Fabrication and characterization of betulin/hydroxypropyl-beta-cyclodextrin inclusion complex nanofibers: A potential edible antibacterial and antioxidant packaging material.

Active food packaging made from edible materials was considered as a promising alternative to traditional food packaging. Betulin (BE) is a natural active ingredient extracted from the bark of the birch tree, which has anti-inflammation, antibacterial and antioxidant properties. However, the low solubility of BE in water limits its application in active food packaging. In this research, in order to expand the application range of BE, an innovative potentially antimicrobial and antioxidant packaging material was developed. Betulin/hydroxypropyl-beta-cyclodextrin inclusion complex nanofibers (BE/HPβCD-IC-NF) with a stoichiometric ratio of 1:2 was prepared by electrospinning. Scanning electron microscopy results showed a smooth surface with no beads on the free-standing BE/HPβCD-IC-NF. The results of NMR hydrogen spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy proved that the BE was successfully encapsulated in the cavity of HPβCD. Meanwhile, the results of thermogravimetric analysis and phase solubility studies proved that the BE/HPβCD-IC-NF enhanced the aqueous solubility and thermal stabilization of BE. Fast dissolving experiment proved that the BE/HPβCD-IC-NF was disintegrated rapidly in water. Furthermore, the free radical scavenging activity and antimicrobial test demonstrated that BE/HPβCD-IC-NF has antioxidant properties and good antimicrobial properties, respectively. Meanwhile, in vivo antimicrobial tests on strawberries proved that BE/HPβCD-IC-NF has an effective effect on the preservation and stabilization of fruits. In conclusion, BE/HPβCD-IC-NF prepared in this study can effectively improve thermal stability, aqueous solubility, antibacterial and antioxidant activity of BE, which provides potential for its application in the field of active food packaging.