The purpose of the research was to evaluate the mechanism of action of the preparation ‘Fitomag’ in the postharvest period on the maturation-senescence processes of the fruits of the most widespread cultivars of apples ( ‘Idared’, ‘Golden Delicious’, ‘Florina’, and ‘Reinette Simirenko’), cultivated under pedoclimatic conditions in the Republic of Moldova. Several parameters have been studied, some of which (titratable acidity, firmness, weight loss, the amount of healthy fruits) are presented in this article. Fruits were collected in harvesting maturity and treated with 1-MCP at the recommended dose (‘Fitomag’, 0.44 g·m-3). Apples were stored for five months at the temperature of 1°C and humidity 85–90%. As a result of treating the fruits with the Fitomag preparation, the processes of biodegradation of the biochemical compounds have slowed down, the fruits have retained their firmness, aroma, crispiness, juiciness and reduced the degree of fungal diseases and physiological disorders. Research has shown that postharvest use of Fitomag treatments is promising for maintaining fruit quality and can compete with the method of storage under controlled atmosphere.