IMPROVEMENT OF THE BLENDING TECHNOLOGY OF MEDIUM DRY AND SEMI-SWEET WHITE TABLE WINES

The paper reviews the literature on the existing technologies of medium dry and semi-sweet table wines. The main problems of manufacturing this type of wines have been outlined, as well as how they are solved by domestic and foreign winemakers. The classical scheme of producing medium dry and semi-sweet wines allows retaining the aroma of a certain grape variety and obtaining quality wines, but it is not applied in Ukraine as it is technologically complicated and costly. The scheme that involves blending is far more economical, but does not allow retaining all the fine aromatic nuances of a variety. So, the article considers the ways of obtaining medium dry and semi-sweet wines using grape must that has been concentrated by freezing. It has been shown that this technology will allow retaining the valuable substances of the variety aroma and will be the basis for producing the highest-quality wines of this type. For the research, the following samples have been analysed: clarified must of the Rkatsiteli and Citronny Magaracha grape varieties, must concentrated by freezing, vacuum must, dry wine materials, and the medium dry white table wines made from them. In the musts and wines, the main physical and chemical characteristics have been studied (the mass concentrations of sugar, titrated acids, total and free sulphur dioxide), as well as some additional parameters (the pH, mass concentrations of phenolic substances, free and bound terpene alcohols, optical density with the wavelength 420 nm). The mass concentrations of volatile acids and the sensory characteristics of the wine materials and wines have been determined, too. The research has shown that in the medium dry wines obtained by cryotechnology, the concentrations of free terpene compounds increased from 1.01 mg/dm3 to 1.21 mg/dm3 in Rkatsiteli, and from 2.89 mg/dm3 to 3.24 mg/dm3 in Citronny Magaracha. The flavour and aroma improved substantially, too. So, the blending technology of producing medium dry and semi-sweet table wines using cryomust allows retaining, to the greatest possible degree, the bright and peculiar aroma of the grape variety, and obtaining the highest-quality wines of this type.

Two-Step Synthesis of Tungsten and Molybdenum Disulfides

Efficient two-step technique of tungsten and molybdenum disulfides obtaining from metal nanopowders produced by EEW and elementary sulphur is described. Tungsten and molybdenum nanopowders surface area dependence on wire length is studied. Features of metal and sulphur combustion process are discussed. It is determined sulphur excess in reagents 15 wt.% results in mono-phase metal disulfide formation with small free sulphur concentration in reaction products.

Metabolism of elemental sulphur (S°) during fungal spore germination

35S-labelled elemental sulphur (S°) at nontoxic levels (3 μM) was incorporated into sulphur amino acids and glutathione by the spores of the fungus Phomopsis viticola. Incorporation studies were performed with 3 μM 35S° during the pregermination period of P. viticola spores. The free sulphur amino acids and protein sulphur amino acids were purified by column and thin-layer chromatography. During the first minutes of the pregermination process of the spores, the S° was essentially metabolized into free cysteine and glutathione. Detectable concentrations of methionine and homocysteine were measured after 1 h of incubation. Azide (2 mM final concentration), an inhibitor of the mitochondrial respiratory chain at the level of cytochrome oxidase, strongly inhibited the incorporation of S°. In contrast, the uncoupler 2,4-dinitrophenol (15 μM final concentration) and sulphate did not affect the incorporation of S°. The metabolism of 35S° into the protein sulphur amino acids cysteine and methionine during the germination of spores of P. viticola and conidia of Neurospora crassa is also discussed. It appears that S° does not necessarily have to be oxidized to sulphate prior to its incorporation into sulphur amino acids, but could be directly reduced to sulphide at the level of the respiratory chain.Key words: elemental sulphur, assimilation, sulphur amino acids, Phomopsis viticola, Neurospora crassa.