**2.1 Flavonoid grape polyphenols: Anthocyanins, flavan-3-ols, procyanidins, and flavonols**

Flavonoids are basically formed by a structure of 15 carbons (C6-C3-C6) divided in 2 aromatic rings, A and B, which are joined by a 3-carbon chain that is part of a heterocyclic C ring (**Figure 1**). Depending on the oxidation state of C ring, this family can be subdivided in anthocyanins, flavan-3-ols, or flavonols.

**3**

*a*

**Table 1.**

*Phenolic Compounds of Grapes and Wines: Key Compounds and Implications in Sensory…*

Structurally, anthocyanins are mainly present in nature in the form of heterosides. The aglycone form of anthocyanins, also called anthocyanidin, is based on the flavylium or 2-phenylbenzopyrilium ion having hydroxyl and methoxyl groups in

Anthocyanins are the most important natural pigments in wine grapes. These compounds are predominately accumulated in skins of red grapes during the ripening, and they are also present in the flesh of "teinturier" varieties [9]. In addition, it has been recently demonstrated that certain white grape cultivars (Sauvignon

**Compound g/kg dm Grape variety References**

19–40.5 36.6–88.7 20.2–52.3 Grenache, Syrah,

Carignan noir, Mourvèdre, Counoise

Lemberger, Spätburgunder, Schwarzriesling, Trollinger

Carignan noir, Mourvèdre, Counoise Cabernet Sauvignon, Chardonnay, Sauvignon blanc, Moscatel de Grano Menudo, Gewürztraminer, Riesling, Viognier, Merlot, Cencibel

Riesling

Sauvignon, Merlot, Cabernet Mitos

[13]

[12, 14]

[13, 15–19]

[14]

[12, 14, 19]

Pomace Seeds Skins

Total 11.47–29.82 11–47–29.82 ND Cabernet Mitos,

Catechin 0–0.3 2.14–2.42 0–0.3 Grenache, Syrah,

0–0.007 0.06–0.07 ND

Total 0.03–0.63 0.48–0.63 0.02–0.05 Merlot Weisser

Total 0.03–8.31 0.10–0.11 0.17–8.23 Cabernet

Delphidin-3-*O*-glucoside 0.44–1.11 0.44–1.11 ND Cyanidin-3-*O*-glucoside 1.51–3.81 1.51–3.81 ND Petunidin-3-*O-*glucoside 0.53–1.34 0.53–1.34 ND Peonidin-3-*O*-glucoside 0.99–2.49 0.99–2.49 ND Malvidin-3*-O*-glucoside 4.12–10.19 4.12–10.19 ND Total acetylated 3.88–10.88 3.88–10.88 ND

Epicatechin 0–0.2 0.88–1.60 0–0.13 Epigallocatechin 0–0.05 0.05 ND

Epicatechin-3-*O*-gallate 0.003 0.25–0.31 0.04 Procyanidin B1 0.11–0.60 0.14–0.17 0.18–0.6 Procyanidin B2 0.01–0.84 0.04–0.18 0.01–0.84 Total tannins 39.1–105.8 62.3–167.8 44.9–73.0

Gallic acid 0.03–0.11 0.03 0.01–0.11 Coutaric acid 0–1.23 0.03–1.23 — Caftaric acid 0–6.97 0.11–6.97 —

*Main phenolic compounds in different grape parts (expressed in g/kg of dm).*

*DOI: http://dx.doi.org/10.5772/intechopen.93127*

*2.1.1 Anthocyanins*

different positions.

**Total polyphenol content**<sup>a</sup>

**Anthocyanins**

**Flavan-3-ols/proanthocyanidins**

Epigallocatechin-3-*O*-

gallate

**Flavonols**

**Phenolic acids**

*Gallic acid equivalents (GAE) per g dry weight.*

**Figure 1.** *General chemical structure of flavonoid family.*

*Phenolic Compounds of Grapes and Wines: Key Compounds and Implications in Sensory… DOI: http://dx.doi.org/10.5772/intechopen.93127*
