Biochemical composition of zoned apple varieties growing in different agrocenoses

The study of variability in the chemical composition of fruits under the influence of external factors is important both in terms of adaptation processes of fruit plants and for practical purposes. In this research, we aimed to carry out a comparative analysis of the biochemical composition of apples of such zoned varieties, as Ekrannoe (autumn ripening), Blagaya Vest’ and Krasa Sverdlovska (winter ripening). The trees were growing in different agrocenoses: in a horticultural research station (conventional extensive cultivation) and in a farm (intensive cultivation). For all the studied apple varieties, the content of insoluble nutrients (1.4–1.6 g/100 g), as well as the level of flavonoids (0.4%) and titratable acidity (1.5–1.7%) for winter fruits, were characterized by the lowest variability among other indicators. These indicators, therefore, can be considered species-specific. The level of polyphenols and antioxidant activity of winter apples can be considered variety-specific indicators for Blagaya Vest’ (0.52–0.53 mmol/l gallic acid equivalent; 71.2–75.9%) and Krasa Sverdlovska (0.65 mmol/l gallic acid equivalent; 89.7–90.1%), respectively. In all apple varieties, the contents of organic acids, vitamin C, dry matter, sugars and mineral elements showed the greatest dependence on growing conditions. In winter varieties, this list also included the sugar/acid ratio. In terms of biochemical composition, autumn-ripening apples proved to be more responsive to changes in external environmental factors.