CO_2 supercritical fluid extraction of pulp and nut oils from Terminalia catappa fruits: Thermogravimetric behavior, spectroscopic and fatty acid profiles

摘要

The aim of this study was to investigate the attributes of the pulp and nut oils from Terminalia catappa fruits obtained by supercritical fluid extraction (SFE) with pressurized CO2. The yield, physico-chemical characterization and fatty acid profiles of both oils were assessed based on their acidity and peroxide indices, thermogravimetric behavior, infrared spectroscopic and gas chromatographic analyses. The extraction yields were 7.4% and 61.5% for the pulp and nut from T. catappa, respectively. The pulp and nut oils exhibited low levels of acidity, 3.3 and 1.9 mg KOH g(-1), and peroxides, 3.8 and 1.7 mEq kg(-1), respectively. These values are lower than the maximum recommended levels given by the Codex Alimentarius for virgin oils (4.0 mg KOH g(-1) and 15 mEq Kg(-1), respectively). Unsaturated fatty acids were a major constituent of the oils (58%), of which omegas 3 and 6 were predominant. The infrared spectroscopy of the nut oil showed high intensity bands between 2912 and 716 cm(-1), representative of chemical groups commonly present in unsaturated fatty acids. The pulp oil displayed higher thermal stability than the nut oil, whereby the initial degradation temperatures (T-onset) were 280 degrees C and 230 degrees C, respectively. This difference may be related to a greater amount of saturated fatty acids in the pulp oil compared to the nut oil. Thus, both pulp and nut oils displayed good physicochemical properties, which are desirable in diverse industrial sectors.