Essential Oils: Quality Indicators of Spices in Supermarkets
Chemical composition of oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.) and thyme (Thymus vulgaris L.) essential oils traded as spices at supermarkets was determined by Gas-Chromatography-Mass Spectrometry analysis. One hundred-five compounds accounting for 84-98 % of the total essential oils were identified. Significant differences were found in both yield and chemical composition of spice essential oils and the trademarks employed. Oxygenated monoterpenes (51.58-95.39 %) were the principal fraction in all analyzed essential oils. Thymol was the main compound in oregano (79.53 and 27.87 %) and thyme (30.70 and 18.74 %) essential oils followed by carvacrol (15.42 %) or terpinen-4-ol (9.97 %) in oregano trademarks and carvacrol (19.59 %) or borneol (18.00 %) in thyme trademarks. 1,8-cineole (36.74 and 47.39 %) and camphor (20.78 and 15.96 %) were the main compounds in commercial rosemary food items. Large differences in the amount of the main bioactive compounds that can affect both aroma and health benefits are found in the analyzed trademarks.
Keywords: oregano, rosemary, thyme, essential oils, GC-MS.