Preparation of mandarin oil microcapsules and its product quality evaluation

Mandarin oil is characterized by easy volatilization and oxidization, which is difficult for long-term storage. Spray drying and freeze-drying methods were adopted in this work to encapsulate the mandarin oil in order to prolong its shelf life and enrich its application scope. Microcapsules qualities, such as encapsulation efficiency and product microstructure, were evaluated. Optimal operating conditions of spray drying were air inlet temperature 194°C, feed flow rate 90.2mL/min, and feed solid content 34.7%. Operating conditions of freeze-drying were freezing temperature -30°C, chamber pressure 30Pa, and radiation temperature 30°C. Encapsulation efficiencies of products prepared by spray drying and freeze-drying were 90.17% and 82.48%, respectively, under the present conditions. The products by spray drying were fine and sphere-like with dense microcapsule walls, while the products by freeze-drying were irregular and platelet-shaped but with lower moisture content and better fluidity. Both products exhibited certain heat resistances, which could reduce the heat-induced loss of core materials in storage and application. In general, the spray drying method was more suitable than the freeze-drying method for the preparation of mandarin oil microcapsules. © 2023 Chemical Industry Press. All rights reserved.