3. Results and discussions
3.1. Mathematical modeling
In the present study, extraction yield of pectin was investigated according to BBD (29 batch experiments) and its results are shown in Table 2. Then, BBD experimental data are investigated using multi regression analysis namely the sequential model sum of squares (Table 3). From the results, second order polynomial equation was selected to represent the MAE extraction process, due to higher F-value with low p-value. The equation with coded factors was given below where Y is extraction yield of pectin (%); A, B, C and D are power,temperature, extraction time and solid–liquid ratio respectively. ANOVA results of the quadratic model in Table 4 indicated that the model equation derived by RSM could adequately be used to describe the extraction process under a wide range of operating conditions. As can be seen in Table 4, F-value was >27 and implied that the quadratic model was significant. Moreover, each term in the model was also tested for significance. A p-value less than 0.05 implies that the corresponding model term is significant. Moreover,individual and interactive model terms also shows the significance of the developed model. The obtained CV of this study is not greaterthan 10% and shows the reproducible nature. In the present study,adequate precision value was obtained as >4, demonstrate a significant and intense correlation between the observed and predicted values. The actual and predicted pectin yields are plotted in Fig. 1. Actual values are data for each specific run from Table 2, and predicted values are produced by the model, Eq. (3). The data points on this plot lie reasonably close to the straight line and indicate that an adequate agreement between real data and the data obtained from the model (Prakash Maran, Sivakumar, Thirugnanasambandham, &Sridhar, 2013a).