Table 2. Design and results of RSM experiment for extraction yield of PSC and PPN.
| No. | Coded parameter levels of PSC | Coded parameter levels of PPN | Observer | Predicted | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| X1 (mL/g) | X2 (°C) | X3 (min) | X′1 (mL/g) | X′2 (°C) | X′3 (min) | Yield of PSC (%) | Yield of PPN (%) | Yield of PSC (%) | Yield of PPN (%) | |
| 1 | 0 | 1 | −1 | 0 | 1 | −1 | 14.46 | 7.8 | 14.40 | 7.80 |
| 2 | −1 | −1 | 0 | −1 | −1 | 0 | 15.05 | 7.4 | 14.89 | 7.49 |
| 3 | 1 | −1 | 0 | 1 | −1 | 0 | 15.19 | 8.4 | 15.19 | 8.39 |
| 4 | 0 | 0 | 0 | 0 | 0 | 0 | 16.92 | 8.6 | 16.93 | 8.53 |
| 5 | −1 | 1 | 0 | −1 | 1 | 0 | 16.10 | 8.0 | 16.10 | 8.01 |
| 6 | 0 | 0 | 0 | 0 | 0 | 0 | 16.84 | 8.6 | 16.93 | 8.53 |
| 7 | 1 | 0 | 1 | 1 | 0 | 1 | 15.56 | 8.9 | 15.51 | 8.91 |
| 8 | −1 | 0 | −1 | −1 | 0 | −1 | 15.50 | 7.8 | 15.56 | 7.79 |
| 9 | 1 | 1 | 0 | 1 | 1 | 0 | 15.19 | 8.3 | 15.35 | 8.21 |
| 10 | 0 | 1 | 1 | 0 | 1 | 1 | 15.81 | 8.5 | 15.71 | 8.58 |
| 11 | 1 | 0 | −1 | 1 | 0 | −1 | 15.59 | 8.3 | 15.49 | 8.39 |
| 12 | 0 | 0 | 0 | 0 | 0 | 0 | 17.02 | 8.4 | 16.93 | 8.53 |
| 13 | −1 | 0 | 1 | −1 | 0 | 1 | 15.80 | 8.5 | 15.90 | 8.41 |
| 14 | 0 | −1 | −1 | 0 | −1 | −1 | 14.74 | 7.9 | 14.84 | 7.83 |
| 15 | 0 | −1 | 1 | 0 | −1 | 1 | 13.84 | 8.2 | 13.90 | 8.20 |