TY  - JOUR
AU  - Živković, Milovan
AU  - Rakić, Sveto
AU  - Maletić, Radojka
AU  - Povrenović, Dragan
AU  - Nikolić, Miloš
AU  - Kosanović, Nada
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1846
AB  - In this study, drying kinetics of autochthonous variety Požegača plum was examined in a laboratory dryer at three temperatures. The whole plum fruits, together with the kernels were subjected to the drying process. The effect of drying has been examined at temperatures of 55, 60 and 75°C, with a constant air velocity of 1.1 m s-1. The corresponding experimental results were tested using six nonlinear regression models. Coefficient of determination (R2), standard regression error (SSE), model correlation coeficient (Vy), as well as the maximum absolute error (ΔY) showed that the logaritmic model was in good agreement with the experimental data obtained. During drying of plums, the effective diffusivity was found to be between 5.6×10-9 for 55°C and 8.9×10-9 m2 s-1 at 75°C, respectively. The physical characteristics of fresh (length 39.64 mm and width 29.15 mm) and dried (length 37.52 mm and width 22.85 mm) plum fruit were determined. Finally, by chemical analysis, the contents of micro- and macro-elements (Fe, Mn, Cu, B and N, F, K, Ca, Mg and S) in the skin and flesh of the dried product, prunes, has been established.
AB  - Predmet ispitivanja ove studije je kinetika sušenja šljive autohtone sorte Požegača u laboratorijskoj sušari na tri temperaturna režima. Tretirani su celi plodovi šljiva, zajedno sa košticom. Ispitivan je efekat sušenja pri različitim temperaturama 55; 60 i 75°C, praćenjem promene vlažnosti materijala u funkciji vremena sušenja pri stalnoj brzini vazduha od 1,1 m s-1. Eksperimentalni rezultati ovih ispitivanja sušenja testirani su na šest nelinearnih regresionih modela. Koeficijent determinacije (R2), standardna greška regresije (SSE), koeficijent varijacije modela (Vy), kao i maksimalna apsolutna greška ocenjenog modela (ΔY), su pokazali da je Logarithmic model najbolje prilagođen eksperimentalnim podacima. Tokom sušenja plodova šljiva, utvrđen je koeficient difuzije čija se vrednost kretala između 5,6×10-9 za 55°C i 8,9×10-9 m2 s-1 za 75°C, respektivno. Određene su fizičke karakteristike svežih (dužina 39,64 mm i širine 29,15 mm) i sušenih (dužina 37,52 mm i širine 22,85 mm) plodova šljive. Hemijskom analizom određen je sadržaj mikro-i makroelemenata (Fe, Mn, Cu, B i N, C, K, Ca, Mg i S) u koži i mesu kod sušenih plodova šljive.
PB  - Association of the Chemical Engineers of Serbia
T2  - Chemical Industry & Chemical Engineering Quarterly
T1  - Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Požegača variety
T1  - Uticaj temperature na fizičke promene i kinetiku sušenja šljive (Prunus domestica L.) sorte požegača
EP  - 289
IS  - 3
SP  - 283
VL  - 17
DO  - 10.2298/CICEQ101109013Z
ER  - 

@article{
author = "Živković, Milovan and Rakić, Sveto and Maletić, Radojka and Povrenović, Dragan and Nikolić, Miloš and Kosanović, Nada",
year = "2011",
abstract = "In this study, drying kinetics of autochthonous variety Požegača plum was examined in a laboratory dryer at three temperatures. The whole plum fruits, together with the kernels were subjected to the drying process. The effect of drying has been examined at temperatures of 55, 60 and 75°C, with a constant air velocity of 1.1 m s-1. The corresponding experimental results were tested using six nonlinear regression models. Coefficient of determination (R2), standard regression error (SSE), model correlation coeficient (Vy), as well as the maximum absolute error (ΔY) showed that the logaritmic model was in good agreement with the experimental data obtained. During drying of plums, the effective diffusivity was found to be between 5.6×10-9 for 55°C and 8.9×10-9 m2 s-1 at 75°C, respectively. The physical characteristics of fresh (length 39.64 mm and width 29.15 mm) and dried (length 37.52 mm and width 22.85 mm) plum fruit were determined. Finally, by chemical analysis, the contents of micro- and macro-elements (Fe, Mn, Cu, B and N, F, K, Ca, Mg and S) in the skin and flesh of the dried product, prunes, has been established., Predmet ispitivanja ove studije je kinetika sušenja šljive autohtone sorte Požegača u laboratorijskoj sušari na tri temperaturna režima. Tretirani su celi plodovi šljiva, zajedno sa košticom. Ispitivan je efekat sušenja pri različitim temperaturama 55; 60 i 75°C, praćenjem promene vlažnosti materijala u funkciji vremena sušenja pri stalnoj brzini vazduha od 1,1 m s-1. Eksperimentalni rezultati ovih ispitivanja sušenja testirani su na šest nelinearnih regresionih modela. Koeficijent determinacije (R2), standardna greška regresije (SSE), koeficijent varijacije modela (Vy), kao i maksimalna apsolutna greška ocenjenog modela (ΔY), su pokazali da je Logarithmic model najbolje prilagođen eksperimentalnim podacima. Tokom sušenja plodova šljiva, utvrđen je koeficient difuzije čija se vrednost kretala između 5,6×10-9 za 55°C i 8,9×10-9 m2 s-1 za 75°C, respektivno. Određene su fizičke karakteristike svežih (dužina 39,64 mm i širine 29,15 mm) i sušenih (dužina 37,52 mm i širine 22,85 mm) plodova šljive. Hemijskom analizom određen je sadržaj mikro-i makroelemenata (Fe, Mn, Cu, B i N, C, K, Ca, Mg i S) u koži i mesu kod sušenih plodova šljive.",
publisher = "Association of the Chemical Engineers of Serbia",
journal = "Chemical Industry & Chemical Engineering Quarterly",
title = "Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Požegača variety, Uticaj temperature na fizičke promene i kinetiku sušenja šljive (Prunus domestica L.) sorte požegača",
pages = "289-283",
number = "3",
volume = "17",
doi = "10.2298/CICEQ101109013Z"
}

Živković, M., Rakić, S., Maletić, R., Povrenović, D., Nikolić, M.,& Kosanović, N.. (2011). Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Požegača variety. in Chemical Industry & Chemical Engineering Quarterly
Association of the Chemical Engineers of Serbia., 17(3), 283-289.
https://doi.org/10.2298/CICEQ101109013Z

Živković M, Rakić S, Maletić R, Povrenović D, Nikolić M, Kosanović N. Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Požegača variety. in Chemical Industry & Chemical Engineering Quarterly. 2011;17(3):283-289.
doi:10.2298/CICEQ101109013Z .

Živković, Milovan, Rakić, Sveto, Maletić, Radojka, Povrenović, Dragan, Nikolić, Miloš, Kosanović, Nada, "Effect of temperature on the physical changes and drying kinetics in plum (Prunus domestica L.) Požegača variety" in Chemical Industry & Chemical Engineering Quarterly, 17, no. 3 (2011):283-289,
https://doi.org/10.2298/CICEQ101109013Z . .

TY  - JOUR
AU  - Rakić, Sveto
AU  - Petrović, Silvana
AU  - Kukić, Jelena
AU  - Jadranin, Milka
AU  - Tešević, Vele
AU  - Povrenović, Dragan
AU  - Šiler-Marinković, Slavica
PY  - 2007
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1097
AB  - The aim of the present work was to investigate and compare phenolic compounds and antioxidant activity of methanol extracts of Quercus robur and Quercus cerris acorn kernels obtained before and after thermal treatment. Content of total phenolics, tannins, non-tannin phenolics and flavonoids was determined spectrophotometrically and content of gallic acid with HPLC. Antioxidant activity of the samples was assayed through FRAP (Ferric Reducing Antioxidant Power), DPPH scavenging test and inhibition of Fe2+/ascorbate induced lipid peroxidation. Extracts of native and thermally treated kernels showed high antioxidant activity, with extracts of thermally treated kernels being more active than extracts of native ones. Hydrolysable tannins and gallic acid were identified in all samples. Non-tannin phenolics, including gallic acid, were present in significantly higher quantities in thermally treated samples, whilst tannin content decreased. This indicates that during thermal treatment hydrolysable tannins were degraded. As the result of this degradation and consequent increase of non-tannin phenolics content, and amongst them especially gallic acid, thermally treated samples possess higher antioxidant activity than do the native ones. The obtained results have provided further grounds for establishing Q. robur and Q. cerris acorn kernels as a source for functional food preparation,
PB  - Elsevier Sci Ltd, Oxford
T2  - Food Chemistry
T1  - Influence of thermal treatment on phenolic compounds and antioxidant properties of oak acorns from Serbia
EP  - 834
IS  - 2
SP  - 830
VL  - 104
DO  - 10.1016/j.foodchem.2007.01.025
ER  - 

@article{
author = "Rakić, Sveto and Petrović, Silvana and Kukić, Jelena and Jadranin, Milka and Tešević, Vele and Povrenović, Dragan and Šiler-Marinković, Slavica",
year = "2007",
abstract = "The aim of the present work was to investigate and compare phenolic compounds and antioxidant activity of methanol extracts of Quercus robur and Quercus cerris acorn kernels obtained before and after thermal treatment. Content of total phenolics, tannins, non-tannin phenolics and flavonoids was determined spectrophotometrically and content of gallic acid with HPLC. Antioxidant activity of the samples was assayed through FRAP (Ferric Reducing Antioxidant Power), DPPH scavenging test and inhibition of Fe2+/ascorbate induced lipid peroxidation. Extracts of native and thermally treated kernels showed high antioxidant activity, with extracts of thermally treated kernels being more active than extracts of native ones. Hydrolysable tannins and gallic acid were identified in all samples. Non-tannin phenolics, including gallic acid, were present in significantly higher quantities in thermally treated samples, whilst tannin content decreased. This indicates that during thermal treatment hydrolysable tannins were degraded. As the result of this degradation and consequent increase of non-tannin phenolics content, and amongst them especially gallic acid, thermally treated samples possess higher antioxidant activity than do the native ones. The obtained results have provided further grounds for establishing Q. robur and Q. cerris acorn kernels as a source for functional food preparation,",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Food Chemistry",
title = "Influence of thermal treatment on phenolic compounds and antioxidant properties of oak acorns from Serbia",
pages = "834-830",
number = "2",
volume = "104",
doi = "10.1016/j.foodchem.2007.01.025"
}

Rakić, S., Petrović, S., Kukić, J., Jadranin, M., Tešević, V., Povrenović, D.,& Šiler-Marinković, S.. (2007). Influence of thermal treatment on phenolic compounds and antioxidant properties of oak acorns from Serbia. in Food Chemistry
Elsevier Sci Ltd, Oxford., 104(2), 830-834.
https://doi.org/10.1016/j.foodchem.2007.01.025

Rakić S, Petrović S, Kukić J, Jadranin M, Tešević V, Povrenović D, Šiler-Marinković S. Influence of thermal treatment on phenolic compounds and antioxidant properties of oak acorns from Serbia. in Food Chemistry. 2007;104(2):830-834.
doi:10.1016/j.foodchem.2007.01.025 .

Rakić, Sveto, Petrović, Silvana, Kukić, Jelena, Jadranin, Milka, Tešević, Vele, Povrenović, Dragan, Šiler-Marinković, Slavica, "Influence of thermal treatment on phenolic compounds and antioxidant properties of oak acorns from Serbia" in Food Chemistry, 104, no. 2 (2007):830-834,
https://doi.org/10.1016/j.foodchem.2007.01.025 . .

TY  - JOUR
AU  - Rakić, Sveto
AU  - Povrenović, Dragan
AU  - Tešević, Vele
AU  - Simić, Milena R.
AU  - Maletić, Radojka
PY  - 2006
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/908
AB  - In this paper, are presented the results of physical and chemical investigations of differently treated samples of oak acorn. The aim of this investigation is to estimate the influence of thermal treatment on physical and nutritive characteristics of investigated samples. Oak acorn, Quercus robur, (belonging to Fagaceae family) was investigated in native and thermally treated forms. By subsequent extraction of dry toasted oak acorn (Quercus semen tostum) the aqueous extract was obtained which is then dried in a spout-fluid bed. The content of total polyphenols, then polyphenols unadsorbed on hide powder and tannins was determined by spectrophotometric methods with phosphor-wolfram acid according to Ph. Yug. V. Galic acid was determined by HPLC. The total antioxidant activity (TAA) of the aqueous extract compared to the control samples of pigs fat and synthetic antioxidant butylated hydroxyanisole BHA was estimated by Schall-Oven test at 60 +/- 1 degrees C in dark, and oxidative changes were determined by measuring the Peroxide value (PV). For determination of macro- and microelements the method of AAS was used. By detecting the changes of PV it is established that aqueous extract was influencing the stability of pigs fat, that is, showing the antioxidant activity. The activity was increasing with increasing concentration in tested samples. The obtained results regarding the total polyphenols content, the content of galic acid, nitrogen compounds, macro and microelements show that acorn, after treatment, was retaining and in some cases improving its functional properties.
PB  - Elsevier Sci Ltd, Oxford
T2  - Journal of Food Engineering
T1  - Oak acorn, polyphenols and antioxidant activity in functional food
EP  - 423
IS  - 3
SP  - 416
VL  - 74
DO  - 10.1016/j.jfoodeng.2005.03.057
ER  - 

@article{
author = "Rakić, Sveto and Povrenović, Dragan and Tešević, Vele and Simić, Milena R. and Maletić, Radojka",
year = "2006",
abstract = "In this paper, are presented the results of physical and chemical investigations of differently treated samples of oak acorn. The aim of this investigation is to estimate the influence of thermal treatment on physical and nutritive characteristics of investigated samples. Oak acorn, Quercus robur, (belonging to Fagaceae family) was investigated in native and thermally treated forms. By subsequent extraction of dry toasted oak acorn (Quercus semen tostum) the aqueous extract was obtained which is then dried in a spout-fluid bed. The content of total polyphenols, then polyphenols unadsorbed on hide powder and tannins was determined by spectrophotometric methods with phosphor-wolfram acid according to Ph. Yug. V. Galic acid was determined by HPLC. The total antioxidant activity (TAA) of the aqueous extract compared to the control samples of pigs fat and synthetic antioxidant butylated hydroxyanisole BHA was estimated by Schall-Oven test at 60 +/- 1 degrees C in dark, and oxidative changes were determined by measuring the Peroxide value (PV). For determination of macro- and microelements the method of AAS was used. By detecting the changes of PV it is established that aqueous extract was influencing the stability of pigs fat, that is, showing the antioxidant activity. The activity was increasing with increasing concentration in tested samples. The obtained results regarding the total polyphenols content, the content of galic acid, nitrogen compounds, macro and microelements show that acorn, after treatment, was retaining and in some cases improving its functional properties.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Journal of Food Engineering",
title = "Oak acorn, polyphenols and antioxidant activity in functional food",
pages = "423-416",
number = "3",
volume = "74",
doi = "10.1016/j.jfoodeng.2005.03.057"
}

Rakić, S., Povrenović, D., Tešević, V., Simić, M. R.,& Maletić, R.. (2006). Oak acorn, polyphenols and antioxidant activity in functional food. in Journal of Food Engineering
Elsevier Sci Ltd, Oxford., 74(3), 416-423.
https://doi.org/10.1016/j.jfoodeng.2005.03.057

Rakić S, Povrenović D, Tešević V, Simić MR, Maletić R. Oak acorn, polyphenols and antioxidant activity in functional food. in Journal of Food Engineering. 2006;74(3):416-423.
doi:10.1016/j.jfoodeng.2005.03.057 .

Rakić, Sveto, Povrenović, Dragan, Tešević, Vele, Simić, Milena R., Maletić, Radojka, "Oak acorn, polyphenols and antioxidant activity in functional food" in Journal of Food Engineering, 74, no. 3 (2006):416-423,
https://doi.org/10.1016/j.jfoodeng.2005.03.057 . .

TY  - JOUR
AU  - Rakić, Sveto
AU  - Povrenović, Dragan
AU  - Maletić, Radojka
AU  - Živković, Milovan
PY  - 2005
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/770
AB  - The results of the chemical investigations of variously treated acorn samples are presented in this paper with the aim of obtaining data on the amount of nutritious components and biologically active substances. The Quercus robur acorn, which belongs to the Fagaceae family, was investigated in a raw, thermally treated form and as an extract that was subsequently dried in a dryer with a fluidized bed. The obtained results regarding the content of tannin, nitrogen containing compounds, macro- and microelements indicate that acorn maintains its functional characteristics after the investigated treatments.
AB  - U ovom radu su predstavljeni rezultati hemijskih ispitivanja različito tretiranih uzoraka hrastovog žira, u cilju dobijanja podataka o količini hranljivih komponenti i supstanci sa biološki aktivnim dejstvom. Ispitivan je žir Quercus robur, koji pripada familiji Fagaceae, u sirovom, termički tretiranom obliku i ekstraktu koji je naknadno sušen u sušioniku sa fontansko-fluidizovanim slojem. Dobijeni rezultati u pogledu sadržaja, tanina, azotnih jedinjenja, makro i mikroelemenata pokazuju da hrastov žir, nakon ispitivanih tretmana, zadržava svoje funkcionalne karakteristike. Hemijski sastav nativnog hrastovog žira kao i proizvodi dobijeni opisanim postupcima u ovom radu, ukazuje na prihvatljivost ove sirovine sa aspekta njegove primene u ljudskoj ishrani. Hrastov žir Quercus robur se odlikuje raznovrsnošću hranljivih, energetskihe i funkcionalno-zaštitnih materija. Postupkom termičkog i hidrotermičkog tretmana kao i postupkom sušenja vodenog ekstrakta postižu se značajni rezultati u pogledu koncentrisanja materija koje imaju funkcionalna svojstva. Povećanje sadržaja je evidentno kod proteina, ukupnih mineralnih materija, makroelemenata (fosfor i kalijum), kao i mikroelemenata (gvožđe i bakar) s tim što se u u budućim istraživanjima mora definisati razlog pada koncentracije gvožđa pri sušenju tečnog ekstrakta. Hrastov žir je sirovina koja nije komercijalizovana, a kao jeftin i lako dostupan biljni materijal, predstavlja potencijalni izvor biološki aktivnih komponenti, čija je primena moguća u prehrambenoj , farmaceutskoj i drugim industrijama.
PB  - University of Belgrade - Faculty of Agriculture, Belgrade
T2  - Journal of Agricultural Sciences (Belgrade)
T1  - Drying of the aqueous extract of acorn Quercus robur in a spout-fluid bed
T1  - Sušenje vodenog ekstrakta hrastovog žira Quercus robur u sušioniku sa fontansko-fluidizovanim slojem
EP  - 182
IS  - 2
SP  - 173
VL  - 50
DO  - 10.2298/JAS0502173R
ER  - 

@article{
author = "Rakić, Sveto and Povrenović, Dragan and Maletić, Radojka and Živković, Milovan",
year = "2005",
abstract = "The results of the chemical investigations of variously treated acorn samples are presented in this paper with the aim of obtaining data on the amount of nutritious components and biologically active substances. The Quercus robur acorn, which belongs to the Fagaceae family, was investigated in a raw, thermally treated form and as an extract that was subsequently dried in a dryer with a fluidized bed. The obtained results regarding the content of tannin, nitrogen containing compounds, macro- and microelements indicate that acorn maintains its functional characteristics after the investigated treatments., U ovom radu su predstavljeni rezultati hemijskih ispitivanja različito tretiranih uzoraka hrastovog žira, u cilju dobijanja podataka o količini hranljivih komponenti i supstanci sa biološki aktivnim dejstvom. Ispitivan je žir Quercus robur, koji pripada familiji Fagaceae, u sirovom, termički tretiranom obliku i ekstraktu koji je naknadno sušen u sušioniku sa fontansko-fluidizovanim slojem. Dobijeni rezultati u pogledu sadržaja, tanina, azotnih jedinjenja, makro i mikroelemenata pokazuju da hrastov žir, nakon ispitivanih tretmana, zadržava svoje funkcionalne karakteristike. Hemijski sastav nativnog hrastovog žira kao i proizvodi dobijeni opisanim postupcima u ovom radu, ukazuje na prihvatljivost ove sirovine sa aspekta njegove primene u ljudskoj ishrani. Hrastov žir Quercus robur se odlikuje raznovrsnošću hranljivih, energetskihe i funkcionalno-zaštitnih materija. Postupkom termičkog i hidrotermičkog tretmana kao i postupkom sušenja vodenog ekstrakta postižu se značajni rezultati u pogledu koncentrisanja materija koje imaju funkcionalna svojstva. Povećanje sadržaja je evidentno kod proteina, ukupnih mineralnih materija, makroelemenata (fosfor i kalijum), kao i mikroelemenata (gvožđe i bakar) s tim što se u u budućim istraživanjima mora definisati razlog pada koncentracije gvožđa pri sušenju tečnog ekstrakta. Hrastov žir je sirovina koja nije komercijalizovana, a kao jeftin i lako dostupan biljni materijal, predstavlja potencijalni izvor biološki aktivnih komponenti, čija je primena moguća u prehrambenoj , farmaceutskoj i drugim industrijama.",
publisher = "University of Belgrade - Faculty of Agriculture, Belgrade",
journal = "Journal of Agricultural Sciences (Belgrade)",
title = "Drying of the aqueous extract of acorn Quercus robur in a spout-fluid bed, Sušenje vodenog ekstrakta hrastovog žira Quercus robur u sušioniku sa fontansko-fluidizovanim slojem",
pages = "182-173",
number = "2",
volume = "50",
doi = "10.2298/JAS0502173R"
}

Rakić, S., Povrenović, D., Maletić, R.,& Živković, M.. (2005). Drying of the aqueous extract of acorn Quercus robur in a spout-fluid bed. in Journal of Agricultural Sciences (Belgrade)
University of Belgrade - Faculty of Agriculture, Belgrade., 50(2), 173-182.
https://doi.org/10.2298/JAS0502173R

Rakić S, Povrenović D, Maletić R, Živković M. Drying of the aqueous extract of acorn Quercus robur in a spout-fluid bed. in Journal of Agricultural Sciences (Belgrade). 2005;50(2):173-182.
doi:10.2298/JAS0502173R .

Rakić, Sveto, Povrenović, Dragan, Maletić, Radojka, Živković, Milovan, "Drying of the aqueous extract of acorn Quercus robur in a spout-fluid bed" in Journal of Agricultural Sciences (Belgrade), 50, no. 2 (2005):173-182,
https://doi.org/10.2298/JAS0502173R . .