Evaluation of Antimicrobial Effect of Cinnamomum verum Methanolic Extract and Essential Oil: A Study on Bio-preservative in Ketchup Sauce

Abstract

Use of natural antimicrobial compounds extracted from plants such as cinnamon as preservative to extend the shelf life has gain much attention. In this study, we evaluated the antimicrobial activity and bio- preservative potential of the methanolic extract of Cinnamomum verum bark and its oil against Bacillus subtilis, Pseudomonas aeruginosae and Escherichia coli in ketchup sauce. In order to evaluate the Minimum Inhibitory Concentration (MIC) of essential oil and methanolic extract from the bark of C. verum, agar dilution method was performed. Then the effective inhibitory concentrations were evaluated on growth of test bacteria in ketchup sauce at 4 °C and room temperature in different storage times (1, 7, 14 and 30 days). In addition, the sensory quality of treated ketchups was assessed. This study showed bacteriostatic effect of the essential oils and methanolic extract on all tested bacteria. The best treatment in ketchup sauce was obtained on days 14 at 4 °C in concentrations of 1500 µg/ml essential oil. In sensory evaluation, the sample containing 1000 µg/ml essential oil had higher score in odor, taste and overall acceptability than other treated samples (P<0.05). This study shows that cinnamon oil is a more potent antimicrobial agent than cinnamon extract and it has the potential to be used as food preservative and is recommended for quality attributes enhancement.