Chromatic characterisation of three consecutive vintages of Vitis vinifera red wine

Abstract

Both standard and CIELAB colour parameters have been evaluated for three consecutive vintages of Vitis vinifera (Tempranillo variety). A simple and straightforward relationship between CI and L* has been derived. Dilution effects on colour for samples under fermentation and for several commercial wines have been studied under pH controlled conditions. Disruptions of equilibria responsible for colour at the typical wavelengths upon addition of iron have been assessed.

Significance of CIELAB parameters in the routine analysis of red wines Relevancia de los parámetros CIELAB en el análisis de rutina de vinos tintos

“…On the other hand, TP analysis is cumbersome with a derivatization reaction that demands a careful timing of the spectroscopic measurements, while TA quantification is straightforward and individual anthocyanins measurements are more reproducible enabling the number of replicas to be low. It should be kept in mind that the Prussian blue method here utilized for TP analysis was chosen for it was found to be less interference prone than the Folin-Ciocalteu, Chromatic characterization of the three aforementioned vintages have been previously studied and reported (Esparza et al, 2006). It is now feasible to try and find whether definite relationships exist among those parameters and the organic fraction of the same wines here analyzed.…”

“…For statistical purposes, results presented in this paper are completed with those reported elsewhere (Esparza et al, 2004) for the precedent vintage (2002), in order to ascertain a better statistical significance. On the other part, this entire group of data is employed together with chromatic parameters exhaustively studied for these three vintages (Esparza et al, 2006), in order to check the influence of the former on the latter.…”

“…A thorough study was undertaken in order to definitely and unambiguously check whether metal addition onto a wine would originate a color change, as previously advanced (Esparza et al, 2006). For that purpose, care was taken to use experimental conditions that would not induce changes unrelated to metal additions.…”

Chemical speciation and fractionation of metals in wine

“…Recently, complexation studies have been carried out involving copper and zinc with synthetic solutions of selected polyphenols (catechin, rutin and quercetin) as well as with wine samples, concluding that both metals chelate with the studied polyphenols . Esparza et al (2006) studied the disruptions of equilibria responsible for colour of samples undergoing vinification and on a few commercial red wines at the typical wavelength upon addition of Fe(III). They concluded that a small quantity of iron in wines produces an increment of blue colour and in a decrease of red colour.…”

Determination of the hydrophobic fraction of Ca, Fe, Mg and Zn in dark color honeys using solid phase extraction and flame atomic absorption spectrometry

“…The significance of this dependence points out that the contribution of complexes of Fe with polyphenols to the color of dark honeys could be quite high. By similarity to the formation of blue complexes of Fe with polyphenols in wine, 30 this effect, especially evident in dark honeys, could be related to the batochrome displacement to the blue region and an increase of the intensity of the red increment, however, a further elucidation is required. No such effect has been described so far.…”