Abstract

Minko Govedarov*, Teodora Baldjieva and Nenko Nenov

ABSTRACT

Thyme herb (Thymus vulgaris L.) was processed by pressurized hot water extraction under the identical conditions- temperature of 170 ? and pressure. The aim is to study the dynamics of extracting the essential oil from the raw material. One experiment is on the raw material subjected to a single extraction, lasting up to 30 min, and in the other, thyme (Thymus vulgaris L.) was processed through a sixfold extraction, lasting 60 min. For comparison, a control sample was made using a Clevinger apparatus in order to determine the total content of essential oil in the raw material, as well as an analysis of the processed raw material to determine the unextracted essential oil. The essential oil extracted from the miscellas was also derived. The obtained essential oils were analysed on a gas chromatograph with a mass spectrometer (GC- FID- MS). The results show that with a single extraction for 30 min, the yield of dry matter is 26 %, while with a triple extraction with the same total extraction time, the integral yield of dry matter is 31 %. The analyses of the essential oils showed similar or higher extraction of the alcohols thymol and carvacrol in the oils isolated from the miscella after extraction with superheated water under pressure than those obtained by water distillation.