Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 2nd International Congress on Bioactive Compounds

Brazil has a rich biodiversity of fruits and seeds, source of lipids with high functionality for the human body. Several of them are very important for the income of local communities, which is the case of the Amazon region. Oils from these matrices are generally obtained by cold pressing, resulting in a bagasse that still contains a significant fraction of oil. Several works have shown the potential of bioethanol as a sustainable solvent for the extraction of this residual oil. For the development of the extraction process, however, it is important to evaluate the mutual solubility between this solvent and the oil to be extracted to correctly determine the process conditions. Therefore, this work was aimed at evaluating the mutual solubility of ethanol and vegetable oils from Brazilian biodiversity. The liquid-liquid phase equilibrium (LLE) diagrams of pseudo-binary mixtures (vegetable oils + anhydrous bioethanol) were experimentally described for peanut and pequi oils provided by local suppliers (Amazon oil, Ananindeua, Brazil). Data were also modelled with the LLE theory by using the NRTL equation for calculation of the activity coefficients, considering the oil as a pseudo-compound. The oils’ fatty acid (FA) composition was determined by Gas Cromatograph and the probable triacylglycerol (TAG) composition calculated. Systems were placed in a jacketed glass cell coupled to a temperature-controlled bath, magnetically stirred during 30 min followed by a rest for 24 h to achieve the equilibrium. Both phases were sampled through holes in the glass cell and both oil and bioethanol composition determined by gravimetry after drying of the samples in a forced circulation oven at 80°C for complete evaporation of the alcohol. LLE were evaluated from 298,15 to 333,15 K, with 5 tie-lines per system. Results showed that, at 298,15 K the oil composition in the ethanol phase was at 5 to 10 % by mass and the bioethanol composition in oil phase was at 15 to 20 % ethanol by mass. Mutual solubility softly increases up to the consolute point, close to 338,15 K. The two-phase region was almost similar for all oils used but slight differences were observed. When results are compared to the LLE of soybean oil + bioethanol, presented in literature, a higher solubility at higher temperatures was observed in case of peanut oil, which is an operational advantage. Indeed, peanut oil presents a higher oleic acid:linoleic acid composition ratio when compared to soybean oil. These small compositional changes could affect the solubility of the system in anhydrous bioethanol. Additionally, the lower concentration of linoleic acid in peanut oil makes it less affected by oxidation problems, which points to an advantage in terms of oils’ physicochemical quality. This is also the case for pequi oil, mostly composed by palmitic and oleic acid. Therefore, it is possible to provide a better operational condition for the performance of the extraction of the oil from the bagasse of these species, considering the use of bioethanol promoting development of new products and socioeconomic growth for the regions where these matrices are produced.