Microencapsulation of refined kenaf ( Hibiscus cannabinus L.) seed oil by spray drying using β-cyclodextrin/gum arabic/sodium caseinate

This study aimed to evaluate the potential of β-cyclodextrin combination with different wall materials (gum arabic and sodium caseinate) in the microencapsulation of refined kenaf seed oil by spray drying. Three models of microcapsules were developed, including protein-based (β-cyclodextrin/sodium caseinate), carbohydrate-based (β-cyclodextrin/gum arabic) and mixed-based (β-cyclodextrin/gum arabic/sodium caseinate). The characteristics of the obtained microcapsules including moisture content, water activity, wettability, solubility, density, flowability, cohesiveness, bulk porosity, microencapsulation efficiency, particle size, surface morphology, and possible interactions between the oil and wall materials were evaluated. The moisture content and water activity were in the range of 2.7–3.9% and 0.2 to 0.3, respectively, which is suitable for long-term storage. The obtained microcapsules showed a particle size distribution (D[4,3]) of 25.4–37.3 μm. Scanning electron micrographs of microcapsules showed spherical shapes without any apparent cracking on the surfaces. Fourier transform infrared spectroscopy revealed that the oil was well encapsulated in the microcapsules. The highest microencapsulation efficiency was achieved for the carbohydrate-based microcapsule (95.3%), followed by the protein-based microcapsule (93.1%) and mixed-based microcapsule (90.0%). Three formulations offered high microencapsulation efficiency to encapsulate the refined kenaf seed oil in this study.