Chen, Xi. Development of liquid 1-methylcyclopropene delivery formulations for modifying ethylene response of fresh produce. Retrieved from https://doi.org/doi:10.7282/T3571DZZ
DescriptionThe objective of this dissertation is to develop 1-methylcycopropene (1-MCP) liquid formulations for fresh produce, to manage the undesirable effects of ethylene. The formulation can be used as a sprayable formulation for pre-harvest application, or made into a capsule for post-harvest application. The formulation consists of (1) a cyclodextrin based material (α or modified β-cyclodextrin) as the encapsulant for 1-MCP, (2) a moisture blocking formulation (e.g. polyol/hydrocolloid formulation) to further enclose 1-MCP, and (3) a water based solution to facilitate the release of the formulation. To develop this formulation, five sub-objectives were achieved. 1. Synthesis and characterization of modified β-cyclodextrin 2. Encapsulation of 1-MCP into modified β-cyclodextrin and quantification of 1-MCP inclusion ratio 3. Stabilization of the complex as liquid formulation using materials such as polyol/hydrocolloid blend and mineral oil 4. Evaluation of the sprayability of the liquid formulation and release of 1-MCP 5. Evaluation of biological efficacy of the 1-MCP released from the liquid formulation The key conclusions of this dissertation are as follows. • Modification of β-cyclodextrin was optimized to yield 90-95% powder. The powder has better modified pore size and particle size, which are more favorable for 1-MCP encapsulation than β-cyclodextrin. • 1-MCP can be encapsulated under 0.1 atm headspace concentration both using solid-gas method (inclusion level 0.5%) and in solution-gas method (inclusion level 0.3%). • A stable formulation was developed consisting of mineral oil, HPC and polysorbate for both α and modified β-cyclodextrins. After 30 days of storage at room temperature, more than 90% of 1-MCP can be retained in the formulation. After 14 days of storage at 55°C (equivalent to 1 year storage at room temperature), more than 80% of 1-MCP can be retained in the formulation. • After hydration using different concentrations of xanthan gum, liquid formulation can be sprayed and complete release can be obtained in 6 hours. • 1-MCP released from the formulation is biologically effective that no dimer or isomer formation at treatment level (1 ppm). It was able to extend the shelf life of bananas (color stage 2-2.5) from 2 days to 5 days at room temperature.