Varijabilnost fenolnih i hlapljivih sastojaka djevičanskih maslinovih ulja sorti Leccino i Istarska bjelica ovisno o sastavu mješavina njihovih plodova

Phenolic and volatile compounds are closely related to valuable gastronomic and nutritional properties, as well as oxidative stability of virgin olive oil. Since biochemical synthesis and transformation of these compounds during olive processing depend on the activity of endogenous enzymes, which are partially influenced by genetic factors, mixtures of different cultivars could have either a synergistic or antagonistic effect on phenolic and volatile compounds in the resulting oil. In this context, two specific cultivars from the Istrian peninsula, Leccino (L) and Istarska bjelica (B), were selected. Two monovarietal fruit samples (L100 and B100) and four mixtures in the following mass ratios: L/B=80:20, L/B=60:40, L/B=40:60 and L/B=20:80 were prepared. The mass fraction of total phenols was determined colourimetrically, while C6 and C5 volatiles from lipoxygenase pathway were determined by headspace solid-phase microextraction-gas chromatography. Mass fraction of total phenols in the oil samples from fruit mixtures changed linearly from (199.5±7.2) in Leccino to (642.0±61.7) mg/kg in Istarska bjelica, in a strict correlation with fruit mass ratio of the two cultivars. Leccino monovarietal samples had statistically higher values (p≤0.05) of C6 aldehydes ((15.32±1.69) vs. (10.91±0.62) mg/kg) and C6 alcohols ((2.96±0.98) vs. (0.17±0.05) mg/kg), but lower values of C5 compounds ((0.77±0.12) vs. (0.96±0.05) mg/kg) compared to Istarska bjelica samples. Volatiles having a direct contribution to the oil aroma (odour activity value >1.0) were 1-penten-3-one (84–201), E-2-hexenal (26–42), hexanal (1.8–2.4) and Z-2-penten-1-ol (1.3–2.6). A significant synergistic effect was observed for C6 aldehydes in the case of L/B=40:60 fruit mixture. The addition of Istarska bjelica to Leccino fruits caused a significant antagonistic effect on C6 alcohols, but no significant deviations from the expected values were found in the case of C6 esters and C5 compounds. Results suggest that fruit combinations of two chosen cultivars in olive processing offer interesting possibilities for targeted modulation of phenolic and volatile compounds in virgin olive oil, and consequently, their sensory and nutritional characteristics.Fenolni i hlapljivi spojevi te oksidacijska stabilnost djevičanskog maslinovog ulja utječu na njegova gastronomska i hranjiva svojstva. Budući da biokemijska sinteza i transformacija fenolnih i hlapljivih spojeva tijekom prerade maslina ovisi o aktivnosti endogenih enzima, koja je dijelom određena genetskim faktorima, mješavine plodova različitih sorti mogu imati bilo sinergistički, bilo antagonistički učinak na njihov udjel u dobivenim uljima. Odabrane su dvije specifične sorte Istarskog poluotoka, Leccino (L) i Istarska bjelica (B). Dva sortna uzorka plodova (L100 i B100) te četiri mješavine plodova (masenih omjera: L/B=80:20, L/B=60:40, L/B=40:60 i L/B=20:80) prerađeni su u laboratorijskom uređaju. Maseni udjel ukupnih fenola određen je kolorimetrijski dok su C6 i C5 hlapljive tvari iz lipoksigenaznog puta određene mikroekstrakcijom na čvrstoj fazi iz para iznad ulja i plinskom kromatografijom. Maseni se udjel ukupnih fenola u uzorcima ulja dobivenim od mješavina plodova mijenjao linearno od (199,5±7,2) u ulju sorte Leccino do (642,0±61,7) mg/kg sorte Istarska bjelica, ovisno o promjeni masenih udjela plodova tih sorata. Ulje sorte Leccino imalo je statistički značajno više (p≤0,05) C6 aldehida ((15,32±1,69) mg/kg) i alkohola ((2,96±0,98) mg/kg), ali manje C5 spojeva ((0,77±0,12) mg/kg) u usporedbi s uljem sorte Istarska bjelica, koje je imalo ove vrijednosti: (10,91±0,62) mg/kg C6 aldehida, (0,17±0,05) mg/kg C6 alkohola i (0,96±0,05) mg/kg C5 spojeva. Hlapljivi spojevi koji utječu na aromu ulja (mirisna aktivnost >1,0) bile su 1-penten-3-on (84-201), E-2-heksenal (26-42), heksanal (1,8-2,4) i Z-2-penten-1-ol (1,3-2,6). Miješanjem plodova u omjeru L/B=40:60 postignut je sinergistički učinak na udjel C6 aldehida. Dodatak Istarske bjelice plodovima sorte Leccino utjecao je antagonistički na udjel C6 alkohola, ali ne i na udjele C6 estera i C5 spojeva. Rezultati upućuju na zaključak da se miješanjem plodova dviju odabranih sorti u preradi mogu dobiti ulja s ciljanim udjelom fenolnih i hlapljivih sastojaka ulja, te željenih senzorskih i hranjivih svojstava

Cold and hot hexane extraction of oil from olive pulp and seeds of Leccino cultivar

U ovom radu istražena je učinkovitost hladne i tople (Soxhlet) ekstrakcije ulja iz suhe tvari liofiliziranih maslinovih tijesta (bez koštice i s košticom) te iz sjemenki ploda masline sorte Leccino. Istražen je i utjecaj ekstrakcije na sadržaj ukupnih fenolnih tvari i orto-difenola u dobivenim uljima. U maslinovim tijestima i sjemenkama određen je udio ukupnih fenola i antioksidacijski kapacitet (IC50). Hladna i topla ekstrakcija pokazale su se podjednako učinkovite u izdvajanju ulja iz liofiliziranih maslinovih tijesta, dok je topla ekstrakcija bila učinkovitija u izdvajanju ulja iz sjemenki. Maslinova tijesta bez koštice imala su najveći udio fenolnih tvari (12,9 mg g-1 s.t.) od tri ispitivana biljna materijala. Stoga su i ulja dobivena iz njih, osobito ona dobivena toplom ekstrakcijom, sadržavala najveće udjele ukupnih fenola (396,7 mg kg-1) i orto-difenola (206,3 mg kg-1). U odnosu na maslinova tijesta, sjemenke su imale statistički značajno niži udio ukupnih fenola te višestruko niži antioksidacijski kapacitet. Rezultati su potvrdili da se uklanjanjem koštice smanjuje negativni utjecaj peroksidaza iz sjemenki na fenolne tvari u tijestu i ulju, te upućuju da se primjenom tople ekstrakcije povećava topljivost fenolnih tvari iz biljnog materijala u ulju.In this work, the effectiveness of cold and hot (Soxhlet) extraction of oil from the dry matter of lyophilized olive pastes (without pit and with pit) and seeds of olive fruits of Leccino cultivar, was investigated. The effect of extraction on the content of total phenols and ortho-diphenols in the obtained oils was also investigated. Total phenols content and antioxidant capacity (IC50) were determined in olive pastes and seeds. Cold and hot extraction proved to be equally effective in extracting oil from lyophilized olive pastes, while hot extraction was more efficient in extracting oil from seeds. Olive pastes without pits had the highest total phenols content (12.9 mg g-1 of dry mass) of the three investigated plant materials. Therefore, the oils obtained from them, particularly those obtained by Soxhlet extraction, contained the highest total phenols content (396.7 mg kg-1) and ortho-diphenols (206.3 mg kg-1). Compared to olive pastes, the seeds had a statistically significantly lower total phenols content and a multiple lower antioxidant capacity. The results confirmed that pits removal reduces the negative influence of peroxidases from seeds on the phenol compounds in the olive paste and in the oil, also suggesting that hot extraction increases the solubility of phenols from plant material in the oil

Natural enrichment of refined rapeseed oil with phenols and chlorophylls from olive leaves of Oblica cultivar

Olive leaves as by-products of olive farming are rich natural source of bioactive compounds with antioxidant properties. In this study, the efficiency of the natural maceration of fresh and steam blanched olive leaves in refined rapeseed oil was investigated, as well as the effect of degree of leaf fragmentation (whole, cut, ground) and maceration time on transfer of bioactive compounds (polyphenols) and pigments (chlorophylls) in oil. In oils obtained by maceration, changes of total phenolic compounds and total chlorophylls were determined spectrophotometrically. The effect of these oil preparation procedures on oil quality indicators was also investigated through free fatty acid content and spectrophotometric indices. The content of total phenols and chlorophylls increased in oils obtained by maceration of fresh and steam blanched olive leaves, and were in statistically significant correlation with leaf fragmentation degree. The highest content of total phenols was achieved in oils with whole fresh leaves (220.4 mg/kg) after seven days of maceration while the chlorophylls transfer to oils was the most efficient when ground steam blanched leaves were macerated for 28 days (79.10 mg/kg). Maceration of olive leaves slightly deteriorated the quality of refined rapeseed oil, equally in oils with fresh and steam blanched olive leaves. This simple preparation procedure can be efficiently used for enrichment of refined oils with natural antioxidants

Utjecaj pomoćnih tvari na učinkovitost procesa proizvodnje i orto-difenole djevičanskih maslinovih ulja autohtonih sorti

Cilj ovog rada bio je istražiti utjecaj pomoćnih tvari na pokazatelje uspješnosti procesa proizvodnje i na sadržaj o-difenola u djevičanskim maslinovim uljima autohtonih hrvatskih sorti 'Buža', 'Oblica' i 'Rosinjola'. Tijekom laboratorijske prerade plodova ispitivane su tri pomoćne tvari (talk, NaCl i CaCO3) koje su zasebno i u različitim masenim udjelima dodavane u maslinova tijesta istraživanih sorti. Kod 'Buže' i 'Oblice' sol je pokazala bolju učinkovitost u povećanju randmana i ekstraktabilnosti ulja u odnosu na talk i kalcijev karbonat. Primjena pomoćnih tvari kod 'Rosinjole' nije doprinjela boljoj ekstrakciji ulja. Dodatak soli značajno je povećao udio o-difenola u uljima 'Buže' i 'Rosinjole'

Utjecaj pomoćnih tvari na učinkovitost procesa proizvodnje i orto-difenole djevičanskih maslinovih ulja autohtonih sorti

Cilj ovog rada bio je istražiti utjecaj pomoćnih tvari na pokazatelje uspješnosti procesa proizvodnje i na sadržaj o-difenola u djevičanskim maslinovim uljima autohtonih hrvatskih sorti 'Buža', 'Oblica' i 'Rosinjola'. Tijekom laboratorijske prerade plodova ispitivane su tri pomoćne tvari (talk, NaCl i CaCO3) koje su zasebno i u različitim masenim udjelima dodavane u maslinova tijesta istraživanih sorti. Kod 'Buže' i 'Oblice' sol je pokazala bolju učinkovitost u povećanju randmana i ekstraktabilnosti ulja u odnosu na talk i kalcijev karbonat. Primjena pomoćnih tvari kod 'Rosinjole' nije doprinjela boljoj ekstrakciji ulja. Dodatak soli značajno je povećao udio o-difenola u uljima 'Buže' i 'Rosinjole'

Effect of Olive (Olea europaea L.) Variety on Leaf Biophenolic Profile

Olive leaves are rich in valuable biophenolic compounds, characterised by high antioxidant activity, antimicrobial properties and beneficial effects on human health. Leaf biophenols are essential for metabolic adaptation of olive to various abiotic or biotic stressors and maintenance of homeostasis. The aim of this study was to determine the influence of olive variety (‘Buža’, ‘Karbonaca’ and ‘Oblica’) on the leaf biophenols concentrations. The experiment was conducted as a completely randomised design in 3 replicates. Olive leaves were collected in three sampling periods, starting from harvest in October 2017 until pruning in March 2018. The variety ‘Buža’ differed significantly from the other cultivars with its highest content of oleuropein (5239.88 mg 100 g-1 DW) and total biophenols (5943.25 mg 100 g-1 DW). The highest levels of 4-hydroxybenzoic acid (3.92 mg 100 g-1 DW), luteolin (48.17 mg 100 g-1 DW) and apigenin (7.55 mg 100 g-1 DW) were recorded in ‘Karbonaca’ samples. Tyrosol concentrations were not significantly different between ‘Karbonaca’ (4.79 mg 100 g-1 DW) and ‘Oblica’ (4.96 mg 100 g-1 DW) cultivars, however both differed from ‘Buža’ with the highest tyrosol concentration (6.67 mg 100 g-1 DW). The obtained results showed significant differences in the content of important biophenols between the selected olive varieties. Accordingly, the highest concentration of oleuropein, the most important secoiridoid in olive leaves, in cultivar ‘Buža’ could strongly determine their metabolic response to different stressors

Characteristics of Nutritive Value of Virgin Olive Oils from Buža, Istarska bjelica, Leccino and Rosulja Cultivars

Istraživanje prehrambene vrijednosti sortnih djevičanskih maslinovih ulja provedeno je 2010. i 2011. godine na području Istarske županije (Hrvatska), Slovenske Istre (Slovenija) i otoka Krka (Hrvatska). Uzorci ulja dobiveni su laboratorijskim uređajem za preradu maslina a analizirano je ukupno 190 uzorka (25 uzoraka Buže, 98 Istarske bjelice, 48 Leccina i 19 Rosulje). Sve četiri sorte imale su visoki udjel oleinske kiseline, od 65,6% (Rosulja) do 79,8% (Istarska bjelica). Uzorci Buže, Leccina i Rosulje bili su bogati vitaminom E (155 – 490 mg/kg). Ulja Istarske bjelice sadržavala su najmanje vitamina E (89 – 169 mg/kg) ali značajno više hidrofilnih fenola (426 – 882 mg/kg) u odnosu na ostale sorte (155 – 590 mg/kg). Sastav masnih kiselina i podatci o hidrofilnim fenolima uspoređeni su s vrijednostima dobivenim obradom literaturnih podataka za razdoblje 1992. – 2009. na području Istre (56 uzoraka Buže, 49 Istarske bjelice i 40 Leccina). Ulja svih četiriju sorti u potpunosti ispunjavaju kriterije za isticanje prehrambenih i zdravstvenih tvrdnji koje se odnose na oleinsku kiselinu. Ulja Buže, Leccina i Rosulje u potpunosti ispunjavaju kriterije za navođenje tvrdnji vezanih uz vitamin E, a ona Istarske bjelice za isticanje zdravstvene tvrdnje koja se odnosi na hidrofilne fenolne tvari. Navedene karakteristike mogle bi biti iskorištene kao sredstvo tržišnog natjecanja u vidu isticanja tvrdnji na pretpakovinama djevičanskih maslinovih ulja te kao posebna obilježja proizvoda zaštićenog oznakom izvornosti.The study of the nutritive value of monocultivar virgin olive oils from Istrian County (Croatia), Slovenian Istria (Slovenia) and Krk island (Croatia) was performed during the years 2010 and 2011. Oil samples were obtained by laboratory mill. In total, 190 samples were analysed (25 Buža, 98 Istarska bjelica, 48 Leccino and 19 Rosulja samples). The oils from all four cultivars had high ratio of oleic acid, from 65.6% (Rosulja) to 79.8% (Istarska bjelica). Buža, Leccino and Rosulja oil samples had high content of vitamin E (155 – 490 mg/kg). The oils from Istarska bjelica contained the lowest amounts of vitamin E (89 – 169 mg/kg) but significantly higher values of hydrophilic phenols (426 – 882 mg/kg) regarding the other cultivars (155 – 590 mg/kg). Fatty acid composition and content of hydrophilic phenols were compared to the values from literature related to Istria area in period 1992 – 2009 (56 Buža, 49 Istarska bjelica and 40 Leccino samples). The oils from all four cultivars fully comply with criteria for stating nutrition and health claims related to oleic acid, Buža, Leccino and Rosulja oils for claims related to vitamin E, while Istarska bjelica oils for the health claim related to hydrophilic phenols. Mentioned characteristics could be used as a mean of market competition through the claims on virgin olive oil pre-packages and as specific characteristics of product with protected designation of origin

Phenolic leaf profile of olive cultivar \u27Istarska bjelica\u27 at different boron concentrations in the nutrient solution

Bor (B) je esencijalni biogeni element neophodan za rast i razvoj masline, a nedostatak B općenito se smatra jednim od najčešćih nedostataka mikroelemenata u maslinarstvu. Iako nedostatak B može dovesti do promjene koncentracije različitih fenolnih spojeva u listu masline utjecaj ishranjenosti masline B na fenolni profil lista udomaćenih sorata masline nije dovoljno istražen. Stoga, cilj ovog istraživanja bio je utvrditi utjecaj primjene hranive otopine s (B+) (30 μM B) ili bez (B-) (0 μM B) bora na fenolni profil lista masline (Olea europaea L.) sorte \u27Istarska bjelica\u27. Pokus je postavljen kao slučajni blokni raspored u četiri ponavljanja na ukupno 40 sadnica masline sorte \u27Istarska bjelica\u27. Uzorkovanje lista provedeno je nakon 60 dana od početka pokusa. Koncentracija B u listu masline bila je značajno veća u B+ tretmanu, dok su utvrđene koncentracije ukupnih fenola i verbaskozida u listu masline bile značajno veće u B- tretmanu. Gnojidba B nije značajno utjecala na koncentraciju ostalih fenolnih spojeva. Značajno veća koncentracija ukupnih fenola i verbaskozida u listu sorte \u27Istarska bjelica\u27 kod B- tretmana može se povezati s fiziološkim odgovorom biljke na nedostatak B.Boron (B) is an essential nutrient for growth and development of olive, whereas B deficiency is among the most common micronutrient disorders in olive production. Boron deficiency contributes changes in the concentration of different phenolic compounds in olive leaves, the impact of B nutrition on the phenolic leaf profile of autochthonous olive varieties is mainly unknown. This study aimed to investigate the impact of nutrient solutions, with (B+) and without (B-) boron addition, on the phenolic profile in olive leaves of cultivar ‘Istarska bjelica’. The experiment was set up in random block design in four repetitions, on 40 olive plantlets of cultivar ‘Istarska bjelica’. Olive leaves were sampled 60 days after the beginning of the experiment. Boron concentration in olive leaves was significantly higher in the B+ treatment, whereas total phenolic content and verbascoside concentration were significantly higher in the olive leaves of the B- treatment. Boron nutrition had no significant impact on other phenolic compounds. A significantly higher total phenolic content and verbascoside concentration, determined in olive leaves of cultivar ‘Istarska bjelica’, indicate the relation between physiological plant response and B deficiency

Compositional changes of volatile and phenolic compounds during processing of virgin olive oils of Buža, Istarska bjelica and Leccino variety

Hlapljive i fenolne tvari odgovorne su za senzorska i prehrambena svojstva djevičanskih maslinovih ulja. Određeni postupci u proizvodnji mogu dovesti do promjena sastava ovih tvari. Istražen je utjecaj miješanja plodova različitih hrvatskih sorti u preradi i dodatka pomoćnih tvari u proizvodnji sortnih ulja Buže, Istarske bjelice i Leccina na sastav fenolnih i hlapljivih tvari. Ispitan je utjecaj fenolnih tvari iz ploda maslina tijekom miješenja maslinovog tijesta na konačne produkte lipoksigenaznog puta i fenolne tvari ulja Buže.Organoleptic and nutritive properties of virgin olive oils are related to volatile and phenolic compounds. Specific treatments during processing could affect volatile and phenolic profiles. The influence of mixing fruits of different Croatian varieties and addition of technological coadjuvants in processing of monovarietal oils of Buža, Istarska bjelica and Leccino on the phenolic and volatile composition. The effect of phenols from olive drupes during the olive paste malaxation on the final products of lipoxygenase pathway and the phenolic composition of Buža oil was also investigated

Compositional changes of volatile and phenolic compounds during processing of virgin olive oils of Buža, Istarska bjelica and Leccino variety

Hlapljive i fenolne tvari odgovorne su za senzorska i prehrambena svojstva djevičanskih maslinovih ulja. Određeni postupci u proizvodnji mogu dovesti do promjena sastava ovih tvari. Istražen je utjecaj miješanja plodova različitih hrvatskih sorti u preradi i dodatka pomoćnih tvari u proizvodnji sortnih ulja Buže, Istarske bjelice i Leccina na sastav fenolnih i hlapljivih tvari. Ispitan je utjecaj fenolnih tvari iz ploda maslina tijekom miješenja maslinovog tijesta na konačne produkte lipoksigenaznog puta i fenolne tvari ulja Buže.Organoleptic and nutritive properties of virgin olive oils are related to volatile and phenolic compounds. Specific treatments during processing could affect volatile and phenolic profiles. The influence of mixing fruits of different Croatian varieties and addition of technological coadjuvants in processing of monovarietal oils of Buža, Istarska bjelica and Leccino on the phenolic and volatile composition. The effect of phenols from olive drupes during the olive paste malaxation on the final products of lipoxygenase pathway and the phenolic composition of Buža oil was also investigated