Preliminary Investigation of Different Drying Systems to Preserve Hydroxytyrosol and Its Derivatives in Olive Oil Filter Cake Pressurized Liquid Extracts

Abstract

Phenolic compounds present in extra virgin olive oil (EVOO) could be retained in its byproducts during processing. Among them, hydroxytyrosol and its derivatives deserve special attention due to their health benefits recognized by The European Food Safety Authority (EFSA). In the present research, the presence of these compounds in the filter cake byproduct was studied by combining pressurized liquid extraction (PLE) and high-performance liquid chromatography coupled to time-of-flight mass spectrometry (HPLC-TOF-MS). The applied optimum extraction parameters were 1500 psi, 120 °C and aqueous ethanol (50:50, v/v). The influence of different drying methods (vacuum-, freeze- and spray-drying) in the recovery of phenolic compounds was also evaluated. A total of 16 compounds from EVOO were identified in the extracts, 3 of them being hydroxytyrosol-related compounds, 6 substances of oleoside and elenolic acid derivatives, together with 6 secoiridoids and 1 lignan. The results highlighted the great number of phenolic compounds recovered from filter cake with these techniques, being even higher than the reported content in EVOO and other byproducts. The combination of PLE and freeze-drying resulted in being the best procedure for the recovery of phenolic compounds from filter cake byproduct.

Compostos bioativos presentes no azeite de oliva e seus subprodutos: revisão bibliográfica

“…Também a Extração Líquida Pressurizada tem se mostrado efetiva para recuperar compostos fenólicos de subprodutos (López-Salas et al, 2021;Katsinas et al, 2021); além da destilação das águas residuais com membrana de contato direto para separar, purificar e concentrar compostos fenólicos bioativos da água como alternativa ao uso de extração líquido-líquido e cromatográfico ressaltando que convêm tratar a água residual da produção de azeite por dois motivos, primeiro por ser altamente contaminante e uso dispendioso, segundo por essa água ser fonte rica de compostos fenólicos, sendo incoerente seu descarte (Tundis et al, 2021).…”

“…Compostos fenólicos têm adquirido grande importância por suas propriedades benéficas à saúde, atuando como antioxidantes, anti-inflamatórios, anticancerígenos, antiaterogênicos, antimicrobianos, cardioprotetores (López-Salas et al, 2021;Katsinas et al, 2021). Sobressaindo a atenção dada a substâncias naturais como forma de neutralizar os danos produzidos pelo estresse oxidativo principalmente (Alemán-Jiménez et al, 2021).…”

“…Assim, compostos fenólicos naturalmente presentes no azeite de oliva extra virgem, como o hidroxitirosol, a oleuropeína, os flavonóides, têm despertado grande interesse no mundo científico, principalmente a partir do momento em que a Autoridade Europeia de Segurança Alimentar (EFSA) reconheceu seus efeitos antioxidantes benéficos à saúde (López-Salas et al, 2021).…”

“…A maioria dos países do Mediterrâneo (especialmente Espanha, Itália e Marrocos) produzem quase todo o azeite do mundo. Neste processamento industrial, grandes quantidades de resíduos são gerados, os quais são fontes de compostos bioativos fenólicos, fornecendo assim subprodutos de alto valor nutricional (López-Salas et al, 2021).…”

Valorization of Olive By-Products: Innovative Strategies for Their Production, Treatment and Characterization

“…For example, a few recent reports have studied the influence of the different extraction conditions on the achievement of phenolic antioxidants from these substances. López-Salas et al [24] have conducted research on preliminary investigation of different drying systems to preserve hydroxytyrosol and its derivatives in olive oil filter cake pressurized liquid extracts. This aspect appears interesting considering that the filtration process of EVOO is widely applied in most olive-oil industries of the main producing countries of the Mediterranean as a final step prior to selling the oil.…”