Fruit growing
and viticulture of South Russia
Malic acid plays an important role in the addition of the taste and aroma of grape wines. Its high concentrations lead to the appearance of herbaceous tones and tones of "green acidity", sharpness and softening of taste. To reduce the concentration of malic acid it used the different methods of acid acidification. The work provides data on the effect of the combined acidization method the concentration of organic acids, potassium cations and calcium. The combined method involves reducing the concentration of wine acid with chemical reagents followed by biological acid-acidization with different strains of bacteria of apple (malolactic) fermentation. It has been established that chemical reagents help to reduce the concentration of organic acids mainly due to wine acid. At the same time, neo-antiticide and malicide were the most effective. The ensuring of wine materials with potassium and calcium cations is shown in the process of chemical acid reducing. Analysis of experimental data indicates the slow flow of the process of biological decline of apple acid in the wine materials. At the same time, more active acid-lowering took place in white wine in comparison with red wine. Among the bacteria in terms of the decrease rate in the concentration of apple acid in the white wine material stood out the strains of Vitilactic and Inobacter, which reduced the concentration of malic acid to 1 g/dm3 . The joint use of chemical and biological acid acidization helps to accelerate the reduction of the malic acid concentration in both white and red table wine material`s due to the greater accumulation of biomass of malic-milk fermentation bacteria. There was an improvement in the organoleptic properties of wine materials, and the absence of their enrichment with potassium and calcium cations.
Experimental data on the reological (viscosity-plasticity) characteristics of yeast and adhesive precipitation of wine production are presented. Their knowledge is necessary for calculating the technological equipment when designing the recycling lines. Yeast sediments obtained in the production of white and red grapes by different technologies were used as objects of the study. The effective viscosity of yeast and adhesive precipitation was determined by the Reotest-2 rotary viscosimeter with a cylindrical measuring device. Comparing the amount of plastic viscosity of yeast sediments of white wine materials of Chardonnay and Sauvignon blanc, produced using the same race of yeast, it can be noted its greater importance in Sauvignon blanc, which is associated with the accumulation of more extractive components. The greatest importance of plastic viscosity among red wines is revealed in the sediments of the Krasnostop AZOS during the pulp fermentation. Plastic viscosity of sediments precipitation was caused by the grape variety and the type of sorbent used to process wine. It was established that bentonite sediments had a large amount of plastic viscosity in comparison with gelatin sediment. The joint use of gelatin and bentonite to process wine have led to slight increase in the plastic viscosity of adhesive sediment in comparison with bentonite. When processing the wine materials, especially red ones, with polyvinylpyrrolidone together with bentonite suspension, the more dense sediments was obtained, the plastic viscosity of which had the highest values. The effect of grape variety and wine production technology the amount of plastic viscosity of adhesive sediments has been proved: with the increase in the concentration of high-molecular substances (colloids) in processed wine materials, the plastic viscosity increases.
Research aimed at improving the biotechnology of red table wines production, taking into account the characteristics of raw materials, used yeast races, region of origin, climate and fermentation conditions, is relevant. The object of research was wines from Cabernet-Sauvignon grapes of the 2019 harvest, grown on chestnut, calcareous soils of medium loamy texture of the terroir of the Mugarty village near the Mugartychay river (Kamyshchay river basin) in the Derbent region of the Daghestan Republic, and obtained at OJSC "Derbent Sparkling Wine Factory". The strains S. cerevisiae Y-4270 and S. cerevisiae D-19 were used for fermentation. The qualitative and quantitative composition of volatile substances in the wines under study was determined by gas-liquid chromatography. It is shown that "Kara-Koisu" wine obtained using the Y-4270 strain, was more aromatic due to the greater accumulation of esters and acetate. The content of ethyl acetate (by 2.4 times), ethyl lactate (on 9.9 %), and ethyl laurate, which give roundness to fruit or floral aromas, is on 29.7 % higher in the test sample (with the exception of ethyl capronate). Aliphatic alcohols formed an important basis for the aroma of wine, the total amount of which was 433.84 mg / dm3 , which is on 39.7 % higher than that in the control. Isoamyl (62.3 %), isobutyl (42.5 %), 1-propanol (31.2%), methanol (32.5 %) prevailed in the tested wines. The aromatic alcohols are twice as high in phenylethanol, which adds floral nuances to the wine. New data indicated the role of the biochemically active S. cerevisiae strain VKPM Y-4270 in the creation of dry red wines.
The change in the content of terpene alcohols in sparkling wines at the main stages of production, depending on the sugar-containing components used in champagne, has not been sufficiently studied. The aim of the work was to study the effect of sugar-containing components used in the production of sparkling wines on the accumulation and preservation of terpene alcohols in the products under production. Under the conditions of the southern coast of Crimea, the influence of sugar-containing substances in the production of Muscat sparkling wines from Muscat white grapes the content of terpene alcohols (terpenes) in them was studied. As a result of research carried out it was found that the use in the technology of wine production of the Sevastopol 23 yeast race contributes to an increase in the mass concentration of terpene alcohols in table dry and liqueur wine materials made of white Muscat grape variety in comparison with the original must. When concentrating using a vacuum of grape must from white Muscat, part of the terpenes is removed together with water, which, in general, can lead to a decrease in their content in the concentrated grape must (vacuum-must). Higher content of terpene alcohols and high tasting ratings are established in sparkling wines produced using liqueur Muscat wine material and unfermented must. A more striking" rich " bouquet, combining all the aromatic descriptors inherent in nutmeg sparkling wines, was characterized by a sample developed using unermented must. At the same time, it was found that reducing the period of post-fermented aging on yeast leads to the preservation of more free forms of terpenes. In this regard, the use of technology for preparing young Muscat sparkling wines by the bottle method is promising.
The direction of redox processes during biological aging of wine material is caused by the oxygen uptake, that is why its amount in sherry production is of decisive importance for the quality of the finished product. The aim of this work was to study changes in the volume components and physic-chemical characteristics of sherry base wines during biological aging, depending on the area of film overgrowing. The research was carried out on sherry base wines of Aligote, Rkatsiteli and Kokur Belyi grape varieties. Regulation of sherry yeast activity was carried out by introducing of tartaric acid as a metabolism inhibitor in experimental samples in the amount of 2.0 and 4.0 g/l. It was shown that the access of air oxygen at a time of biochemical transformation of metabolites provoked the non-enzymatic oxidative processes. Under the conditions of complete sherry film overgrowing in the base wines during aging, there is a decrease in the value of redox potential, optical dense D420, mass concentration of glycerin and all forms of phenolic substances, as well as a significant increase in the mass concentration of aldehydes, acetoin and diacetyl. When a discontinuous film overgrowing the increasing mass concentration of aldegides and their derivatives is observed in smaller amounts (in 1.4 and 2.6 times, respectively), in this case the values of optical dense (by 6 and 40 %), redox potential (by 6 and 17 %), and acetic acid increase. There is also an insignificant decrease in the concentration of glycerin, as a source of nutrition for sherry yeast, by 17 and 6 %, while in the control the content of the component decreases by 39 %. Under the conditions of incomplete film overgrowing on the surface of the base wines, the light fruit notes are observed against the background of aldehyde tones, as well as brown shades in color negatively affecting the tasting evaluation of the samples.