Estudo da degradação térmica de misturas dos óleos da macaúba (Acrocomia aculeata) por espectroscopia molecular

Abstract

Oils of pulp (31±3% (w/w) and the nut (39±4% (w/w) of Macaúba (Acrocomia aculeata) were obtained by solvent extraction. Samples for this study were prepared by mixtures of pulp oils and nuts, represented by PX (P0, P10, P25, P50, P75 and P100) where X is the percentage by mass of pulp oil added to oil Chestnut. These samples were thermally degraded at 110 ° C for 144h collecting Aliquots every 24h. aliquots were subjected to analyzes: Acid value, absorption of ultraviolet and visible light and fluorescence molecular and infrared. acidity index values of 0.03 ± 0.01 mgKOH / g for P0 (nut oil) and 0.40 ± 0.00 mg KOH / g for P100 (pulp oil) and intermediate values for mixtures PX. certain values were higher paras blends with higher percentage of pulp oil. however, these Samples that are rich in -Tocopherol and -carotene retained their original values close to those during the degradation. analysis by absorption of ultraviolet-visible, with readings at 232nm ([sample] = 0.04% w/v) and 270 nm ([sample] = 0.75% w / v), allows monitoring the thermal degradation of oils studied, as well as confirm the presence of antioxidants naturally present in the samples compared to the patterns of -Tocopherol and -Carotene. In Molecular analysis by fluorescence ([sample] = 1.50% w/v) were used three wavelengths: 324nm emission for the - Tocopherol, referring to 520nm and emission -carotene due to degradation products originating from 424nm, shown to be possible to monitor changes in physical and chemical characteristics of oils by molecular spectroscopy. absorption spectroscopy in the midle infrared was used to characterize the oils Macaúba, but this technique did not appear effective in monitoring the thermal degradation.