Ana Bucić-Kojić - Academia.edu (original) (raw)

Papers by Ana Bucić-Kojić

The effect of process conditions such as extraction solvent, solid-liquid ratio, temperature, par... more The effect of process conditions such as extraction solvent, solid-liquid ratio, temperature, particle size and time on extraction yield of total polyphenols from grape seeds were studied. The concentration of total polyphenols in the extracts was determined by spectrophotometric Folin Ciocalteau method and results were expressed in gallic acid equivalent per a dry basis of grape seeds (mg GAE/gdb). The best extraction yield of total polyphenols was obtained from the smallest particle by 50% of aqueous ethanol at 80 °C and 40 ml/g solid-liquid ratio during 200 minutes.

U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70... more U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70 i 96%-tnog etanola), vremena (10-200 minuta) te ve

Tijekom proizvodnje vina u vinarijama zaostaju velike kolicine organskog otpada (trop grožđa, otp... more Tijekom proizvodnje vina u vinarijama zaostaju velike kolicine organskog otpada (trop grožđa, otpadne vode i staklenicki plinovi). Trop grožđa je kruti otpad na kojeg otpada cak 20 – 30 % ukupne mase grožđa. Godisnje, na svjetskoj razini, nastaje oko 9 milijuna t, a u Hrvatskoj oko 40 600 t tropa grožđa koji se sastoji uglavnom od sjemenki, kožice i pulpe te ponekad i peteljki grožđa. Trop grožđa zbog svog kemijskog sastava predstavlja potencijalni izvor visokovrijednih produkata, međutim, njegovo iskoristenje u tu svrhu, posebice u Hrvatskoj, je neznatno. Najcesce se upotrebljava kao stocna hrana ili gnojivo, a najvecu komercijalnu vrijednost imaju ulja sjemenki grožđa zbog visokog udjela nezasicenih masnih kiselina te ekstrakti tropa grožđa zbog visokog udjela bioaktivnih polifenolnih spojeva. U ovom poglavlju dan je kratki prikaz procesa proizvodnje vina te karakterizacija otpada koji nastaje tijekom i nakon proizvodnje vina, s posebnim naglaskom na trop grožđa. Dan je detaljan pregled kemijskog sastava tropa grožđa i svojstava polifenolnih spojeva tropa grožđa te mogucnosti njihove izolacije, pregled najcesce upotrebe tropa grožđa (upotreba kao stocne hrane, biognojiva, proizvodnja ulja iz sjemenki grožđa) te su prikazane novije, alternativne mogucosti njegove primjene u svrhu proizvodnje biogoriva (bioplin, bioetanol, biodizel) i nekih drugih visokovrijednih produkata (enzima).

U radu se istraživao utjecaj omjera-kruto-tekuće (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70... more U radu se istraživao utjecaj omjera-kruto-tekuće (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70 i 96%-tnog etanola), vremena (10-200 minuta) te veličine čestica (> 0,63 mm; 0,63 - 0,4 mm; 0,4 - 0,16 mm i < 0,16 mm) na prinos ekstrakcije ukupnih fenola iz sjemenki grožđa, kao i utjecaj temperature (25, 40, 50, 60, 70 i 80 °C) na kinetiku ekstrakcije ukupnih i individualnih fenolnih tvari. Istraživao se i utjecaj različitih načina ekstrakcije (ekstrakcija uz zagrijavanje u vodenoj kupelji s tresilicom, ekstrakcija na univerzalnom sustavu za ekstrakciju, kombinacija ekstrakcije superkritičnim fluidima i ekstrakcije otapalom) na ekstraktibilnost fenolnih tvari, antioksidacijsku aktivnost i boju ekstrakata. Prijenos fenolnih tvari tijekom kruto-tekuće ekstrakcije odvijao se difuzijom, a određene vrijednosti koeficijenata efektivne difuzije ukupnih (0,2 - 1,96·10-10 m2/min) i individualnih fenolnih tvari (0,02 - 0,69·10-10 m2/min) povećavale su se s porastom temperature ekstrakcij...

International Conference 18th Ružička days “TODAY SCIENCE – TOMORROW INDUSTRY” Book of Abstarcts Zagreb, Osijek: Croatian Society of Chemical Engineers (CSCE) ; Faculty of Food Technology Osijek University of Josip Juraj Strossmayer in Osijek, 2020. str. 88-88 (poster, međunarodna recenzija, saže..., 2020

International Conference 18th Ružička days “TODAY SCIENCE – TOMORROW INDUSTRY” Book of Abstarcts, 2020

Abstract Book/11th World Congress on Polyphenols Applications, 2017

Th e drying characteristics of “Granny Smith ” apples were analysed using a tunnel drier at diff ... more Th e drying characteristics of “Granny Smith ” apples were analysed using a tunnel drier at diff erent temperatures and diff erent pre-treatments. „Granny Smith “ apples were cut into rectangle-shaped samples 20x20x5 mm in size. Th e drying temperatures for non-treated samples varied from 50ºC to 80ºC at airfl ow velocity of 2.8 m s-1. Prior to drying at 60ºC, the samples were pre-treated either thermally or chemically, or both (blanching in hot water, steam blanching, blanching in hot 0.6 % CaCl2 solution, freezing to temperature of –18ºC and dipping in 1 % ascorbic acid solution). Th e aim of the study was to get dried apples with approximately 10 % water content, with good texture, rehydration capability and colour quality. Th e eff ect of the temperatures and pre-treatments on the quality of dried apple samples was determined on the basis of colour and volume changes and reconstitution characteristics. Th e kinetic equations were estimated using exponential mathematical model. T...

Asparagus maritimus L. is a rare species growing in the Mediterranean region and is morphological... more Asparagus maritimus L. is a rare species growing in the Mediterranean region and is morphologically similar to A. officinalis. Green asparagus, as a healthy but perishable vegetable, is processed after harvest to prevent spoilage and minimize the deterioration of its physical and chemical quality. Similar to other vegetables, changes in color, chemical and textural properties of asparagus occur during thermal treatments, such as drying. The aim of the investigation was to examine the influence of different drying temperatures on the color quality, rehydration capability and chlorophyll content in green asparagus. Drying was performed in a pilot plant tray drier. The drying temperatures for asparagus samples have varied from 40°C, 50°C, 60°C and 70°C at airflow velocity of 2, 75 ms-1. Drying temperature has a significant effect on reducing the chlorophyll content (Chla 54-71%, Chlb 37-63%), rehydration coefficient and total color change of dried ( E* = 3, 3 12, 5) and rehydrated asp...

U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70... more U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70 i 96%-tnog etanola), vremena (10-200 minuta) te ve

Grape pomace is an inexpensive solid by-product remained after winemaking process representing th... more Grape pomace is an inexpensive solid by-product remained after winemaking process representing the rich source of bioactive phenolic compounds. Extraction of bioactive phenolic compounds is the first step in their utilization from natural sources and is usually performed by organic solvents. This method is however only effective for simple and free phenolic compounds, while the highly polymerized phenolic compounds bonded in complexes with proteins, fibres and polysaharides are not extractible by this method. One of the possible ways to release that compounds is biological pretreatment of natural sources, e.g. agro-food industrial residues. The aim of this work was to investigate the influence of biological pretreatment of grape pomace with white-rot fungi Trametes versicolor on the enhancement of phenolic compounds (total phenolic compounds, TPC ; total extractible proanthocyanidins, TPA ; total flavonoids, TF) extraction efficiency as well as antioxidant activity (AA) of grape pom...

Drveni ugljen se proizvodi termickom razgradnjom drva (suha destilacija drva), i to razlicitim pr... more Drveni ugljen se proizvodi termickom razgradnjom drva (suha destilacija drva), i to razlicitim primitivnim, klasicnim i modernim postupcima. Jedan od klasicnih industrijskih postupaka proizvodnje drvenog ugljena je suha destilacija drva u horizontalnim retortama. U takvim retortama drvo se podvrgava postepenom zagrijavanju do oko 400 °C bez pristupa kisika (zraka) pri cemu se drvo u kemijsko-toplinskom procesu razgrađuje dajuci drveni ugljen, a kao sekundarni proizvodi nastaju retortni plinovi i pare. Retortni plinovi i pare odvode se tijekom procesa iz retorti u kondenzatore gdje se podvrgavaju kondenzaciji i pri tome nastaje tzv. sirovi drvni ocat (SDO), koji se sastoji od oko 20% razlicitih organskih tvari i oko 80% vode, te nastaju nekondenzirani retortni plinovi. SDO je međuprodukt koji se frakcionom destilacijom prevodi u niz korisnih produkata (octena kiselina, razliciti alkoholi, aldehidi, ketoni, i sl.). Međutim, suvremeni sintetski nacini dobivanja tih proizvoda daleko su ...

There is a great awareness about the importance of lignocellulose waste utilization in different ... more There is a great awareness about the importance of lignocellulose waste utilization in different purposes. One of the possible ways is its application for biogas production as a sole substrate or as a co-substrate. However, biofuel production from lignocellulosic material is hampered by biomass recalcitrance towards hydrolysis due to the compact architecture of the plant cell wall and the presence of lignin. In this work, biological pretreatment of corn silage obtained after the harvest 2015 (Osatina Ltd., Ivankovo, Croatia) was performed with white-rot fungus T. versicolor in laboratory flasks within 20 days with the aim of lignin degradation. Chemical composition of the corn silage was done before, during and after the fermentation process. Two different laboratory solid-state bioreactors (tray bioreactor and horizontal bioreactor with mechanical mixing) were designed and constructed based on preliminary laboratory flasks results. Biologically treated corn silage was used in bioga...

The effect of process conditions such as extraction solvent, solid-liquid ratio, temperature, par... more The effect of process conditions such as extraction solvent, solid-liquid ratio, temperature, particle size and time on extraction yield of total polyphenols from grape seeds were studied. The concentration of total polyphenols in the extracts was determined by spectrophotometric Folin Ciocalteau method and results were expressed in gallic acid equivalent per a dry basis of grape seeds (mg GAE/gdb). The best extraction yield of total polyphenols was obtained from the smallest particle by 50% of aqueous ethanol at 80 °C and 40 ml/g solid-liquid ratio during 200 minutes.

U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70... more U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70 i 96%-tnog etanola), vremena (10-200 minuta) te ve

Tijekom proizvodnje vina u vinarijama zaostaju velike kolicine organskog otpada (trop grožđa, otp... more Tijekom proizvodnje vina u vinarijama zaostaju velike kolicine organskog otpada (trop grožđa, otpadne vode i staklenicki plinovi). Trop grožđa je kruti otpad na kojeg otpada cak 20 – 30 % ukupne mase grožđa. Godisnje, na svjetskoj razini, nastaje oko 9 milijuna t, a u Hrvatskoj oko 40 600 t tropa grožđa koji se sastoji uglavnom od sjemenki, kožice i pulpe te ponekad i peteljki grožđa. Trop grožđa zbog svog kemijskog sastava predstavlja potencijalni izvor visokovrijednih produkata, međutim, njegovo iskoristenje u tu svrhu, posebice u Hrvatskoj, je neznatno. Najcesce se upotrebljava kao stocna hrana ili gnojivo, a najvecu komercijalnu vrijednost imaju ulja sjemenki grožđa zbog visokog udjela nezasicenih masnih kiselina te ekstrakti tropa grožđa zbog visokog udjela bioaktivnih polifenolnih spojeva. U ovom poglavlju dan je kratki prikaz procesa proizvodnje vina te karakterizacija otpada koji nastaje tijekom i nakon proizvodnje vina, s posebnim naglaskom na trop grožđa. Dan je detaljan pregled kemijskog sastava tropa grožđa i svojstava polifenolnih spojeva tropa grožđa te mogucnosti njihove izolacije, pregled najcesce upotrebe tropa grožđa (upotreba kao stocne hrane, biognojiva, proizvodnja ulja iz sjemenki grožđa) te su prikazane novije, alternativne mogucosti njegove primjene u svrhu proizvodnje biogoriva (bioplin, bioetanol, biodizel) i nekih drugih visokovrijednih produkata (enzima).

U radu se istraživao utjecaj omjera-kruto-tekuće (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70... more U radu se istraživao utjecaj omjera-kruto-tekuće (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70 i 96%-tnog etanola), vremena (10-200 minuta) te veličine čestica (> 0,63 mm; 0,63 - 0,4 mm; 0,4 - 0,16 mm i < 0,16 mm) na prinos ekstrakcije ukupnih fenola iz sjemenki grožđa, kao i utjecaj temperature (25, 40, 50, 60, 70 i 80 °C) na kinetiku ekstrakcije ukupnih i individualnih fenolnih tvari. Istraživao se i utjecaj različitih načina ekstrakcije (ekstrakcija uz zagrijavanje u vodenoj kupelji s tresilicom, ekstrakcija na univerzalnom sustavu za ekstrakciju, kombinacija ekstrakcije superkritičnim fluidima i ekstrakcije otapalom) na ekstraktibilnost fenolnih tvari, antioksidacijsku aktivnost i boju ekstrakata. Prijenos fenolnih tvari tijekom kruto-tekuće ekstrakcije odvijao se difuzijom, a određene vrijednosti koeficijenata efektivne difuzije ukupnih (0,2 - 1,96·10-10 m2/min) i individualnih fenolnih tvari (0,02 - 0,69·10-10 m2/min) povećavale su se s porastom temperature ekstrakcij...

International Conference 18th Ružička days “TODAY SCIENCE – TOMORROW INDUSTRY” Book of Abstarcts Zagreb, Osijek: Croatian Society of Chemical Engineers (CSCE) ; Faculty of Food Technology Osijek University of Josip Juraj Strossmayer in Osijek, 2020. str. 88-88 (poster, međunarodna recenzija, saže..., 2020

International Conference 18th Ružička days “TODAY SCIENCE – TOMORROW INDUSTRY” Book of Abstarcts, 2020

Abstract Book/11th World Congress on Polyphenols Applications, 2017

Th e drying characteristics of “Granny Smith ” apples were analysed using a tunnel drier at diff ... more Th e drying characteristics of “Granny Smith ” apples were analysed using a tunnel drier at diff erent temperatures and diff erent pre-treatments. „Granny Smith “ apples were cut into rectangle-shaped samples 20x20x5 mm in size. Th e drying temperatures for non-treated samples varied from 50ºC to 80ºC at airfl ow velocity of 2.8 m s-1. Prior to drying at 60ºC, the samples were pre-treated either thermally or chemically, or both (blanching in hot water, steam blanching, blanching in hot 0.6 % CaCl2 solution, freezing to temperature of –18ºC and dipping in 1 % ascorbic acid solution). Th e aim of the study was to get dried apples with approximately 10 % water content, with good texture, rehydration capability and colour quality. Th e eff ect of the temperatures and pre-treatments on the quality of dried apple samples was determined on the basis of colour and volume changes and reconstitution characteristics. Th e kinetic equations were estimated using exponential mathematical model. T...

Asparagus maritimus L. is a rare species growing in the Mediterranean region and is morphological... more Asparagus maritimus L. is a rare species growing in the Mediterranean region and is morphologically similar to A. officinalis. Green asparagus, as a healthy but perishable vegetable, is processed after harvest to prevent spoilage and minimize the deterioration of its physical and chemical quality. Similar to other vegetables, changes in color, chemical and textural properties of asparagus occur during thermal treatments, such as drying. The aim of the investigation was to examine the influence of different drying temperatures on the color quality, rehydration capability and chlorophyll content in green asparagus. Drying was performed in a pilot plant tray drier. The drying temperatures for asparagus samples have varied from 40°C, 50°C, 60°C and 70°C at airflow velocity of 2, 75 ms-1. Drying temperature has a significant effect on reducing the chlorophyll content (Chla 54-71%, Chlb 37-63%), rehydration coefficient and total color change of dried ( E* = 3, 3 12, 5) and rehydrated asp...

U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70... more U radu se istraživao utjecaj omjera-kruto-tekuce (10, 20, 30 i 40 mL/g), otapala (vode, te 50, 70 i 96%-tnog etanola), vremena (10-200 minuta) te ve

Grape pomace is an inexpensive solid by-product remained after winemaking process representing th... more Grape pomace is an inexpensive solid by-product remained after winemaking process representing the rich source of bioactive phenolic compounds. Extraction of bioactive phenolic compounds is the first step in their utilization from natural sources and is usually performed by organic solvents. This method is however only effective for simple and free phenolic compounds, while the highly polymerized phenolic compounds bonded in complexes with proteins, fibres and polysaharides are not extractible by this method. One of the possible ways to release that compounds is biological pretreatment of natural sources, e.g. agro-food industrial residues. The aim of this work was to investigate the influence of biological pretreatment of grape pomace with white-rot fungi Trametes versicolor on the enhancement of phenolic compounds (total phenolic compounds, TPC ; total extractible proanthocyanidins, TPA ; total flavonoids, TF) extraction efficiency as well as antioxidant activity (AA) of grape pom...

Drveni ugljen se proizvodi termickom razgradnjom drva (suha destilacija drva), i to razlicitim pr... more Drveni ugljen se proizvodi termickom razgradnjom drva (suha destilacija drva), i to razlicitim primitivnim, klasicnim i modernim postupcima. Jedan od klasicnih industrijskih postupaka proizvodnje drvenog ugljena je suha destilacija drva u horizontalnim retortama. U takvim retortama drvo se podvrgava postepenom zagrijavanju do oko 400 °C bez pristupa kisika (zraka) pri cemu se drvo u kemijsko-toplinskom procesu razgrađuje dajuci drveni ugljen, a kao sekundarni proizvodi nastaju retortni plinovi i pare. Retortni plinovi i pare odvode se tijekom procesa iz retorti u kondenzatore gdje se podvrgavaju kondenzaciji i pri tome nastaje tzv. sirovi drvni ocat (SDO), koji se sastoji od oko 20% razlicitih organskih tvari i oko 80% vode, te nastaju nekondenzirani retortni plinovi. SDO je međuprodukt koji se frakcionom destilacijom prevodi u niz korisnih produkata (octena kiselina, razliciti alkoholi, aldehidi, ketoni, i sl.). Međutim, suvremeni sintetski nacini dobivanja tih proizvoda daleko su ...

There is a great awareness about the importance of lignocellulose waste utilization in different ... more There is a great awareness about the importance of lignocellulose waste utilization in different purposes. One of the possible ways is its application for biogas production as a sole substrate or as a co-substrate. However, biofuel production from lignocellulosic material is hampered by biomass recalcitrance towards hydrolysis due to the compact architecture of the plant cell wall and the presence of lignin. In this work, biological pretreatment of corn silage obtained after the harvest 2015 (Osatina Ltd., Ivankovo, Croatia) was performed with white-rot fungus T. versicolor in laboratory flasks within 20 days with the aim of lignin degradation. Chemical composition of the corn silage was done before, during and after the fermentation process. Two different laboratory solid-state bioreactors (tray bioreactor and horizontal bioreactor with mechanical mixing) were designed and constructed based on preliminary laboratory flasks results. Biologically treated corn silage was used in bioga...