| Abstract [eng] |
Kamile Armalaitė‘s Master‘s Thesis „Effect of Distillation Duration on the Amount of Phenolic Compounds in Thymus × citriodorus Deodorised Raw Material and Aqueous Extracts, and on Essential Oil Percentage“. Aim of the study: To evaluate the influence of distillation time on the content of total phenolic compounds in deodorized lemon thyme (T. × citriodorus) material and water extracts, as well aso n the yield of essential oil. Objectives of the study: 1. To determine the effect of distillation time on the essential oil yied of Thymus × citriodorus. 2. To determine and compare the contents of total phenolic compounds extracted using different organic solvents (methanol, ethanol and acetone) in non-deodorized and differently deodorized T. × citriodorus material. 3. To evaluate the effect of extraction time on the content of total phenolic compounds in water extract of T. × citriodorus. Object and methods: The aerial parts of T. × citriodorus were collected during the flowering stage and then dried. Essential oils from T. × citriodorus raw material were obtained by distillation using a Clevenger-type apparatus, applying different distillation durations. The total phenolic compounds in the deodorized plant material and in the aqueous extracts obtained during essential oil distillation was determined spectrophotometrically using the Folin-Ciocalteau method. Phenolic compounds from the deodorized plant materiant were extracted using different organic solvents – methanol, ethanol and acetone. Results and conclusions: A positive correlation was established between essential oil yield and distillation time (rs = 0,92, p < 0,05). The highest yield of essential oil was obtained after 40 minutes of distillation (0.57 ± 0.02%), while longer distillation (50 – 120 minutes) was no longer effective. In non-deodorized T. × citriodorus raw material, the total phenolic compounds, regardless of the extraction solvent used, averaged 73.9 ± 6.7 mg GRE/g, whereas in deodorized samples it was 1.5 – 3.8 times lower and decreased with increasing distillation time. The highest phenolic contents in T. × citriodorus deodorized material were found at shorter distillation times, and acetone was the most effective solvent for their extraction. In contrast, when extracting phenolic compounds from non-deodorized T. × citriodorus raw material, ethanol was the most effective solvent (79.6 ± 1.0 mg GRE/g), while acetone was the least effective (65.8 ± 1.5 mg GRE/g). In T. × citriodorus water extracts, the total phenolic compounds increased with distillation time (rs = 0,63, p = 0,05). The lowest total phenolic content was found in the extract obtained after 5 minutes of distillation (63.4 ± 1.5 mg GRE/ml), and the highest after 30 minutes (95.4 ± 1.0 mg GRE/ml), with the difference being statistically significant (p < 0.05). |
