Orientador: Makoto Matsushita

Data da Defesa: 19/10/2020


Edible vegetable oils extracted from different food oil matrices have an energetic, structural, and hormonal function in the human body. The consumption of vegetable oils rich in omega 3, omega 6, and omega 9, helps in the reduction of cardiovascular diseases and some types of cancer. The ultraviolet and visible (UV-Vis) and near infrared (NIR) techniques together with chemometrics allow an analysis that is simple, fast, low cost, and without sample preparation that agrees with the standard of Green Chemistry to obtain information from a complex matrix such as vegetable oils. The main objective was to evaluate through the spectroscopies UV-Vis and NIR, vegetable oil extracted of soybean added with natural antioxidants and oils subjected to cold press extraction of different food matrices, using exploratory analysis, Parallel Factor Analysis
(PARAFAC), and Independent Components Analysis (ICA). The first work had the objective of evaluating the protective effect of natural antioxidants on soybean oil, without synthetic antioxidant, through NIR spectroscopy in a three-way arrangement (sample versus temperature versus absorbance in different wavelengths) using the chemometric method PARAFAC. The pumpkin seeds (Cucurbita maxima), poppy seeds (Papaver somniferum), dehydrated goji berry (Lycium barbarum), and Provence herbs (mix of herbs composed by thyme (Thymus vulgaris) oregano (Origanum vulgare), sage (Salvia
officinalis), and rosemary (Salvia rosmarinus), were directly added to the soybean oil (the vegetable bases were crushed and added to the soybean oil, separately), and in the form of a hydroalcoholic extract. Also, were evaluated synthetic antioxidants tercbutylhydroquinone (TBHQ), butylated hydroxytoluene (BHT), and the control sample (pure soybean oil). The evaluation was made via thermic degradation of the soybean oil at different temperatures (from 25 ºC to 170 ºC). The PARAFAC results demonstrate information related to the oxidation products and the antioxidant effect. Being possible
to observe the changes and evolution of the spectral profile during the oil heating, the oxidation products increased from 50 ºC and, the antioxidant decreased with the temperature. These observations allowed us to conclude that the antioxidant from the hydroalcoholic extracts was more effective to improve the soybean oil stability than, the vegetable bases directly added to the oil, TBHQ, BHT, and the control sample. The second work, evaluated using the spectroscopy UV-Vis and ICA, oils obtained by coldpressing from brown flaxseed (Linum usitatissimum), golden flaxseed (Linum usitatissimum), white sesame seeds (Sesamum indicum), black sesame seeds (Sesamum indicum), sunflower seeds (Helianthus annuus), chia seeds (Salvia
hispanica), pumpkin seeds (Cucurbita maxima), Brazil nuts (Bertholletia excelsa), Chilean nuts (Juglans regia), Baru nuts (Dipteryx alata) and cashew nuts (Anacardium accidentale), under heating process in different temperatures (from 25 ºC to 190 ºC). The ICA model allowed us to compare the oils accordingly to their composition, besides providing information about the primary and secondary oxidation compounds, tocopherol, and carotenoids. Given the results, the spectroscopies NIR and UV-Vis associated with chemometric methods PARAFAC and ICA, showed an alternative to evaluate the quality of edible vegetable oils, being efficient in their evaluation and behavior, demonstrating adequate analytical applicability. KEYWORDS: Spectroscopy; PARAFAC; ICA, Thermal degradation; Oxidation products; Antioxidant.

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