Table 2.

Content of the identified phenolic compounds in Touriga Nacional (TN) and Tinta Roriz (TR) extracts obtained by ultrasound assisted extraction (UAE) performed at lab scale without an ice bath after 60 min of extraction; results are expressed as mean ± standard deviation (mg of compound/100 g DW, n = 3).

Compound	TN	TR
Phenolic acids
Gallic acid	13.8 ± 0.7	15.1 ± 0.8
Protocatechuic acid	13.7 ± 0.7	10.7 ± 0.5
4-hydroxyphenilacetic acid	4.4 ± 0.2	8.3 ± 0.4
4-hydroxybenzoic acid	6.8 ± 0.3	5.3 ± 0.3
4-hydroxybenzaldehyde	8.6 ± 0.4	9.4 ± 0.5
Chlorogenic acid	11.1 ± 0.6	11.5 ± 0.6
Vanillic acid	4.8 ± 0.2	6.5 ± 0.3
Caffeic acid	6.4 ± 0.3	6.3 ± 0.3
Syringic acid	<LOQ a	<LOQ
p-coumaric acid	10.8 ± 0.5	8.9 ± 0.4
Ferulic acid	4.3 ± 0.2	4.4 ± 0.2
Sinapic acid	6.6 ± 0.3	6.6 ± 0.3
Ellagic acid	<LOD b	<LOD
Cinnamic acid	6.5 ± 0.3	7.6 ± 0.4
∑Phenolic acids	97.7 ± 4.9	100.4 ± 5.0
Flavanols
Catechin	35.5 ± 1.8	131.4 ± 6.6
Epicatechin	7.5 ± 0.4	18.1 ± 0.9
∑Flavanols	43.0 ± 2.1	149.5 ± 7.5
Flavanones
Naringin	4.4 ± 0.2	4.9 ± 0.2
Naringenin	2.6 ± 0.1	3.0 ± 0.1
Pinocenbrin	10.3 ± 0.5	10.3 ± 0.5
∑Flavanones	17.3 ± 0.9	18.2 ± 0.9
Flavonols
Rutin	23.3 ± 1.2	21.8 ± 1.1
Quercetin-3-O-glucopyranoside	12.8 ± 0.6	14.2 ± 0.7
Myricetin	74.9 ± 3.7	74.3 ± 3.7
Kaempferol-3-O-glucoside	9.9 ± 0.5	9.7 ± 0.5
Kaempferol-3-O-rutinoside	10.8 ± 0.5	12.4 ± 0.6
Quercetin	20.1 ± 1.0	19.7 ± 1.0
Tiliroside	8.2 ± 0.4	8.0 ± 0.4
Kaempferol	23.9 ± 1.2	22.8 ± 1.1
∑Flavonols	183.8 ± 9.2	173.4 ± 8.7
Stilbenes
Resveratrol	84.0 ± 4.2	153.4 ± 7.7
∑Stilbenes	84.0 ± 4.2	153.4 ± 7.7
Others
Phloridzin	7.9 ± 0.4	8.1 ± 0.4
Phloretin	5.6 ± 0.3	3.9 ± 0.2
∑Others	13.5 ± 0.7	12.0 ± 0.6
∑All phenolic compounds	439	617

^a LOQ: limit of quantification; ^b LOD: limit of detection.