Effect of stepwise humidity change on the release rate constant of 1-methylcyclopropene (1-MCP) in a cyclodextrin inclusion complex powder

The release behaviour of 1-methylcyclopropene (1-MCP) is important during postharvest treatment of fruit and vegetable. Effect of humidity and temperature on the release rate of 1-MCP in an α-cyclodextrin (α-CD) inclusion complex powder were investigated on the potential of direct application of 1-MCP inclusion complex powder and developing of functional packaging. The aim of this research was to study the release behaviour of 1-MCP from an inclusion complex powder under a stepwise humidity change. 1-MCP release experiments were conducted using a dynamic vapour sorption (DVS) system at different temperatures (40, 50, and 60 °C) with stepwise humidity changes (20% RH for 2 h to 40, 50, 60, and 80% RH for 2 h, respectively). The results showed that the release rate constant of 1-MCP from inclusion complex powders increased linearly with moisture concentration at 40, 50, and 60% RH. The highest release rate constant of 1-MCP was 1.5 × 10−3 s−1 for 80% RH at 60 °C. The activation energy at the highest humidity condition of 80% RH was 27.5 kJ/mol. The release rate constant of 1-MCP from the inclusion complex powders was well correlated with a first-order release rate equation. The results obtained showed that 1-MCP inclusion complex in α-CD has a potential as an active compound that could be incorporated into active packaging systems where storage condition below 60% RH is needed.