CHEMICAL AND THERMOANALYTICAL CHARACTERIZATION OF THE PINK PEPPER (Schinus terebinthifolius Raddi) SEEDS ESSENTIAL OIL

Abstract

The essential oil (EO) of pink pepper has important biological properties that can enhance its application in the pharmaceutical, cosmetic and food industries. The objective of this study was to characterize the EO of pink pepper seeds in terms of their chemical composition and thermophysical properties. Certified pink pepper seeds obtained commercially were used. The EO was extracted by hydrodistillation and chemically characterized in a gas chromatograph coupled to mass spectrometer (GC/MS). The thermoanalytical characterization was performed on a simultaneous high resolution equipment, and the Thermogravimetric Analysis (TG) and Differential Scanning Calorimetry (DSC) were used to determine the physical-chemical and kinetic properties of the OE in the room temperature range up to 250 ºC in the 20 ºC.min-1 ratio under nitrogen atmosphere. The Arrhenius kinetic model was applied to determine the activation energy of the EO. A total of 51 chemical compounds were detected in the pink pepper EO, of which 42 compounds were identified (54.7% of monoterpene compounds and 45.3% sesquiterpenes). The major components were ?-pinene (26.80%), germacrene D (11.25%), sabinene (11.13%) and terpinen-4-ol (8.59%). The thermogravimetric analysis indicated a single stage of thermo-degradation of the pink pepper EO between 74.8 ºC and 184.7 ºC, being an endothermic peak in the physical transition of vaporization. The variation of enthalpy and activation energy of EO were found with values of = - (39.8 ± 9.5) KJ.Kg-1 and = - (2,546 ± 0.033) KJ.mol-1, respectively. The data presented in the thermogravimetric analysis of pink pepper seeds EO allowed observing important thermal parameters for the definition of industrial processes that can use it as raw material, so that its biological activities can remain stable under controlled temperature conditions and below the range degradation.