Retention of green colour of tomatoes marketed as a green vegetable at ambient conditions in Cambodia with modified atmosphere storage and fumigation with 1-methylcyclopropene (1-MCP)

Introduction - Unripe, green tomatoes are marketed in Cambodia but have a short market life due to rapid ripening under tropical temperatures and the unavailability of refrigerated technology. This paper examines the potential for storage in modified atmospheres (MA) and/or fumigation with 1-MCP to extend the green life of tomatoes held at ambient tropical conditions. Materials and methods - Laboratory studies were conducted in Australia at 25 degrees C with 'Neang Pich' tomatoes to determine the optimum conditions for fumigation with 1-MCP and controlled atmospheres (CA) to delay loss of green colour. A commercial polyethylene film bag was identified to generate the desired atmosphere and field trials with the bag were then conducted in Cambodia under ambient conditions (25 to 35 degrees C) to determine the extension in green life of 'Mongal' and 'Plai Bi' tomatoes. Results and discussion - Maximum retention of green life was achieved either by fumigation with mu L L(-1)1-MCP for 1 h, or by storage in 5% oxygen and 10% carbon dioxide, but no cumulative benefit combining the two treatments was observed. MA storage was considered the most viable technology in Cambodia and field trials in Cambodia found the green life increased from the 2-3 days when held in air to 7-9 days in the MA bag. Conclusions - Use of MA with a plastic bag offers an easy to implement technology for Cambodian farmers to delay the loss of green life of tomatoes and thereby greatly increase marketing options.