Essential oils are complex mixtures composed by volatile compounds such as terpenes and their oxygenated derivatives, and by non-volatile compounds, such as waxes and pigments, being used by industry as flavorings. The oxygenated compounds are pointed as being the main responsible for aroma and quality of essential oil. In contrast, the terpene compounds are hydrocarbons of easy modification, being very unstable to degradation reactions, when exposed to air, light and high temperatures. Due to this fact, the terpenes are pointed as the responsible for essential oil instability, being responsible for the generation of unpleasant aroma and taste compounds, which impair their quality. By concentrating oxygenates components through reducing the content of terpene compounds, using separation processes, the industry is able to increase the quality of the essential oil and, consequently, their commercial value. Among the processes available for the fractionation of components of essential oils, the solvent extraction, or liquid-liquid extraction is highlighted due to its low cost and the possibility to be conducted under conditions of ambient temperature and pressure, preventing unstable compounds present in the essential oil to deteriorate. The physical properties of the phases present in the system not only influence the process of mass transfer, but also the step of coalescence of drops and their phase separation in the extraction equipment. Among the relevant properties can be cited the density, viscosity and interfacial tension, which is the subject of this research project. Thus, this project aims to determine the values of interfacial tension between the phases from the study of the liquid-liquid equilibrium of model systems of orange essential oil, composed by limonene and linalool, and acid lime essential oil model systems, composed by limonene, ³-terpinene , ²-pinene, citral. For both systems it will be used hydrous ethanol as solvent, at 25 °C.This work will be developed in conjunction with doctoral thesis entitled "Fractionation of citrus essential oils using ethanol with different levels of hydration as solvents: Phase equilibrium, physical properties and continuous extraction equipment" (FAPESP nº 2013/11150-3), under development by the post graduate student Daniel Gonçalves, supervised by Profa. Dra. Christianne Elisabete da Costa Rodrigues who is the advisor of this research project.
News published in Agência FAPESP Newsletter about the scholarship: