Fruit Maturity and 1-Methylcyclopropene Influence Quality Retention and Chlorophyll Degradation in ‘Golden Ball’ Apples During Cold Storage

Fruit quality and skin color are key determinants of apple marketability. This study investigated the effect of fruit maturity and 1-methylcyclopropene (1-MCP) treatment on quality attributes and chlorophyll (Chl) degradation in ‘Golden Ball’ apples during long-term cold storage. Apples were harvested at two maturity stages—low maturity (LM, starch pattern index [SPI] 6) and high maturity (HM, SPI 8)—based on Cornell’s SPI method, and subsequently treated with 1-MCP (LM+1-MCP and HM+1-MCP) before storage. At harvest, HM fruits exhibited significantly higher soluble solid content (SSC), titratable acidity (TA), red coloration (a*), index of absorbance difference (IAD), and respiration rate compared to LM fruits, although ethylene production, internal ethylene concentration (IEC), and firmness were not affected by maturity stage. During storage, HM fruits showed a more rapid decline in firmness, SSC, and TA, along with increased IEC, respiration rate, and a* value, and reduced IAD and Chl contents. Consistently, expression levels of genes associated with ethylene biosynthesis and Chl degradation were also higher in HM fruits. However, application of 1-MCP effectively suppressed ethylene production and respiration, thereby slowing the deterioration of fruit quality and Chl degradation in both maturity groups. Notably, the LM+1-MCP group demonstrated stronger ethylene inhibition and retained higher Chl levels than the HM+1-MCP group. Overall, the findings demonstrate that applying 1-MCP at the LM stage is a superior strategy for maintaining the postharvest quality of the apples.