Production of thymol rich extracts from ajwain (Carum copticum L.) and thyme (Thymus vulgaris L.) using supercritical CO2

• Published in: Industrial crops and products 2020-03, Vol.145, p.112072, Article 112072
• Main Author: Morsy, Nashwa F.S.
• Format: Article
• Language: English
• Subjects: Carum copticum L; Essential oils; Hydrodistillation; Supercritical fluid extraction; Thymol; Thymus vulgaris L
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2019.112072

•Supercritical extraction by CO2 improved selectivity compared to hydrodistillation.•The effect of pressure variation has been investigated.•Ajwain extract with more than 60 % thymol was obtained.•Supercritical fluid extraction allows the production of high quality extracts. Supercritical fluid extraction is the most efficient technique to extract flavor and fragrance compounds. This study aims to obtain thymol rich extracts by supercritical fluid CO2-extraction (SFE) of Carum copticum L. (ajwain) and Thymus vulgaris L. (thyme). The yield, chemical constituents analyzed by gas chromatography-mass spectrometry and sensory characteristics of the extracts were compared with their volatile oil counterparts extracted by hydrodistillation (HD). The SFE extracts were obtained at a low temperature (40 °C) and two pressures (10.4 and 16.7 MPa). The yield of the ajwain and thyme extracts reached 2.78 ± 0.04 and 1.28 ± 0.15 % (w/w), respectively, at 16.7 MPa. The SFE successfully increased the thymol relative amount in the ajwain and thyme extracts by 1.7 and 2.49 fold compared with its level in the hydrodistilled essential oils, respectively. The extract obtained at high pressure exhibited the most valued sensory characteristics (spicy, pungent, aromatic/herbaceous, phenol-like and absence of burnt note).