Table 2. Central composite design and responses of dependent variables for fermented milk by Lactiplantibacillus plantarum K79 to independent variables
| Run no. | Coded levels of variables | Response |
| X1 | X2 | X3 | X4 | Y1 | Y2 |
| 1 | –1 | –1 | –1 | –1 | 64.5 | 5.94 |
| 2 | 1 | –1 | –1 | –1 | 78.1 | 5.93 |
| 3 | –1 | 1 | –1 | –1 | 73.5 | 5.40 |
| 4 | 1 | 1 | –1 | –1 | 83.4 | 5.46 |
| 5 | –1 | –1 | 1 | –1 | 80.1 | 4.85 |
| 6 | 1 | –1 | 1 | –1 | 86.5 | 5.07 |
| 7 | –1 | 1 | 1 | –1 | 75.2 | 4.73 |
| 8 | 1 | 1 | 1 | –1 | 87.7 | 4.86 |
| 9 | –1 | –1 | –1 | 1 | 72.1 | 5.67 |
| 10 | 1 | –1 | –1 | 1 | 77.3 | 5.81 |
| 11 | –1 | 1 | –1 | 1 | 68.5 | 5.25 |
| 12 | 1 | 1 | –1 | 1 | 81.5 | 5.41 |
| 13 | –1 | –1 | 1 | 1 | 79.6 | 4.48 |
| 14 | 1 | –1 | 1 | 1 | 89.4 | 4.63 |
| 15 | –1 | 1 | 1 | 1 | 79.1 | 4.71 |
| 16 | 1 | 1 | 1 | 1 | 85.6 | 4.86 |
| 17 | –2 | 0 | 0 | 0 | 78.4 | 4.84 |
| 18 | 2 | 0 | 0 | 0 | 82.9 | 5.08 |
| 19 | 0 | –2 | 0 | 0 | 86.1 | 4.43 |
| 20 | 0 | 2 | 0 | 0 | 73.6 | 5.04 |
| 21 | 0 | 0 | –2 | 0 | 39.7 | 6.39 |
| 22 | 0 | 0 | 2 | 0 | 89.5 | 4.40 |
| 23 | 0 | 0 | 0 | –2 | 85.2 | 5.05 |
| 24 | 0 | 0 | 0 | 2 | 87.4 | 4.97 |
| 25 | 0 | 0 | 0 | 0 | 84.1 | 5.15 |
| 26 | 0 | 0 | 0 | 0 | 85.6 | 5.14 |
| 27 | 0 | 0 | 0 | 0 | 87.3 | 5.15 |
X1, skim milk conc. (%); X2, temperature (°C); X3, incubation time (h); X4, starter conc. (%); Y1, ACE inhibitory activity (%); Y2, pH; ACE, angiotensin converting enzyme.