Effect of different drying temperatures on quality parameters in Laurus nobilis l.

This study evaluated the effect of drying at different temperatures (30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C) on the essential oil yield and composition of Laurus nobilis L. The experiment, using bay leaves harvested from the Artvin Central district, was conducted in Randomized Plots with three replications. Fresh herb and dried samples used as control samples were analyzed for essential oil extraction using a Clevenger device, while qualitative and quantitative component analyses were performed using Gas Chromatography-Mass Spectrometry (GC-MS). The α-pinene, β-pinene, sabinene, d-limonene, 1,8-cineole, terpinen-4-ol, caryophyllene, α-terpinyl acetate, caryophyllene oxide, methyleugenol, trans-cinnamyl acetate, and eugenol ratios affecting the essential oil yield and quality were examined in the experiment. According to the research results, the highest essential oil yields compared to fresh herbs were determined at drying temperatures of 30 °C, 45 °C, and 50 °C for α-pinene and β-pinene ratios, 50 °C for the 1,8-cineole ratio, and 45 °C and 55 °C for the d-limonene ratios. Considering the eugenol ratio, 35 °C stood out. It was determined that the drying temperatures applied did not cause a significant difference in the ratios of sabinene, terpinen-4-ol, caryophyllene, α-terpinyl acetate, caryophyllene oxide, and trans-cinnamyl acetate compared to fresh herb. Based on the research findings, it has been determined that the drying process increases the essential oil yield of Laurus nobilis L. and the ratios of α-pinene, β-pinene, 1,8-cineole, d-limonene, and eugenol. Consequently, although the highest essential oil yields compared to fresh herb were obtained at drying temperatures of 30 °C, 45 °C, and 50 °C, considering the α-pinene and β-pinene ratios, the 50 °C drying temperature was the temperature at which the highest yields of these three studied characteristics were obtained. The d-limonene component had a high ratio at drying temperatures of 45 °C and 55 °C, but the high ratio of 1,8-cineole at 55 °C indicates that 55 °C is a suitable temperature for these components.