Applications of 1-methylcyclopropene concentrations and timing in relation to sunlight-related core browning in ‘Bartlett’ pears after extending regular-air storage

Abstract

Core browning (CB) is a crucial physiological disorder that occurs in ‘Bartlett’ pears after excessive storage. Furthermore, environmental factors such as sunlight exposure cause serious related disorders during storage. 1-methylcyclopropene (1-MCP) positively delays the development of disorders, but results in poor eating quality at retail. Therefore, the primary purpose of this study was to evaluate whether sunlight exposure impacts the development of CB in ‘Bartlett’ pears and to develop optimal postharvest 1-MCP strategies for the pear industry to extend the fruit’s lifespan and deliver desirable eating quality to consumers that prefer melting texture. Over the course of a three-year evaluation, sunlight-exposed (SE) pears consistently displayed a higher CB index than the control and non-exposed (NE) pears after 150 d of regular-air (RA) storage at − 1.1 ± 0.5 °C plus 5 d at 20 ± 0.5 °C. The rapid development of CB was facilitated by decreases in ethylene production rate (EPR), peel chlorophyll content (PCC), and titratable acidity associated with increases in malondialdehyde and soluble o-quinones. Applying 0.15 and 0.3 μL L−1 1-MCP after 15 d of harvest completely protected the fruit from CB for up to 150 d of RA storage. However, these treated pears did not ripen. Lowering the 1-MCP concentration to 0.075 μL L−1 and postponing treatment to 60 d after harvest could control the CB index in the 1.53–2.33 range with a normal ripening process. For SE pears, the use of 0.15 μL L−1 1-MCP applied after 60 d of harvest reduced the CB index to 1.63 without impairing ripening capacity. It was difficult for the pear industry to monitor the EPR of 1-MCP-treated pears over the entire storage period. However, when the PCC of the treated pears fell to 0.4–0.5 IAD after 5 d of ripening, these pears could recover their ethylene generation capacity and softening behavior. Overall, the 0.15–0.075 μL L−1 1-MCP applied after 60 d of harvest provided great benefits in delaying CB development, improving storability, and retaining ripening capacity in SE ‘Bartlett’ pears following the prolonged RA storage.