Effect of microencapsulation on chemical composition and antimicrobial, antioxidant and cytotoxic properties of lemongrass (Cymbopogon flexuosus) essential oil

Abstract

Research background: Lemongrass (Cymbopogon flexuosus) essential oil (LEO) exhibits antimicrobial and antioxidant properties due to the presence of α-citral and β-citral. Essential oils (EOs) are susceptible to volatilization and oxidation when applied to food matrices. Therefore, a barrier is needed to protect this material. The present study aimed to produce microparticles containing LEO, using Arabic gum (AG) and maltodextrin (MD) through the spray drying technology. Experimental approach: LEO was extracted by the hydro-distillation method and later microencapsulated with different wall materials. Free and microencapsulated LEO were evaluated for their cytotoxic activity (Artemia salina), chemical composition (GC-MS), encapsulation efficiency, antioxidant activity (DPPH, ABTS and FRAP), antimicrobial activity and minimum inhibitory concentration. Results and conclusions: LEO had a lethal concentration (LC50) of 8.43 μg/mL against Artemia salina in the cytotoxic test; a high activity that can be associated with the presence of α-citral (~33 %) and β-citral (~21 %) in the samples, since these compounds were the main ones that presented bioactive properties. The highest value of microencapsulation efficiency (88.11 %) was obtained when only AG was used as wall material. In general, the microparticles showed satisfactory antioxidant activity (between 348.66 and 2042.30 µmol TE/100 g) and bactericidal effect, in vitro, against Gram-positive and Gram-negative microorganisms. In conclusion, the microencapsulated lemongrass essential oils are a promising functional additive to be used in the food and pharmaceutical industries. Novelty and scientific contribution: This study shows that microparticles containing LEO can be prepared using AG and MD as wall materials via the spray drying process, resulting in high microencapsulation efficiency. The drying process maintained the essential oil’s antimicrobial and antioxidant properties. Therefore, the microencapsulated LEO is considered a natural, functional, and a promising additive to be incorporated in the food industry. This material may have an application in several food products due to the investigated and proven potential addressed in this study. Its antimicrobial action can increase the shelf life of fresh and semi-fresh products such as cheese, yogurts, and meat products. In addition, its antioxidant action can delay the lipid and protein oxidation in food products.