Changes in skin cell wall composition during the maturation of four premium wine grape varieties
✍ Scribed by Ana Ortega-Regules; José María Ros-García; Ana Belén Bautista-Ortín; José María López-Roca; Encarna Gómez-Plaza
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 353 KB
- Volume
- 88
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Abstract
BACKGROUND: Grape skin cell walls form a barrier against the diffusion of colour. The colour of red wines is mainly due to anthocyanins, although their concentration in wine is not always correlated with the anthocyanin content of grape skins. The cell wall composition changes during fruit ripening, so it was thought that a study of the ripening behaviour of four premium varieties might provide information on how the composition changes during ripening and explain the technological differences.
RESULTS: The largest quantities of skin cell wall material (CWM) were isolated from Monastrell grapes, probably owing to the greater number of cell layers they contain and the thicker cell walls. During ripening, a loss of skin CWM (e.g. 120–60 and 65–45 mg CWM g^−1^ fresh skin for Monastrell J and Cabernet Sauvignon respectively) and galactose (e.g. 36–20 and 55–30 mg g^−1^ CWM for Cabernet Sauvignon and Monastrell J respectively) was observed, together with a decrease in the degree of pectin methylation and acetylation, except in Syrah, in which pectin methylation remained unchanged. These changes were accompanied by the accumulation of glucose, while other neutral sugars showed no significant variations. A correlation was found between the degree of ripening and those constituents changing in the grape skin cell wall.
CONCLUSION: The cell wall composition differs sufficiently between grape varieties to allow discrimination between them. Ripening was associated with a decrease in the quantity of CWM and galactose in the cell walls. Monastrell showed the largest quantities of both throughout ripening. The differences observed between Monastrell and the other varieties would explain the technological differences between them. Copyright © 2007 Society of Chemical Industry