Ispitivanje fenolnih spojeva i senzorski profil dalmatinskih djevičanskih maslinovih ulja

Fenolni spojevi su prirodni antioksidansi prisutni u djevičanskom maslinovom ulju (DMU) koji utječu na konačnu procjenu kvalitete pojedinog maslinovog ulja. To su bioaktivni spojevi koji imaju izraženu antioksidacijsku aktivnost i značajno utječu na oksidacijsku stabilnost DMU, ali i na njegova senzorska svojstva. U ovom radu ispitivan je sastav fenola u djevičanskim maslinovim uljima iz odabranih autohtonih hrvatskih sorta s nekoliko lokacija na području srednje Dalmacije. Trogodišnja istraživanja provedena su na sortnim uljima dobivenim istovjetnim tehnološkim postupkom prerade. Provedeno je i senzorsko ocjenjivanje sortnih DMU kojima su definirana specifična obilježja okusa i arome koja se pripisuju isključivo sorti. U preliminarnim istraživanjima određeni su osnovni parametri kvalitete prema propisima za ekstra djevičansko maslinovo ulje, kao i ukupni udjel fenolnih tvari te sastav pojedinačnih fenola za pojedino sortno ulje. Kod nekih sorti su pojedine grupe fenolnih spojeva (sekoiridoidi, flavoni, lignani) pokazale veću antioksidacijsku aktivnost nego ukupni fenoli. Kod ulja drugih sorti, oksidacijska stabilnost ovisi upravo o udjelu ukupnih fenola. Kod svih ispitivanih uzoraka u ovom istraživanju vrlo je dobar udjel fenola i različitih sastava pojedinačnih fenolnih spojeva, ovisno o sorti. Senzorske karakteristike razlikuju se kod uzoraka ulja ovisno o ishodnoj sorti i imaju određena svojstva za svako pojedino sortno ulje.
Phenolic compounds are natural antioxidants present in virgin olive oil (VOO) that influence the final assessment of the quality of certain olive oil. These are the bioactive compounds that have a pronounced antioxidant activity and significantly affect the oxidative stability of the VOO, but also its sensorial properties. This paper examined the composition of phenolic compounds in VOO's from selected indigenous Croatian varieties from several locations in central Dalmatia. A three-year study was conducted on varietal oils obtained by identical chemical processing procedure. Sensory evaluation of monovarietal VOO’s was also conducted and specific characteristics of taste and aroma due to the olive variety were defined. In preliminary research, the basic quality parameters were determined according to the regulations for the extra virgin olive oil, as well as the total phenol content and the composition of individual phenolic compounds for particular monovarietal oils. Some varieties showed that a particular group of phenols (secoiridoided, flavones, lignans) had higher antioxidant activity than total phenols. In oils from other olive varieties, oxidative stability depended on the proportion of total phenols. In all samples in this study very good total phenol content was detected as well as different composition of individual phenolic compounds, depending on the olive cultivar. Sensorial characteristics of the samples varied depending on the variety and had specific attributes for each monovarietal VOO.