RIPENING CONTROL OF PAPAYA (Carica papaya L.) FRUITS WITH 1-METHYLCYCLOPROPENE AND 2-CHLOROETHYL PHOSPHONIC ACID

Abstract

In order to find an effective strategy to control papaya (Carica papaya L. cv. ‘Maradol’) ripening, fruit responses to the application of 300 nL L^-1 of the inhibitor 1-methylcyclopropene (1-MCP) and 2.5 g L^-1 of the inducer 2-chloroethyl phosphonic acid (ethephon) were evaluated. Fruits harvested at 1/4 ripening stage were treated with: control, 1-MCP, ethephon, 1-MCP+ethephon and ethephon+1-MCP; in combined treatments, the second compound was applied 24 h after the first treatment. Fruits were stored in simulated marketing conditions and postharvest quality was evaluated during 9 d. 1-MCP treatment inhibited ethylene production and fruit softening, decreased significantly the respiratory rate, color development in peel and flesh, and the content of organic acids in fruits. Three days after application, ethephon accelerated color changes and caused a loss of 80 % on fruit firmness. Fruits of the treatment 1-MCP+ethephon did not lose firmness, thus suggesting that 1-MCP’s action in suppressing fruit softening was irreversible. An alternative to control papaya ‘Maradol’ ripening was the treatment ethephon+1-MCP, since the 1- MCP application delayed the ripening changes induced by ethephon.