Table 2.
Individual polyphenols and furans (mg/L) in TNM sweet wine during heating at 45 °C (3 months) and 70 °C (1 month).
| TNM sweet | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 m | ± SD | 1 m, 45 °C | ± SD | 2 m, 45 °C | ± SD | 3 m, 45 °C | ± SD | 1 m, 70 °C | ± SD | ||
| Non-flavonoids | |||||||||||
| Hydroxybenzoics | |||||||||||
| Gallic acid | 3.70a | 0.01 | 4.91b | 0.07 | 5.29c | 0.03 | 6.23d | 0.12 | 9.16e | 0.09 | |
| Protocatechuic acid | 2.57a | 0.11 | 2.35b | 0.06 | 1.97c | 0.02 | 1.55d | 0.08 | 1.64d | 0.05 | |
| p-Hydroxybenzoic acid | 0.94a | 0.05 | 0.57b | 0.02 | 0.77c | 0.03 | 0.51b | 0.02 | 1.00a | 0.06 | |
| Vanillic acid | 2.52a | 0.09 | 2.57a | 0.06 | 2.23b | 0.06 | 2.24b | 0.11 | 3.08c | 0.08 | |
| Syringic acid | 4.89a | 0.06 | 5.29b | 0.08 | 5.03a | 0.18 | 5.03a | 0.06 | 5.93c | 0.04 | |
| Ellagic acid | n.d. | n.d. | n.d. | n.d. | n.d. | ||||||
| Total | 14.62 | 15.69 | 15.29 | 15.56 | 20.81 | ||||||
| Hydroxycinnamates | |||||||||||
| trans-Caftaric acid | 14.53a | 0.01 | 13.37b | 0.01 | 11.31c | 0.02 | 10.82d | 0.05 | 3.24e | 0.04 | |
| cis-Coutaric acid | 4.45a | 0.04 | 3.71b | 0.02 | 2.91c | 0.01 | 2.73d | 0.11 | 0.62e | 0.02 | |
| trans-Coutaric acid | 7.87a | 0.02 | 7.66b | 0.01 | 7.07c | 0.03 | 6.67d | 0.15 | 2.99e | 0.06 | |
| trans-Fertaric acid | 0.91a | 0.02 | 0.82b | 0.02 | 0.71c | 0.02 | 0.78b | 0.01 | 1.80d | 0.05 | |
| Unk 5 * | 2.20a | 0.04 | 2.57b | 0.10 | 2.34c | 0.03 | 2.40c | 0.03 | 2.70d | 0.02 | |
| Caffeic acid | 1.72a | 0.02 | 1.82a | 0.07 | 2.06b | 0.02 | 2.53c | 0.10 | 3.34d | 0.15 | |
| Unk 6 * | 1.96a | 0.05 | 2.07b | 0.02 | 1.91a | 0.01 | 2.05b | 0.02 | 2.09b | 0.01 | |
| p-Coumaric acid | 0.58a | 0.01 | 0.85b | 0.02 | 1.02c | 0.01 | 1.27d | 0.01 | 4.31e | 0.09 | |
| Ferulic acid | n.q. | 0.45a | 0.02 | 0.47a | 0.00 | 0.68b | 0.03 | 0.45a | 0.02 | ||
| Total | 34.22 | 33.32 | 29.81 | 29.93 | 21.52 | ||||||
| Stilbene | |||||||||||
| trans-Resveratrol | n.d. | n.d. | n.d. | n.d. | n.d. | ||||||
| Flavonoids | |||||||||||
| Flavonols | |||||||||||
| Unk 7 ** | 8.03a | 0.07 | 7.13b | 0.06 | 5.71c | 0.09 | 5.30d | 0.04 | 0.56e | 0.03 | |
| Myricetin | n.d. | n.d. | n.d. | n.d. | n.d. | ||||||
| Quercetin | n.q. | n.q. | n.q. | 0.53a | 0.01 | 0.67b | 0.01 | ||||
| Kaempferol | n.q. | n.q. | n.q. | n.q. | n.q. | ||||||
| Total | 8.03 | 7.13 | 5.71 | 5.83 | 1.23 | ||||||
| Flavan-3-ols | |||||||||||
| (−)-Epigallocatechin | n.d. | n.d. | n.d. | n.d. | n.d. | ||||||
| (+)-Catechin | 3.94a | 0.02 | 2.49b | 0.05 | 1.48c | 0.02 | 0.93d | 0.03 | 0.47e | 0.00 | |
| (−)-Epicatechin | 0.92a | 0.01 | 0.65b | 0.03 | 0.47c | 0.03 | 0.40d | 0.01 | 0.36d | 0.01 | |
| Total | 4.86 | 3.13 | 1.95 | 1.32 | 0.84 | ||||||
| Furans | |||||||||||
| HMF | 1.56a | 0.02 | 17.90b | 0.00 | 49.32c | 0.03 | 97.50d | 0.12 | 1728.07e | 2.80 | |
| Furfural | n.d. | n.q. | 2.02a | 0.05 | 3.08b | 0.05 | 20.26c | 0.18 | |||
| Total | 1.56 | 17.90 | 51.34 | 100.58 | 1748.32 | ||||||
* Quantification relative to caffeic acid; ** Quantification relative to rutin; n.d. - not detected, bellow LOD; n.q. - not quantified, bellow LOQ; HMF - 5-hydroxymethylfurfural; Different letters in the same row (in bold) means that there are significant differences at p < 0.050.