The chemical composition of the essential oil and volatile compounds from caraway fruit (Carum carvi L.) extracted by headspace-solid phase microextraction and the antioxidant activity

Abstract

The aim of this study was to isolate the essential oil from ripe and disintegrated caraway fruit by Clevenger-type hydrodistillation, to determine its qualitative and quantitative composition and to examine its antioxidant activity, as well as to determine the qualitative and quantitative chemical composition of the caraway volatile compounds extracted by HS-SPME technique. The essential oil from disintegrated caraway fruit was obtained by Clevenger-type hydrodistillation with hydromodulus 1:10 m/V during 180 minutes. Volatile compounds from caraway fruit were extracted by headspace-solid phase microextraction (HS-SPME) using 75 μm fiber coated with Carboxen®/Polydimethylsiloxane (PDMS). The qualitative and quantitative composition of the essential oil and volatile compounds was determined by gas chromatography coupled with mass spectrometry (GC-MS) and flame ionization detection (GC-FID). Twenty-seven different compounds were separated and identified in the essential oil. Twenty-six compounds were identified in the volatiles extracted by HS-SPME. The most abundant compounds in both examined samples were limonene and carvone. The content of carvone in the essential oil was 72%, while the limonene content was 25.6%. In the volatiles obtained by HS-SPME, the limonene was present with 72.1% and carvone with 24.6%. The difference in the chemical composition is due to the oxidation of limonene to carvone during the hydrodistillation. The antioxidative activity of the caraway essential oil was determined by using DPPH assay immediately after adding DPPH radical and after 20 and 40 min of incubation with the radical. The caraway fruit essential oil showed a satisfactory antioxidant activity. The oil incubated for 40 min (EC50=4.6 mg/cm3) showed the best antioxidant activity.