Fruit growing
and viticulture of South Russia

Annotation

One of the most common ways to counterfeit the red wines is to adjust the coloring of cheaper white wine materials with both synthetic food colors (indigocarmine, carmoazine, etc.) and natural colors (extracts of blueberries, currants, etc.). The color characteristics of juice and wine products vary considerably depending on the type of feedstock, the technology of production, and the composition of the blend. In this regard, some unscrupulous manufacturers often use cheaper fruit and berry raw materials for coloring of grape wines. The purpose of the present research was the comparative characteristics of the phenolic complex and the optical characteristics of genuine red wines and falsifiers obtained using natural and synthetic dyes. The objects of research were table wine materials from Cabernet-Sauvignon and Rkatsiteli grapes, juices and fruit extracts, a mixture of synthetic dyes. The impact of natural and synthetic colourants on the optical characteristics of wine-making materials has been studied. Variation ranges were obtained for physical-chemical and optical parameters of model test solutions in terms of their colour intensity variation. The relation between colour intensity and phenolic compounds content along with monomeric anthocyanins was established (r=0.96 and 0.94, respectively). It was demonstrated that monomeric anthocyanins were absent in the model systems that contained synthetic adulterated winemaking materials. It is the significant difference in the qualitative composition of native and adaltirative wine materials: the total phenolic compounds and colour intensity index colourants were much lower in the coloured samples as compared to the established and recommended values for authentic wines, that allow to use these indicators in a set of criteria for identifying adulteration of wine products.

Annotation

Stabilization of wine means the removal of causes that provoke sediment formation in it, and giving stable transparency to the beverage during the warranty period using various technological operations. The aim of this work was to assess the impact of various technological methods at the stage of must (acidification with organic acids (citric, tartaric and malic), as well as must clarification with bentonite) on the tendency of base wines to crystalline haze and morphological features of crystalline sediment. The object of research was white dry base wines produced from the autochthonous grape variety Kokur Belyi, cultivated in the Republic of Crimea. It is established that the method of must acidification by adding citric acid provides a significant decrease in the temperature of saturation with calcium tartrate by 4.6 times compared to the control. Processing of must with bentonite also contributed to a decrease in the Tsat (�aT) indicator by 33.5-44.9 %. It was shown that methods of must acidification with tartaric acid, as well as must clarification with bentonite, provided a stabilizing effect towards crystalline calcium haze for young wine to the end of experiment (3 months). The characterization of crystalline sediment by visual assessment and microscopy showed that potassium bitartrate was present in all tested samples. At the same time, the volume of sediment and morphological features of crystals were significantly different: in experimental variants with introduction of citric, tartaric and malic acids, as well as in the control sample, an abundance of small transparent crystals of potassium bitartrate, which resemble �crushed glass� in shape, was observed. Presence of large crystals was noted in samples with introduction of bentonite at the stage of must, as well as malic acid in the amount of 2 g/dm3 . The results obtained are intended to support preventive measures in the production of wines to ensure their stability to crystalline haze.