Table 3.
Discriminant phenolic compounds according to the comparison ‘cold’ vs ‘regular’ brewing and considering both green and red rooibos tea. Compounds were identified by the VIP (variable importance in projection) approach following OPLS-DA discriminant analysis and are provided together with VIP scores (measure of variable’s importance in the OPLS-DA model), LogFC values (obtained by Fold Change analysis) and accumulation.
| VIP Marker (OPLS-DA) | VIP Score | LogFC | Accumulation | |
|---|---|---|---|---|
| Green Rooibos | ||||
| Flavonoids | Formononetin | 1.90 ± 0.53 | −2.26 | Down |
| Isorhamnetin-3-O-glucuronide | 1.46 ± 0.78 | −1.06 | Down | |
| Galangin; Genistein | 1.56 ± 0.78 | −0.83 | Down | |
| Xanthohumol; Isoxanthohumol | 2.13 ± 0.47 | −0.80 | Down | |
| Hispidulin; Chrysoeriol | 1.08 ± 0.87 | −0.76 | Down | |
| Isorhamnetin-3-O-rutinoside; Chrysoeriol-7-O-glucoside | 1.84 ± 0.55 | −0.52 | Down | |
| Kaempferol-3-O-rhamnoside | 1.11 ± 0.91 | −0.28 | Down | |
| Petunidin-3-O-galactoside | 1.58 ± 0.86 | 0.31 | Up | |
| Cyanidin-3-O-(6’’-caffeoyl-glucoside) | 1.01 ± 0.50 | 0.34 | Up | |
| Peonidin-3-O-galactoside | 1.65 ± 1.04 | 0.35 | Up | |
| 3-Methoxysinensetin | 1.01 ± 0.50 | 0.43 | Up | |
| Cyanidin-3-O-(6’’-acetyl-galactoside) | 1.11 ± 1.30 | 0.62 | Up | |
| Gardenin B | 2.00 ± 0.49 | 0.76 | Up | |
| Chrysin | 1.52 ± 1.02 | 1.20 | Up | |
| Daidzin | 1.16 ± 1.23 | 1.66 | Up | |
| Apigenin-6,8-C-galactoside-C-arabinoside | 1.35 ± 0.79 | 2.51 | Up | |
| Lignans | Lariciresinol | 1.12 ± 0.81 | 0.09 | Up |
| Other polyphenols | Psoralen | 1.27 ± 1.11 | −1.07 | Down |
| Coumarin | 1.18 ± 0.48 | 0.35 | Up | |
| p-Anisaldehyde | 1.26 ± 0.72 | 0.36 | Up | |
| Phenolic acids | 3,4/3,5-Diferuloylquinic acid | 1.14 ± 1.28 | −13.62 | Down |
| Ferulic acid | 1.27 ± 1.02 | −1.64 | Down | |
| 2,4/2,6-Dihydroxybenzoic acid; Gentisic acid; Gallic aldehyde | 1.03 ± 1.15 | 0.26 | Up | |
| p-Coumaric acid ethyl ester | 1.09 ± 1.02 | 1.84 | Up | |
| Sinapic acid | 1.10 ± 0.59 | 2.02 | Up | |
| Red Rooibos | ||||
| Flavonoids | Xanthohumol; Isoxanthohumol | 1.54 ± 1.55 | −9.59 | Down |
| Peonidin-3-O-(6’’-p-coumaroyl-glucoside) | 1.46 ± 1.58 | −2.36 | Down | |
| Gardenin B | 1.50 ± 1.89 | −2.16 | Down | |
| Hemiphlorin; Naringenin-6-C-glucoside; Naringenin-7-O-glucoside | 1.40 ± 1.04 | −2.08 | Down | |
| Kaempferol-7-O-glucoside | 1.51 ± 1.55 | −1.90 | Down | |
| Chrysoeriol-7-O-glucoside; Isorhamnetin-3-O-rutinoside | 1.13 ± 1.48 | −1.70 | Down | |
| Chrysoeriol; Hispidulin | 2.22 ± 0.51 | −1.50 | Down | |
| Naringin | 1.28 ± 1.71 | −1.42 | Down | |
| Kaempferol-3-O-(6’’-acetyl-galactoside)-7-O-rhamnoside | 1.53 ± 1.01 | −1.39 | Down | |
| Peonidin | 1.61 ± 1.21 | −1.36 | Down | |
| Phloretin-2’-O-xylosyl-glucoside | 1.06 ± 0.86 | −1.09 | Down | |
| Pelargonidin-3-O-sambubioside | 1.15 ± 0.66 | −1.07 | Down | |
| Petunidin-3-O-(6’’-acetyl-galactoside) | 1.15 ± 0.77 | −0.18 | Down | |
| Chrysin | 1.23 ± 1.49 | 0.79 | Up | |
| Malvidin-3-O-glucoside | 1.51 ± 0.74 | 1.12 | Up | |
| 6-Geranylnaringenin | 1.13 ± 1.15 | 1.89 | Up | |
| Kaempferol-3-O-acetyl-glucoside | 1.04 ± 0.95 | 1.96 | Up | |
| 3-Methoxysinensetin | 1.31 ± 0.78 | 2.24 | Up | |
| Peonidin-3-O-galactoside | 1.16 ± 0.77 | 2.53 | Up | |
| Isorhamnetin-3-O-galactoside | 1.39 ± 0.92 | 5.73 | Up | |
| Cyanidin-3-O-(6’’-acetyl-galactoside) | 1.03 ± 1.14 | 6.38 | Up | |
| Lignans | Lariciresinol | 1.11 ± 1.23 | 1.02 | Up |
| Other polyphenols | Psoralen | 1.73 ± 1.16 | −10.28 | Down |
| Juglone | 1.25 ± 1.15 | −4.46 | Down | |
| 3,4-DHPEA-EDA | 1.53 ± 1.13 | −1.79 | Down | |
| Ligstroside | 1.07 ± 1.69 | 0.33 | Up | |
| 5-Pentadecylresorcinol | 2.44 ± 0.25 | 1.33 | Up | |
| p-Anisaldehyde | 1.23 ± 1.09 | 1.74 | Up | |
| 4-Hydroxycoumarin | 1.13 ± 0.71 | 2.40 | Up | |
| Phenolic acids | Feruloyl glucose | 1.03 ± 0.38 | 0.11 | Up |
| Ferulic acid | 1.15 ± 0.83 | 0.39 | Up | |
| Sinapine | 1.22 ± 0.80 | 1.93 | Up | |
| 4-Hydroxybenzoic acid | 1.33 ± 0.79 | 10.91 | Up | |
| Stilbenes | Piceatannol-3-O-glucoside | 1.43 ± 0.76 | 1.49 | Up |