Table 1.
Central composite experimental design with coded extraction parameters of NADES 4 and experimentally observed values of target responses: total phenol content and antioxidant activity (DPPH, FRAP, and ABTS).
| Input Factors | Response 1 | Response 2 | Response 3 | Response 4 | |||
|---|---|---|---|---|---|---|---|
| Run | A: Temperature [°C] | B: Extraction Time [min] | C:S/L Ratio [g/g] | TP [mg GAE/g DW] | DPPH [µM TE/g] | FRAP [µM Fe2+/g] | ABTS [µM TE/g] |
| 1 | 1 | 0 | 0 | 8.17 | 10.09 | 72.54 | 16.78 |
| 2 | −1 | −1 | 1 | 3.42 | 9.80 | 55.94 | 9.22 |
| 3 | 0 | 0 | 0 | 5.94 | 9.87 | 60.97 | 14.05 |
| 4 | 1 | −1 | −1 | 5.50 | 8.08 | 63.46 | 14.91 |
| 5 | 0 | 0 | 0 | 6.16 | 11.66 | 61.55 | 13.38 |
| 6 | 1 | −1 | 1 | 6.59 | 12.46 | 80.10 | 19.96 |
| 7 | 0 | 0 | 0 | 6.03 | 10.85 | 57.99 | 16.73 |
| 8 | 1 | 1 | −1 | 10.09 | 8.38 | 62.34 | 21.10 |
| 9 | 0 | 1 | 0 | 7.72 | 10.44 | 55.38 | 16.37 |
| 10 | 0 | 0 | 0 | 7.92 | 10.84 | 56.78 | 16.00 |
| 11 | −1 | −1 | −1 | 3.86 | 6.65 | 41.57 | 7.68 |
| 12 | 1 | 1 | 1 | 10.27 | 11.84 | 63.86 | 20.16 |
| 13 | 0 | 0 | −1 | 4.04 | 7.80 | 40.03 | 10.31 |
| 14 | 0 | −1 | 0 | 4.85 | 9.87 | 47.89 | 12.61 |
| 15 | −1 | 0 | 0 | 5.30 | 9.81 | 46.19 | 13.03 |
| 16 | 0 | 0 | 1 | 4.61 | 12.08 | 54.42 | 13.39 |
| 17 | 0 | 0 | 0 | 5.97 | 11.39 | 60.71 | 18.26 |
| 18 | −1 | 1 | −1 | 5.20 | 8.26 | 49.97 | 15.17 |
| 19 | −1 | 1 | 1 | 4.79 | 10.08 | 56.51 | 12.46 |
TP—total phenol content; DPPH—2,2-diphenyl-1-picrylhydrazyl; ABTS—2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid); FRAP—ferric-ion-reducing antioxidant power; GAE—gallic acid equivalent; TE—Trolox equivalent.