Brazil has a large number of native forest species and fruits, and some of them proved to be good sources of nutrients, such as baru. The cumbaru or baru (Dipteryx alata Vogel) is an important leguminous tree species from the Brazilian Cerrado. The oil extracted from the baru seeds has a high content of oleic and linoleic acid, which is widely used in pharmaceutical and food industries. The objective of this study was to obtain extracts of baru using supercritical fluid extraction with CO2 (SFE) assisted by ultrasound (US). About 500 g of baru seed were separated from the pulp and grounded. The seed were characterized in terms of proximate composition and fatty acids profile of the extracted oil by the Bligh and Dyer method. The SFE experiments were performed at temperature of 45 ± 3°C, pressure of 20 ± 0.5 MPa and CO2 flow rate of 0.5 ± 0.1 kg/h. To study the influence of ultrasonic waves in the extraction rate and yield, extractions were performed with and without ultrasound at power of 360 W. The moisture content of the baru seeds was 7.5 %, and the extracted oil showed a predominant presence of unsaturated fatty acids. The yield obtained in first hour of extraction without ultrasound was of 13 % (kg extract /kg sample) while the yield obtained at the same time for the ultrasound at 360 W SFE were near 24 %. The kinetics extraction curve for the US assisted extraction showed a shorter constant extraction rate period (tCER) compared to extraction without ultrasound. The global yield for the SFE experiments with and without ultrasound was 37.45 % and 36.37 %, respectively. These values are similar to total lipids obtained by the Bligh and Dyer method (35 %), which indicates that SFE-CO2 is effective for the extraction of lipids from baru seeds.
The baru nut is a seed of the Baruzeiro plant (Dipteryx alata Vog.), a species of shrub belonging to the Leguminosae Faboideae family that is native to the Cerrado. The Cerrado, the second largest biome in South America after the Amazon rainforest, is characterized by a typical hot climate, semi-humid and notably seasonal with rainy summers and dry winters, similar to the savannas. In Brazil the baru nut is known by several popular names such as: barujó, baruzeiro, baruí, coco beans, cumbaru and cumaru. The baru nut is rich in high-quality proteins (23.9 to 29.9%) and in lipids (38.2 to 41.9%) that are predominantly unsaturated fatty acids. Moreover, the baru nut contains high concentration of calcium, iron and zinc [1,2,3]. The extraction of active compounds from raw materials from plant sources is a promising area in the food industry. On the other side, it is a complex task because, in most cases, the target compounds are oxidative or thermolabile substances. Furthermore, severe legal restrictions are proposing the removal of general use of organic solvents in extraction industrial plants. Therefore, there is considerable interest in replacing processes such as steam distillation and extraction with organic solvents traditionally used for the recovery of these active compounds  The technology of supercritical fluid extraction (SFE) came forward as an alternative to traditional methods for the extraction and fractionation of active compounds. Among the most commonly used supercritical fluid is carbon dioxide (CO2), whose advantages in extraction processes are: low cost, nontoxicity, no flammability, inert and good extraction capacity . Generally, in a supercritical extraction unit one can observe the effects of temperature, pressure, extraction bed size, solvent flow rate, among others, in order to maximize the yield of a specific compound . The morphology of the particle can also influence the extraction yield of a specific compound, since the extraction occurs also through the path that the solvent must pass inside the solid particle, in order to extract specific compounds . Moreover, the SFE unit capacity has changed by using combined extraction techniques, such as the use of different co-solvents and ultrasonic waves . The ultrasound technique is based on the formation of ultrasonic waves of high frequency, which are capable of causing cavitations due to expansion and contraction cycles undergone by the material. Such cycles disrupt the cell walls of the vegetable matrix, favoring the penetration of the solvent and mass transfer, thus increasing the extract yield . The objective of this investigation was to obtain extracts of baru nut by supercritical fluid extraction (SFE) assisted by ultrasound,