Table 3.
Concentrations of phenolic compounds found in the studied fruit and vegetable samples.
| Analytes | Concentrations ± σ (µg/g Mass Fresh) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Beetroot | Red Onion | Yellow Onion | Garlic | Orange Carrot | White Carrot | Watercress | Spinach | Broccoli | Tamarillo | Tomato | |
| Protocatechuic acid | n.d. | n.d. | n.d. | n.d. | 4.6 ± 0.2 | n.d. | 7.8 ± 0.2 | n.d. | n.d. | n.d. | n.d. |
| (+)-Catechin | n.d. | n.d. | n.d. | 5.3 ± 0.01 | 5.3 ± 0.01 | n.d. | n.d. | 5.8 ± 0.03 | 5.6 ± 0.03 | 14.8 ± 0.3 | 7.1 ± 0.02 |
| Gentisic acid | 2.5 ± 0.2 | n.d. | n.d. | n.d. | n.d. | n.d. | 6.9 ± 0.2 | 2.7 ± 0.3 | n.d. | 14.8 ± 0.5 | 3.0 ± 0.1 |
| Vanillic acid | n.d. | n.d. | n.d. | n.d. | 1.1 ± 0.04 | n.d. | n.d. | n.d. | n.d. | 5.8 ± 0.1 | n.d. |
| Seringaldehyde | 1.1 ± 0.01 | n.d. | n.d. | 1.0 ± 0.03 | 1.0 ± 0.03 | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. |
| p-Coumaric acid | n.d. | n.d. | n.d. | n.d. | 0.7 ± 0.01 | n.d. | 0.7 ± 0.02 | n.d. | n.d. | n.d. | 0.7 ± 0.01 |
| Ferulic acid | 0.5 ± 0.01 | n.d. | n.d. | 0.5 ± 0.04 | 0.6 ± 0.1 | n.d. | 18.0 ± 0.5 | < LOQ | n.d. | n.d. | n.d. |
| m-Coumaric acid | n.d. | n.d. | n.d. | n.d. | < LOD | n.d. | n.d. | n.d. | n.d. | n.d. | < LOD |
| o-Coumaric acid | n.d. | n.d. | n.d. | n.d. | < LOD | n.d. | n.d. | < LOQ | n.d. | n.d. | n.d. |
| Cinnamic acid | n.d. | n.d. | n.d. | n.d. | 0.4 ± 0.2 | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. |
| Quercitin | n.d. | 17.1 ± 0.5 | 5.3 ± 0.4 | n.d. | n.d. | n.d. | 0.4 ± 0.03 | n.d. | n.d. | n.d. | n.d. |
| Kaempferol | n.d. | 9.2 ± 0.4 | 2.4 ± 0.4 | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | 1.1 ± 0.03 |
n.d.: not detected; LOD: limit of detection; LOD: limit of quantification.