Effects of cultivar, harvesting time and isolation techniques on the essential oil compositions of some lemon cultivars

In this study, Batem Pınarı, Interdonato, Meyer, and Ak Limon lemon cultivars were studied. Lemon peel's essential oils were obtained by two different methods (hydrodistillation and cold pressing) during four different harvest periods for each cultivar. Essential oil content, density, refractive index, optical activity, and composition were evaluated. The highest essential oil amount was found in the Interdonato cultivar (2.54%) and the lowest in Ak Limon (1.37%). The highest density value was 0.8471 g/mL (Ak Limon) and the lowest was 0.8423 g/mL (Meyer). Essential oil densities obtained by cold pressing were higher than those obtained by hydrodistillation. The highest refractive index values were determined for Batem Pınarı and Meyer (1.4747), and the lowest were determined for Ak Limon (1.4740). The refractive index values obtained by cold pressing were higher than those obtained by hydrodistillation. Optical activity values were found to be highest in Ak Limon and lowest in Batem Pınarı, and higher following hydrodistillation than cold pressing. The essential oil compositions of the samples showed significant differences depending on the cultivar and isolation method. Limonene, the highest component proportionally, composed 76.0%–89.0% of samples. The highest limonene content was determined for Ak Limon (88.7%), and the lowest for Batem Pınarı (76.7%). Limonene content did not change significantly between hydrodistillation (82.2%) and cold press (82.2%) isolation methods. Findings show that there is significant variation in quality parameters of lemon peel essential oils.