Table 2.
Central composite design with experimental values of target responses of from cinnamon extract by UAE method
| Exp. No.a | Extraction condition | Target responses | |||
|---|---|---|---|---|---|
| Ethanol conc. (%) | Extraction time (min) | Total yield (%) | Cinnamic acid (mg/100 mL) | Cinnamaldehyde (mg/100 mL) | |
| 1 | 75 (1)b | 40 (1) | 0.82 ± 0.02 | 6.35 ± 0.01 | 224.27 ± 0.11 |
| 2 | 75 (1) | 20 (− 1) | 0.75 ± 0.02 | 6.07 ± 0.03 | 217.16 ± 0.05 |
| 3 | 25 (− 1) | 40 (1) | 0.65 ± 0.01 | 5.31 ± 0.00 | 163.04 ± 0.02 |
| 4 | 25 (− 1) | 20 (− 1) | 0.54 ± 0.03 | 5.00 ± 0.03 | 150.09 ± 0.03 |
| 5 | 50 (0) | 30 (0) | 0.75 ± 0.01 | 6.15 ± 0.10 | 209.16 ± 0.25 |
| 6 | 50 (0) | 30 (0) | 0.75 ± 0.03 | 6.16 ± 0.09 | 209.05 ± 0.41 |
| 7 | 100 (2) | 30 (0) | 0.61 ± 0.02 | 4.49 ± 0.01 | 187.01 ± 0.03 |
| 8 | 0 (− 2) | 30 (0) | 0.31 ± 0.03 | 3.90 ± 0.02 | 94.50 ± 0.25 |
| 9 | 50 (0) | 50 (2) | 0.75 ± 0.03 | 5.72 ± 0.02 | 193.99 ± 0.09 |
| 10 | 50 (0) | 10 (− 2) | 0.74 ± 0.01 | 5.66 ± 0.06 | 196.20 ± 0.27 |
| R2 | 0.9690 | 0.9191 | 0.9786 | ||
| Morphology | Maximum | Maximum | Maximum | ||
| F-ratio of ethanol concentration | 35.90*** | 14.22** | 58.70*** | ||
| F-ratio of extraction time | 0.81 | 0.86 | 1.05 | ||
aThe number of experimental conditions by central composite design
bCoded level of independent variables
*Significant at p < 0.1; **Significant at p < 0.05; ***Significant at p < 0.01