Microcapsules stabilized by cellulose nanofibrils/whey protein complexes and modified with cinnamaldehyde: Characterization and release properties

This work aims to optimize encapsulation of Zanthoxylum schinifolium essential oil (ZSEO) in microcapsule to enhance its stability and slow-release capability. Herein, the ZSEO microcapsules stabilized by bacterial cellulose nanofibrils/whey protein isolate (BCNFs/WPI) complexes and modified by cinnamaldehyde (CA) were successfully prepared via spray drying. The microcapsules formed by 1.0 wt% BCNFs/WPI complexes at a ratio of 1:7 and fortified with 0.7 wt% CA, exhibited superior physical properties, a smaller powder size and the highest encapsulation efficiency (90.81 %). The spectroscopy analysis and molecular dynamics simulations demonstrated the presence of hydrogen bonding and electrostatic interactions between CA and BCNFs/WPI/ZSEO components, contributing to an increase in the binding energy. The release kinetic modeling revealed that the microcapsules exhibited the delayed release capability in both aqueous and oily model fluids. Moreover, the ZSEO microcapsules modified with CA exhibited enhanced stability during in vitro digestion, offering valuable insights into the microencapsulation of essential oils.