Table 8.
Rotatable central composite design in the coded A and uncoded form of the independent variables (X1 and X2) for cold ethanol extraction at different temperatures (−20 °C, −40 °C, and room temperature).
| Run | Sample (g) Solvent (g)−1 (w/w) |
Sample (g) Solvent (40 mL)−1
(w/v) (X1) |
Extraction Time (min) (X2) |
|---|---|---|---|
| 1 | 1/2.93 | 10.77 (−1.414) | 20 (0) |
| 2 | 1/5 | 6.31 (−1) | 10 (−1) |
| 3 | 1/5 | 6.31 (−1) | 30 (+1) |
| 4 | 1/10 | 3.16 (0) | 5.86 (−1.414) |
| 5 | 1/10 | 3.16 (0) | 20 (0) |
| 6 | 1/10 | 3.16 (0) | 20 (0) |
| 7 | 1/10 | 3.16 (0) | 20 (0) |
| 8 | 1/10 | 3.16 (0) | 20 (0) |
| 9 | 1/10 | 3.16 (0) | 20 (0) |
| 10 | 1/10 | 3.16 (0) | 34.14 (+1.414) |
| 11 | 1/15 | 2.1 (+1) | 10 (−1) |
| 12 | 1/15 | 2.1 (+1) | 30 (+1) |
| 13 | 1/17.07 | 1.85 (+1.414) | 20 (0) |
A Values in parentheses represent coded forms of the variables.