Photos courtesy of the author
Honolulu, HI: A new study by the University of Hawaii, Manoa, reveals the significant impact of 1-methylcyclopropene (1-MCP) and harvest maturity on the postharvest storage life of the 'Ma'afala' breadfruit. This research investigated how the application of 1-MCP, a synthetic plant growth regulator, interacts with different stages of harvest maturity to influence the storage longevity and quality of the breadfruit.
Breadfruit (Artocarpus altilis) is typically consumed as a mature, unripe fruit. As a climacteric fruit, breadfruit undergoes a significant increase in respiration and ethylene production, continuing to ripen after being detached from the tree. The climacteric peak (fast period of ripening when fruits develop flavor and aroma) corresponds with the fruit's complete softening. This softening makes the fruit prone to compression damage and difficult to handle, making it a challenge for marketers to transport it before it reaches this stage. The softening and climacteric peak mark the end of the breadfruit's marketable period.
The ethylene response inhibitor 1-MCP is used to delay ripening of other climacteric fruit, but its effects on breadfruit had not been studied. 1-MCP inhibits ethylene binding and slows ethylene-facilitated ripening. Responses to 1-MCP vary widely among fruit types, commonly resulting in reduced ethylene production, lower respiration rates, delayed softening, and delayed loss of greenness and organic acids. The effectiveness of 1-MCP depends on factors such as cultivar, dosage, treatment temperature, fruit maturity, ripening stage, and interactions with fruit disorders, suggesting that its impact on the maintenance of breadfruit quality may be condition-specific.
The effect of 1-MCP on delaying the climacteric respiratory peak and softening of breadfruit confirmed that these are ethylene-mediated processes in breadfruit. Ethylene was previously shown to be involved in breadfruit ripening by the observation of a temporary increase in the ethylene-forming 1-aminocyclopropane-1-carboxylic acid oxidase as breadfruit flesh softens and yellows.
With knowledge of optimal harvest maturity and the benefits of 1-MCP, farmers can make informed decisions to maximize the postharvest life of their produce, reducing losses and increasing profitability. Longer shelf life translates into wider distribution opportunities, allowing breadfruit to reach distant markets without compromising quality. Finally, the extended freshness means that consumers can enjoy high-quality breadfruit with better texture and taste.
According to the author, "We have been interested for a number of years in how to extend the postharvest life of breadfruit. Breadfruit has great potential for expanded production and marketing but is limited by its short postharvest life and its sensitivity to storage at chilling temperatures. An earlier attempt to use 1-MCP did not have any significant effect, although ethylene was associated with breadfruit ripening. When we secured funding for research on this orphan crop, a reliable source of fruit, and an interested graduate student, Ben Wiseman, the project took off.
Dr. Paull is a professor and researcher in the Department of Tropical Plant & Soil Sciences, College of Tropical Agriculture & Human Resources, University of Hawaii at Manoa. His research interest is in plant physiology and its relevance to the postharvest physiology, handling and storage of tropical fruits, vegetables and ornamentals
