ISHS Acta Horticulturae 388: International Symposium on Viticulture and Enology
COLOUR EVOLUTION OF SHERRY WINES BY DISCOLOURING WITH ACTIVATED CARBON |
| Authors: | D. Escolar, Ma. R. Haro, A. Saucedo, J. Ayuso, A. Jiménez, J.A. Alvarez |
| Abstract:
The adsorption of substances, in gaseous phase or in solution, by activated carbon is a well known phenomenon with abundant bibliographic references. Activated carbon, although not a specific adsorbent, presents a partial graphited structure with a great affinity for bencenic rings. As an adsorbent it is frequently used in wines due to market demand for paler wines. However, from a chemical point of, its use produces an indiscriminate adsorption of many of the wine's compounds related to aroma, flavour and colour. Traditionally a wine's absorbance value at several wavelengths has been one of the indicators of the compounds responsable for colour. For the colour characterization, the uniform chromatic space CIELAB 1976 was used. First the X,Y,Z tristimulus were obtained from the absorption spectra of the wine samples in the visible intervals (380–770 nm). Thus the relation of the concentration of coloured compounds with the values of the chromatic parameters L*,a* and b* is more precise, since the parameters have been obtained using the absorbances at all wavelengths in the visible spectral at 1 nm intervals. This permits the detection of small colour differences in the samples. The paper discusses the evolution of the colour coordinates L*,a* and b*, chroma, hue, and hence the concentration according to the adsorbent mass, and shows the equation adsorption isotherm- which better defines the adsorption mechanism of the compounds responsible for the colour of Sherry wines. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
