Dipteryx lacunifera seed oil: characterization and thermal stability

Abstract

The Dipteryx lacunifera Ducke is an oleaginous legume with high oil and protein content that can be used in human nutrition. The specie is a native of the Piauí and Maranhão state in the north east of Brazil. The measure physico-chemical properties of the oil are specific density, refractive index, acid, peroxide, iodine and saponification values of 0.91, 1.4651, 0.60 (% oleic acid), 2.81, 70.80 and about 179, respectively. Gas chromatographic analysis of the oil showed the presence of 20.6% saturated, 65.1% monounsaturated and 14.3% polyunsaturated fatty acids. The saturated fatty acids C6:0, C8:0, C12:0 and C17:0 were present in trace (<0.01%) amounts while the C16:0, C18:0, C20:0, C22:0 and C24:0 were at concentrations of 10.3, 5.4, 3.4, 0.9 and 0.6% of the total fatty acids. Unsaturated fatty acids C18:1, C18:2, C18:3 and C22:2 contents were 65.1, 14.1, 0.3% and trace (0.01%), respectively. Thermal analysis (TG/DTG) revealed that the thermal decomposition of the oil occurs in two steps corresponding to the unsaturated and saturated fatty acids. The oil, when heated to a temperature of 180º C for 400 min showed smaller loss in mass than commercial soy, sunflower and corn oils. The curve DSC indicated an endothermic event with enthalpy variation (DH) of -56.7 Cal.g-1 in the temperature interval of 340 ºC (Ti) the 463º C (Tf), with maximum in 411.1º C (Tm).