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The presence of stilbenes in wine is becoming an important issue due to their claimed relation to a low incidence in coronary diseases and their increasing implication as cancer chemopreventive and neuroprotective agents. Total resveratrol content, quantified as glucoside and aglycone forms of resveratrol, has been determined in a survey of 45 Monastrell monovarietal Spanish red wine types (around 135 wine samples), belonging to Alicante and Bullas appellations. The average between ratio glucoside/aglycone forms of resveratrol in these wines was considerably high, ranging from 82 to 91% of resveratrol in its glycosidic form. This characteristic was observed in a high percentage of the studied wines, which were made under different winemaking procedures, and from different vintages (1995-2002). In addition, wines made using macerative fermentations with double amount of solid parts ("doble pasta") reached the highest levels of total stilbene content expressed as resveratrol equivalent, i.e., 30 mg/L (average of 18.8 mg/L). It can be concluded that high resveratrol glucoside concentration and low free isomer content can be considered characteristics of the Monastrell variety, as it happens to red wines deriving from other varieties grown at warm climates. This fact, also observed for other French and Portuguese red varieties, might play an important role in food habits involving these types of wines.

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The influence of the prefermentative addition of copigments and different winemaking technologies on the polyphenolic composition of Tempranillo red wines after malolactic fermentation, was studied. Six experiments dealing with the prefermentative addition of caffeic acid, rutin, (+) catechin, white grape skin tannin, white grape seed tannin and control wines were realised. Three different winemaking technologies (traditional vinification, prefermentative cold maceration at 6-8 ºC and cold soak at 0-2 ºC with dry ice) were studied. Prefermentative addition of copigments increases anthocyanin copigmentation reactions and produces wines with a greater colour, a higher anthocyanin concentration, a superior contribution of anthocyanins to the colour of the wine, a superior percentage of tannins polymerized with polysaccharides and less astringency.Cold prefermentative maceration increases the extraction of polyphenols, the anthocyanin copigmentation reactions and the polymerization reactions between tannins and polysaccharides.The effectiveness of the combination of copigments and prefermentative maceration treatments was demonstrated by the increase of the concentration of the polyphenolic compounds.