Optimization of Osmotic Dehydration of Carrot Using Response Surface Methodology (Rsm)



Response surface methodology was applied to determine the optimum processing conditions that lead to maximum water loss, weight reduction and minimum solid gain as well as water activity during osmotic dehydration of carrots. Temperature (30-50?C), processing time (120-240 min), glucose syrup DE=42 (30-50% w/w) and salt (5-15%) concentrations were the factors investigated with respect to water loss (WL), Weight Reduction (WR), Solid Gain (SG), and water activity (aw). Experiments were arranged according to Central Composite Rotatable Design with these four factors each at three different levels, including central and axial points. Experiments were conducted with constant agitation rate of 200 rpm and solution to sample ratio of 10:1 (w/w). With respect to water loss, solid gain, weight reduction and water activity, both linear and quadratic effects of variables were found to be significant (p<0.001). For each response, second order polynomial models were developed using Multiple Linear Regression Analysis. Analysis of Variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The optimal conditions for maximum water loss and weight reduction as well as minimum solid gain and water activity correspond to temperature of 30 ?C, glucose syrup concentration of 43.315%, salt concentration of 5%, time of 227.19 min to obtain water loss of 66.97 (g/100 g fresh sample), weight reduction of 62.52 (g/100 g fresh sample), solid gain of 4.475 (g/100 g fresh sample) and water activity of 0.789.