Efeito protetor do fruto da aroeira (Schinus terebinthifolius Raddi) sobre a oxidação lipídica em sistemas modelo contendo óleo de sardinhas (Sardinella brasilliensis)

Abstract

Fish and fish products are constantly characterized as functional due to the high content of polyunsaturated fatty acids, however they contain appreciable concentrations of cholesterol. Thus, high temperatures lead to the degradation of these compounds and formation of oxidized compounds, compromising the nutritional quality and safety of these foods. Therefore, it is essential to search for alternative sources of natural antioxidants that minimize the thermo-oxidative processes and attend the demand for food free of synthetic additives. The objective of this work was to evaluate the protective effect of aroeira fruits in two concentration levels (0.2% and 0.5%) against lipid oxidation in a model systems containing sardines oil heated at different temperatures (150 °C and 180 °C), besides the control. The fruits were previously characterized presenting relevant nutritional potential. It was determined the presence of essential fatty acids and bioactive compounds. Among the bioactive compounds, flavonoids presented the higher content (10.33 ± 0.34 mg QE/g), and compounds such, tetrahydroamentoflavone, agathisflavone and hikinoflavone, were identified by liquid chromatography coupled to mass spectrometry. The antioxidant activity was verified in in vitro and in vivo analyzes. The β-carotene/linoleic acid assay determined 61.41% of oxidative inhibition for the fruits extract. In vivo experiments demonstrated the low toxicity of the aqueous extracts of aroeira fruits against Saccharomyces cerevisiae cells and the pretreatment with the extract (10 μg/mL) increased the cell survival by 31.72% against oxidative stress due to the presence of H 2 0 2 . For the determination of lipid oxidation, the formation of reactive species to thiobarbituric acid (TBA) and alterations in the fatty acids composition and cholesterol were identified, quantifying the formation of cholesterol oxidation products (COPs). The heating caused the decrease of the polyunsaturated fatty acids (PUFAs) content and the increase in the content of substances reactive to TBA and COPs, mainly at 180 °C. The PUFAs content was reduced by approximately 7 and 23% in the samples without antioxidants addiction heated at 150 and 180 °C, respectively. However, the addition of aroeira fruits minimized PUFAs degradation, reducing the percentage of degradation of these compounds in 17.07%, for the treatment using 0.5% of aroeira fruits (180 °C). Heating at 180 °C reduced the cholesterol content by 84.75%, with an increase in the content of total COPs from 58.9 ± 0.26 to 577.5 ± 2.14 μg/g of sample. However, the treatment with aroeira fruits showed protective effect of 15.51 and 23.22% for the additions with 0.2 and 0.5%, respectively. Although the synthetic antioxidant presented a more significant protective action against cholesterol oxidation under the evaluated conditions, even though it has been applied at the limit concentration permitted by the legislation, the protective effect exhibited by aroeira fruits suggests the use of these as natural antioxidant, helping to preserve the nutritional aspects and providing safe food free of compounds harmful to health.