Table 2.
Chemical composition, fatty acids, total phenolics, total flavonoids, and antioxidant activity for the four Quercus species.
| Chemical Composition | Q. virginiana | Q. suber | Q. ilex | Q. coccifera | Anova (p ≤ 0.05) |
|---|---|---|---|---|---|
| Water content (%) | 73.5 ± 0.61 a | 71.6 ± 1.8 a | 74.3 ± 2.2 a | 72.3 ± 3.6 a | 0.15 |
| Ash content (%) | 1.6 ± 0.10 ab | 1.8 ± 0.0 c | 1.7 ± 0.1 bc | 1.6 ± 0.1 a | 0.01 |
| Protein content (%) | 4.3 ± 0.51 b | 4.5 ± 0.3 b | 4.2 ± 0.2 b | 3.2 ± 0.5 a | 0.01 |
| Total lipids (%) | 12.0 ± 1.62 c | 8.0 ± 1.6 b | 12.9 ± 0.7 c | 2.9 ± 0.4 a | 0.01 |
| Carbohydrates (%) | 82.1 ± 1.0 a | 85.7 ± 1.0 b | 81.2 ± 1.0 a | 92 ± 1.0 c | 0.01 |
| Sugar content (%) | 11.3 ± 0.91 c | 6.9 ± 0.4 ab | 6.0 ± 0.5 a | 7.5 ± 1.4 b | 0.01 |
| Fiber content (%) | 2.3 ± 0.03 a | 2.3 ± 0.0 a | 2.3 ± 0.0 a | 2.3 ± 0.0 a | 0.61 |
| Starch content (%) | 57.6 ± 1.57 a | 61.9 ± 1.3 b | 62.0 ± 1.5 b | 63.9 ± 1.7 b | 0.01 |
| Digestibility (%) | 69.1 ± 02.15 c | 59.7 ± 01.0 b | 69.0 ± 03.1 c | 32.8 ± 1.1 a | 0.01 |
| Energy (kcal/100 g) | 490.1 ± 8.6 c | 466.3 ± 8.2 b | 488.6 ± 4.6 c | 444.5 ± 3.9 a | 0.01 |
| Palmitic acid (%) | 16.4 ± 0.4 c | 12.5 ± 0.4 a | 15.3 ± 0.7 b | 16.9 ± 0.7 c | 0.01 |
| Stearic acid (%) | 4.3 ± 0.2 b | 3.1 ± 0.0 a | 3.1 ± 0.2 a | 2.8 ± 0.3 a | 0.01 |
| Oleic acid (%) | 66.0 ± 1.6 a | 67.9 ± 1.2 a | 66.5 ± 1.7 a | 66.5 ± 1.9 a | 0.01 |
| Linoleic acid (%) | 13.4 ± 2.6 a | 15.8 ± 1.1 b | 14.8 ± 1.2 ab | 19.8 ± 2.0 c | 0.01 |
| Total polyphenolics (NIRS) (%) | 1.03 ± 0.05 b | 0.80 ± 0.05 a | 0.73 ± 0.10 a | 2.98 ± 0.36 c | 0.01 |
| Total phenolics (Folin Ciocalteau) * | 29.4 ± 1.4 a | 31.8 ± 1.6 a | 25.9 ± 0.9 a | 130.5 ± 10.0 b | 0.01 |
| Total flavonoids ** | 13.9 ± 1.9 a | 9.2 ± 1.0 a | 9.2 ± 1.1 a | 56.3 ± 3.4 b | 0.01 |
| ABTS *** | 394.1 ± 32.2 b | 271.9 ± 14.5 ab | 157.6 ± 19.7 a | 1990.0 ± 167.1 c | 0.01 |
| FRAP *** | 272.1 ± 29.0 b | 323.1 ± 24.4 b | 157.9 ± 18.1 a | 1343.4 ± 68.9 c | 0.01 |
* mg gallic acid equivalents (GAE)·g−1 of dry weight; ** mg catechin equivalents (CE)·g−1 of dry weight; *** mmol trolox equivalents (TE)·g−1 dry weight. Data were analyzed using a one-way ANOVA (p ≤ 0.05). The results are expressed as the mean ± SD (n = 20). Different letters (a–c) indicate a significant difference at p ≤ 0.05 (The analysis was performed in row of the characteristics evaluated).