Antimicrobial and antioxidant activities of commercially available essential oils and their oleoresins

Abstract

Entidades Financiadoras: Junta de Castilla y León” (Proyecto LE331A12-2) y Universidad de León (Proyecto ULE2010-6) The objectives of this study were to evaluate and compare in vitro antibacterial and antioxidant activities of commercially available oregano, rosemary, sage and thyme essential oils (EOs) against their corresponding oleoresins (ORs) for potential application in food packaging systems. Thyme EO showed the best antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas fluorescens (MIC values ranging 0.4±0.1 - 8.7±2.3 mg/mL). Overall, the antimicrobial efficacy of thyme and oregano EOs was found to be higher than that observed for their ORs. Additionally, these ORs did not exhibit better antioxidant properties when compared with their EOs, providing 90% lower antiradical activity and without significant differences in reducing power. The results suggested that commercially available thyme and oregano EOs could be used effectively as hurdle against food-borne pathogens and spoilage bacteria, as well as in terms of preventing lipid oxidation in foods