Table 4.
Concentration of phenolic acids 1 in selected extracts from BPKO SMS with different extractions methods, mg/L. Mean values from triplicate analyses. The standard deviations are shown in parentheses.
| Extract Sample 2 | Chlorogenic Acid | Caffeic Acid | p-Coumaric Acid | Ferulic Acid | Gallic Acid | Vanillic Acid |
|---|---|---|---|---|---|---|
| SoE-80 | 6.0 (0.2) | 0.7 (0.2) | 2.3 (0.1) | 0.9 (0.1) | 5.5 (0.4) | 12.4 (1.0) |
| SoE-40 | 7.3 (0.3) | 1.1 (0.2) | 2.3 (0.1) | 1.1 (0.1) | 3.6 (0.4) | 8.2 (2.5) |
| SoE-20 | 4.6 (0.3) | 0.6 (<0.1) | 1.6 (<0,1) | 0.8 (<0.1) | 3.0 (0.6) | 6.9 (1.3) |
| ReE-60 | 4.8 (0.3) | 0.7 (0.1) | 1.7 (0.1) | 0.7 (<0.1) | 2.8 (0.3) | 3.8 (0.4) |
| ReE-120 | 4.2 (0.2) | 0.7 (0.1) | 1.1 (0.1) | 0.6 (<0.1) | 2.8 (0.4) | 4.5 (0.4) |
| ReE-240 | 4.8 (<0.1) | 0.7 (0.1) | 1.5 (0.1) | 0.7 (0.1) | 2.5 (0.3) | 5.8 (0.6) |
| UAE 35–30 | 3.1 (<0.1) | 0.2 (0.1) | 1.3 (0.1) | 0.5 (<0.1) | 2.6 (0.1) | 2.9 (0.3) |
| UAE 50–45 | 3.6 (<0.1) | 0.3 (<0.1) | 1.3 (0.1) | 0.6 (<0.1) | 3.2 (0.2) | 1.8 (0.4) |
| UAE 65–60 | 4.6 (0.1) | 0.3 (<0.1) | 1.7 (<0.1) | 0.8 (0.1) | 3.0 (0.3) | 3.0 (0.2) |
| SWE 10 | 5.4 (<0.1) | 1.7 (0.4) | 1.2 (0.1) | 0.7 (0.1) | 11.1 (0.5) | 16.4 (0.2) |
1 Determined by HPLC; 2 Sample codification: for Soxhlet extraction (SoE), the numeral indicates the volumetric share of ethanol in the solvent system; for reflux extraction (ReE), the numeral indicates the time (in min); for UAE, the numerals indicate, respectively, the temperature (in °C) and the time (in min); for SWE, the numeral indicate the holding time (in min).