9A Anthocyanins and Anthocyanin-Derived Compounds 455
identified in Port wine fractions (Mateus et al. 2005). Similarly, the pigment phenyl-
vinylpyranomalvidin-3-glucoside hasbeen recently detected in aged red wine
(Mateus et al. 2006).
Factors affecting the reaction.Factors affecting the formation vinylpyranoantho-
cyanins must comprised those previously described for their precursor compounds.
9A.3 Enzymatic Deglycosilation of Anthocyanins During
Winemaking
Theβ-glucosidase activity of certain strains ofSaccharomyces cerevisiaewine
yeast, which has a positive effect in wine aroma releasing the volatile aglycone
of terpenol glycosides (Palmeri and Spagna 2007 and references therein), is also
responsible for breakdown of the glucosidic bond of the anthocyanidin-3-glucosides
(anthocyanin-β-glucosidase or anthocyanase activity). The released anthocyanidin
is very unstable and is rapidly degraded leading to losses in wine color (Mazza and
Miniati 1993).
There is very little information in relation to the effects of yeastβ-glucosidase
activity on grape and wine anthocyanins. AlthoughS. cerevisiae, the main wine
yeast, is not a good producer ofβ-glucosidase, other non-Saccharomyceswine
yeasts (Brettanomyces, Candida, Debaromyces, Dekkera, Hanseniaspora, Hanse-
nula, Kloeckera, Pichia, Rhodotorula, Saccharomycodes, Schizosaccharomyces,
Torulaspora,among others) are considered potential sources of this enzyme.
S ́anchez-Torres et al. (1998) reported that the action of aCandida molischianaβ-
glucosidase activity resulted in a 50% color loss during the fermentation time. More
recently, Manzanares et al. (2000) studied the glucosidase activity in 53 yeast strains
belonging to the generaCandida, Dekkera, Hanseniaspora, Metschnikowia, Pichia,
Rhodotorula, SchizosaccharomycesandZygosaccharomyces, mainly isolated from
grape and wine. Yeast strains showing the largestβ-glucosidase activity belonged to
the generaCandida, HanseniasporaandPichiaand exhibited cell wall bond activity.
The anthocyanin-β-glucosidase activity resulted in 30–70% color loss among yeast
strains considered as best producers of the enzyme. To date, no structural dependent
effect on anthocyanin-β-glucosidase activity has been reported.
9A.4 Adsorption of Anthocyanins on Yeast Cell Walls
The main structural constituents ofSaccharomyces cerevisiaeyeast cell wall are
glucans and mannans with a minor proportion of chitin (Walker 1998). Manno-
proteins are located in the outer layer of the yeast cell wall and determine most
of the surface properties of the wall. Vasserot et al. (1997) studied the capacity of
yeast lees to adsorb anthocyanins in an attempt to reduce the detrimental effects of
charcoal on the color of red musts and wines. Experiments based on model wine
solutions revealed that yeast lees possessa greater affinity for anthocyanins than