Impact of cyclodextrin encapsulation on phenolic content of olive pomace extract

Plod masline (Olea europaea L.) je izvor prirodnih bioaktivnih spojeva fenolnog tipa međutim ekstrakcijom ulja samo 2% polifenola iz ploda prelazi u uljnu fazu, dok najveći dio (98%) zaostaje u komini. Obzirom na širok spektar njihovih bioloških učinaka i sve veću primjenu u farmaceutskoj i prehrambenoj industriji, raste potreba za razvojem učinkovitih postupaka njihove ekstrakcije iz širokodostupne komine masline te formulacijom stabilnih i kvalitetnih suhih ekstrakata. Cilj ovog rada bio je istražiti utjecaj enkapsulacije ciklodekstrinima na udio polifenola u ekstraktu komine masline. U tu su svrhu korišteni β-ciklodektrin (βCD), γ-ciklodekstrin (γCD), hidroksipropil β-ciklodekstrin (HPβCD) i metil β-ciklodekstrin (MetβCD) različitih koncentracijskih razina (8 g/L ili 16 g/L otapala) tijekom ultrazvučne ekstrakcije i sušenja smrzavanjem. Udio oleuropeina (OLE), hidroksitrosola (HTS) i tirosola (TS) u dobivenim ekstraktima određen je RP HPLC-DAD analizom. Istraženi ciklodekstrini pokazali su pozitivan utjecaj na organoleptička svojstva pripremljenih ekstrakata. Znatno povećani prinosi OLE određeni su u ekstraktima pripremljenim uz βCD (8 g/L) te γCD (8 g/L i 16 g/L). Suprotno tome, prinosi tirosola, neovisno o vrsti i koncentraciji ekscipijensa, smanjeni su za oko 30%. Iako je utjecaj ekscipijensa na prinos HTS bio negativan, βCD (8 g/L) i γCD (8 g/L) minimalno su smanjili njegove prinose. Dobiveni rezultati ukazuju kako enkapsulacija OLE u βCD i γCD može pridonijeti povećanoj topljivosti OLE u ekstrakcijskom sredstvu, kao i pokazati protektivne učinke tijekom ekstrakcije i sušenja smrzavanjem.Olive fruit (Olea europaea L.) is a rich source of bioactive compounds, mostly phenols. However, during the extraction of olive oil, only 2% of fruit phenolic is transferred to the oil phase while most phenols (98%) remain in olive mill waste. Having in mind wide range of their health-promoting properties and growing utilization in food- and pharmaceutical industry, there is a growing interes in developing efficient methods for their extraction from widely available olive pomace and formulation of high-quality dry extracts. The aim of this study was to investigate the impact of cyclodextrin encapsulation on phenolic content of olive pomace extract. For this purpose β-cyclodextrin (βCD), γ-cyclodextrin (γCD), hydroxypropyl-βCD (HPβCD) and methyl-βCD (MetβCD) in different concentration levels (8 g/L and 16 g/L solvent) were used during ultrasound assisted extraction and freeze drying. Obtained extracts were analyzed for oleuropein (OLE), hydroxytyrosol (HTS) and tyrosol (TS) content using RP HPLC-DAD. Investigated cyclodextrins showed positive effect on organoleptic properties of products obtained. Considerable higher yields of OLE were found in extracts containing βCD (8 g/L) and γCD (8 g/L and 16 g/L). On the other hand, TS yields were approximately 30% reduced, regardless of the type and concentration of used cyclodextrin. Although cyclodextrins decreased yields of HTS, extraction with βCD (8 g/L) and γCD (8 g/L) resulted in its minimal yield reduction. Results indicate that encapsulation of OLE in βCD and γCD can inhance its solubility in extraction solvent, as well as it can provide protection during extraction and freeze drying