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

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'

Phenolic Compounds in Olive Leaf Extract as a Source of Useful Antioxidants

Using electron paramagnetic resonance (EPR) spectroscopy, antioxidant properties of olive leaves extracts obtained of three autochthonous olive varieties grown in Istria, Buža, Istarska bjelica and Rosinjola have been investigated. The highest content of total phenolic compounds ((57.6 ± 0.1) mg quercetin equivalents/g of dry extract) was obtained for extract of Buža. The analysis of chemical composition of extracts was performed by HPLC/DAD and LC/MS method. Futhermore, Buža has shown the highest antioxidant activity in scavenging DPPH radical (AA=80.0 ± 3.0%), followed by extracts of Rosinjola and Istarska bjelica. In DPPH radical scavenging assay fi nal concentration of extracts in was 0.1 mg/mL. Antioxidant activity was in good correlation with total phenolics. It seems that these bioproducts could be useful in therapy of conditions related with oxidative stress. The results have indicated a high potential of application of olive leaf and olive leaf extract in foodstuff and food additive. Also, it can be used to improve the shelf life of foods and to develop functional foods

Influence of winemaking practices on biogenic amine production in wine

Praćen je utjecaj vinifikacije, skladištenja i kontaminacije kvasca Brettanomyces na formiranje biogenih amina u vinu sorte Teran sa istarskog vinorodnog područja. Biogeni amini određeni su tekućinskom kromatografijom visoke djelotvornosti (HPLC) uz fluorescentnu detekciju. U vinu su određeni sljedeći biogeni amini: histamin, serotonin, tiramin, spermidin, triptamin, 2- feniletilamin, putreskin, kadaverin i spermin. Najveći udjel biogenih amina određen je tijekom inducirane jabučno-mliječne fermentacije.Concentration of biogenic amines in grape variety Teran from growing regions in Istria were determined during winemaking practices, storage and effect of the yeast Brettanomyces affecting the formation of biogenic amines were investigated. Biogenic amines were determinated by highperformance liquid chromatography (HPLC) with fluorescence detection. Determinated biogenic amines were: histamine, serotonine, tyramine, spermidine, tryptamine, 2- phenylethylamine, putrescine, cadaverine and spermine. The maximum concentration of biogenic amines was detected after induced malolactic fermentation

Influence of winemaking practices on biogenic amine production in wine

Praćen je utjecaj vinifikacije, skladištenja i kontaminacije kvasca Brettanomyces na formiranje biogenih amina u vinu sorte Teran sa istarskog vinorodnog područja. Biogeni amini određeni su tekućinskom kromatografijom visoke djelotvornosti (HPLC) uz fluorescentnu detekciju. U vinu su određeni sljedeći biogeni amini: histamin, serotonin, tiramin, spermidin, triptamin, 2- feniletilamin, putreskin, kadaverin i spermin. Najveći udjel biogenih amina određen je tijekom inducirane jabučno-mliječne fermentacije.Concentration of biogenic amines in grape variety Teran from growing regions in Istria were determined during winemaking practices, storage and effect of the yeast Brettanomyces affecting the formation of biogenic amines were investigated. Biogenic amines were determinated by highperformance liquid chromatography (HPLC) with fluorescence detection. Determinated biogenic amines were: histamine, serotonine, tyramine, spermidine, tryptamine, 2- phenylethylamine, putrescine, cadaverine and spermine. The maximum concentration of biogenic amines was detected after induced malolactic fermentation

Sodium chloride compared to talc as processing aid has similar impact on volatile compounds but more favourable on ortho-diphenols in virgin olive oil

The possibility of improvement of olive paste extractability by addition of talc or NaCl (1%, 2% and 3% mass ratio in olive paste), or their combinations (“talc 1.5% + NaCl 1.5%” ; “talc 1% + NaCl 2%” ; “talc 2% + NaCl 1%”), was investigated on a laboratory scale. Volatiles in oil samples were determined by headspace solid-phase microextraction with GC-MS, while ortho-diphenols by solid phase extraction and UV-VIS spectrophotometer. Significantly higher extractability of oil (from 25 to 29% compared to control, P < 0.05) was obtained by 3% of talc or NaCl and their combinations in mass ratio 1:2 or 2:1. At 3% addition level, no significant decrease of C6 aldehydes was observed, while significant increase of C6 alcohols (talc or salt) as well as of C5 compounds and terpenes (salt) occurred. Mass ratio of ortho-diphenols in oil was not influenced by talc, while NaCl led to significantly higher values compared to control (by 10-15%, P < 0.05). Practical applications: The influence of processing aids on characteristics of virgin olive oil has mainly been evaluated through the standard chemical quality parameters, while limited information about desirable volatile compounds of thus obtained extra virgin olive oils has been published so far. The results of this research show that NaCl can be used not only as a tool for enhancing the extractability, but also as a means for improving the nutritional value of virgin olive oils from cultivars which generally shows low levels of hydrophilic phenols

Variability of Phenolic and Volatile Compounds in Virgin Olive Oil from Leccino and Istarska Bjelica Cultivars in Relation to Their Fruit Mixtures

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

Weed Community in a Conventionally-Grown Olive Orchard Vs. Weed Community in Consociation with Pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch. Bip.)

On the experimental plots of the Institute of Agriculture and Tourism in Poreč, weed communities were analyzed in a conventionally‐grown olive orchard and in consociation with pyrethrum. Phytocenological surveys were conducted in March, June, and September using the Braun-Blanquet Cover Abundance Scale. Altogether, 54 species of vascular plants were recognized in both orchards. However, in a conventionally‐grown olive orchard, 27 were identified, whereas 42 weed species were identified in consociation with pyrethrum. Only 15 weeds were common to both orchards. Between both olive orchards, significant differences existed regarding the floristic and community diversity metrics. In consociation with pyrethrum as a cover crop, olive orchard had a more stable weed community during the season, while two weed species, Mercurialis annuua L. and Medicago arabica (L.) Huds., dominated in a conventionally‐grown orchard in the fall. The weed communities in both orchards significantly differ considering the appearance season (spring, summer, and fall). An autumnal weed community in a conventionally‐grown olive orchard was more diverse, more abundant, and with a more distinct floristic composition than a weed community in the spring and summer periods. However, an olive‐orchard weed community in consociation with pyrethrum also differed regarding the season, but a Canonical Correspondence Analysis (CCA) demonstrated a clear separation of a more diverse estival weed community than the one observed in the spring and summer

Weed Community in a Conventionally-Grown Olive Orchard Vs. Weed Community in Consociation with Pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch. Bip.)

On the experimental plots of the Institute of Agriculture and Tourism in Poreč, weed communities were analyzed in a conventionally‐grown olive orchard and in consociation with pyrethrum. Phytocenological surveys were conducted in March, June, and September using the Braun-Blanquet Cover Abundance Scale. Altogether, 54 species of vascular plants were recognized in both orchards. However, in a conventionally‐grown olive orchard, 27 were identified, whereas 42 weed species were identified in consociation with pyrethrum. Only 15 weeds were common to both orchards. Between both olive orchards, significant differences existed regarding the floristic and community diversity metrics. In consociation with pyrethrum as a cover crop, olive orchard had a more stable weed community during the season, while two weed species, Mercurialis annuua L. and Medicago arabica (L.) Huds., dominated in a conventionally‐grown orchard in the fall. The weed communities in both orchards significantly differ considering the appearance season (spring, summer, and fall). An autumnal weed community in a conventionally‐grown olive orchard was more diverse, more abundant, and with a more distinct floristic composition than a weed community in the spring and summer periods. However, an olive‐orchard weed community in consociation with pyrethrum also differed regarding the season, but a Canonical Correspondence Analysis (CCA) demonstrated a clear separation of a more diverse estival weed community than the one observed in the spring and summer