Postharvest quality of grape tomatoes treated with 1-methylcyclopropene at advanced ripeness stages

Grape tomatoes (Lycopersicon esculentum Mill. ‘Santa’) harvested at light-red (>90% color) and full-red stages were treated with 1 µL·L–1 1-methylcyclopropene (1- MCP) for 24 hours at 20 °C and stored at 20 °C. After 1 day of storage, fruit harvested at light-red stage treated with 1-MCP had a 56% lower respiration rate than untreated fruit. By day 7, respiration rates of the two treatments had converged at about 2 mL·kg–1·h–1. Ethylene production of light-red stage tomatoes treated with 1-MPC was 24% lower than untreated during storage, with rates converging by day 11. For fruit harvested full-red, 1-MCP had similar effects on respiration and ethylene production, although convergence occurred earlier, by day 5. Subsequent tests were conducted only with fruit harvested at full-red stage, since fruit harvested at the light-red stage had lower soluble solids content (4.3%) than fruit harvested at the full-red stage (5.5%). Several combinations of 1-MCP concentrations and exposure times were applied at 20 °C: 1 µL·L–1 for 24 h, 5 µL·L–1 for 6 or 12 h, 25 µL·L–1 for 6 or 12 h, and 50 µL·L–1 for 6 or 12 h; following the respective pretreatment fruits were stored at 20 °C. 1-MCP pretreatment extended marketable life by 1 d, irrespective of pretreatment regime, where untreated and pretreated fruit remained marketable (