Assessment of the oil release of spray-dried gum arabic/citronella oil microcapsules depending on the production parameters

Functionalization by using essential oils is an environmentally friendly approach that can be adapted to many industries. However, the oxidative sensitive and high volatile structures of the essential oils inhibit their potential. Microencapsulation enables the essential oils to be coated and protected by a wall material. The protection and the release of the confined essential oil depend on the morphologies of the microcapsules thus their production parameters. Therefore, selection of the appropriate microencapsulation parameters is crucial. This study aims to determine the optimum parameters to produce gum arabic/citronella essential oil (GA/CEO) spray-dried microcapsules. The effects of wall-to-core ratio, inlet temperature, and feed rate were investigated. Twenty-seven GA/CEO microcapsule samples were produced by using three wall-to-core ratios (3:1, 4:1, 6:1 v/v), three inlet temperatures (120, 150, 180°C), and three feed rates (1, 2.5, 5 mL/min). The morphology, particle size, oil efficiency, and oil release of the microcapsules were evaluated by considering the production parameters. The analyses revealed that GA/CEO microcapsules with smooth surfaces and homogeneous particle sizes were successfully produced. The oil efficiency of the microcapsules ranged between 20–90%, depending on the production parameters. The release rates of CEO varied between 37.8–89.5%. In conclusion, the microcapsules produced with a wall-to-core ratio of 4:1, temperatures above 150°C, and feed rates above 2.5 mL/min have potential for applications where prolonged release are expected.