1-Methylcyclopropene extends postharvest quality of grape tomato fruit harvested at advanced ripeness stage

Abstract

Box 110690, Gainesville, FL, 32611-0690 Grape tomato fruit (Lycopersicon esculentum Mill., cv. Santa) harvested at light-red and full-red stages, were randomized into rigid, vented clamshell containers (473 mL volume; n = 20), treated with 1 µL·L –1-methylcyclopropene (1-MCP) for 24 h at 20 °C and stored at 20 °C. Light-red harvested fruits treated with 1-MCP had 56% lower respiration rate (3.8 mL/kg/h) than untreated fruits on day 1of storage; by day 7 these rates had converged at about 2 mL/kg/h. Ethylene production from light-red harvested tomatoes treated with 1-MPC was 24% lower (2.3 µL/kg/h) than untreated, with rates converging by day 11. For full-red harvested tomatoes, 1-MCP had similar effects on respiration and ethylene production, although convergence occurred earlier, by day 5. Fruit harvested at light-red stage had lower soluble solids content (4.3%) than fruit harvested at full-ripe stage (5.5%). In a second test, full-red harvested tomatoes were treated with several combinations of 1-MCP concentrations (µL·L –1) and exposure times (h), namely 1/24, 5/6, 5/12, 25/6, 25/12, 50/6 or 50/12, and stored at 20 °C. There were no treatment effects on surface and locular gel hue angle (38 and 57 degrees, respectively), pulp soluble solids content (6.6%), pH (4.3), total titratable acidity (0.65%) or firmness. Marketable life (>15% of fruits soft, decayed and/or shriveled) for untreated and treated tomatoes was 6 and 7 d, respectively. In a third test, full-red harvested tomatoes were treated with 1 µL·L –1-MCP for 24 h at either 13 or 20 °C, stored for 4 d at 13 °C then transferred to 20 °C to simulate commercial practices. Marketable life for 1-MCP untreated and treated tomatoes was 7 and 8 d, respectively; treatment temperature had no effect