The purpose of this study was to attempt the encapsulation of lemongrass (Cymbopogon citratus) essential oil utilizing spray drying technique. An array of process parameters including concentration of wall (15–30%), type of wall materials (maltodextrin, maltodextrin and gum Arabic mixture), and concentration of essential oil (0.5–2.0%) were thoroughly investigated. The results show that the use of sole maltodextrin as encapsulant gave microcapsules characteristics comparable to that of powder produced using maltodextrin and gum Arabic mixture. The encapsulation process that was performed with maltodextrin at the concentration of 30% as wall material and lemongrass essential oil at the concentration of 1.5% as core material showed highest drying yield (84.49%), microencapsulation yield (89.31%) and microencapsulation efficiency (84.75%). Encapsulated essential oils retained most of their major constituents in comparison with the bare essential oils without any significant compromise in product quality.

Ocimum gratissimum L. essential oil was studied in this research for its physicochemical characteristics and composition. The essential oil extraction performance achieved 0.3-0.45% by hydrodistillation process. The physicochemical properties of the obtained oil were also discovered including specific gravity at 0.9645 g/cm3, acid index at 13.035 mg KOH/g, ester index at 14.745 mg KOH/g, refractive index at 1.526, and optical rotation at +15.6°. Through gas chromatography/mass spectrometry (GC/MS), it was revealed that the oil is extremely rich in eugenol (59.448 %), trans-ß-Ocimene (10.382 %), β-Cubebene (11.783 %), Caryophyllene (6.966 %) and Copaene (2.479 %). Therefore, optimizing the preservation conditions for the essential oils is suggested as potential pathway to extend the application and enhance the value of Ocimum gratissimum essential oils.

Composition of rosemary essential oil largely depends on the geographical position of the cultivated plant and conditions of the extraction process. In this study, fresh rosemary leaves were used for extraction of essential oil by hydrodistillation and evaluation of chemical compositions and physico-chemical characteristics of the obtained oil were performed. The yield of essential oil was 1.0 %. The physico-chemical parameters showed specific gravity (0.8978 g/cm3), acid index (1.122 mg KOH/g), ester index (15.708 mg KOH/g) and refractive index (1.464). Twenty three components were identified in Rosmarinus officinalis L. oil. The major components were α-pinene (35.54 %), eucalyptol (20.902 %), camphene (4.384 %), bicyclo[3.1.1]hept-3-en-2-one (7.794 %), caryophyllene (1.225 %), endo-borneol (4.147 %) and bornyl acetate (4.065 %). Present study unveiled differences in the chemical composition of Vietnamese rosemary oil comparing with similar studies carried out in other countries.