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The effects of the carbonic maceration and conventional winemaking on the volatile composition and aromatic sensory characteristics of Tempranillo Blanco wines were studied for the first time, during three consecutive vintages. Relationships between instrumental (volatiles) and sensory variables were analyzed applying partial least squares regression (PLS). Carbonic macerated wines had higher contents of alcohols and carbonyl compounds, yet lower concentrations of C6 alcohols and volatile acids than wines conventionally produced. The Odor Activity Values (OAV) exhibited an increase in wines when carbonic maceration was applied. According to the geometric mean (% GM) obtained from aroma descriptors the effect of the winemaking process was significant for seed fruit, ripe fruit and floral notes. When subjected to PLS the data from the instrumental analysis yielded a satisfactory model for the prediction of aroma descriptors in this set of wines.

[EN] The relationship between cell wall composition and extractability of anthocyanins from red grape skins was assessed in Tempranillo grape samples harvested at three stages of ripening (pre-harvest, harvest and over-ripening) and three different contents of soluble solids (22, 24 and 26 !Brix) within each stage. Cell wall material was isolated and analysed in order to determine cellulose, lignin, non-cellulosic poly- saccharides, protein, total polyphenols index and the degree of esterification of pectins. Results showed the influence of ripeness degree and contents of soluble solids on cell wall composition. Furthermore, principal components analysis was applied to the obtained data set in order to establish relationships between cell wall composition and extractability of anthocyanins. Total insoluble material exhibits the biggest opposition to anthocyanin extraction, while the highest amounts of cellulose, rhamnogalacturonans-II and polyphenols were positively correlated with anthocyanin extraction. Moreover, multiple linear regression was performed to assess the influence of the cell wall composition on the extraction of anthocyanin compounds. A model connecting cell wall composition and anthocyanin extractabilities was built, explaining 96.2% of the observed variability.

Oscar Fernández...et al., A practice in wineries is to age wine in the presence of lysated lees instead of fresh lees, in order to reduce the time wine is conserved on lees and avoid possible microbiological and organoleptic risks caused by lees. Two treatments were used to induce lees lysis: acidification and acidification in combination with a mixture of β-glucanases and pectinases. Acidification treatment in combination with enzymes induced significantly greater mannoprotein and glucan release. The presence of lysated lees during wine storage in barrels produced wines with significantly different tannin contents. The ageing technique on lysated lees by acidification in combination with enzymes produced wines with more intense colors, lower luminosity and saturation, and a slight tendency towards red tones, and an increase in sweetness, fullness and mouth length. On the contrary, ageing technique on lysated lees by acidification increased wine acid and fresh sensations., This work was supported by the Gobierno de La Rioja (Project FOMENTA 2007/01) and the Universidad de la Rioja (Projects API). The authors wish to thank Antonio Palacios for conducting the sensory analysis

The influence of commercial enzymes on wine polysaccharide content was studied. Tempranillo wines were made using commercial maceration enzyme preparations along with controls. The analytical method for the quantification of wine polysaccharides was carried out by a multistep procedure. Wine-soluble polysaccharides were isolated by wine concentration polysaccharides precipitation with an acid-alcohol medium and separation of each polysaccharide family by high resolution size-exclusion chromatography on a Superdex-75 HR column. The glycosyl-residue compositions of the fractions obtained were determined by gas chromatography with flame ionisation and mass spectrometry of their trimethylsilyl-ester O-methyl glycosides after acidic methanolysis and derivatization. The content of each fraction was estimated from the concentration of individual glycosyl residues that are characteristic of well-defined wine polysaccharides. The analytical method proposed had good sensitivity, repeatability, reproducibility and accuracy. Soluble polysaccharides in wine were essentially composed of grape cell wall polysaccharides: arabinogalactans and arabinogalactan-proteins (38-41%), and rhamnogalacturonans-II (38-46%). Yeast mannans and mannoproteins were also present but in smaller proportions (14-19%). Wines treated with commercial enzymes had larger concentrations of arabinogalactans, arabinogalactan-proteins and rhamnogalacturonans-II than control wines, but the content of mannans and mannoproteins was similar in both wines. This indicated that the commercial enzymes hydrolysed grape pectic polysaccharides during the maceration- fermentation stage but had no influence on yeast parietal polysaccharides. © 2003 Elsevier B.V. All rights reserved.