PHYSICOCHEMICAL AND SPECTROSCOPIC CHARACTERIZATION OF AMAZONIAN OILS: A SUSTAINABLE FTIR-BASED APPROACH

The Amazon, renowned for its biodiversity, is home to valuable plant resources, among which the oils extracted from bacaba (Oenocarpus bacaba) and patauá (Oenocarpus bataua) stand out. The characterization of these oils aims to guarantee their identity, quality and stability, as well as strengthening the regional bioeconomy and integrating this raw material into industrial chains of production processes in the food industry. This study aimed to carry out the physicochemical characterization of bacaba and patauá oils, focusing on the correlation between physicochemical parameters and spectra obtained by Fourier Transform Infrared Spectroscopy (FTIR). The FTIR technique stands out as a highly advantageous analytical tool because it is fast, non-destructive, and solvent-free. Spectroscopic analyses were conducted in the mid-infrared (MIR) region, from 650 cm⁻¹ to 4000 cm⁻¹, while the physicochemical parameters evaluated included acidity index (mg KOH g⁻¹), iodine index (g I₂ 100 g⁻¹), and density (g mL⁻¹ at 25 °C), according to the methods of the American Oil Chemists' Society (AOCS). The absorption spectra revealed characteristic bands of fatty acids, glycerides, and unsaponifiable compounds, as well as compositional variations between the oils. The low presence of hydroxyl and amine groups indicated minimal oxidation and good preservation of the oils' properties. The physicochemical data confirmed the high quality of the samples: bacaba oil had an acidity of 3.99 ± 0.21 mg KOH g⁻¹, an iodine index of 69.76 ± 0.82 g I₂ 100 g⁻¹, and a density of 0.91 g mL⁻¹ ; while patauá oil had an acidity of 4.03 ± 0.23 mg KOH g⁻¹, an iodine value of 77.19 ± 1.12 g I₂ 100 g⁻¹, and a density of 0.92 g mL⁻¹ . These values are in accordance with the limits established by ANVISA for edible oils, as specified in RDC n°. 270/2005. The iodine index, which is greater in patauá oil, suggests a higher degree of unsaturation, a characteristic valued in the cosmetic and pharmaceutical industries for its bioactive and emollient properties. This parameter is also relevant for industrial processes such as hydrogenation and biofuel production. The high quality of the oils was confirmed by physicochemical and spectroscopic data. The application of the FTIR proved to be an efficient and advantageous approach for the detailed analysis of the properties of Amazonian oils. Understanding these characteristics allows for adjustment and optimization of process conditions, considering the specificities of each oil matrix to achieve maximum efficiency and quality in the final product.