Tocopherols: Chemical Structure, Bioactivity, and Variability in Croatian Virgin Olive Oils

Virgin olive oil (VOO) represents a rich source of natural antioxidants, with tocopherols as the most effective group of lipophilic, phenolic antioxidants. α-Tocopherol represents more than 95% of the total tocopherols in virgin olive oil, and it possesses the highest biological activity among members of the vitamin E family. Content and composition of the tocopherols of virgin olive oil depend on several agronomic factors, as well as olive processing and oil storage conditions

Pomološka svojstava, sadržaj fenola i flavonoida te antioksidativna aktivnost introduciranih sorata šipka (Punica granatum L.) uzgajanih u mediteranskom dijelu Republike Hrvatske

Fruit samples of ‘Granada’, ‘Wonderful’ and ‘Hicaznar’ cultivars were collected in productive pomegranate orchard in Neretva valley, Metković (Croatia) and their pomological and chemical properties were compared. Significant differences among cultivars were noted between the studied traits. Fruit weight ranged from 429.37 g to 359.43 g and the lowest was recorded in cv. ‘Hicaznar’. Color of peel, aril and juice of all investigated cultivars was intensively red and dark red, respectively. ‘Granada’ and ‘Wonderful’ stood out with high juice yield compared with ‘Hicaznar’. Total soluble solid (TSS) of ‘Hicaznar’ (18.61%) was higher than that of ‘Wonderful’ (16.64%). Total acidity (TA) significantly differed among cultivars and ranged from 1.6% to 2.1%. According to the TSS/TA ratio investigated cultivars belong to the group of sour-sweet cultivars. Dissimilarity between cultivars was found in the phenolics content (TPC). It ranged from 679.6 to 906.6 mg/100 g D.W. where ‘Hicaznar’ stood out as a cultivar with highest TPC and also highest flavonoid and non-flavonoid content (521.1 mg/100 g D.W. and 385.5 mg/100 g D.W., respectively). In ‘Granada’ antioxidant activity measured by 1,1-diphenyl-2-picrylhydrazyl was recorded for 64.1%, in ‘Wonderful’ 70.2% and the highest in ‘Hicaznar’ (74.5%). Results of this assessment are the basis for practical determination of the pomegranate use.Uzorci plodova sorata ‘Granada’, ‘Wonderful’ i ‘Hicaznar’ prikupljeni su u proizvodnom nasadu šipka u dolini rijeke Neretve, Metković (Hrvatska) te su uspoređene njihove pomološke i kemijske karakteristike. Između istraživanih sorata utvrđene su značajne razlike. Masa ploda varirala je od 429,37 g do 359,43 g, a najmanja masa ploda utvrđena je kod sorte ‘Hicaznar’. Boja kore i arilusa (zrna) te soka svih istraživanih sorata je crvena odnosno tamno crvena. Plodovi sorte \u27Granada\u27 i \u27Wonderful\u27 istaknuli su se višim randmanom soka u usporedbi sa sortom \u27Hicaznar\u27. Sadržaj topljive suhe tvari (TSS) sorte ‘Hicaznar’ (18,61%) je veći u odnosu na TSS sorte ‘Wonderful’ (16,64%). Ukupna kiselost (TA) se značajno razlikovala između sorata i varirala je od 1,6% do 2,1%. Temeljem TSS/TA odnosa istraživane sorte pripadaju skupini kiselo-slatkih sorata. Različitost između sorata utvrđena je u sadržaju fenolnih spojeva (TPC) koji su bili u rasponu od 679,6 do 906,6 mg/100 g s.tv. Sorta ‘Hicaznar’ se istakla najvećim sadržajem ukupnih fenola, kao i sadržajem flavonoida i ne-flavonoida (521,1 mg/100 g s.tv. i 385,5 mg/100 g s.tv.). Antioksidacijska aktivnost mjerena sa 1,1-diphenyl-2-picrylhydrazyl sorte ‘Granada’ iznosila je 64,1%, ‘Wonderful’ 70,2%, a najveća je bila kod sorte ‘Hicaznar’ (74.5%). Rezultati ovog istraživanja osnova su za definiranje mogućnosti uporabe šipka

Survey of phenolic compounds and sensorial profile of Dalmatian virgin olive oils

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\u27s 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

Quantitatively Unraveling Hierarchy of Factors Impacting Virgin Olive Oil Phenolic Profile and Oxidative Stability

A single phenolic group and even a compound play different roles in the sensory properties and stability of virgin olive oil (VOO), which in turn are strongly influenced by several factors. Understanding the causes of differences in phenolic compound composition and oxidative stability (OS) in VOOs is essential for targeted and timely harvest and processing while maintaining desired oil quality. The phenolic profile and OS of two monocultivar VOOs (Oblica and Leccino) grown in two geographical sites of different altitudes (coastal plain and hilly hinterland) were analyzed throughout the ripening period over two years. Concentration of secoiridoids was 30% higher in the Oblica than in the Leccino VOOs, which in turn had significantly higher values of OS. Both cultivars had more than twice as high concentrations of the two most abundant phenolic compounds, the dialdehyde form of decarboxymethyl oleuropein aglycone and the dialdehyde form of decarboxymethyl ligstroside aglycone, and OS values in a colder growing site of higher altitude. Among the studied monocultivar VOOs, the secoiridoid group did not behave equally during ripening. The hierarchy of different influencing factors was investigated using multivariate statistics and revealed: cultivar > geographical site > harvest period > growing season. In addition, the possibility of traceability of VOO using molecular markers was investigated by establishing SSR profiles of oils of the studied cultivars and comparing them with SSR profiles of leaves

Characterization and genetic identification of Oblica and Leccino virgin olive oils from dalmatian olive orchards

Cilj ovog istraživanja bio je odrediti udio bioaktivnih komponenata, senzorska svojstva i oksidacijsku stabilnost djevičanskih maslinovih ulja autohtone sorte Oblice i introducirane sorte Leccino uzgajanih na području srednje Dalmacije. Ispitane su promjene sastava i svojstava u uljima koje nastaju pod utjecajem okolišnih čimbenika, stupnja zrelosti plodova te postupka filtracije. Cilj rada također je bio i utvrditi genetičke profile ispitivanih sortnih djevičanskih maslinovih ulja te procijeniti mogućnost sljedivosti djevičanskog maslinovog ulja pomoću mikrosatelitnih biljega.The objective of this study was to determine the proportion of bioactive compounds, sensory characteristics and oxidative stability of virgin olive oils from indigenous Croatian cultivar Oblica and introduced cultivar Leccino grown in the middle Dalmatia. Influence of environmental factors, the fruit ripening degree and process of oil clarification on the chemical comopsition and properties of tested virgin olive oil were investigated. The objective was also to determine the gentic profile of tested monocultivar virgin olive oils, and assess virgin olive oil traceability using microsatellite markers

Characterization and genetic identification of Oblica and Leccino virgin olive oils from dalmatian olive orchards

Cilj ovog istraživanja bio je odrediti udio bioaktivnih komponenata, senzorska svojstva i oksidacijsku stabilnost djevičanskih maslinovih ulja autohtone sorte Oblice i introducirane sorte Leccino uzgajanih na području srednje Dalmacije. Ispitane su promjene sastava i svojstava u uljima koje nastaju pod utjecajem okolišnih čimbenika, stupnja zrelosti plodova te postupka filtracije. Cilj rada također je bio i utvrditi genetičke profile ispitivanih sortnih djevičanskih maslinovih ulja te procijeniti mogućnost sljedivosti djevičanskog maslinovog ulja pomoću mikrosatelitnih biljega.The objective of this study was to determine the proportion of bioactive compounds, sensory characteristics and oxidative stability of virgin olive oils from indigenous Croatian cultivar Oblica and introduced cultivar Leccino grown in the middle Dalmatia. Influence of environmental factors, the fruit ripening degree and process of oil clarification on the chemical comopsition and properties of tested virgin olive oil were investigated. The objective was also to determine the gentic profile of tested monocultivar virgin olive oils, and assess virgin olive oil traceability using microsatellite markers

Virgin Olive Oil Phenols, Fatty Acid Composition and Sensory Profile: Can Cultivar Overpower Environmental and Ripening Effect?

The authenticity and typicity of monocultivar oils and knowledge of the changes that environmental olive growing conditions bring to naturally present antioxidants and sensory attributes of virgin olive oils (VOO) are important for quality and safety improvement. This study delivers a comprehensive evaluation of the factors affecting phenolics, fatty acid composition and sensory characteristics of cultivars Oblica and Leccino VOOs throughout ripening season at two distinct olive growing environments during three consecutive crop years, and ranks the importance of each factor. Specified parameters were significantly influenced by olive growing environmental conditions. At the colder location of higher altitude, both cultivars gained higher amount of stearic, linoleic and linolenic fatty acids, as well as a higher proportion of phenolic compounds, but lower amounts of oleic fatty acid. At the warmer location of lower altitude, both cultivars had oils with lower level of fruitiness, bitterness and pungency. Analysis of the main components showed that VOOs were primarily differentiated by the cultivar, then main groups were divided with regard to the growing site, while harvest period affected the biosynthesis of natural VOOs antioxidants but had the least impact. These results reveal that the composition of fatty acids, phenolic content and sensory profile are predominantly characteristics of a cultivar

Comparative Study of Volatile Compounds and Sensory Characteristics of Dalmatian Monovarietal Virgin Olive Oils

Volatile compounds are chemical species responsible for the distinctive aroma of virgin olive oil. Monovarietal olive oils have a peculiar composition of volatiles, some of which are varietal descriptors. In this paper, the total phenolic content (TPC), fatty acid composition, volatile compounds, and sensory profile of monovarietal olive oils from four Dalmatian most common olive cultivars—Oblica, Lastovka, Levantinka, and Krvavica—were studied. The volatile composition of olive oils was analyzed using headspace solid-phase microextraction with gas chromatography/mass spectrometry. The highest mean TPC value was measured in Oblica and Krvavica oils (around 438 mg/kg). The difference among cultivars for fatty acids composition was detected for C16:1, C17:0, C18:1, C18:2, and the ratio C18:1/C18:2. Krvavica oils showed clear differences in fatty acid composition compared to oils from other cultivars. The most prevalent volatile compound in all oils was C6 aldehyde E-2-hexenal, with the highest value detected in Levantinka oils (75.89%), followed by Lastovka (55.27%) and Oblica (54.86%). Oblica oils had the highest value of Z-3-hexen-1-ol, which influenced its characteristic banana fruitiness, detected only in this oil. Lastovka oils had the highest amount of several volatiles (heptanal, Z-2-heptenal, hexanal, hexyl acetate), with a unique woody sensation and the highest astringency among all studied cultivars. Levantinka oils had the highest level of almond fruitiness, while Krvavica oils had the highest level of grass fruitiness