Fruit growing
and viticulture of South Russia

Annotation

A comparative analysis of wine and grape distillates and wine and grape alcohols obtained by rectification from bulk wine and yeast sediments from Kristall grape variety was carried out. The process of distillation of bulk wine and yeast sediments was conducted in two stages. The process of primary distillation with the production of crude alcohol was carried out in a distiller, and secondary distillation with the production of alcohols � in a small rectification unit with electric heating. Obtaining crude alcohol from yeast sediments was conducted using a steam generator as a source of live steam. It was found that during the distillation (primary distillation) of bulk wine and yeast sediments into crude alcohol, the volume fraction of ethyl alcohol in the raw alcohol depended on the volume fraction of ethyl alcohol in the initial distilled raw material. In distillates and grape alcohols from yeast sediments, the content of esters is significantly higher than in wine distillate and alcohol. Wine alcohol contains fewer volatile components compared to grape alcohol from yeast sediments. Rectification made it possible to significantly reduce the concentration of unwanted volatile components (fusel alcohols � isobutanol, isopentanol, and others). It was found that the content of esters and higher alcohols during distillation varies depending on the volume fraction of ethyl alcohol in the distillate. At a lower volume fraction of ethyl alcohol of wine or grape alcohol (less than 95% vol.), the content of undesirable higher alcohols in the rectified alcohol increases. A 2-fold increase in the content of methanol in the distillate and alcohol from yeast sediments was revealed, which requires additional research to optimize the technology for obtaining safe grape alcohol from yeast sediments.

Annotation

Organic acids are the main indicators of the chemical composition of grapes and wine, participate actively in the processes occurring in the wine formation, determine the acidic properties and taste of wines, the stability of products to turbidity, the intensity of redox processes is affected, and they are the markers of the authenticity of wines. The results of study of the behavior of one of the main grapes and wine acids � malic acid are given in the paper. It is characterized by a sharp taste and can be transformed into lactic acid during biological acid reducing of wines. We analyzed the aqueous solutions of malic acid in concentrations from 0.549 103 to 1.792 103 mol / dm3 in the presence of strong electrolytes during continuous potentiometric titration with a coulometrically generated base in order to determine its effect the integral characteristics of wine quality. The titration of solutions was carried out against a background of 1.0 mol / dm3 KCl to maintain the constant ionic strength and conductivity in a setup consisting of a diaphragmless cell with generator and indicator electrodes. It has been hypothesized that in highly diluted solutions, malic acid and its anionic forms are in dimeric form. An analysis of experimental data and its theoretical interpretation show that malic acid is titrated as tetrabasic acid, and its existence in a stable dimeric form is confirmed. The nature of hydrogenic and intermolecular bonds is discussed. Critical points of malic acid solutions were found using the titration curves (�, pH0, pH1, t1, t2 etc.) whose values can be used for the integral quality control of wines. It is proposed to use the results obtained to improve methods for assessing quality and identifying the grape raw materials and the wines.

Annotation

The issues of global geographical identification of wine products are considered. It has been found that for most modern studies, the use of chemometric processing of data obtained by promising methods for controlling macro- and microelements in wines is characteristic: atomic absorption spectroscopy, atomic emission spectroscopy, mass spectrometry with inductively coupled plasma and atomic emission spectroscopy with inductively coupled plasma. Analysis of macro - and microelements of wines from different countries of the world showed that a large variety of elemental composition of wine products and significant variability caused by technological treatments require the use of modern mathematical processing methods to establish the relationship of the composition of wines with a certain terroir. It is shown that on the basis of analysis of studies of the distribution and relationship of the content of micro and macro elements in wines and soils on which the corresponding grape varieties were grown, can be used to establish the geographical identification of wines. Studies aimed at assessing the relationship of the geographical location of the plots and cultivated grape varieties were carried out according to the correlations between the content of a number of macro- and microelements in wine and soils and the main parameters (grape variety, crop year). The results of the assessment of the relationship between individual samples of wines and soils using correlation, cluster analysis, the �random forest� algorithm and multi-label classification allowed us to evaluate the relationship of the geographical location of the plots and cultivated grape varieties with the content of elements and their pairwise ratios in the wines. Rb, Al, and Na were selected as markers for variety identification for the first year of research. Positive results for Cabernet Sauvignon, Riesling and Pinot Noir are obtained. Applying of selective indexes based on cross-validation allowed to reduce a set of significant indicators to 4: Ca, Ca / Sr, Sr and Ca / Al.

Annotation

The results of studying the qualitative composition and quantitative content of amino acids in red table wines made from Cabernet-Sauvignon grape variety using S. cerevisiae Y-4270 and Derbentskaya-19 strains are presented. It was found that the concentration of amino acids in wine samples was influenced by the individual characteristics of the yeast strains applicated in the preparation process, and certain climatic parameters in the region, which are different in 2019 and 2020 � the amount of annual precipitation and the insolation intensity. In all variants of wine, there was a significant variation in both the sum and the concentrations of individual amino acids. The highest content of free amino acids was found in the 2020 yield sample prepared using the D-19 strain. It was found that proline prevails in all variants; as a percentage of the total amount of amino acids, its content in all variants is approximately the same, however, in mg/dm3 , these indicators are several times higher in the samples of 2020. In the wine obtained using the new strain of S. cerevisiae Y-4270, the concentration of proline is 2 times less than in the second variant (S. cerevisiae D-19), which affected its organoleptic assessment. As a result of a comparative analysis, it was shown that the total content of essential amino acids in the studied wines did not exceed the level of 77.31 mg/dm3 . Formed during fermentation mainly from amino acids, substances that enhance the fullness of the aroma, influenced the quality of wine materials. Obviously, the optimal concentration of free amino acids in the samples studied by us contributed to the formation of high organoleptic characteristics of dry red wines.

Annotation

Grape berries, which contain organic substances, vitamins, amino acids, minerals, aromatic substances, have valuable taste and nutritional properties. An important source of biologically active substances are the pulp, skin and seeds of grape berries containing a significant amount of essential components. The purpose of the work is to determine the biochemical parameters: biologically active, mineral and aroma-forming substances in the structural elements of Narma and Rkatsiteli grape varieties cultivated in Dagestan. A capillary electrophoresis system was used to determine vitamins, composition and number of cations. The research was carried out on the device �Kapel 104T�, RF, NPF LUMEX. The aroma-forming components in the experimental samples were identified using a gas chromatograph �Crystal 2000M� (RF). The mass concentration of antioxidants was measured on the device TSVET YAUZA 01-AA, (RF). The total amount of vitamins and vitamin-like substances in the autochthonous Narma variety was: in the pulp - 0.7123 mg/dm3 , in the skin � 3.4101 mg/dm3 and in the seeds � 3.7827 mg/dm3 . The total concentration of mineral elements in the skin of the studied grapes (Narma �33,2 mg/dm3 , Rkatsiteli � 20,8 mg/dm3 ) is higher than in the pulp and seeds. Significant total amounts of antioxidants were found in the seeds of the studied grapes: Narma � 6.71 mg/dm3 , Rkatsiteli � 8.51 mg/dm3. High concentrations of aroma-forming substances were determined in the skin and seeds of berries of the Narma variety � 376.26 and 253.71 mg/dm3 , and in the Rkatsiteli variety the content of these compounds was 82.34 and 91.00 mg/dm3 , respectively. The research results complement the biochemical characteristics of Narma and Rkatsiteli grape varieties, which can be successfully used as raw materials in the food industry to enrich food with biologically active, mineral and aroma-forming substances.