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

Abstract

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).

Comparison of the Chemical Composition and Antimicrobial Activity of <i>Thymus serpyllum</i> Essential Oils

“…Soković et al (2010) have proved that this compound had the greatest antimicrobial properties among all tested ingredients, including: camphor, 1,8-cineole, linalool, linalyl acetate, limonene, menthol, α -pinene, β -pinene and thymol. The similar activity of essential oils containing large amount of carvacrol has been pointed out by other researchers (Rasooli and Mirmostafa, 2002;Abed et al 2014). Varga et al (2015) additionally emphasize that essential oils of Thymus species, whose one of the most important ingredients is carvacrol, show a very wide spectrum of activity both against Gram-positive and Gram-negative bacteria and against yeast.…”

Chemical composition and antibacterial activity of the essential oil of Thymus ciliatus growing wild in North Eastern Algeria

“…Indeed inhibition diameters were 28.6 mm for L. monocytogenes and 40 mm for B. cereus and MICs of about 0.18mg / ml (Table-2). Other studies have shown that the essential oil of Thymus capitata harvested in Tunisia (El Abed et al, 2014), has had a more importance activity on L. monocytogenes ATCC 19118and B. cereus with an inhibition diameter of 70 to 80mm and MIC least low of 2.5 and 1.25mg/ml for the two respective strains. For this, another essential oil of France Thymus vulgaris (Cristani et al, 2007) exerted an inhibitory effect on stem with low MIC 0,45mg / ml.…”

“…By cons, another Tunisian variety of T. capitata (Zaghouan region) has a completely different composition from that of T. ciliatus with comparable percentages;carvacrol (88.98 %), p-cymene (1.14 %), Thymol (0.51 %) and γ -terpinene (0.40 %) (El Abed et al, 2014). …”

“…According to the study (Faleiro et al, 2003)on Portuguese Thyme:essential oil of Thymus mastichina, established a rather low yield of about 0.5%.…”

Use of Rhodomyrtus tomentosa ethanolic leaf extract for the bio-control of Listeria monocytogenes post-cooking contamination in cooked chicken meat

“…For example Syzygium aromaticum, Cinnmomum cassia, Origanum vulgare, and Brassica nigra extracts were evaluated as antimicrobials and antioxidants in raw chicken meat against L. monocytogenes (Babuskin et al 2014). Essential oil from Thymus capitata was studied as a preservative in minced meat (El Abed et al 2014), and Vaccinium spp. powder was used as a bio-control agent in cured cooked meat (Xi et al 2011) against L. monocytogenes.…”