Fruit growing
and viticulture of South Russia

Annotation

Research was conducted to identify and study the technological characteristics of autochthonous strains of wine yeast isolated from vineyards in the Krasnodar region. From natural populations, 90 yeast strains were isolated from the surface of grapes of the following varieties: Petit Mansan, Merlot, Krasnostop Anapskiy. Generic identification of the studied strains was carried out. The proportion of Saccharomycetes varied over a wide range. Analysis of 90 yeast strains made it possible to isolate 40 representatives of the genus Saccharomyces. Species identification was carried out using molecular genetic methods. A working sample of 40 strains of Saccharomyces cerevisiae was obtained. Yeast screening for the ability to ferment sugars made it possible to isolate 13 yeast strains. Strains TK20-2 and LM19-19 are noted as weak fermenters with the formation of non-fermenters. An analysis of the ability of yeast to synthesize hydrogen sulfide showed that 21 strains produce hydrogen sulfide in an insignificant amount. In the course of studying the main technological properties, 4 strains were isolated, with the use of which white wine materials were prepared from the Onitskanskiy grape variety. In wine materials produced using local strains, a variation in the concentrations of organic acids, amino acids and volatile aroma-forming components was noted. The conducted tasting of the studied samples showed that 3 out of 4 wine materials were characterized by high quality. The sample produced using strain LM19-3 had the highest tasting score. The use of strains LP19-1, TK20-11 and LM19-3 ensures the production of high-quality wine materials with high organoleptic characteristics.

Annotation

The mass concentration of biogenic amines is an important indicator of the quality and the safety of food products, including alcohol. This indicator is standardized in wine products in most European countries. Many factors influence the concentration of biogenic amines in wines. The important factors among them are the conditions and duration of storage. As a result of studying the influence of air temperature, type of packaging, bottle position and keeping period of white wine materials on the concentration of biogenic amines, it was found that storage in a barrel does not significantly affect biogenic amines. In white wine stored n bottles in a vertical position, with an increase in temperature to 22 º� and with an increase in the duration of storage, an increase by 2 times on average in the concentration of all the studied biogenic amines was noted. In wine stored in bottles in a horizontal position, with an increase in temperature and duration of storage, an increase in the concentration of biogenic amines was also noted, but to a lesser extent than in a vertical position. During the storage of red wine materials in a barrel, the total concentration of biogenic amines decreased due to a decrease in the concentrations of phenylethylamine, putrescine and cadaverine. These biogenic amines were not detected in the samples after 60 days, which could be due to the inhibitory effect of phenolic compounds on decarboxylase enzymes. Statistical processing of the obtained experimental data made it possible to establish the dependence of the change in biogenic amines on several qualitative features (type of packaging, bottle position, temperature and storage time), which contributed to the discovery of the relationship between factors in the study of a complex model. The obtained data confirm that during the storage of wines it is necessary to control the conditions (at temperatures from 5 �C to 20 �C) established in the regulatory documentation and ensuring the quality and safety of the finished product.

Annotation

One of the most important tasks in the production of high-quality red wines is the preservation of intense color, which exposed to atmospheric oxygen, can change and acquire garnet or brown shades. The intensity of color, its shades and stability are determined by the presence of phenolic compounds in wine, among which polymeric forms of polyphenols and anthocyanins have a rich color. In addition, the phenolic substances of red wines are represented by monomeric forms, catechins and procyanidins, etc. The impact of oxygen at various stages of the technological process of making wine can have both positive and negative effects on its chemical composition and organoleptic characteristics. The purpose of this research was to study the effect of oxygen introduced at various technological stages of the preparation of wine materials. As a result of studies of the indicators of the mass concentration of oxygen and phenolic substances that cause wine oxidation, as well as the organoleptic indicators of dry red wines (production samples) made from the Cabernet Sauvignon grape variety in various geographical zones of southern Russia, significant differences have been revealed due to agro-climatic conditions of growing grapes in a particular area, as well as the grape processing technology used at enterprises. Under the conditions of the laboratory and production unit �Micro wine-making�, the possibility of using the microoxidation method both at the stage of must and pulp fermentation, and after the fermentation process (stabilization and clarification) for the purpose of deliberate oxidation of polyphenols, was shown. Based on the conducted studies, the optimal dosage of exogenous oxygen, which has a positive effect on the organoleptic characteristics of wine materials, is a concentration of 4-6 mg/dm3 both during microoxidation at the stage of must and pulp fermentation, and at the end of the fermentation of wine.

Annotation

In the process of wine production, the yeast is subjected to various stresses. This is a heat treatment during typing or the need to inactivate microflora, and the effect of low temperatures on wine processing for the prevention and elimination of dimness. If the yeast in the process of functioning are exposed to undergo similar stresses and their fermenting activity decreases. Of great interest is the study of resistance to technological stresses of new yeast strains isolated from the spontaneous microflora of grapes growing in various regions of the Krasnodar Territory. The aim of the work is to evaluate the resistance of new strains of wine yeast to the action of ethanol, sulfur dioxide, high and low temperatures. New strains of yeast isolated from spontaneous microflora of grapes were used as the object of study. As the control variant the known yeast races were selected. The stability of new yeast strains to sulfur dioxide was determined by the number of dead cells in the medium under study with various mass concentrations. The results obtained showed that the most of the strains tested are resistant to the presence of sulfur dioxide in the medium with a concentra-tion up to 200 mg/ dm3. It was found that the most of the new yeast strains of retained the ferment ability even at minus 6 ºC. It is shown that the most of new yeast strains studied have shown the greatest activity in the temperature range from 20 to 37.5 ºC. The study carried out confirm the expediency of using the new strains of wine yeast in the production of white table wines. Their technological characteristics are not worse and even superior to the known yeast races, including imported ones.

Annotation

The results of comparative evaluation of the cognac quality (including the composition of their non-volatile impurities), produced by enterprises of Krasnodar, Stavropol region and the Republic of Armenia are presented