Compuestos azufrados volátiles en vinos - Fundación para la ...

Effect of Micro-oxygenation on Color and Anthocyanin-Related Compounds of Wines with Different Phenolic ContentsFigure 3. Development of direct anthocyanin-flavanol adducts and polymeric compounds in W1, W2, andW3 wines (±SD). Each point corresponds to t 0, t 1, t 2, and t 3.hydroxyl group attached to C5 in the anthocyaninmolecule. Some compounds result from the additionof anthocyanin and pyruvic acid (carboxypyranoanthocyanins).Several of these compounds weredetected in our samples: petunidin 3-glucoside pyruvate,vitisin A (malvidin 3-(glucoside)pyruvate), acetylvitisin A (malvidin 3-(acetylglucoside) pyruvate), andcoumaryl vitisin A (malvidin 3-(coumarylglucoside)pyruvate). Another pyranoanthocyanin resulting fromthe cycloaddition of acetaldehyde to malvidin 3-glucoside,and referred to as vitisin B, also was found, andits quantification was included with the carboxypyranoanthocyanins.Pyranoanthocyanins are consideredto be important compounds concerning the color ofred wine since the cycloaddition process seems tostrongly increase the stability of the products, and, inthis way, vitisin A has been reported as being morestable than malvidin 3-glucoside or ethyl-linked compoundsand more resistant to oxidation (41). The sumof carboxypyranoanthocyanins and vitisin B increasedfrom t0 to t1 (Figure 2), with MO wines increasingmore (except for W1). At the end of the experiment,carboxypyranoanthocyanins showed lower concentrationsin the control wines than in the MO wines,the greatest increases being detected in W2. Otherauthors found a strong decrease in vitisin A and re-lated compounds during the first year of wine storage,after which the concentration remained relativelyconstant (42–44). Such a decrease, observed mainly inour study between t1 and t2, was ascribed to their incorporationinto polymeric compounds (42). The concentrationof carboxypyranoanthocyanins in wines isa result of a balance between the formation reactionsand their incorporation in the polymeric compounds.The formation of vitisin A and related compoundsrequires the presence of free monoglucosides andpyruvic acid. Oxygen or reactive oxygen species arealso necessary for the reaction to proceed since allcycloaddition pathways require an oxidation step torecover the flavylium moiety within the final structures(45–47). Therefore, the MO process seemed toenhance the formation of vitisin-type compounds byproviding oxygen. This result is contrary to that of Atasanovaet al. (8), who stated that the addition of pyruvicacid to anthocyanins is not influenced by oxygen.W2, with a higher anthocyanin monoglucoside content(as quantified by HPLC), was the wine showingthe highest final concentration of carboxypyranoanthocyanins.Another group of anthocyanins, constituted byhydroxyphenyl- pyranoanthocyanins, results from96