Aromatização assistida por ultrassom seguida de oleogelação como estratégia para agregação de valor ao óleo de bagaço de oliva

Abstract

In the processing of olive fruits, large amounts of by-products are generated. The olive oil extraction process generates about 80% of by-products, such as bagasse. With this by-product, olive pomace oil (OB) can be produced when a mixture of olive pomace and water is subjected to a second centrifugation. Bagasse oil is a product of low resistance to lipid oxidation thanks to the low content of phenolic compounds, tocopherols and volatile compounds present. Thus, the aromatization of OB could increase the content of bioactive and volatile compounds that could benefit the product itself and the consumer. In addition to this process to add value to OB, oleogelation that aims at structuring oils and can be an innovation for the solid fat industries, since oleogels have a low content of saturated fatty acids and are free of trans isomers. Therefore, in this work, two strategies were used to add value to OB (aromatization with spices, by means of ultrasound to accelerate the process and increase the migration of bioactive and volatile compounds from spices to OB and oleogelation from aromatized OB). After optimizing the OB aromatization process with rosemary and basil, the samples were evaluated for quality parameters, content of total phenolic compounds, antioxidant capacity, oxidative stability, volatile compounds and fatty acid profile. The results were compared with OB and conventional flavoring for 7 and 15 days. Afterwards, the OB flavored with rosemary was structured with carnauba wax (CW) in two proportions (7 and 10%) and were evaluated: analysis of color (AC), oil binding capacity (OBC), crystal formation time (CFT), thermal analysis (DSC), texture analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), peroxide index (PV) and viscosity analysis, in comparison with commercial margarine (M). The greatest advantage of using the ultrasonic method is related to the acceleration in the OB aromatization process and, although this method has presented some less satisfactory results than the conventional method, it can be verified that it was efficient, especially in the migration of bioactive compounds. As for oleogelation, the two formulations of oleogel resembled, in many respects, to M and, although some results obtained for oleogels had a significant difference in relation to M, it can be confirmed that there was an efficient structuring of OB. In view of the above, it was possible to increase the bioactive potential of OB by means of the ultrasonic aromatization method, as well as to promote the oleogelation of olive pomace oil flavored with rosemary in order for it to be a product with the potential to replace products commercially available spreads, often rich in saturated fatty acids and trans isomers.