9A Anthocyanins and Anthocyanin-Derived Compounds 451
acid/malvidin-3-glucoside since the concentration of caffeic acid remained very
stable during the storage time. However, a minimum concentration of malvidin-
3-glucoside (5–10 mg/L) was found to beneeded to maintainthe reaction rate
high enough to compensate for its simultaneous incorporation into other prod-
ucts. Recently, Rentzsch et al. (2007) also confirmed that Pinotin A formation
in Grenache red wines only takes place after a prolonged aging time, whereas
hydroxyphenyl-pyranoanthocyanins derived fromp-coumaric and ferulic acids were
produced by the enzymatic pathway during fermentation and by chemical synthesis
during the aging process.
9A.2.4.2 Anthocyanin-Vinylflavanol Condensation Reactions:
Flavanyl-Pyranoanthocyanins
Precursors.The precursors for this reaction are anthocyanins, flavanols or flavanols
containing a vinyl residue at C-8 (i.e., 8-vinylflavanols). 8-Vinylflavanols could arise
from the cleavage of flavanol-ethyl-flavanol oligomers or from the dehydration of
the flavanol-ethanol adduct formed after the attack of aldehyde cation to the flavanol
(Chapter 9B). Saucier et al. (1997) have supported evidence for this precursor when
detecting an ion corresponding to vinyl-catechin from the fragmentation of ethyl-
linked catechin dimers under ESI-MS in positive or negative mode.
Mechanism of reaction.The mechanism proposed for the formation of flavanyl-
pyranoanthocyanins (Francia-Aricha et al. 1997; Mateus et al. 2003a,b) (Fig. 9A.3g),
is similar to that described above by Fulcrand et al. (1996) for the formation of
hydroxyphenyl-pyranoanthocyanins (Sect. 9A.2.4.1; Fig. 9A.3f).
Evidence in wine.Flavanyl-pyranoanthocyanins derived from the reaction bet-
ween malvidin-3-glucosideand (+)-catechin, (–)-epicatechin and procyanidin B2,
first reported in model solutions containing malvidin-3-glucoside, acetaldehyde and
the respective flavan-3-ol (Francia-Aricha et al. 1997), have also been identified in
wines (Mateus et al. 2003a,b; Atanasova et al. 2002a; Alcalde-Eon et al. 2004, 2006;
Mateus et al. 2003a; Monagas et al. 2003; Wang et al. 2003a; Boido et al. 2006).
Complete NMR characterization has been provided for the flavanyl-pyrano
derivatives of malvidin-3-glucoside and itsp-coumaroyl ester with (+)-catechin, (–)-
epicatechin and procyanidin B3 and for derivatives of malvidin-3-(6-p-coumaroyl)-
glucoside with (+)-catechin, (–)-epicatechin and procyanidin B1 isolated from Port
wines (Mateus et al. 2002b, 2003a). Asenstorfer et al. (2001) have identified a large
family of flavanyl pyranoanthocyanins of oligomeric nature including the –di-, tri-
and tetra-catechin-pyrano derivatives of malvidin-3-glucoside and its acylated forms
in a commercial grape marc. Atanasova et al. (2002a) also demonstrated, via thiol-
ysis, that both monomeric flavanols and proanthocyanidins could be involved in the
formation of anthocyanin-vinylflavanol adducts.
He et al. (2006a) isolated and quantified oligomeric flavanyl-pyranomalvidin-
3-glucosides [(+)-catechin, (–)-epicatechin and procyanidin B3] and flavanyl-
pyrano-malvidin-3-(6-p-coumaroyl)-glucosides [(+)-catechin, (–)-epicatechin and
procyanidin B1] from Port wine from different ages (3-, 4- and 6-year-old wines). In
general, the profile of flavanyl-pyranoanthocyanin pigments in the different wines