EFFECT OF OVEN DRYING ON THE FATTY ACID PROFILE AND BIOACTIVE COMPOUNDS IN OLIVE OIL EXTRACTION RESIDUE (Olea europaea L.)

The olive oil extraction process generates byproducts with promising potential for use in the agri-food chain. Among these byproducts, olive pomace stands out for being rich in nutrient and non-nutrient bioactive compounds. However, this pomace resulting from olive oil extraction is highly perishable, and strategies that promote its durability, such as drying processes, may be interesting. Therefore, the objective of this study was to evaluate the effects of a drying process on the fatty acid profile and bioactive compounds of olive pomace, compared to the fresh material. The olive pomace was collected in the state of Espírito Santo, Brazil, donated by the Association of Olive Growers of the State of Espírito Santo. Part of the samples was oven-dried  at 40°C for 16 hours. The fatty acids were identified using a gas chromatograph-mass spectrometer (GC-MS—Shimadzu QP1020). Given the above, the potential for utilizing olive pomace as an alternative for enriching food formulations is evident, adding nutritional value and sustainable principles. Antioxidant activity was determined using the  total phenolic compounds (TPC), total flavonoid compounds (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, ABTS cation radical (ABTS), and ferric reducing antioxidant power (FRAP) assay. The raw olive pomace presented 12.82% saturated fatty acids, 67.61% monounsaturated fatty acids, and 3.9% polyunsaturated fatty acids (omega-6). The presence of tridecanoic acid (15.67%), 9-octadecenoic acid (67.61%), and hexadecanoic acid (9.26%) was particularly noteworthy. After the drying treatment, the composition was 11.84% saturated fatty acids, 80.54% monounsaturated fatty acids, and 5.33% polyunsaturated fatty acids (of which 4.55% are omega-6 and 0.78% are omega-3). The most prominent fatty acids were 9-octadecenoic acid (79.74%), hexadecanoic acid (8.54%), and tridecanoic acid (2.29%). According to the antioxidant analyses, the raw sample presented TPC of 3,27 mg GAE/g, TFC of 1,77 mg CE/g,  DPPH of 276.97 µmol TE/g, ABTS of 7.70 µmol TE/g, and FRAP of 8.3 µmol TE/g. The dried sample, on the other hand, exhibited TPC of 6,35 mg GAE/g, TFC of 5,46 mg CE/g, DPPH of 174.88 µmol TE/g of sample, ABTS of 4.21 µmol TE/g of sample, and FRAP of 7.82 µmol TE/g of sample. The results demonstrate a lipid profile that is interesting for cardiovascular health. Although drying favored the concentration of some fatty acids, a reduction in antioxidant activity was observed, indicating the degradation of temperature-sensitive bioactive compounds. Given the results, the potential use of olive pomace as an alternative to enrich food formulations seems promising as a way to add nutritional value and strengthen sustainability initiatives. Acknowledgments: This study was financed in part by the Coordenação de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001, Fundação de Amparo à Pesquisa de Minas Gerais  - FAPEMIG and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).