Table 1.
Box–Behnken design for the experimental study
| Run no. | Coded values | Uncoded values | ||||
|---|---|---|---|---|---|---|
| X1 | X2 | X3 | Feed moisture (% wet basis) | Screw speed (rpm) | Temperature of barrel (°C) | |
| 1 | − 1 | − 1 | 0 | 12 | 275 | 140 |
| 2 | 1 | − 1 | 0 | 18 | 275 | 140 |
| 3 | − 1 | 1 | 0 | 12 | 425 | 140 |
| 4 | 1 | 1 | 0 | 18 | 425 | 140 |
| 5 | − 1 | 0 | − 1 | 12 | 350 | 130 |
| 6 | 1 | 0 | − 1 | 18 | 350 | 130 |
| 7 | − 1 | 0 | 1 | 12 | 350 | 150 |
| 8 | 1 | 0 | 1 | 18 | 350 | 150 |
| 9 | 0 | − 1 | − 1 | 15 | 275 | 130 |
| 10 | 0 | 1 | − 1 | 15 | 425 | 130 |
| 11 | 0 | − 1 | 1 | 15 | 275 | 150 |
| 12 | 0 | 1 | 1 | 15 | 425 | 150 |
| 13 | 0 | 0 | 0 | 15 | 350 | 140 |
| 14 | 0 | 0 | 0 | 15 | 350 | 140 |
| 15 | 0 | 0 | 0 | 15 | 350 | 140 |
X1 is feed moisture, X2 is screw speed and X3 is temperature of barrel no. 6