Development of a 1-methylcyclopropene package delivery system to control tomato ripening

1-methylcyclodextrin (1-MCP) was used to prolong the freshness of tomatoes during postharvest storage. The effect of storage temperature and 1-MCP treatment conditions on the ripening process of tomatoes was evaluated. Change in two major tomato pigment (chlorophyll and lycopene) contents in tomatoes was also investigated. Sorption behavior for the 1-MCP/adsorbing agents was studied using inverse gas chromatography. The specific retention volume and various thermodynamic parameters relating to adsorption of 1-MCP on the adsorbing agents were calculated. Adsorption and 1-MCP release studies from the adsorbing agents in the sachet system were conducted to evaluate delivery of the 1-MCP gas to the tomatoes under the environmental conditions within the package.; Skin color, firmness, fruit weight, and ethylene production were used as quality indicators for the stored tomatoes. Total chlorophyll and lycopene contents in tomatoes were quantified using a specific extinction coefficient method. Sorption isotherms of 1-methylcyclopropene (1-MCP) on silica gel, Tenax-TA, and activated clay were determined at low sorbate concentration. Sachets made from Tyvek®, paper, LDPE, and PVA materials were fabricated to contain silica gel and activated carbon. The 1-MCP release study was performed using a closed system under two different environmental conditions, dry air (0%RH) and 90%RH. The partitioning of 1-MCP between the gas/polymer matrix was determined for several adsorbing agents, and in sachet materials to estimate the adsorb ability of 1-MCP in dry air at 23°C. The water and 1-MCP permeability of the sachet pouch film were measured.; Once-a-day 1-MCP treatment at 10°C was very effective in retarding changes in the skin color of the tomatoes. Exposure of tomatoes to 1-MCP gas at 10°C, using a once-a-day method was the most effective in delaying chlorophyll degradation and lycopene synthesis. The sorption isotherms followed Henry's law, and behaved according to the binding site theory. Silica gel had a much higher number of binding sites for 1-MCP, compared to Tenax-TA and activated clay agents. PVA sachets containing silica gel indicated slow release of 1-MCP. The amount of 1-MCP released from the PVA sachet containing silica gel at 90%RH was larger than the amount of 1-MCP released at dry air condition.; The results showed that combination of 1-MCP treatment with low storage temperature was very effective in delaying color change in tomatoes. PVA sachets containing silica gel have potential use for slow release of 1-MCP from the experimental results in a closed system. Delivering the 1-MCP gas to the tomatoes, from the sachet containing an adsorbing agent may help maintain the freshness of tomatoes during postharvest storage.