Preparation of eugenol/1-methylcyclopropene composite microsphere by S/O/W method and study on the postharvest quality of loquat

The S/O/W method of solvent evaporation was utilized in this work for manufacturing poly (epsilon-caprolactone) (PCL) microspheres loaded with 1-methylcyclopropene (1-MCP-alpha-CD) and eugenol (EUG) for temperature- and humidity-regulated EUG release. The composite microspheres with higher encapsulation efficiency (71.39 % +/- 2.71 %) were attained by optimizing the rotation speed and mass ratio of PCL to composite powder. The microspheres had good spherical shape without large pores. The rate of release could be managed by different temperature and relative humidity conditions with the release of microspheres (96.82 % +/- 0.81 % in 12 days) at the temperature of 60 degrees C (90 % relative humidity) and (86.50 % +/- 2.71 % in 12 days) at the 90 % relative humidity (60 degrees C). Microsphere encapsulation of EUG and 1-MCP-alpha-CD was demonstrated by Fourier transform infrared spectroscopy and X-ray diffractometer. Thermal gravity analysis demonstrated that the degradation of EUG@beta-CD and 1-MCP-alpha-CD was delayed after encapsulation. The deterioration of loquat (Baiyu, white-fleshed) can be postponed after treatment of EUG/1-MCP composite microspheres. Relative conductivity, total soluble solids, hardness, color, titratable acid, and weight loss of the loquat were also improved. It could significantly inhibit polyphenol oxidase (PPO) and peroxidase (POD) activities and inhibited browning of loquat tissue. EUG/1-MCP composite microspheres we formulated in this work might be employed to increase the shelf life of loquat.