Commercial thyme essential oil as natural beverage preservative and molecular docking study on its mode of action against Saccharomyces cerevisiae

Abstract

The present investigation explored the possible use of Thymus vulgaris essential oil (TVEO) as a beverage antifungal preservative instead of chemical ones. The chemical profile of TVEO exposed carvacrol (60.47%) as the predominant compound. The antifungal properties of TVEO were assessed on various food spoilage yeast and mould species using two tests. TVEO showed a powerful antimicrobial effect against all the fungal strains at the three volumes of essential oil (EO) used (i.e. 10, 20, and 30 µL). The minimum inhibition concentration (MIC) of TVEO was also evaluated and ranged from 0.0625% to 0.015% (v/v). Furthermore, the potency of TVEO as a beverage antimicrobial preservative was tested at four distinct concentrations (0.6, 1.25, 4, and 6 μL.mL-1) against Saccharomyces cerevisiae alone and combined with medium heating (70 °C for 2 min) in a real food matrix (Orangina® drink) for eight storage days. TVEO exhibited a significantly higher preservative effect than chemical preservatives (sodium benzoate and potassium sorbate). Lastly, a molecular docking examined the mechanism of action of carvacrol against two crucial enzymes in S. cerevisiae viability [ERG2 (sterol C8-isomerase) and ERG3 (sterol C5-desaturase)] compared to a chemical preservative (potassium sorbate). The two ligands highly interacted with the two target enzymes. However, carvacrol achieved a better score than potassium sorbate against ERG2 and ERG3, with binding energy of -10.19 kcal.mol-1 and -11.73 kcal.mol-1, respectively. Our results open up the perspective of using TVEO as a natural food preservative.

Keywords

• thymus vulgaris
• natural food preservative
• carvacrol
• orangina®
• drink