A Green Modified Microsphere of Chitosan Encapsulating Dimethyl Fumarate and Cross-Linked by Vanillin and Its Application for Litchi Preservation

A green sustained delivery biomaterial was prepared to encapsulate dimethyl fumarate (DMF) by an emulsion–cross-linking method for sustained release. The average size of the microspheres was 20–150 μm. The highest encapsulation efficiency and loading efficiency were 85.7 and 13.2%, respectively. The release of DMF in phosphate buffer saline followed a Fickian diffusion. In addition, the results of inhibition zone showed that DMF-loaded microspheres exhibited antimicrobial and antifungal properties much better than those of CS microspheres. Furthermore, weight loss of treated fruit was reduced insignificantly, and storage time was extended with the stable quality of litchi as compared with that of the control group. Thus, the microspheres were synthesized successfully as a sustained delivery system for DMF, which might have broad prospect and development value in preservation of fruits and vegetables.