Análise lipídica de algumas espécies de palmeiras oleaginosas nativas da Amazônia

Abstract

The Amazon region presents numerous vegetal species from which oils and fats of chemical composition and diverse physicochemical properties are extracted. Among these, the palm trees (Arecaceae) stand out that despite the great abundance, few are those explored economically, such situation may be related to the lack of further studies on the lipid composition of the same. In this way, aiming to contribute to obtaining more comprehensive knowledge about the quality and chemical composition of Amazonian species, the present work had the objective to evaluate the structural composition of triacylglycerides (TAGs) present in three species of Amazonian palms: bacaba Oenocarpus bacaba Martius, pupunha Bactris gasipaes Kunth e tucumã Astrocaryum aculeatum G. F. W Meyer. The fruits of these species were purchased at local fairs and had their oils from the dry and fresh materials of the husks, pulps and almonds subjected to extraction with cold acetone. After obtaining the oils, they had their fatty acids characterized and quantified chemically after process of derivatization by CG-FID and confirmed by GC-MS. Subsequently, the TAGs were separated of the diverse lipid classes by solid phase extraction (SPE) and then isolated by high efficiency liquid chromatography (HPLC) using C18 and C30 columns. The isolated TAGs were identified and characterized regiospecifically by multi-stage mass spectrometry (MSn) with the aid of lithium and ammonium salts, using electrospray ionization (ESI) source in positive mode and detection in ion-trap analyzer. The GC-MS and GC-FID analyzes showed similar fatty acid profiles in all oils from fruit peels and pulps, with predominance of unsaturated fatty acids, highlighting the significant presence of oleic acid and essential fatty acids as linoleic acid (ω6) and linolenic acid (ω3), the latter only identified in the oils of the barks and pulps of the fruits of tucumã. In the almonds of the fruits of pupunha and tucumã the predominance of saturated fatty acids as lauric, myristic and palmitic acids was observed, besides the relevant presence of oleic acid (monounsaturated fatty acid). Through the analysis by mass spectrometry of TAGs isolated by HPLC, it was possible to identify and characterize regiospecifically 30 to 75 TAGs present in the oil of the pulp and almond of the fruits. The fruit pulp oils showed an abundance of unsaturated fatty acids, such as oleic and / or petroselinic, palmitoleic and essential fatty acids linoleic (ω6) and linolenic (ω3) fatty acids, the latter in oils from pulps of tucumã, esterified in the sn-2 position of different TAGs. The oils of the almonds the pupunha and tucumã fruits have been shown to be rich in medium chain saturated fatty acids, such as lauric, myristic and palmitic acids, as well as the presence of oleic and / or petroselinic acid esterified indistinctly in the regional, sn- 1 / sn-3 and sn-2 of the TAG molecules. The presence of fatty acids important for the human diet, such as unsaturated acids and essential fatty acids esterified at the sn-2 position of triacylglycerides, demonstrate the lipid potential of the Amazonian oils for food purposes, since this regional position has great biological importance in the process storage and metabolism of lipids.