Effects of controlled atmosphere, 1-MCP and dynamic controlled atmosphere on the metabolism and firmness of ‘Nicoter’ apples

In commercial apple storage, temperature and atmosphere are adjusted to inhibit ripening and respiration in order to maintain fruit quality.
Apple cultivars show different sensitivities to reduced storage temperatures and extremely low oxygen concentrations.
The purpose of this study was to describe the effect of controlled atmosphere (CA), 1-MCP treatment and dynamic controlled atmosphere (DCA) based either on chlorophyll fluorescence (CF) or respiratory quotient (RQ) on the metabolism and flesh firmness maintenance of ‘Nicoter’ apples after harvest and 9 months of storage plus 7 days of shelf life.
Long-term storage increased activity of ACC oxidase in all treatments with both DCA methods displaying lower measurements than CA and CA + 1-MCP. Storage under CA resulted in high ethylene production and showed the largest loss of flesh firmness.
Overall, 1-MCP application in CA or DCA methods leads to firmness retention.
After storage, fruit degraded glucose and accumulated fructose when compared to harvest, regardless of the storage condition.
Fruit stored under CA + 1-MCP, DCA-CF and DCA-RQ 1.3 accumulated large quantities of sorbitol, presumably as a coping mechanism to stress caused by extremely low oxygen concentrations or 1-MCP treatment.
How 1-MCP application under CA presents a stressful environment for ‘Nicoter’ apples needs to be further evaluated.
The different storage conditions had a significant influence on acid content.
Fruit stored under DCA-RQ 1.3 had higher concentrations of Pyruvate, Malate and Succinate compared to CA and CA + 1-MCP. All treatments led to a significant loss of malate when compared to harvest, while both DCA methods successfully conserved pyruvate content.
Succinate increased under DCA-RQ 1.3. In general, ‘Nicoter’ apples appear to be sensitive to extremely low oxygen concentrations during storage.

IV International Symposium on Horticulture in Europe – SHE2021

D.A. Neuwald, F.R. Thewes, F. Büchele, A. Brackmann, J.N. Wünsche, B.P. Espíndola, C.K. Sautter

Malus domestica, ‘Nicoter’, CA, DCA, ethylene, sugar metabolism, sorbitol

https://doi.org/10.17660/ActaHortic.2021.1327.72