Table 2.
ANOVA and regression coefficients of the first- and second-order polynomial models
| Variables | Main effects | Quadratic effects | Interaction effects | ||||||
|---|---|---|---|---|---|---|---|---|---|
| X 1 | X 2 | X 3 | X 1 2 | X 2 2 | X 3 2 | X 1 X 2 | X 1 X 3 | X 2 X 3 | |
| Colour L | |||||||||
| P value | 0.000* | 0.002* | - | 0.000* | - | - | 0.001* | - | - |
| F ratio | 38.07 | 14.41 | - | 28.46 | - | - | 15.43 | - | - |
| Colour a | |||||||||
| P value | 0.001* | - | 0.000* | 0.000* | - | - | - | - | - |
| F ratio | 16.35 | - | 64.15 | 22.38 | - | - | - | - | - |
| Colour b | |||||||||
| P value | 0.000* | 0.008* | 0.005* | - | - | - | - | - | - |
| F ratio | 40.40 | 9.17 | 10.86 | - | - | - | - | - | - |
| Browning Index | |||||||||
| P value | 0.078** | - | - | 0.028* | - | - | - | - | - |
| F ratio | 3.51 | - | - | 5.77 | - | - | - | - | - |
| Fracturability | |||||||||
| P value | 0.036* | 0.007* | 0.038* | 0.030* | 0.011* | 0.025* | - | - | - |
| F ratio | 5.68 | 10.85 | 5.56 | 6.17 | 9.25 | 6.67 | - | - | - |
Values of P value and F ratio less than 0.050 indicate model terms are significant. Values of P value and F ratio greater than 0.050 indicate model terms are not significant.
*Significant (p < 0.05).
**Not significant (p > 0.05).
Coded forms for response variables X 1: Roasting temperature; X 2: Roasting time; X 3: pH.