Inhibiting tomato ripening with 1-methylcyclopropene

The capacity for I-methylcyclopropene (1-MCP) to inhibit color change and firmness loss and alter aroma profiles for tomato (Lycopersicon esculentum Mill.) fruit was evaluated as a function of 1-MCP concentration, multiple and continuous applications, and stage of ripeness. In addition, the relationship between external and internal fruit color and firmness was determined. 1-MCP reduced the rate of red color development in fruit of all stages of ripeness. A single application of 1-MCP delayed color development by approximate to6 days. A second application of 1-MCP 10 days after first treatment additionally delayed color development of mature green fruit by another 8 to 10 days. Continuous 1-MCP application completely inhibited color development of breaker and half-ripe fruit for the duration (34 days) of application, but only partially inhibited firmness loss. When fruit at 50% color development were treated with 1-MCP, gel color development tended to lag behind the external fruit color change compared to nontreated fruit. Some aroma volatiles were affected by 1-MCP applied at the mature green and breaker stages, but the effect was relatively minor; 1-MCP did not affect sugar or titratable acid levels in these fruit. Collectively, the data indicate 1-MCP caused minor shifts in the quality attributes of locule color, aroma, and firmness relative to external color, which may reduce the value of this treatment, but benefits accrued by slowed firmness loss and color development may afford sufficient compensation to make 1-MCP application commercially feasible.