Late summer pruning improves the quality and increases the content of functional compounds in Fuji apples

Abstract

The objective of this paper was to evaluate the effect of the time of summer pruning on the quality of Fuji apples, on the red color and functional properties, at harvest and after 3.5 months of cold storage. The treatments evaluated consisted of the control (without summer pruning) and summer pruning in December, January, and February. The percentage of fruit with more than 50% red color on the skin was 20.5% higher when summer pruning was performed later than when performed early. In general, summer pruning in January and February provided fruit with a relatively high content of anthocyanins (19 and 25.1 mg cyaniding 3-glycoside·100 g-1 FW, respectively), relatively high values of total phenolic compounds (370.1 and 438.7 mg EAG·100 g-1 FW, respectively) and total antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method (8,097.5 and 8,089.2 µMol Trolox·100 g-1 FW, respectively) in the 2017/18 season. Summer pruning did not affect fruit quality after cold storage. Summer pruning performed in January or February increased functional compounds content and improved red color, while in February it increased flesh firmness.