Combination of ultrasound assisted extraction and encapsulation for the extraction of olive pomace polyphenols

Abstract

Posljednjih desetljeća, kako se sve više razvijaju izolacijski i identifikacijski postupci tako i biljke koje su se prije koristile isključivo kao namirnice sada služe kao izvor tvari s farmakološkim svojstvima. Maslina (Olea europea, Oleacae) je izvor ulja koje se koristi u ljudskoj prehrani još od davnih vremena, a posebice području Mediterana gdje se nalaze brojni maslinici. Sve veća popularnost maslinovog ulja zbog pozitivnih učinaka na zdravlje povezana je s povećanjem količine krutog otpada. Razvojem prikladnog procesa ekstrakcije bioaktivnih spojeva iz krutog otpada (komine masline) i formulacije stabilnog, tehnološki prihvatljivog produkta ostvaruje se ekonomska i ekološka korist. Cilj ovog rada bio je razviti prikladan proces ekstrakcije polifenola iz komine i formulirati stabilni, tehnološki prihvatljiv produkt optimizacijom kombiniranog postupka ultrazvučne ekstrakcije i enkapsulacije ciklodekstrinima. Rezultati isptivanja govore da je ultrazvučnom ekstrakcijom moguće ostvariti isti prinos polifenola kao i kod klasične, ali u značajno kraćem vremenu i s manjim utroškom otapala. Odmašćivanjem komine prije postupka ekstrakcije može se dobiti bistar ekstrakt pogodan za daljnja ispitivanja, a bez značajnih gubitaka polifenola. Dodavanjem ciklodekstrina u ekstrakcijsko sredstvo bitno su poboljšana organoleptička svojstva liofiliziranog ekstrakta bez značajnog utjecaja na udio fenola i antiradikalni učinak. Ciklodekstrini značajno povećavaju prinos oleuropeina, glavnog biološki aktivnog polifenola masline. Razlog većim prinosima oleuropeina vjerojatno je stvaranje inkluzijskih kompleksa s β- i ɣ-ciklodekstrinom čime se molekula štiti tijekom procesa ekstrakcije i sušenja.For the last several decades, with the development of isolation and identification processes, plants previously used only as food are now being used as sources of pharmacologically active compounds. The olive has been a source of oil in human nutrition since ancient times, especially in the Mediterranean region. The increased production, consumption and popularity of olive oil has resulted in significant increase of solid waste remaining after oil production. By developing an appropriate, sustainable process of extraction of bioactive compounds from the solid waste and formulating a stable, technologically acceptable product, the economical and ecological benefits can be achieved. The goal of this thesis was to develop efficient and sustainable process for extraction of polyphenols from olive pomace and to formulate stable, technologically acceptable product. For that purpose, optimized processes of ultrasound assisted extraction was combined with encapsulation with cyclodextrins. The results showed that by ultrasonund assisted extraction significantly lower amounts of extraction solvent are needed and the time of extraction is significantly shortened in comparisson to classic solvent extraction.. By removing lipid component from pomace, we can get a clear extract that can be used for further examination without significant loss of polyphenols. By adding cyclodextrin to the extraction solvent organoleptic characteristics of lyophilized extracts were improved, without significant impact on polyphenolic yields and antiradical efficiency. Applied combination of ultrasound assisted extraction and cyclodextrin encapsulation significantly increased the content of oleuropein, the main active biological polyfenol of olive, in obtained extracts. The reason for higher oleuropein yields is probably the formation of inclusion complexes with β- and γ-cyclodextrin. In that way the molecule is protected from degradation during the process of extraction and drying