Fruit growing
and viticulture of South Russia
Now, there is no systematic scientific knowledge about the mechanisms of specific agrochemical preparations influence the qualitative and quantitative indicators of grapes and wine products obtained from areas with high rockiness, salinity and low level of soil fertility. The article presents the results of studies on the influence of various non-root products the quality and biological value of wine products from infertile soil. The objects of research were grapes of varying degrees of bush suppression and Chardonnay wine with treatment of non-root preparations (Gumel Lux, Phylloton, Agrumax). The experience of studying the influence of foliar top dressing the productivity of a grape plant and the wine quality was laid in the Anapa Region on grape plantings grafted on Berlandieri x Riparia Kober 5BB rootstock, 2006 planting, scheme of a 3x1.5, formation of two-armed cordon Cazenava. The results of studies in 2019 showed that the treatment of bushes growing on conditionally suitable soil with the studied non-root preparations had a positive effect on the yield and technological quality of Chardonnay grapes. Variants of normally developed bushes treated with Agrumax and Phylloton 9.2 and 8.1 kg/bush, respectively, showed the best yield results. The most extractive in the experiment proved to be the wine materials with bush`s treatment of Gumel Lux, which affected the taste of these samples. In terms of organoleptic parameters, in the year of the study, the wine material from grapes processed with the Gumel Lux proved to be the best. In the experiment, there is a tendency to increase the organoleptic evaluation of white wine as the concentration of malic acid decreases. So, wine materials from Gumel Lux processing grapes were most highly rated, where the amount of malic acid was minimal 2.1-2.2 g / dm3.
The varietal characteristics of the grapes are of great importance when choosing the direction of their use. These features include the color of the grape and its flavor characteristics, the presence of coloring agents in the berry, the ripening period, etc. Features of the variety are reflected in the quality of the wine and its organoleptic properties. The physical and chemical composition of the must and wine varies greatly depending on the quality of the grape and its variety, the natural conditions of the cultivation area, agricultural technology and technology of wine preparation. So, different grape varieties have different amounts of sugar, organic acids, minerals, enzymes and vitamins in the berries. This paper presents the results of a comparative analysis of must and wines prepared from white grape varieties of interspecific origin, grown under the same conditions. The objects of research were must and wines from white technical grape varieties of the ARSRFVW breeding Tsvetochny, Donus, Platovsky, Stanichny, Hungarian varieties Crystal, Bianka, Lakhed mezesh and the Western European Aligote grape variety grown in the vineyards of the Novocherkassk department of the Experimental Field located at the SRFVW. The research was carried out on the basis of the wine-making technology laboratory and the quality control of grape and wine products laboratory of SRFVW. Experienced wines were prepared under micro-winemaking conditions according to the classical technology for dry white wines using the technological equipment for grape processing. The organoleptic analysis of the wines under the study showed that the experimental samples of wines from grape varieties of Aligote, Lakhed Mezesh and Stanichny had the brightest varietal aroma and full harmonious taste and received a high tasting score (8.7 points). It has been established that the chemical composition and organoleptic properties of wines made from grape varieties of interspecific origin largely depend on the varietal characteristics of the grapes.
An experimental study of the behavior of dilute (c < 2×10-3, mol/dm3) aqueous solutions of malic acid in the presence of strong electrolytes in the process of continuous potentiometric titration with an electrogenerated base was performed. A phenomenological model of malic acid ionization is proposed, based on the assumption that its molecular and ionized forms exist in dimeric forms in solutions, including highly diluted ones. The proof of the correctness of the proposed model was performed by solving two mathematical models and testing them experimentally. The first classical model was that malic acid under experimental conditions is in monomeric form and in the process of titration is successively ionized by two steps. The second model was based on the fact that malic acid, like its anionic forms, is in aqueous solutions in a stable dimeric form and is titrated as a four-base acid. Ionization constants are found for each of the models, and the relationship between them is described. For the second model, it is shown that the process of ionization of malic acid in the third and fourth stages is difficult due to the fact that protons are located in a ring of carboxyl groups and are titrated much more difficult than the terminal ones, since their bond with oxygen atoms is strengthened during titration. Distribution curves of the assumed molecular and ionic forms of malic acid formed during titration are constructed, and the nature of hydrogen and intermolecular bonds is discussed. The influence of malic acid the appearance of wine titration curves was revealed. The results of comparing the ionization constants of dimernic forms of tartaric, malic, citric, formic, lactic, succinic and acetic acids found by this method are presented. The results obtained are used in titrimetry methods for evaluating the quality of grape raw and wines.
A method for assessing the virulence of the apple scab pathogen on unripe fruits is offered in the paper. The necessary conditions for its effective implementation were determined experimentally. It is shown that unripe fruits should be selected from the genotypes of apple-trees, which are controlled by chemical preparations for fungal diseases, in the "walnut" development phase. Surface disinfection of fruits is not effective if they are infected with rot agents in the garden, which may prevent of further analysis. The same conditions for the preparation and selection of unripe fruits should be observed when they are further stored for deferred experiments. The method was tested on 9 monospore isolates of Venturia inaequalis isolated from the apple variety of Renet Simirenko. The manifestation of symptoms of scab lesions was characterized by the development of diffuse spots of dark olive or dark gray color with mainly superficial development of pathogen mycelium. The studied isolates of V. inaequalis characterized by different levels of virulence and aggressiveness on different genotypes of the host plant, reflecting the high heterogeneity of the pathogen population. Pathogenicity of most isolates was higher for immature fruits from the variety Renet Simirenko, showing their adaptability to the variety from which they were isolated. Slightly lower virulence and aggressiveness of isolates was observed for the Idared apple variety. Only one of the 9 isolates of the scab pathogen was virulent to the species of Malus x purpurea var pendula ornamental apple. The study carried out showed the effectiveness of the proposed method, under the conditions of fruit selection, in assessing the virulence and pathogenicity of monospore isolates of the apple scab pathogen in laboratory conditions.
The article presents the data on the study of amino acids of fresh and fermented juices from apples grown in the Krasnodar Territory. As a result of the studies revealed: the highest concentration of amino acids in fresh juices from Jonathan and Florina apples.The most of the amino acids, both fresh apple juices and fermented, were proline, alanine, asparagine and glycine. During fermentation, a change in the concentration of amino acids occurred: the concentration (on average 2 times) of proline, alanine, valine, glycine (except for juice from Florina variety) histidine, isoleucine, lysine, serine, methionine is increased; the concentration of asparagine, leucine, phenylalanine, cystine and cysteine is decreased. The identified trend is the same for all varieties of apples, which suggests that the physiological properties of the yeast race, but not the varietal characteristics of apples, mainly affected the change in the amino acids of apple juices during fermentation. It is known that aromatic components are formed from the amino acids of apple juices during fermentation. The aromatic substances of finished ciders were studied, among which the higher alcohols, volatile acids, esters, aldehydes, which determine a special bouquet and taste, were identified. Higher alcohols were represented mainly by isoamyl alcohol (more than 50 %), 1-propanol, isobutanol, 1-butanol, 1-hexanol. Volatile acids for the most part, with acetic acid, propionic, butyric, isobutyric, isovalerianic and valerianic in the juices of all apple varieties had similar values. The main component (up to 90%) of esters was ethyl acetate, the content of which in apple wine materials varied from 41.8 mg/dm3 in Golden Delishes up to 128.0 mg/dm3 in Jonathan. It has been established that the composition of aromatic substances of apple wine materials, made from apples grown in the Krasnodar Territory, is significantly affected by varietal characteristics of apples.