Influence of drying and solvent choice on the extractability of phenolic compounds from olive pomace

Komina masline je nusproizvod koji se odlikuje visokom koncentracijom fenolnih spojeva te se može koristiti kao jeftina sirovina za njihovu ekstrakciju. S obzirom da je svježa komina masline pogodna mikrobiološkoj i enzimatskoj aktivnosti, nužno ju je osušiti kako bi se sigurno skladištila. Cilj ovog rada bio je odrediti utjecaj procesa sušenja na ekstraktibilnost fenolnih spojeva. Na mikrovalno-ultrazvučnom ekstraktoru/reaktoru provedene su ekstrakcije fenolnih spojeva iz svježe i suhe komine 60%-tnim metanolom. Sušenjem je došlo do razgradnje fenolnih spojeva, no koncentracija nekih fenolnih spojeva veća je u suhoj komini. Veća koncentracija uočena je za vrlo traženi fenolni spoj vanilin. Drugi cilj rada bio je odrediti ekstraktibilnost fenolnih spojeva ekstrakcijom 60%-tnim metanolom i prirodnim eutektičkim otapalom, 70%-tnim kolin citratom. Ekstrakcije su provedene iz suhe komine na mikrovalno-ultrazvučnom ekstraktoru/reaktoru. Gotovo dvostruko veća koncentracija ukupnih fenolnih spojeva ekstrahirana je 70%-tnim kolin citratom, stoga ono predstavlja učinkovito otapalo za ekstrakciju fenolnih spojeva, a ujedno je ekološki prihvatljivo.Olive pomace is a byproduct that contains high amounts of phenolic compounds and can be used as a cheap material for their extraction. Fresh olive pomace is susceptible to microbiological and enzymatic degradation and it is necessary to dry it so it can be safely stored. The aim of this study was to determine the influence of the drying process on the extraction of phenolic compounds. By using microwaves and ultrasound assisted extractor, phenolic compounds were extracted from fresh and dry olive pomace with 60% methanol. Even though drying leads to significant degradation of the total phenolic compounds, the concentration of some phenolic compounds is higher in dry olive pomace. A higher concentration of vanillin was observed. Another aim of this study was to determine the impact of the extraction solvent, 60% methanol, and a natural deep eutectic solvent, 70% choline citrate on extractability of phenolic compounds. Extractions were carried out on a dry olive pomace by using microwaves and ultrasound. Almost two times higher concentrations of total phenolic compounds were extracted with choline citrate, so it is an effective solvent for extraction of phenolic compounds that is also environmentally acceptable