Included in the workshops organized by the University of Castilla-La Mancha
Professors Fernando Zamora Marín, of the University Rovira i Virgili in Tarragona, and Isidro Hermosín Gutiérrez, of the University of Castilla-La Mancha, have been the speakers at Session 3 on "Innovation in Enology" that has taken place this morning within the frame of the National Trade Fair on Wine (FENAVIN 2009), which is being held in Ciudad Real from May 5th to the 7th.
Professor Zamora has been the first to take the floor, focusing his chat on presenting the effects of applying the micro-oxygenation technique over color, phenolic composition and the astringency of red wines. After briefly describing the chemical mechanism of the oxygen action over phenolic composites, Zamora has shown the experimental results that have been obtained by his research group. "These results confirm that micro-oxygenation increases the color of wines, while simultaneously causing a gradual reduction in the concentration of free and total anthocyanins", he said, underlining that the combination of anthocyanins with flavonols increases when micro-oxygenation is applied, which is a symptom that this technique not only increases color, but that it also makes it more stable. Likewise, micro-oxygenation induces a reduction of the wine's astringency.
On his part, Professor Isidro Hermosín, focused his conference on "Flavonols and their action on co-pigmentation and traceability". Hermosín explained that flavonols are phenolic composites that are present in the grape, which upon passing over to the wine, exercise a series of very interesting effects that to date had not been very highly considered. Apart from having a high antioxidant activity, thus contributing to the beneficial effects for health that are associated to moderate consumption of wine, from a technological point of view flavonols decisively contribute to the interesting effect denominated co-pigmentation. "Co-pigmentation", he said, "is a phenomenon that increases the intensity of red wine's red color, while in turn conferring purple tones to it, which are typical characteristics of young red wines".
He explained that his research group has contributed to the study on grape and wine flavonols in various senses: on the one hand, it has been possible to define the complete profile of grape and wine flavonols, readying the identification and quantification methods, allowing us to obtain knowledge of the exact content of the flavonols; on the other hand, the role that flavonols exercise during the elaboration of red wines has been demonstrated, contributing to a greater rate of anthocyanin extraction (red color) and stabilization of the latter in wine, which displays a more intense red color, with more purple tones and that is more stable over time.
He also referred to the fieldwork carried out to establish the ideal viniculture conditions to produce red grapes with the highest possible combined content of anthocyanins and flavonols, as these are the ones that have more power in order to obtain red wines with a more intense and stable color. "Finally, despite the hydrolysis that flavonols suffer in the wine (initially found as glycosides in the grape, which is how they pass over to the wine), the profile of the flavonols has proven to be a useful tool to establish the traceability of wines, in particular in that relative to the grape variety that is used in the elaboration", he pointed out.