| Abstract [eng] |
Oregano (Origanum vulgare L.) is a perennial flowering plant, widely cultivated in Europe, Asia and America. Oregano is used as a spice in culinary, it is also used in folk medicine for its antiseptic, antioxidant, toning, immune-enhancing properties. For important aroma compounds presence in oregano, oregano essential oil has wide application in cosmetics and personal hygiene products. This research was aimed to process oregano (Origanum vulgare L.), grown in Lithuania, into aroma compound and antioxidant fractions by conventional and multi-step high pressure extraction techniques. In order to achieve this goal there were carried out different extractions: hydrodistillation, Soxhlet extraction, solid-liquid extraction (conventional extraction techniques) and supercritical fluid extraction with carbon dioxide, pressurized liquid extraction (high pressure extraction techniques). Solid residues after supercritical fluid extraction with carbon dioxide has been applied for the pressurized liquid extraction (using response surface methodology for pressurized liquid extraction with acetone was performed optimization of extraction time and pressure, which produces the highest extract yields). After optimization, the solid residues further were utilized by pressurized liquid extraction with different solvents. Total extract phenolics determined using the Folin-Ciocalteu's method, antioxidant activity was measured using DPPH•, ABTS+ scavenging assays. Oxygen radicals absorbance capacity was measured by ORAC assay. Solid residues antioxidant activity was measured with the same in vitro antioxidant activity methods by approaching QUENCHER procedure. Selected extracts oxidative stability in rapeseed oil was measured with oksipres method. Phytochemical characterization of chosen extracts were assessed: preliminary composition was identified by UPLC-QTOF-MS, fatty acids composition was determined by GC-FID method, squalene amount in different extracts was evaluated by HPLC analysis. |
