Abstract:

The present study investigated the influence of 1-methylcyclopropene (1-MCP) on fruit quality and reactive
oxygen species of blueberry fruit by multivariate analysis. The results showed that 1-MCP reduced the decay index, and
inhibited the increase of respiratory intensity as well as pH, glutathione (GSH) and malonaldehyde (MDA) of blueberry
fruit during storage at 1 ℃ and subsequent shelf life. The decline of H2O2 content was promoted at the earlier stage, but
effective delay was observed in fruits treated with 15 μL/L 1-MCP. Principal component analysis (PCA) showed that at the
earlier stage of storage, treatment with 5 μL/L 1-MCP significantly influenced the activities of polyphenol oxidase (PPO) and
peroxidase (POD) and the content of MDA, and affected GSH content, catalase (CAT) activity, pH and respiratory intensity during the
earlier period of shelf life. In contrast, POD activity and MDA content of fruit were mainly influenced by 15 μL/L 1-MCP at the later
stage of storage, and 5 μL/L1-MCP showed a significant impact on decay index and the activities of ascorbic peroxidase
(APX), lipoxygenase (LOX) and superoxide dismutase (SOD) of blueberry fruit during the later period of shelf life. Partial
least squares regression (PLSR) and path analysis showed that APX, LOX and SOD were the key factors to evaluate decay
index of blueberry fruit. The influences of respiratory intensity, the content of MDA and protein on decay index were
impacted by CAT activity and GSH content. In addition, the content of H2O2 was mainly influenced by the activities of SOD
and CAT, and the impact of MDA on H2O2 was manifested through GSH.

Key words: 1-methylcyclopropene, blueberry fruit, quality, reactive oxygen species, multivariate analysis