Effect of Thymus vulgaris and Origanum compactum essential oils on the shelf life of fresh goat cheese

Abstract

We have carried out our study on the chemical composition and antimicrobial activity of Thymus vulgaris and Origanum compactum essential oils that were harvested in the northeast of Morocco. Carvacrol was the major component in the two investigated essential oils. A high antimicrobial activity has been shown on all tested bacterial strains. The effect of the incorporation of these two essential oils at concentrations of 0.05% and 0.1% on physicochemical, microbiological and sensorial characteristics of goat fresh cheese stored at 8°C has also been studied. No significant differences have been showed between control and aromatized cheeses with respect to pH, titrable acidity, dry matter, lactic acid bacteria and aerobic mesophylic flora. However, coliforms were completely inhibited by the presence of both essential oils from the first storage day. Shelf life estimation has been determined by the reparameterized Gompertz equation by monitoring the growth of molds and yeasts. Origanum compactum essential oil was more effective on extending the shelf life of fresh goat cheese than Thymus vulgaris essential oil. Nevertheless, the aromatized cheese with Thymus vulgaris essential oil was the most appreciated by the tasting panel.

Keywords:

• soft cheese
• essential oils
• shelf life
• sensorial quality

Acknowledgements

This study was supported by ICARDA (International Centre of Agricultural Research in Dried Area). The authors are grateful to the personnel of the experimental station of Begdour for providing raw goat milk.