TY  - JOUR
AU  - Stefanović, Andrea
AU  - Jovanović, Jelena
AU  - Dojčinović, Marina
AU  - Lević, Steva
AU  - Nedović, Viktor
AU  - Bugarski, Branko
AU  - Knežević-Jugović, Zorica
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3725
AB  - The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 +/- 0.2 kHz and an amplitude of 40%) for 2-20 min on the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from similar to 370 to similar to 260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect.
PB  - Springer, New York
T2  - Food and Bioprocess Technology
T1  - Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins
EP  - 1239
IS  - 7
SP  - 1224
VL  - 10
DO  - 10.1007/s11947-017-1884-5
ER  - 

@article{
author = "Stefanović, Andrea and Jovanović, Jelena and Dojčinović, Marina and Lević, Steva and Nedović, Viktor and Bugarski, Branko and Knežević-Jugović, Zorica",
year = "2017",
abstract = "The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 +/- 0.2 kHz and an amplitude of 40%) for 2-20 min on the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from similar to 370 to similar to 260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect.",
publisher = "Springer, New York",
journal = "Food and Bioprocess Technology",
title = "Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins",
pages = "1239-1224",
number = "7",
volume = "10",
doi = "10.1007/s11947-017-1884-5"
}

Stefanović, A., Jovanović, J., Dojčinović, M., Lević, S., Nedović, V., Bugarski, B.,& Knežević-Jugović, Z.. (2017). Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins. in Food and Bioprocess Technology
Springer, New York., 10(7), 1224-1239.
https://doi.org/10.1007/s11947-017-1884-5

Stefanović A, Jovanović J, Dojčinović M, Lević S, Nedović V, Bugarski B, Knežević-Jugović Z. Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins. in Food and Bioprocess Technology. 2017;10(7):1224-1239.
doi:10.1007/s11947-017-1884-5 .

Stefanović, Andrea, Jovanović, Jelena, Dojčinović, Marina, Lević, Steva, Nedović, Viktor, Bugarski, Branko, Knežević-Jugović, Zorica, "Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins" in Food and Bioprocess Technology, 10, no. 7 (2017):1224-1239,
https://doi.org/10.1007/s11947-017-1884-5 . .

TY  - JOUR
AU  - Knežević-Jugović, Zorica
AU  - Žuža, Milena
AU  - Jakovetić, Sonja
AU  - Stefanović, Andrea
AU  - Džunuzović, Enis
AU  - Jeremić, Katarina B.
AU  - Jovanović, Slobodan M.
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3457
AB  - The use of penicillin G acylase (PGA) covalently linked to insoluble carrier is expected to produce major advances in pharmaceutical processing industry and the enzyme stability enhancement is still a significant challenge. The objective of this study was to improve catalytic performance of the covalently immobilized PGA on a potential industrial carrier, macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) [poly(GMA-co-EGDMA)], by optimizing the copolymerization process and the enzyme attachment procedure. This synthetic copolymer could be a very promising alternative for the development of low-cost, easy-to-prepare, and stable biocatalyst compared to expensive commercially available epoxy carriers such as Eupergit or Sepabeads. The PGA immobilized on poly(GMA-co-EGDMA) in the shape of microbeads obtained by suspension copolymerization appeared to have higher activity yield compared to copolymerization in a cast. Optimal conditions for the immobilization of PGA on poly(GMA-co-EGDMA) microbeads were 1mg/mL of PGA in 0.75mol/L phosphate buffer pH 6.0 at 25 degrees C for 24h, leading to the active biocatalyst with the specific activity of 252.7U/g dry beads. Chemical amination of the immobilized PGA could contribute to the enhanced stability of the biocatalyst by inducing secondary interactions between the enzyme and the carrier, ensuring multipoint attachment. The best balance between the activity yield (51.5%), enzyme loading (25.6mg/g), and stability (stabilization factor 22.2) was achieved for the partially modified PGA.
PB  - Wiley, Hoboken
T2  - Biotechnology Progress
T1  - An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as a potential industrial biocatalyst
EP  - 53
IS  - 1
SP  - 43
VL  - 32
DO  - 10.1002/btpr.2181
ER  - 

@article{
author = "Knežević-Jugović, Zorica and Žuža, Milena and Jakovetić, Sonja and Stefanović, Andrea and Džunuzović, Enis and Jeremić, Katarina B. and Jovanović, Slobodan M.",
year = "2016",
abstract = "The use of penicillin G acylase (PGA) covalently linked to insoluble carrier is expected to produce major advances in pharmaceutical processing industry and the enzyme stability enhancement is still a significant challenge. The objective of this study was to improve catalytic performance of the covalently immobilized PGA on a potential industrial carrier, macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) [poly(GMA-co-EGDMA)], by optimizing the copolymerization process and the enzyme attachment procedure. This synthetic copolymer could be a very promising alternative for the development of low-cost, easy-to-prepare, and stable biocatalyst compared to expensive commercially available epoxy carriers such as Eupergit or Sepabeads. The PGA immobilized on poly(GMA-co-EGDMA) in the shape of microbeads obtained by suspension copolymerization appeared to have higher activity yield compared to copolymerization in a cast. Optimal conditions for the immobilization of PGA on poly(GMA-co-EGDMA) microbeads were 1mg/mL of PGA in 0.75mol/L phosphate buffer pH 6.0 at 25 degrees C for 24h, leading to the active biocatalyst with the specific activity of 252.7U/g dry beads. Chemical amination of the immobilized PGA could contribute to the enhanced stability of the biocatalyst by inducing secondary interactions between the enzyme and the carrier, ensuring multipoint attachment. The best balance between the activity yield (51.5%), enzyme loading (25.6mg/g), and stability (stabilization factor 22.2) was achieved for the partially modified PGA.",
publisher = "Wiley, Hoboken",
journal = "Biotechnology Progress",
title = "An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as a potential industrial biocatalyst",
pages = "53-43",
number = "1",
volume = "32",
doi = "10.1002/btpr.2181"
}

Knežević-Jugović, Z., Žuža, M., Jakovetić, S., Stefanović, A., Džunuzović, E., Jeremić, K. B.,& Jovanović, S. M.. (2016). An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as a potential industrial biocatalyst. in Biotechnology Progress
Wiley, Hoboken., 32(1), 43-53.
https://doi.org/10.1002/btpr.2181

Knežević-Jugović Z, Žuža M, Jakovetić S, Stefanović A, Džunuzović E, Jeremić KB, Jovanović SM. An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as a potential industrial biocatalyst. in Biotechnology Progress. 2016;32(1):43-53.
doi:10.1002/btpr.2181 .

Knežević-Jugović, Zorica, Žuža, Milena, Jakovetić, Sonja, Stefanović, Andrea, Džunuzović, Enis, Jeremić, Katarina B., Jovanović, Slobodan M., "An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as a potential industrial biocatalyst" in Biotechnology Progress, 32, no. 1 (2016):43-53,
https://doi.org/10.1002/btpr.2181 . .

TY  - JOUR
AU  - Stefanović, Andrea
AU  - Jovanović, Jelena
AU  - Grbavčić, Sanja
AU  - Šekuljica, Nataša
AU  - Manojlović, Verica
AU  - Bugarski, Branko
AU  - Knežević-Jugović, Zorica
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2701
AB  - The objective of this study was to investigate the effects of different ultrasound pretreatment on enzymatic hydrolysis of egg white proteins (EWPs) by Alcalase as well as evaluating some functional and antioxidant properties of hydrolysates obtained by various proteases treatment and ultrasound technology. The effects of chosen ultrasound pretreatment parameters including frequency of ultrasonic waves (35 and 40 kHz), temperature (25 and 55 A degrees C), time of pretreatment (15-60 min) and pH of egg white solution (7.00-10.00) were examined. It appeared that controlled ultrasound treatment can improved the hydrolysis process compared with untreated samples, but optimization of the power and length of sonication was important. The optimal ultrasound pretreatment at calorimetric power of 21.3 W and frequency of 40 kHz for 15 min at 25 A degrees C and with naturally basic egg white (pH 9.25) resulted in increased initial rate and equilibrium degree of Alcalase hydrolysis by about 139.8 and 13.86 % compared with the control, respectively. EWP hydrolysates with a parts per thousand 27.0 % degree of hydrolysis obtained with heat pretreatment and ultrasound pretreatments under optimal conditions were further separated by sequential ultrafiltration into 4 hydrolysate fractions ( lt  1, 1-10, 10-30 and  gt  30 kDa) which were investigated for protein content, peptide yield and antioxidant activity. The hydrolysis after heat pretreatment generated more peptides  lt  1 kDa (19.04 +/- A 1.02 %) than ultrasound pretreatment did (11.90 +/- A 0.53 %), whereas the proportion of peptides  lt  10 kDa were higher in the second case (28.80 +/- A 0.07 vs. 20.46 +/- A 0.39 %). The fraction obtained by the ultrasound pretreatment containing peptides with a molecular weight between 1 and 10 kDa demonstrated the strongest ABTS radical scavenging efficacy among the fractions (97.54 +/- A 0.30) with IC50 value of 4.31 mg/mL. Compared with single-enzyme processes, the two-stage enzymatic processes did not significantly improve both antioxidant and functional hydrolysates' properties.
PB  - Springer, New York
T2  - European Food Research and Technology
T1  - Impact of ultrasound on egg white proteins as a pretreatment for functional hydrolysates production
EP  - 993
IS  - 6
SP  - 979
VL  - 239
DO  - 10.1007/s00217-014-2295-8
ER  - 

@article{
author = "Stefanović, Andrea and Jovanović, Jelena and Grbavčić, Sanja and Šekuljica, Nataša and Manojlović, Verica and Bugarski, Branko and Knežević-Jugović, Zorica",
year = "2014",
abstract = "The objective of this study was to investigate the effects of different ultrasound pretreatment on enzymatic hydrolysis of egg white proteins (EWPs) by Alcalase as well as evaluating some functional and antioxidant properties of hydrolysates obtained by various proteases treatment and ultrasound technology. The effects of chosen ultrasound pretreatment parameters including frequency of ultrasonic waves (35 and 40 kHz), temperature (25 and 55 A degrees C), time of pretreatment (15-60 min) and pH of egg white solution (7.00-10.00) were examined. It appeared that controlled ultrasound treatment can improved the hydrolysis process compared with untreated samples, but optimization of the power and length of sonication was important. The optimal ultrasound pretreatment at calorimetric power of 21.3 W and frequency of 40 kHz for 15 min at 25 A degrees C and with naturally basic egg white (pH 9.25) resulted in increased initial rate and equilibrium degree of Alcalase hydrolysis by about 139.8 and 13.86 % compared with the control, respectively. EWP hydrolysates with a parts per thousand 27.0 % degree of hydrolysis obtained with heat pretreatment and ultrasound pretreatments under optimal conditions were further separated by sequential ultrafiltration into 4 hydrolysate fractions ( lt  1, 1-10, 10-30 and  gt  30 kDa) which were investigated for protein content, peptide yield and antioxidant activity. The hydrolysis after heat pretreatment generated more peptides  lt  1 kDa (19.04 +/- A 1.02 %) than ultrasound pretreatment did (11.90 +/- A 0.53 %), whereas the proportion of peptides  lt  10 kDa were higher in the second case (28.80 +/- A 0.07 vs. 20.46 +/- A 0.39 %). The fraction obtained by the ultrasound pretreatment containing peptides with a molecular weight between 1 and 10 kDa demonstrated the strongest ABTS radical scavenging efficacy among the fractions (97.54 +/- A 0.30) with IC50 value of 4.31 mg/mL. Compared with single-enzyme processes, the two-stage enzymatic processes did not significantly improve both antioxidant and functional hydrolysates' properties.",
publisher = "Springer, New York",
journal = "European Food Research and Technology",
title = "Impact of ultrasound on egg white proteins as a pretreatment for functional hydrolysates production",
pages = "993-979",
number = "6",
volume = "239",
doi = "10.1007/s00217-014-2295-8"
}

Stefanović, A., Jovanović, J., Grbavčić, S., Šekuljica, N., Manojlović, V., Bugarski, B.,& Knežević-Jugović, Z.. (2014). Impact of ultrasound on egg white proteins as a pretreatment for functional hydrolysates production. in European Food Research and Technology
Springer, New York., 239(6), 979-993.
https://doi.org/10.1007/s00217-014-2295-8

Stefanović A, Jovanović J, Grbavčić S, Šekuljica N, Manojlović V, Bugarski B, Knežević-Jugović Z. Impact of ultrasound on egg white proteins as a pretreatment for functional hydrolysates production. in European Food Research and Technology. 2014;239(6):979-993.
doi:10.1007/s00217-014-2295-8 .

Stefanović, Andrea, Jovanović, Jelena, Grbavčić, Sanja, Šekuljica, Nataša, Manojlović, Verica, Bugarski, Branko, Knežević-Jugović, Zorica, "Impact of ultrasound on egg white proteins as a pretreatment for functional hydrolysates production" in European Food Research and Technology, 239, no. 6 (2014):979-993,
https://doi.org/10.1007/s00217-014-2295-8 . .

TY  - JOUR
AU  - Moftah, Omar A.S.
AU  - Grbavčić, Sanja
AU  - Moftah, Walid A.S.
AU  - Luković, Nevena
AU  - Prodanović, Olivera
AU  - Jakovetić, Sonja
AU  - Knežević-Jugović, Zorica
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2362
AB  - In this study, the solid and liquid wastes from the olive oil processing industry were evaluated as substrates for Yarrowia lipolytica growth with the aim of lipase production. Olive mill wastewater and olive oil cake seemed to provide the necessary nutrients and physical support for yeast growth and enzyme production. The highest lipolytic activity of 850 IU dm-3 was achieved after 4 days of submerged cultivation in supplemented olive mill wastewater. In addition, olive oil cake appeared to be a convenient substrate for lipase production under a solid-state fermentation mode. Lipase production was further improved by media supplementation and/or change in the physical settings of the experiment. However, the most significant improvement of lipase production under solid-state fermentation was achieved by an alkaline treatment of the substrate (more than 10-fold), when the amount of produced lipase reached up to ≈40 IU g-1 of substrate.
AB  - U ovom radu, tečne i čvrste otpadne sirovine koje zaostaju prilikom prerade maslina ispitane su kao potencijalni supstrati za rast kvasca Yarrowia lipolytica sa ciljem proizvodnje lipaza. Otpadna voda iz mlina, kao i pogača koja zaostaje nakon ceđenja ulja iz maslina, pokazali su se kao dobri izvori nutrijenata za rast ovog kvasca i proizvodnju enzima. U optimizovanoj tečnoj podlozi, prinos lipaza dostiže i do 850 IU dm-3. Pored toga, pogača koja zaostaje nakon ceđenja ulja iz maslina se pokazala kao pogodan čvrsti supstrat za gajenje proizvodnog mikroorganizma. Produkcija lipaza na ovom medijumu je dodatno optimizovana suplementacijom različitim izvorima azota i ugljenika, kao i promenom ostalih parametara fermentacije. Utvrđeno je da se najznačajnije poboljšanje produkcije lipaze ostvaruje alkalnim predtretmanom supstrata (više od 10 puta).
PB  - Serbian Chemical Society, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - Lipase production by Yarrowia lipolytica using olive oil processing wastes as substrates
T1  - Proizvodnja lipaze iz Yarrowia lipolytica korišćenjem otpadnih sirovina industrije prerade maslina kao supstrata
EP  - 794
IS  - 6
SP  - 781
VL  - 78
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2362
ER  - 

@article{
author = "Moftah, Omar A.S. and Grbavčić, Sanja and Moftah, Walid A.S. and Luković, Nevena and Prodanović, Olivera and Jakovetić, Sonja and Knežević-Jugović, Zorica",
year = "2013",
abstract = "In this study, the solid and liquid wastes from the olive oil processing industry were evaluated as substrates for Yarrowia lipolytica growth with the aim of lipase production. Olive mill wastewater and olive oil cake seemed to provide the necessary nutrients and physical support for yeast growth and enzyme production. The highest lipolytic activity of 850 IU dm-3 was achieved after 4 days of submerged cultivation in supplemented olive mill wastewater. In addition, olive oil cake appeared to be a convenient substrate for lipase production under a solid-state fermentation mode. Lipase production was further improved by media supplementation and/or change in the physical settings of the experiment. However, the most significant improvement of lipase production under solid-state fermentation was achieved by an alkaline treatment of the substrate (more than 10-fold), when the amount of produced lipase reached up to ≈40 IU g-1 of substrate., U ovom radu, tečne i čvrste otpadne sirovine koje zaostaju prilikom prerade maslina ispitane su kao potencijalni supstrati za rast kvasca Yarrowia lipolytica sa ciljem proizvodnje lipaza. Otpadna voda iz mlina, kao i pogača koja zaostaje nakon ceđenja ulja iz maslina, pokazali su se kao dobri izvori nutrijenata za rast ovog kvasca i proizvodnju enzima. U optimizovanoj tečnoj podlozi, prinos lipaza dostiže i do 850 IU dm-3. Pored toga, pogača koja zaostaje nakon ceđenja ulja iz maslina se pokazala kao pogodan čvrsti supstrat za gajenje proizvodnog mikroorganizma. Produkcija lipaza na ovom medijumu je dodatno optimizovana suplementacijom različitim izvorima azota i ugljenika, kao i promenom ostalih parametara fermentacije. Utvrđeno je da se najznačajnije poboljšanje produkcije lipaze ostvaruje alkalnim predtretmanom supstrata (više od 10 puta).",
publisher = "Serbian Chemical Society, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "Lipase production by Yarrowia lipolytica using olive oil processing wastes as substrates, Proizvodnja lipaze iz Yarrowia lipolytica korišćenjem otpadnih sirovina industrije prerade maslina kao supstrata",
pages = "794-781",
number = "6",
volume = "78",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2362"
}

Moftah, O. A.S., Grbavčić, S., Moftah, W. A.S., Luković, N., Prodanović, O., Jakovetić, S.,& Knežević-Jugović, Z.. (2013). Lipase production by Yarrowia lipolytica using olive oil processing wastes as substrates. in Journal of the Serbian Chemical Society
Serbian Chemical Society, Belgrade., 78(6), 781-794.
https://hdl.handle.net/21.15107/rcub_technorep_2362

Moftah OA, Grbavčić S, Moftah WA, Luković N, Prodanović O, Jakovetić S, Knežević-Jugović Z. Lipase production by Yarrowia lipolytica using olive oil processing wastes as substrates. in Journal of the Serbian Chemical Society. 2013;78(6):781-794.
https://hdl.handle.net/21.15107/rcub_technorep_2362 .

Moftah, Omar A.S., Grbavčić, Sanja, Moftah, Walid A.S., Luković, Nevena, Prodanović, Olivera, Jakovetić, Sonja, Knežević-Jugović, Zorica, "Lipase production by Yarrowia lipolytica using olive oil processing wastes as substrates" in Journal of the Serbian Chemical Society, 78, no. 6 (2013):781-794,
https://hdl.handle.net/21.15107/rcub_technorep_2362 .