Delaying papaya fruit ripening by 1-MCP

Abstract

Papaya fruit have a limited shelf life due to rapid fruit softening. Preclimacteric (PC) and ripe (R) ‘Sunrise Solo’ papaya fruit were treated with 1 to 10 ppm 1-methylcyclopropene (1-MCP), an ethylene action inhibitor, at 20 °C for 12 to 18 h, and the fruit were stored at 20 °C. Firmness, skin color, respiration and ethylene rate, brix, and electrolyte leakage were monitored during storage for 12 days at 20 °C. Both PC and R fruit fumigated with 1-MCP retained firmness longer than control fruit although the response to 1-MCP was greater in PC fruit. After 12 days, PC fruit treated with 1-MCP had significantly higher mesocarp firmness (14 N) than control fruit (6.1 N) (P = 0.005). R fruit treated with 1-MCP also had higher mesocarp firmness (4.7 N) than controls (3.9 N) (P≤ 0.05). Ethylene production was significantly lower in PC fruit treated with 1-MCP than fruit without 1-MCP (P ≤ 0.001). Ethylene production by PC control fruit reached a maximum of 1.81 µL·kg–1·h–1 on day 5, at which time ethylene production in MCP-treated fruit was 0.38 µL·kg–1·h–1. Maximum ethylene production in MCP-treated fruit (1.38 µL·kg–1·h–1) was observed after 10 days of storage. 1-MCP treated PC fruit had lower electrolyte leakage than non-treated ones (P ≤ 0.005). The total electrolyte leakage of 1-MCP treated and non-treated PC fruit was 18.9% and 20.7%, respectively, on the last day of the treatment. PC fruit treated with 1-MCP maintained green skin color 2 more days. On the basis of firmness, skin color, and overall appearance, 1-MCP extended the shelf life of papaya fruit 2–3 d at 20 °C. Current experiments are addressing the effect of MCP on the performance of fresh-cut papaya fruit.