Table 1.
Three factor and three-level central composite face design and the observed responses
| Experiment number | Independent variables | Responses | ||||||
|---|---|---|---|---|---|---|---|---|
| Enzyme concentration (%) | Temperature (°C) | Time (h) | Hesperetin (mg/g) | Naringenin (mg/g) | TPC (mg GAE/100g) | DPPH RSC (%) | FRAP (mg AAE/100g) | |
| 1 | 1 (−1) | 40 (−1) | 2 (−1) | 0.139 | 0.185 | 304.58 | 40.22 | 174.88 |
| 2 | 1 (−1) | 60 (1) | 2 (−1) | 0.470 | 0.248 | 292.63 | 35.33 | 138.84 |
| 3 | 4 (1) | 40 (−1) | 2 (−1) | 0.521 | 0.316 | 334.72 | 34.64 | 190.15 |
| 4 | 4 (1) | 60 (1) | 2 (−1) | 1.554 | 0.436 | 347.56 | 28.75 | 176.23 |
| 5 | 1 (−1) | 40 (−1) | 24 (1) | 1.033 | 0.338 | 331.30 | 34.62 | 162.19 |
| 6 | 1 (−1) | 60 (1) | 24 (1) | 1.403 | 0.318 | 288.72 | 25.11 | 122.09 |
| 7 | 4 (1) | 40 (−1) | 24 (1) | 2.002 | 0.482 | 382.86 | 33.68 | 184.53 |
| 8 | 4 (1) | 60 (1) | 24 (1) | 2.567 | 0.509 | 375.30 | 28.31 | 150.07 |
| 9 | 2.5 (0) | 40 (−1) | 13 (0) | 1.195 | 0.402 | 369.57 | 34.41 | 191.98 |
| 10 | 2.5 (0) | 60 (1) | 13 (0) | 2.326 | 0.499 | 327.84 | 28.68 | 156.54 |
| 11 | 1 (−1) | 50 (0) | 13 (0) | 1.234 | 0.350 | 360.19 | 35.17 | 174.88 |
| 12 | 4 (1) | 50 (0) | 13 (0) | 2.460 | 0.542 | 392.49 | 33.00 | 172.86 |
| 13 | 2.5 (0) | 50 (0) | 2 (−1) | 0.737 | 0.355 | 338.62 | 34.98 | 190.29 |
| 14 | 2.5 (0) | 50 (0) | 24 (1) | 2.462 | 0.535 | 398.22 | 30.62 | 168.92 |
| 15 | 2.5 (0) | 50 (0) | 13 (0) | 1.946 | 0.495 | 385.84 | 32.89 | 178.90 |
| 16 | 2.5 (0) | 50 (0) | 13 (0) | 2.080 | 0.512 | 409.91 | 34.03 | 183.82 |
| 17 | 2.5 (0) | 50 (0) | 13 (0) | 2.096 | 0.511 | 377.59 | 33.66 | 172.15 |
TPC total phenolic compounds, DPPH RSC 2,2-diphenyl-1-picrylhydrazyl radical’s scavenging capacity, FRAP ferric reducing antioxidant power, GAE gallic acid equivalent, QE quercetin equivalent, AAE ascorbic acid equivalent.