THERMAL ANALYSIS OF THE OIL EXTRACTED FROM BACABA SEED

Bacaba (Oenocarpus bacaba Mart.) is a palm tree of Amazonian origin, whose fruits are used in the local population's diet in the form of ice cream, jellies, and beverages, due to its nutritional content. In the processing of this fruit, the pulp, which corresponds to 30-55% of the fruit, is used, and the peels and seeds are discarded. The seeds can be used as a by-product, as they are rich in fibers and lipids of interest to the food, cosmetic, and pharmaceutical industries. Thus, the objective of the study was to extract the oil present in the bacaba seeds and evaluate its thermal stability and fatty acid composition. The bacaba seed oil was extracted by ultrasound (40 kHz frequency and temperature of 35 ± 2°C), using hexane as solvent for 2 hours. To evaluate the thermal stability of the oil, thermogravimetric analysis (TG Curve) and Differential Scanning Calorimetry (DSC Curve) were performed. The characterization of the fatty acid profile was performed in a gas chromatograph coupled to a mass spectrometer (GC-MS). The oil obtained from the bacaba seed showed a yield of 1.18 ± 5.66%, a value possibly associated with the maturation stage, fiber content, and hardness of the seed, as well as its storage conditions and time. The obtained TG curve showed that the oil is stable up to a temperature of 148°C, and from that point on, its decomposition begins, increasing when it reaches 342°C. The absence of water in the obtained oil and an ash content of 2.5% were observed. In the DSC curve, an endothermic event at 34°C related to the melting point of saturated fatty acids was observed. In addition, endothermic and exothermic events associated with oil degradation occurred after the temperature of 360°C, which corroborates the results obtained in the TG curve, as well as the occurrence of an exothermic event in the DSC curve, at 150°C. The GC-MS analysis demonstrated the major presence of saturated fatty acids, mainly palmitic acid (86.81%), probably due to the intense cavitation of the extraction process, which possibly led to the breaking of unsaturated fatty acid bonds, usually found in this type of oil. Therefore, the extraction of bacaba seed oil is a promising alternative to take advantage of by-products of the fruit's processing, but needs further research related to the application of ultrasound-assisted extraction at different times and evaluation of the fiber content, to optimize the preservation of the desired oil characteristics.