature water bath having syrup to papaya cubes ratio of 4:1 (w/w). The cubes were removed from bath at pre-decided time, rinsed with water and weighed. Initial moisture content of papaya samples were 87.5-88.5% (wb), which was reduced to 67.6-81.1% after osmotic dehydration in various experiments showing mass reduction, water loss and sugar gain in the range of 20.6-36.4, 23.2-44.5 and 2.5-8.1%, respectively. The weight reduction, water loss and sugar gain data were statistically analyzed and regression equation of second order were found the best fit for all the experimental data. Maximum water loss of 28% with optimum sugar gain of 4% was predicted for the 60(o)Brix syrup concentration at 37 °C for syrup to fruit ratio as 4:1 in 4.25 h of osmotic dehydration.