Table 2.
The content of individual phenolic compounds in the leaf extracts of the six blueberry varieties, using HPLC-MS and expressed as mg/g.
| Phenolic Compounds | Cultivars | ||||||
|---|---|---|---|---|---|---|---|
| Elliot | Toro | Duke | Bluecrop | Spartan | Nelson | ||
| Flavanols | Gallocatechin | 8.52 ± 0.07 b | 9.03 ± 0.08 a | 4.84 ± 0.05 e | 4.90 ± 0.05 e | 7.18 ± 0.06 c | 6.73 ± 0.08 d |
| Catechin | 6.46 ± 0.07 b | 7.97 ± 0.07 a | 6.03 ± 0.07 c | 5.21 ± 0.05 d | 6.15 ± 0.05 c | 4.87 ± 0.08 e | |
| Epicatechin | 4.19 ± 0.03 | n.d | n.d | n.d | n.d | n.d | |
| Procyanidin dimer I | 3.69 ± 0.04 | n.d | n.d | n.d | n.d | n.d | |
| Procyanidin dimer II | 12.50 ± 0.1 c | 14.13 ± 0.1 b | 12.30 ± 0.1 d | 12.41 ± 0.1 cd | 17.15 ± 0.1 a | 3.92 ± 0.03 e | |
| Procyanidin trimer | 6.36 ± 0.08 f | 15.99 ± 0.2 a | 7.02 ± 0.12 d | 8.98 ± 0.10 c | 6.80 ± 0.09 de | 12.27 ± 0.1 b | |
| Hydroxycinnamic acids | Chlorogenic acid | 0.90 ± 0.01 c | 1.23 ± 0.02 a | 0.52 ± 0.01 d | 0.54 ± 0.01 d | 0.44 ± 0.01 e | 1.03 ± 0.01 b |
| Caffeic acid | 5.93 ± 0.06 a | 4.75 ± 0.03 c | 4.49 ± 0.05 d | 2.62 ± 0.02 f | 3.61 ± 0.02 e | 5.36 ± 0.05 b | |
| Feruloylquinic acid | 40.94 ± 0.3 c | 44.43 ± 0.3 b | 29.15 ± 0.2 d | 25.36 ± 0.2 e | 19.23 ± 0.1 f | 49.62 ± 0.4 a | |
| Dicaffeoylquinic acid | 7.99 ± 0.07 b | 7.30 ± 0.09 c | 4.23 ± 0.05 d | 2.73 ± 0.02 e | 4.58 ± 0.03 d | 10.18 ± 0.1 a | |
| Flavonols (quercetin derivatives) | Quercetin-rutinoside (Rutin) | 31.53 ± 0.1 c | 35.77 ± 0.1 a | 17.64 ± 0.1 e | 19.10 ± 0.1 d | 14.44 ± 0.1 f | 32.50 ± 0.2 b |
| Quercetin-glucoside | 3.46 ± 0.04 b | 6.70 ± 0.08 a | 2.86 ± 0.02 d | 3.54 ± 0.03 b | 3.08 ± 0.03 c | 2.09 ± 0.02 e | |
| Quercetin-acetyl-rhamnoside | 1.22 ± 0.01 b | 1.92 ± 0.02 a | 0.45 ± 0.01 e | 0.68 ± 0.01 d | 0.46 ± 0.01 e | 0.78 ± 0.01 c | |
| Quercetin-arabinoside | n.d | n.d | n.d | n.d | 1.40 ± 0.01 | n.d | |
| Quercetin-diglucoside | 0.35 ± 0.01 b | 0.53 ± 0.01 a | n.d | n.d | n.d | n.d | |
| Quercetin | 2.70 ± 0.02 c | 3.68 ± 0.04 a | 2.25 ± 0.06 d | 2.07 ± 0.04 e | 3.69 ± 0.02 a | 3.56 ± 0.02 ab | |
| Anthocyanins | Cyanidin-glucoside | 0.63 ± 0.01 b | 1.08 ± 0.08 a | n.d | n.d | 0.52 ± 0.01 b | n.d |
| Cyanidin-arabinoside | 0.41 ± 0.01 b | 0.80 ± 0.01 a | n.d | n.d | 0.42 ± 0.01 b | n.d | |
| Cyanidin-acetyl-glucoside | 0.32 ± 0.01 a | 0.35 ± 0.01 a | n.d | n.d | 0.26 ± 0.01 b | n.d | |
| Total phenols | 138.09 b | 155.67 a | 92.46 d | 88.14 e | 89.40 e | 132.91 c | |
In the same rows, the values (means ± SD, mg/g, n = 3) marked by different letters (a–f) report significant differences (p < 0.05) among the six varieties (One-way ANOVA-Tukey multiple range test (p = 0.05)). n.d—not detected.