Table 3.
Phenolic composition (mg/g extract) of the different grape stem extracts analyzed in this study (mean ± SD).
| Gallic Acid | Ellagic Acid | Caftaric Acid | Catechin | trans-Resveratrol | ε-Viniferin | Quercetin | Quercetin-3-Derivative | Procyanidin B1 | Malvidin-3-Glucoside | Unknown Anthocyanin | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Vintage 2016 | |||||||||||
| GAR | 0.12 ± 0.03 a | 0.031 ± 0.007 a | 0.05 ± 0.01 a | 1.0 ± 0.2 a | 0.06 ± 0.01 a | 0.33 ± 0.05 ab | 0.014 ± 0.002 a | 0.24 ± 0.06 a | 0.4 ± 0.1 a | 0.03 ± 0.01 a | <LD a |
| MAZ | 0.23 ± 0.01 b | 0.028 ± 0.001 a | 0.13 ± 0.00 b | 1.2 ± 0.1 ab | 0.24 ± 0.02 b | 0.69 ± 0.03 c | 0.043 ± 0.002 c | 0.99 ± 0.03 d | 0.4 ± 0.0 a | 0.09 ± 0.00 a | 0.10 ± 0.00 b |
| TEM | 0.14 ± 0.02 a | 0.043 ± 0.009 a | 0.12 ± 0.01 b | 1.0 ± 0.2 a | 0.04 ± 0.01 a | 0.20 ± 0.06 a | 0.029 ± 0.008 b | 0.70 ± 0.06 c | 0.5 ± 0.1 a | 0.48 ± 0.04 b | 0.22 ± 0.02 c |
| GRA | 0.18 ± 0.00 ab | 0.042 ± 0.002 a | 0.14 ± 0.01 b | 1.6 ± 0.0 b | 0.37 ± 0.03 c | 0.45 ± 0.03 b | 0.013 ± 0.001 a | 0.52 ± 0.02 b | 1.1 ± 0.1 b | 0.61 ± 0.03 c | 0.37 ± 0.03 d |
| Vintage 2018 | |||||||||||
| GAR | 1.29 ± 0.06 c | 0.097 ± 0.004 a | 0.14 ± 0.01 a | 1.3 ± 0.1 a | 0.13 ± 0.01 c | 0.46 ± 0.04 b | 0.073 ± 0.003 b | 0.62 ± 0.03 ab | 0.9 ± 0.1 a | 0.12 ± 0.00 b | 0.03 ± 0.00 a |
| MAZ | 1.18 ± 0.09 c | 0.054 ± 0.005 a | 0.33 ± 0.03 b | 3.5 ± 0.3 b | 0.30 ± 0.04 d | 0.55 ± 0.08 b | 0.108 ± 0.011 c | 1.50 ± 0.14 c | 2.5 ± 0.2 c | 0.22 ± 0.04 b | 0.24 ± 0.04 b |
| TEM | 0.52 ± 0.04 b | 0.060 ± 0.004 a | 0.23 ± 0.02 ab | 0.9 ± 0.1 a | 0.04 ± 0.00 ab | 0.15 ± 0.03 a | 0.056 ± 0.004 b | 0.79 ± 0.05 b | 0.4 ± 0.0 a | 0.80 ± 0.06 c | 0.55 ± 0.07 c |
| CHA | 0.15 ± 0.02 a | 0.049 ± 0.006 a | 0.20 ± 0.02 a | 1.0 ± 0.2 a | 0.07 ± 0.01 b | 0.42 ± 0.08 b | 0.013 ± 0.001 a | 0.39 ± 0.05 a | 0.7 ± 0.1 a | nd a | nd a |
| CS | 0.25 ± 0.04 a | 0.089 ± 0.015 a | 0.26 ± 0.03 ab | 2.6 ± 0.6 b | 0.01 ± 0.00 a | 0.28 ± 0.06 ab | 0.013 ±0.002 a | 0.75 ± 0.07 ab | 1.8 ± 0.4 b | 0.07 ± 0.01 ab | 0.01 ± 0.00 a |
Results expressed as mg/g extract (n = 9). GRA: Graciano, MAZ: Mazuelo, TEM: Tempranillo, GAR: Garnacha, CHA: Chardonnay and CS: Cabernet Sauvignon. Different letters in the same column and within the same vintage, indicate significantly different results among varieties (ANOVA, significance level: 0.05). nd, not detected.