DYNAMICS OF ETHYLENE ACTIVITY AND CHEMICAL COMPOSITION OF GLOSTER APPLES DEPENDING ON THE COOLING MODE, TREATMENT OF TREES WITH ETHEPHON AND FRUITS WITH ETHYLENE INHIBITOR

Abstract

The article is devoted to the study of changes in the activity of ethylene emission and chemical parameters of Gloster apples during storage depending on the cooling delay, tree treatment with Ethephon and apple treatment with 1-MCP. Research in the storage seasons 2012–2013 and 2013–2014 at Uman National University of Horticulture. Fourteen days before the expected harvest, trees of late-winter cv. Reinette Simirenko were sprayed with Ethephon (ethrel, 180 g/ha) with the addition of NAA to prevent fruit drop (potassium salt of α-naphthylacetic acid, 20 g/ha); control areas were sprayed with water. The apples were collected in the stage of early harvest maturity. On the day of harvest, one part of the fruits was cooled at a temperature of 5±1 °C and a relative humidity of 90–95% and the next day treated with 1-MCP (SmartFresh, 0.068 g/m³). The other part of the apples was exposed for three days at a temperature of 16±1 °C with subsequent cooling to 5±1 °C and treatment with 1-MCP. The fruits were stored for six months in a KHR-12M refrigerating chamber at a temperature of 2±1 °С and a relative humidity of 90–95%. During harvesting, after two, four and six months of storage, ethylene activity, dry soluble solids, titratable and ascorbic acid content were determined. It has been established that with pre-harvest tree treatment with Ethephon and delayed fruit cooling, the ethylene activity of fruits during six-month storage increases by 32 times, and without treatment with Ethephon this indicator increases by 18 times. With immediate cooling, this figure increases by 26 and 16 times, respectively. At the same time, the ethylene activity of apples treated with 1-MCP does not exceed 4.2 μl/kg·h, with the exception of fruits treated with Ethephon and cooled with a delay – 7.6 μl/kg·h. During the first four months of storage, the highest content of dry soluble substances was found when trees were treated with Ethephon and during two months – with a three-day cooling delay. Post-harvest fruit treatment with 1-MCP slowed down the decrease in the content of dry soluble substances and it provided a 1.25% higher content at the end of storage. The lack of tree treatment with an ethylene producer and immediate fruit cooling after picking ensure a higher content of titratable and ascorbic acids in the fruits during storage. Post-harvest treatment of apples with 1-MCP provides a 1.5-fold higher content of titrated acids, including 1,7-fold higher content of ascorbic acid. During storage, the dependence of the content of titrated and ascorbic acids on the ethylene activity of apples is inversely linear.