Table 2.
The effect of temperature on the initial concentration of phenolics in the solvent (C0), the rate constant (k) of each extraction step, the total phenolic content (TPC), antiradical capacity, selectivity, rosmarinic acid, total flavonoids, carnosic acid, and carnosol, recovered after 70 min of extraction performed with acetone 40%, at a solid-to-liquid ratio 1:20 and non-specific particle size. The correlation coefficients (R2) of fitting Equation (1) to experimental data are also presented.
| Temperature (°C) | |||
|---|---|---|---|
| 22 | 40 | 60 | |
| C0 (mg GAE/gdw) | 27.48 ± 1.14 | 28.64 ± 0.65 | 28.60 ± 1.92 |
| k (min−1) (fast stage) | 0.026 ± 0.004 | 0.027 ± 0.002 | 0.074 ± 0.006 |
| R2 (fast stage) | 0.96 | 0.99 | 0.99 |
| k (min−1) (slow stage) | 0.010 ± 0.001 | 0.013 ± 0.001 | 0.015 ± 0.002 |
| R2 (slow stage) | 0.99 | 0.98 | 0.95 |
| Total Phenol Content (mg GAE/gdw) | 58.3 ± 1.5 | 61.7 ± 0.4 | 70.3 ± 1.0 |
| DPPH radical scavenging capacity (mg GAE/gdw) | 26.7 ± 0.5 | 28.5 ± 0.6 | 31.6 ± 0.7 |
| Selectivity (%) | 24.9 | 22.9 | 20.7 |
| Rosmarinic acid (mg/gdw) | 11.12 ± 0.6 | 12.76 ± 0.8 | 12.97 ± 0.5 |
| Total flavonoids (mg Que */gdw) | 7.72 ± 0.4 | 7.70 ± 0.3 | 7.36 ± 0.8 |
| Carnosic acid (mg/gdw) | 10.79 ± 0.5 | 14.49 ± 0.3 | 13.60 ± 0.7 |
| Carnosol (mg CA */gdw) | 5.57 ± 0.1 | 2.96 ± 0.6 | 12.35 ± 0.5 |
* Que: quercetin equivalents, CA: carnosic acid equivalents.