Dependence of the content of ascorbic acid in apples at the beginning and at the end of storage on the hydrothermal conditions of the growing season

Abstract

The degree of fruit maturity varies from year to year, depending on hydrothermal conditions, and therefore it is impossible to focus only on the calendar dates of harvesting due to their seasonal changes. The keeping capacity and quality of apples have variety specificity and depend, among other factors, on the meteorological conditions of the growing season. The analysis of the quantitative content of ascorbic acid (AA) in the fruits of five new columnar scab immune apple varieties – Vostorg, Zvezda Efira, Poezia, Priokskoye and Sozvezdiye at the beginning and at the end of storage in different years (2012, 2014, 2016, 2018) showed the closest dependence of this parameter on the conditions of humidification of the active growing season (hydro-thermal coefficient (HTC)). The dependence of the AA content in fruits on the hydrothermal coefficient was approximated by the second-order parabola equation. Certain regularity was revealed in the content of AA in fruits depending on HTC. The parabolic curve, reflecting the maximum calculated AA content, increases to maximum values at HTC – 0.85-0.90 at the beginning of fruit storage and 0.79-0.89 at the end of storage. Under droughty conditions, the dependence curve decreases. The comparison of the experimental data with calculated data showed that the correlation relations between them had values from 0.61 to 0.88 at the beginning of storage and 0.40-0.99 at the end. The calculated data can be interpolated, and it makes sense to use HTC as one of the predictor parameters of fruit quality during harvesting and potential keeping capacity of fruits.