Microencapsulation of onion ( Allium cepa L .) seed oil: influence of emulsion preparation and drying technologies

AIM: This study aimed to evaluate the influence of emulsification and drying techniques on the microencapsulation efficiency and stability of onion seed oil. METHODS: Emulsions were prepared using rotor-stator homogenisation and cross-flow membrane emulsification, followed by spray drying or freeze drying. Three wall systems were tested: whey protein isolate (WPI), WPI/maltodextrin (MD), and WPI/trehalose (TRH). Encapsulation efficiency, moisture content, particle size, morphology, NIR spectroscopy, and principal component analysis were performed. RESULTS: The highest encapsulation efficiency was obtained with spray-dried WPI/TRH microcapsules (83.08 ± 0.13%), followed by freeze-dried WPI/TRH (81.37 ± 0.36%). Spray-dried samples showed lower moisture and fewer fat-related NIR absorption bands. TRH formulations produced smoother, more spherical particles with reduced surface oil. PCA confirmed clustering according to drying method. CONCLUSIONS: The WPI/TRH system combined with spray drying significantly enhances onion seed oil protection, demonstrating strong potential for functional food applications.