BRAZIL NUT ( BERTHOLLETIA EXCELSA HBK) SEED KERNEL OIL: CHARACTERIZATION AND THERMAL STABILITY.

Brazil nut shows a high nutritive and commercial value, and represents an important export product from the north region of Brazil. The oil extracted from its kernel presents a high coefficient of digestibility, and the flour is a protein rich product. This is mixed with wheat flour in recipes of a highly nutritive value bread. Also, its flour composes pre-cooked food and animal feed. The objective of this work was to extract the oil of Brazil nut kernel and study its physic-chemical, chemical and thermal properties. The mean oil content in the Brazil nut kernel is 68.58%. Mean values for the physic-chemical characteristics of this oil are: specific density-0.94, refractive index-1.4451, peroxide index-2.92, acidity index in oleic acid-0.71, iodine index (Hulb)-97.8 and saponification index-187.5 indexes. Chromatographic analysis resulted in the following mean values of fatty acids: saturated (28.62%) - C7:0, C8:0, C12:0, C13:0, C17:0 and C19:0-traces (<0.06%), C16:0-15.45%, C18:0-12.83%, C20:00.07%, C22:0-0.09% and C24:0-0.19%, monounsaturated (32.03%) and polyunsaturated (39.24%) - C16:1 - traces, C18:1 – 31.95%, C24:1 – 0.08%, C18:2 – 39.14% and C18:3 – 0.10%. TG/DTG curves showed that the process of thermal decomposition of the oil occurs in three phases: decomposition of polyunsaturated, monounsaturated and saturated oils, respectively. DSC curve revealed one endothermic event due to thermal decomposition at Ti = 340°C and Tf = 395°C, and with ΔH = 30.33 Cal/g. Uniterms : Brazil nut, oil, physical and chemical properties, chemistry, thermogravimetry.