Effects of drying temperature of Piper divaricatum G. Mey. leaves on the chemical profile of the essential oil

Abstract

Piper divaricatum G.Mey is a shrub native in Brazil, whose predominant chemotype produces an essential oil rich in phenylpropanoids, especially eugenol and methyl eugenol. Drying is the main post-harvest preservation technique applied to aromatic and medicinal plants; however, inappropriate drying conditions may negatively affect essential oil quality. In this study, the effects of drying temperature on the leaves of P. divaricatum in a tray dryer were evaluated with respect to essential oil quality. The experimental analysis consisted of subjecting the leaves to the drying process for 6 hours at temperatures of 50, 60, and 70 °C. Essential oils were obtained by hydrodistillation, and their chemical composition was analyzed by gas chromatography coupled to mass spectrometry (GC–MS). Hierarchical cluster analysis (HCA) was used to evaluate possible differences between the chemical profiles of the essential oils. The Midilli model provided the best fit to the drying kinetics data. Analysis of the main classes of compounds present in the essential oils indicated similarity among the chemical profiles of oils obtained from leaves dried at different temperatures.

Keywords: Piper divaricatum; phenylpropanoids; drying.