Abstract: The purpose of this work was to obtain good quality and high microencapsulation efficiency of onion essential oil microcapsules by spray drying method. Arabic gum, β-cyclodextrin and maltodextrin were evaluated for their use as wall materials. The effect of wall material type, core to wall material (C/M) ratio and solid content on microencapsulation efficiency was investigated. The morphology under scanning electron microscopy (SEM), sensory attributes, encapsulation degree (ratio between microencapsulated oil and wall material), water content, solubility, bulk density and storage stability of microcapsules were measured. The results showed that the maximum microencapsulation efficiency of 92.35% was achieved under the following conditions: arabic gum and β-cyclodextrin mixture (4:3, m/m) as wall material, C/M ratio 1:4 (mL/g), and solid content 20%. SEM examination showed that the obtained microcapsules were spherical in shape with smooth and continuous surfaces. The microcapsules had good sensory properties, and were homogenous in size and non-sticky, which could effectively hide the pungent odor of onion essential oil, making the product acceptable to consumers. Moreover, the encapsulation degree, water content, solubility, bulk density and glass transition temperature (Tg) of the microcapsules were 21.32%, 3.69%, 97.56%, 0.786 g/cm3 and 46.35 ℃, respectively indicating good solubility, a low water content and a Tg higher than general storage temperature. Therefore, high-quality microcapsules were obtained under the optimized conditions, which had good storage stability and were acceptable to the market.

Key words: spray drying, onion essential oil, microcapsule, quality