Abstract
BACKGROUND: 1‐methylcyclopropene (1‐MCP) has been shown to suppress ethylene response and extend the post‐harvest shelf life and quality of several fruits and vegetables. In the US and Canada, the label treatment dosage for apples is 1.0 and 0.6 µL L^−1^, respectively. It has been demonstrated that wood and corrugated fiberboard materials, commonly found in apple storage facilities, absorb 1‐MCP. Losses of 1‐MCP during the exposure period might compromise the effectiveness of the product. The effects of type of material (corrugated fiberboard and high density polyethylene), relative humidity (50%, 80%, and > 95%), ratios of mass of packaging material (kg) per unit volume (m^3^) of airspace in a treatment chamber, and initial concentration of 1‐MCP (10 and 20 µL L^−1^) on the available concentration of gaseous 1‐methylcyclopropene (1‐MCP) in an enclosed chamber were studied.
RESULTS: The concentration of 1‐MCP declined in the presence of the materials tested, but the rate at which 1‐MCP gas was removed from the chamber headspace differed markedly. The average percentage loss for HDPE was between 10 and 12% at all conditions tested, while for corrugated fiberboard it ranged from 12 to 94%.
CONCLUSIONS: The concentration of 1‐MCP at any time, t, follows an exponential decay behavior. For corrugated boxes, the rate at which 1‐MCP is removed increased up to 10‐fold as the relative humidity increased from 50 to 80%. The 1‐MCP depletion rate doubled as the ratio of material was increased from 4 to 8 kg of corrugated fiberboard m^−3^ air. An increase of initial concentration from 10 to 20 µL L^−1^ reduced the rate by half. This trend was also observed for HDPE boxes. Copyright © 2009 Society of Chemical Industry