Óleo essencial de cravo-da-índia (Syzygium aromaticum, L.): extração, encapsulação, potencial antimicrobiano e antioxidante

Abstract

The potential carcinogenic effects of the use of synthetic chemical preservatives in food makes it necessary to search for substitute alternatives made of natural products, such as the essential oils obtained in the secondary pathway of aromatic plants and which have antioxidant and antimicrobial potential against different microorganisms. Among these, clove essential oil (Syzygium aromaticum, L.) is highlighted due to the presence of eugenol in its composition. However, essential oils have a strong odor, which makes them inadequate to be used in foods, and they are also sensitive to environmental conditions. In this context, encapsulation occurs, which, besides controlling the odor, promotes a greater protection for the compounds present in the essential oil. Thus, the objective of the present study was to extract, encapsulate and evaluate the antioxidant and antimicrobial potential of clove essential oil. It was possible to prove that eugenol is the major component of clove essential oil, and it is possibly, along with the other terpenes, the main responsible for the high percentage of antioxidant activity found by the free radical capture method (DPPH) and for the strong bactericidal activity in vitro against S. aureus, E. coli, L. monocytogenes and S. typhimurium and, in situ, against S. aureus in meat products analogous to hamburgers, being more effective than the chemical preservative. The encapsulation of the essential oil with sodium alginate as wall material alone or associated with emulsifiers glycerol monostearate and polyoxyethylene sorbitan monolaurate made it possible to obtain high encapsulation efficiency, which was confirmed by Differential Scanning Calorimetry. The particles presented low percentage of antioxidant activity by the DPPH method. However, they showed superior inhibitory effect of S. aureus, E. coli, L. monocytogenes and S. typhimurium, in relation to the pure oil. It was possible to observe bactericidal effect of the sodium alginate and essential oil particles for S. aureus and of the sodium alginate particles, glycerol monostearate and essential oil for S. aureus and S. Typhimurium. When evaluated in situ application of the particles in products similar to hamburgers it was observed that they allowed bacterial growth, as well as the chemical preservative nitrite. Pure and encapsulated clove essential oil had strong antimicrobial activity with potential for microbiological control in food as a substitute for chemical preservatives.