Physicochemical Properties and Stability of Encapsulated Ferulago angulata subsp. carduchorum Essential Oil using Polymer Coating

Nowadays, the tendency to use natural preservatives such as essential oils instead of synthetic additives has increased. Due to the volatile compounds of essential oil; encapsulation is an appropriate method to preserve voletile and phenolic compounds, Ferulago angulata subsp. carduchorum (Boiss. & Hausskn.) D.F.Chamb. is a native medical plant in the west of Iran. The aim of this study was to determine physicochemichal properties of encapsulated F. angulata subsp. carduchorum essential oil using Maltodextrin 20% and Maltodextrin 20%+Arabic gum 20% and Modified starch 20% + Maltodextrin 20%. The coating process was performed by spray dryer. The efficiency of the coating process was 59-89%. The antioxidant activity was carried out by ABTS method and the highest percentage of free radical scavenging was related to Maltodextrin 20% + Arabic gum 20% containing 3% essential oil and the obtained result was 52.81%. The highest content of total phenolic compounds was 66.88 mg/mL belonged to Maltodextrin 20% + Arabic gum 20% containing 3% essential oil (P˂0.05). The microstructure of the encapsulated essential oil was characterized using scanning electron microscopy (SEM) and dynamic light scattering technique (DLS) and the presence of the essential oil in the microencapsules was confirmed by fourier-transform infrared spectroscopy (FTIR). The results of the electron microscopy showed the effective and useful role of modified starch in creating a uniform, crack-free structure. The results of the DLS test indicated that the largest sample in terms of sample size was Maltodextrin 20% + Arabic gum 20% containing 3% essential oil. The most significant change in the spectrum of chemical structure in FTIR test was related to Maltodextrin 20% + Arabic gum 20% microcapsule. Results of density test of microcapsules showed that the lowest density was related to Maltodextrin 20% + Arabic gum 20% containing 3% essential oil (0.25 g /cm3). The stability of microcapsules in different environments was evaluated by pH test and the results showed that the most stable microcapsules in alkaline conditions were Maltodextrin 20% + Arabic gum 20% containing 3% essential oil. Therefore, the 3% essential oil coated by Maltodextrin and Arabic gum was selected as the best treatment for protection of essential oil compounds.