Table 1.
Centre composite response surface experimental design [actual and coded value (in bracket)] of the optimization of ferulic acid and NFPC from the black liquor of (a) pineapple peel (PP) and (b) pineapple crown leaves (PCL)
| (a) Pineapple peel (PP)a | |||||
|---|---|---|---|---|---|
| Solid content (%) | Time (min) | Ferulic acid yield (mg L−1) | Ferulic acid recovery (mg g−1 PP) | NFPC yield (mg GAE mL−1) | NFPC recovery (mg GAE g−1 PP) |
| 12.00 (0.000) | 105.00 (0.000) | 486.80 | 4.06 | 3.91 | 32.59 |
| 12.00 (0.000) | 180.00 (1.414) | 578.06 | 4.82 | 4.20 | 34.97 |
| 6.34 (− 1.000) | 158.03 (1.000) | 312.80 | 4.93 | 2.79 | 43.93 |
| 17.66 (1.000) | 158.03 (1.000) | 401.05 | 2.27 | 4.15 | 23.51 |
| 12.00 (0.000) | 105.00 (0.000) | 535.36 | 4.46 | 3.48 | 28.96 |
| 4.00 (− 1.414) | 105.00 (0.000) | 189.96 | 4.75 | 1.75 | 43.73 |
| 20.00 (1.414) | 105.00 (0.000) | 639.08 | 3.20 | 4.06 | 20.31 |
| 12.00 (0.000) | 105.00 (0.000) | 483.68 | 4.03 | 3.57 | 29.72 |
| 12.00 (0.000) | 105.00 (0.000) | 546.18 | 4.55 | 3.60 | 29.97 |
| 17.66 (1.000) | 51.97 (− 1.000) | 634.65 | 3.60 | 4.50 | 25.46 |
| 6.34 (− 1.000) | 51.97 (− 1.000) | 36.99 | 0.58 | 2.28 | 35.88 |
| 12.00 (0.000) | 30.00 (− 1.414) | 190.52 | 1.59 | 3.60 | 29.97 |
| 12.00 (0.000) | 105.00 (0.000) | 527.93 | 4.40 | 3.25 | 27.09 |
| (b) Pineapple crown leaves (PCL)b | |||||
|---|---|---|---|---|---|
| Solid content (%) | Time (min) | Ferulic acid yield (mg L−1) | Ferulic acid recovery (mg g−1 PCL) | NFPC yield (mg GAE mL−1) | NFPC recovery (mg GAE g−1 PCL) |
| 6.00 (0.000) | 105.00 (0.000) | 184.55 | 3.08 | 2.96 | 49.30 |
| 6.00 (0.000) | 180.00 (1.414) | 165.28 | 2.75 | 2.83 | 47.24 |
| 6.00 (0.000) | 105.00 (0.000) | 175.00 | 2.92 | 3.28 | 54.69 |
| 8.83 (1.000) | 158.03 (1.000) | 249.89 | 2.83 | 3.79 | 42.87 |
| 2.00 (− 1.414) | 105.00 (0.000) | 9.48 | 0.47 | 1.15 | 57.57 |
| 6.00 (0.000) | 105.00 (0.000) | 173.36 | 2.89 | 3.08 | 51.36 |
| 6.00 (0.000) | 105.00 (0.000) | 160.54 | 2.68 | 2.91 | 48.51 |
| 6.00 (0.000) | 105.00 (0.000) | 165.00 | 2.75 | 2.98 | 49.62 |
| 6.00 (0.000) | 30.00 (− 1.414) | 201.26 | 3.35 | 2.86 | 47.72 |
| 8.83 (1.000) | 51.97 (− 1.000) | 263.85 | 2.99 | 3.79 | 42.87 |
| 3.17 (− 1.000) | 51.97 (− 1.000) | 28.10 | 0.89 | 1.61 | 50.72 |
| 3.17 (− 1.000) | 158.03 (1.000) | 141.40 | 4.46 | 1.78 | 56.12 |
| 10.00 (1.414) | 105.00 (0.000) | 311.67 | 3.12 | 3.73 | 37.28 |
amg GAE mL−1 and mg GAE g−1 PP means milligram of gallic acid equivalent per milliliter of extract and milligram of gallic acid equivalent per gram of pineapple peel respectively
bmg GAE mL−1 and mg GAE g−1 PP means milligram of gallic acid equivalent per milliliter of extract and milligram of gallic acid equivalent per gram of pineapple crown leaves respectively