Chemical Composition, Antioxidant and Antimicrobial Activities of Thymus capitata Essential Oil with Its Preservative Effect against Listeria monocytogenes Inoculated in Minced Beef Meat

• Published in: Evidence-based complementary and alternative medicine 2014-01, Vol.2014 (2014), p.1-11
• Main Authors: Ben Hadj Ahmed, Sami, Mejri, Mondher, Habibi, Kamel, Chabbouh, Meriem, Smaali, Mohamed Issam, Kaabi, Belhassen, El Abed, Nariman, Marzouki, Mohamed Nejib
• Format: Article
• Language: English
• Subjects: Analysis; Anti-infective agents; Antimicrobial activity; Antimicrobial agents; Antioxidants; Ascorbic acid; Beef; Carvacrol; Chemical composition; Chemical preservatives; Contamination; Control; Essences and essential oils; Essential oils; Food preservation; Food processing industry; Gas chromatography; Health aspects; Inhibition; Lamiaceae; Life Sciences; Listeria; Listeria monocytogenes; Mass spectrometry; Mass spectroscopy; Meat; Microbiological research; Microbiology and Parasitology; Oils & fats; Salmonella; Thymus; Thymus capitatus
• ISSN: 1741-427X; 1741-4288
• DOI: 10.1155/2014/152487

The chemical composition, antioxidant and antimicrobial activities, and the preservative effect of Thymus capitata essential oil against Listeria monocytogenes inoculated in minced beef meat were evaluated. The essential oil extracted was chemically analyzed by gas chromatography-mass spectrometry. Nineteen components were identified, of which carvacrol represented (88.89%) of the oil. The antioxidant activity was assessed in vitro by using both the DPPH and the ABTS assays. The findings showed that the essential oil exhibited high antioxidant activity, which was comparable to the reference standards (BHT and ascorbic acid) with IC50 values of 44.16 and 0.463 μg/mL determined by the free-radical scavenging DPPH and ABTS assays, respectively. Furthermore, the essential oil was evaluated for its antimicrobial activity using disc agar diffusion and microdilution methods. The results demonstrated that the zone of inhibition varied from moderate to strong (15–80 mm) and the minimum inhibition concentration values ranged from 0.32 to 20 mg/mL. In addition, essential oil evaluated in vivo against Listeria monocytogenes showed clear and strong inhibitory effect. The application of 0.25 or 1% (v/w) essential oil of T. capitata to minced beef significantly reduced the L. monocytogenes population when compared to those of control samples ( P -value < 0.01 ).