Figure 1
Solvent-free microwave-assisted extraction of bioactive compounds form Lagenaria siceraria fresh fruit: Independent and response factors along with the predicted values_
| Run order | Power (W) | Time (s) | Extraction yield (%) | TPC (mg GAE · g−1) | TFC (mg RE · g−1) | FRAP (mg AAE · g−1) | DPPH radical scavenging (%) | ICA (%) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Actual | Predicted | Actual | Predicted | Actual | Predicted | Actual | Predicted | Actual | Predicted | Actual | Predicted | |||
| 1 | 630.00 | 60 | 3.77 | 3.71 | 170.79 | 189.03 | 129.55 | 108.59 | 237.57 | 242.85 | 27.75 | 28.54 | 16.65 | 17.12 |
| 2 | 480.00 | 60 | 1.50 | 1.50 | 288.88 | 283.71 | 213.40 | 216.97 | 281.29 | 283.81 | 32.12 | 32.39 | 19.27 | 19.43 |
| 3 | 480.00 | 102 | 1.87 | 1.91 | 218.46 | 233.30 | 148.70 | 159.04 | 183.16 | 172.17 | 22.31 | 21.47 | 13.38 | 12.88 |
| 4 | 480.00 | 60 | 1.50 | 1.50 | 286.83 | 283.71 | 214.10 | 216.97 | 289.67 | 283.81 | 32.96 | 32.39 | 19.27 | 19.43 |
| 5 | 360.00 | 30 | 1.23 | 1.08 | 193.16 | 194.96 | 96.06 | 110.74 | 261.57 | 244.61 | 29.15 | 28.18 | 17.49 | 16.91 |
| 6 | 360.00 | 90 | 1.30 | 1.18 | 250.79 | 241.13 | 143.91 | 143.97 | 153.97 | 159.18 | 20.39 | 21.04 | 12.23 | 12.62 |
| 7 | 600.00 | 30 | 3.56 | 3.56 | 200.81 | 196.99 | 80.13 | 103.01 | 207.03 | 192.65 | 25.70 | 24.49 | 15.42 | 14.69 |
| 8 | 330.00 | 60 | 1.00 | 1.19 | 202.72 | 208.31 | 115.86 | 112.20 | 214.60 | 222.96 | 26.46 | 26.70 | 15.87 | 16.02 |
| 9 | 600.00 | 90 | 4.02 | 4.05 | 151.22 | 135.93 | 61.15 | 59.80 | 198.88 | 206.67 | 23.88 | 24.28 | 14.33 | 14.57 |
| 10 | 480.00 | 18 | 1.41 | 1.49 | 246.07 | 244.68 | 191.36 | 167.20 | 203.56 | 224.13 | 25.35 | 26.81 | 15.21 | 16.08 |
| 11 | 480.00 | 60 | 1.50 | 1.50 | 285.72 | 283.71 | 211.64 | 216.97 | 285.34 | 283.81 | 32.39 | 32.39 | 19.52 | 19.43 |
Predicted and observed means of responses in optimum extraction conditions_
| Optimum conditions | Responses | Predicted mean | Observed mean | Error rate (%) | |
|---|---|---|---|---|---|
| Power (W) | Time (s) | Extraction yield (%) | 4.05 | 4.02 | −0.74 |
| 480 | 60 | DPPH | 32.39 | 32.96 | 1.75 |
| ICA | 19.43 | 19.52 | 0.46 | ||
Factors and their levels for the CCD design (α = 1_4142)_
| Factors | Symbols | Levels | ||||
|---|---|---|---|---|---|---|
| −α | −1 | 0 | 1 | +α | ||
| Microwave power (W) | A | 330 | 360 | 480 | 600 | 630 |
| Time (s) | B | 18 | 30 | 60 | 90 | 102 |
Regression coefficients for different responses_
| Coefficients | Extraction yield | DPPH | ICA |
|---|---|---|---|
| Model | Quadratic | Quadratic | Quadratic |
| Intercept | 1.49644 | 32.3854 | 19.431 |
| A | 1.33722** | −0.11279 | −0.06789 |
| B | 0.147079 | −1.83707* | −1.10224* |
| AB | 0.0975 | 1.73625* | 1.04175* |
| A2 | 0.872308** | −3.73041* | −2.23822* |
| B2 | 0.10136 | −4.15794** | −2.49495** |
| Lack-of-fit p-value | 0.051 | 0.0752 | 0.0753 |
| Model p-value | 0.0001 | 0.0006 | 0.0016 |
| R2 | 0.9935 | 0.9610 | 0.9610 |
| R2adj | 0.9870 | 0.9220 | 0.9220 |
| RMSE | 0.0001 | 0.4190 | 0.2515 |
| PRESS | 2.11 | 46.94 | 16.90 |
| CV (%) | 11.95 | 4.06 | 4.06 |
| Adequate precision | 16.4340 | 14.2238 | 14.2236 |
| F-value | 41.29 | 28.15 | 28.15 |
| BIC | 6.09 | 39.09 | 27.86 |
| AICc | 24.70 | 57.71 | 46.47 |