Table 1.
Experimental and predicted values of response variables for central composite design.
| Run order | ∗Independent variables | ∗∗Dependent variables | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| X 1 | X 2 | X 3 | X 4 |
Y
1 (DH, %) |
Y
2 (DPPH• scavenging activity, %) |
Y
3 (Fe2+-chelating activity, %) |
||||
| Uncoded levels | Experimental | Predicted | Experimental | Predicted | Experimental | Predicted | ||||
| (1) | 4.0 | 70 | 2.00 | 30 | 34.49 | 36.34 | 13.76 | 13.26 | 13.86 | 16.04 |
| (2) | 5.5 | 55 | 1.25 | 195 | 56.66 | 54.64 | 47.26 | 45.99 | 16.96 | 18.57 |
| (3) | 5.5 | 55 | 0.50 | 195 | 42.10 | 43.68 | 47.62 | 49.57 | 7.48 | 7.44 |
| (4) | 4.0 | 70 | 0.50 | 360 | 29.96 | 31.17 | 22.98 | 24.67 | 10.05 | 8.91 |
| (5) | 5.5 | 55 | 1.25 | 360 | 57.82 | 55.52 | 54.98 | 56.22 | 19.37 | 18.40 |
| (6) | 7.0 | 55 | 1.25 | 195 | 43.00 | 44.19 | 30.56 | 32.69 | 29.77 | 30.17 |
| (7) | 7.0 | 40 | 0.50 | 360 | 32.25 | 32.41 | 33.18 | 34.97 | 14.80 | 13.13 |
| (8) | 7.0 | 40 | 0.50 | 30 | 23.96 | 24.35 | 32.92 | 30.72 | 15.54 | 13.48 |
| (9) | 4.0 | 70 | 0.50 | 30 | 28.25 | 28.03 | 21.55 | 20.41 | 11.26 | 9.25 |
| (10) | 4.0 | 40 | 2.00 | 360 | 51.99 | 53.34 | 23.52 | 22.74 | 17.75 | 18.18 |
| (11) | 5.5 | 55 | 1.25 | 195 | 54.81 | 54.64 | 44.98 | 45.99 | 19.02 | 18.57 |
| (12) | 7.0 | 70 | 0.50 | 30 | 29.25 | 28.43 | 26.82 | 25.49 | 8.76 | 10.99 |
| (13) | 4.0 | 40 | 0.50 | 360 | 31.89 | 32.00 | 32.55 | 29.90 | 10.98 | 11.39 |
| (14) | 5.5 | 40 | 1.25 | 195 | 51.86 | 53.83 | 33.65 | 34.47 | 14.32 | 12.84 |
| (15) | 5.5 | 70 | 1.25 | 195 | 57.56 | 55.45 | 27.82 | 29.24 | 8.64 | 10.35 |
| (16) | 5.5 | 55 | 1.25 | 195 | 53.56 | 54.64 | 47.26 | 45.99 | 18.84 | 18.57 |
| (17) | 5.5 | 55 | 2.00 | 195 | 58.64 | 56.20 | 39.95 | 42.41 | 13.95 | 14.23 |
| (18) | 5.5 | 55 | 1.25 | 195 | 53.95 | 54.64 | 46.65 | 45.99 | 18.14 | 18.57 |
| (19) | 5.5 | 55 | 1.25 | 195 | 54.05 | 54.64 | 46.86 | 45.99 | 16.40 | 18.57 |
| (20) | 7.0 | 40 | 2.00 | 360 | 50.62 | 49.13 | 29.05 | 27.82 | 18.43 | 19.92 |
| (21) | 5.5 | 55 | 1.25 | 30 | 41.98 | 43.41 | 50.96 | 51.96 | 23.20 | 18.75 |
| (22) | 4.0 | 40 | 0.50 | 30 | 25.03 | 23.95 | 24.50 | 25.64 | 9.91 | 11.74 |
| (23) | 7.0 | 70 | 0.50 | 360 | 32.90 | 31.57 | 27.91 | 29.75 | 8.21 | 10.65 |
| (24) | 4.0 | 70 | 2.00 | 360 | 51.25 | 52.50 | 17.20 | 17.52 | 18.01 | 15.69 |
| (25) | 7.0 | 40 | 2.00 | 30 | 26.69 | 28.06 | 22.26 | 23.56 | 20.00 | 20.26 |
| (26) | 7.0 | 70 | 2.00 | 30 | 32.65 | 32.14 | 18.42 | 18.34 | 19.37 | 17.78 |
| (27) | 4.0 | 40 | 2.00 | 30 | 34.68 | 32.26 | 16.68 | 18.48 | 17.75 | 18.52 |
| (28) | 4.0 | 55 | 1.25 | 195 | 48.14 | 46.09 | 27.49 | 27.61 | 28.60 | 28.43 |
| (29) | 5.5 | 55 | 1.25 | 195 | 53.82 | 54.64 | 49.18 | 45.99 | 16.16 | 18.57 |
| (30) | 5.5 | 55 | 1.25 | 195 | 53.79 | 54.64 | 48.65 | 45.99 | 19.56 | 18.57 |
| (31) | 7.0 | 70 | 2.00 | 360 | 47.25 | 48.30 | 24.81 | 22.59 | 18.96 | 17.44 |
∗Independent variables for hydrolysis of stone fish protein: X1; pH, X2; temperature (°C), X3; enzyme/substrate ratio and X4; time (min). ∗∗Dependent variables: Y1; degree of hydrolysis (DH, %), Y2; 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging activity (%) and Y3; Fe2+-chelating activity (%).