Colour measurement as a discriminating factor in quality control of Bulgarian red wines

Colour is one of the main organoleptic characteristics of wine having a significant impact on consumers' choices, as such it is considered an important factor in assessing the quality of red wines. Wine colour depends on complex extraction and polymerization reactions'; therefore it could evolve over time. This study is based on few samples of Pinot Noir wines, that achieve both good quality levels and a strong market performance, Mavrud, an ancient variety from Thrace, and Rubin, a Syrah and Nebbiolo crossbreed. The selected wines differ for their anthocyanic profile and polyphenolic content. Furthermore, the quality of the selected national varieties is comparable to the most famous international ones. A comparison was made based on chemical and organoleptic characteristics as well as their performance on the market. The chromatic indices, intensity and hue, the anthocyanic profile and their evolution in time, were determined via the polymerization indices. To allow for an objective assessment, the colour of wines was defined using CIELab colour space, which permits an objective identification of any colour perceivable by the human eye. Finally, analytical results were compared to the organoleptic characteristic of the selected wines.