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 ( ε −caprolactone) (PCL) microspheres loaded with 1−methylcyclopropene (1−MCP−α−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 °C (90 % relative humidity) and (86.50 % ± 2.71 % in 12 days) at the 90 % relative humidity (60 °C). Microsphere encapsulation of EUG and 1−MCP−α−CD was demonstrated by Fourier transform infrared spectroscopy and X-ray diffractometer. Thermal gravity analysis demonstrated that the degradation of EUG@β−CD and 1−MCP−α−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.