Osmotic Dehydration Process Optimization of Papaya

Abstract

Abstract: An investigation was carried out to study the effect of processing parameters on osmotic dehydration in sugar solution and liquid jaggery and to evaluate the quality of the osmotically dehydrated product after tray drying. A Box-Behnken design was used to optimize the level of concentration (500 , 600 , 700 ), temperature (350 ,400 ,450 ), solution to sample ratio (2, 3.5, 5) and agitation (0,100,200rpm). Optimization was done on the basis of overall acceptability. The samples were analyzed for drying characteristics, proximate analysis (moisture content, titratable acidity) and sensory evaluation. Investigations indicated that the lowest moisture content observed was at high levels of operating conditions ( 700 Brix, 450 C, ratio – 5 and agitation – 200 rpm) , while the highest was at low levels of parameters i.e. 500 Brix, 250 C, ratio – 2 and no agitation. The moisture content after the osmotic treatment was in the range between 51.81 and 70.38 % (w.b.) while the final moisture content after tray drying varied from 15.11 – 19.20 % (w.b.). It was also found that weight of the material was reduced by more than 50% using osmotic dehydration. The water loss was in range 27.43- 58.96%, based on initial solid content. On the basis of studies conducted using RSM, the optimum operating condition observed in case of osmotic dehydration process with sugar solution was 69.5 % concentration, 44.5 0C temperature, solution to sample ratio was 2 and agitation speed was 185 rpm while in liquid jaggery solution the optimum operating condition observed was 59.5 % concentration, 38 0C temperature, solution to sample ratio was 5 and agitation speed 185 rpm. The product osmotically dehydrated in sugar solution was found to be better than that when it was osmotically dehydrated in liquid jaggery as overall acceptability value of sugar solution was more than jaggery solution.