Citrus lemon essential oil: chemical composition, antioxidant and antimicrobial activities with its preservative effect against Listeria monocytogenes inoculated in minced beef meat.
BACKGROUND
Lemon (Citrus limon) is a flowing plant belonging to the Rutaceae family. Citrus plants constitute one of the main valuable sources of essential oil used in foods and medicinal purposes.


METHODS
In this study, we assessed chemical composition, antioxidant and antimicrobial activities of C. limon essential oil (ClEO) with its preservative effect against Listeria monocytogenes inoculated in minced beef meat. Gas chromatography/mass spectrometry (GC-MS) was used to identify the major components of the obtained ClEO. The antioxidant activities of this ClEO were determined according to the β-carotene bleaching assay, as well as by 2.2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. For antimicrobial activity, agar well diffusion method was used and the minimum inhibitory concentrations (MICs) as well as the minimum fungicidal concentrations (MFCs) were determined. The in situ effect of the ClEO was evaluated through physicochemical parameters (pH and thiobarbituric acid reactive substances (TBARS), as well as against L. monocytogenes in minced beef meat model.


RESULTS
Twenty one components were identified in the ClEO and the two dominant compounds were limonene (39.74%) and β-Pinene (25.44%). This ClEO displayed an excellent DPPH scavenging ability with an extract concentration providing 50% inhibition (IC50) of 15.056 μg/ml and a strong β-carotene bleaching inhibition after 120 min of incubation with an IC50 of 40.147 μg/ml. The MICs varied from 0.039 to 1.25 mg/ml for Gram positive bacteria and from 0.25 to 2.5 mg/ml for Gram-negative bacteria. The meat preserving potential of ClEO was investigated against L. monocytogenes. ClEO successfully inhibited development of L. monocytogenes in minced beef meat. The application of ClEO at a 0.06 and 0.312 mg/g, may open new promising opportunities for the prevention of contamination from and growth of pathogenic bacteria, particularly L. monocytogenes, during minced beef meat storage at 4 °C. Additionally, during storage period, physicochemical values (pH and TBARS) were higher in control meat than treated meat with ClEO suggesting an efficient antioxidant activity of ClEO.


CONCLUSION
It was suggested that the ClEO may be a new potential source as natural antimicrobial and antioxidant agents applied in food systems and pharmaceutical industry.
['Ben Hsouna|Anis|A|', 'Ben Halima|Nihed|N|', 'Smaoui|Slim|S|', 'Hamdi|Naceur|N|']
D000818:Animals D000900:Anti-Bacterial Agents D000935:Antifungal Agents D000975:Antioxidants D002417:Cattle D002957:Citrus D015169:Colony Count, Microbial D005520:Food Preservatives D016166:Free Radical Scavengers D006863:Hydrogen-Ion Concentration D008089:Listeria monocytogenes D008826:Microbial Sensitivity Tests D050296:Microbial Viability D009822:Oils, Volatile D010938:Plant Oils D000069466:Red Meat D017392:Thiobarbituric Acid Reactive Substances D013997:Time Factors
Essential oil Antimicrobial activity Listeria monocytogenes minced beef meat Citrus limon Antioxidant activity