HIGH-MOLECULAR COMPOUNDS IN THE MUST OF NEW VARIETIES AND CLONES OF THE GRAPES

Abstract

The stability of grape plant to low temperatures depends on many factors, including the synthesis of proteins, polyphenols, polysaccharides, which fulfill shielding functions in the plant. A deep reconstruction of respiratory system and linked biochemical processes occur in the process of hardening, which lead to the accumulation of high-molecular compounds (especially starch) in leaves and the rod, that are been basic spare substances in the winter period. Meanwhile changes of the high-molecular connections in the juice of berries are virtually not investigated. This problem is urgent for the grape processing industries, since high-molecular connections affect the quality of finished production. Purpose of the work is to evaluate the concentrations of high-molecular connections in the juice of berries from the new types, including hybrids and the clones, which possess stress resistance to the external factors. Laboratory investigations are carried out on the base of CCU “Instrument-analytical” and of scientific center “Winemaking” FSBSO NCFSCHVW with the application of spectral method (spectrophotometers UNICO 2800, LEKI SS1207) and electrophoresis in polyacryl gel. It is established that protein concentration in the must of classical types and their clones has close values. The most higher concentration of proteins was found in the must of hybrid varieties (up to 45 mg/dm3, Bianka variety). The analysis of electrophoresis spectra testifies the heterogeneity of the molecular weights of proteins in the must of classical and hybrid varieties. The starch is identified in mature grapes of white varieties with the mass concentration of sugar 12–14 g/100 cm3 from 8.6 to 28.7 mg/dm3 and in the juice of the mature grapes of red varieties from 12.4 (to 38.6 mg/dm3 that correlates with the frost resistance of the studied varieties and clones. Starch concentration in the juice decreases with the complete technical maturity of berries. However, a starch amount was significantly smaller in a number of the varieties with average and low frost resistance. Thus, the represented results testify about a substantial change of the high-molecular compounds in the stress-resistant varieties and the clones in the comparison with the classical European types.