Georgiou, Constantinos A.

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orcid::0000-0003-1242-0283
  • Georgiou, Constantinos A. (3)
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Author's Bibliography

Enzymatic spectrophotometric reaction rate determination of aspartame

Trifković, Kata T.; Łękawska-Andrinopoulou, Lucyna; Bugarski, Branko; Georgiou, Constantinos A.

(Association of Chemical Engineers of Serbia, 2015)

TY  - JOUR
AU  - Trifković, Kata T.
AU  - Łękawska-Andrinopoulou, Lucyna
AU  - Bugarski, Branko
AU  - Georgiou, Constantinos A.
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2892
AB  - Aspartame is an artificial sweetener of low caloric value (approximately 200 times sweeter than sucrose). Aspartame is currently permitted for use in food and beverage production in more than 90 countries. The application of aspartame in food products requires development of rapid, inexpensive and accurate method for its determination. The new assay for determination of aspartame was based on set of reactions that are catalyzed by three different enzymes: α-chymotrypsin, alcohol oxidase and horseradish peroxidase. Optimization of the proposed method was carried out for: i) α-chymotrypsin activity; ii) time allowed for α-chymotrypsin action, iii) temperature. Evaluation of the developed method was done by determining aspartame content in 'diet' drinks, as well as in artificial sweetener pills.
AB  - Aspartam je veštački zaslađivač niske kalorijske vrednosti, približno 200 puta slađi od saharoze. Aspartam se trenutno koristi u industriji hrane i pića kao zamena za šećer u preko 90 zemalja u svetu, pa je stoga nužno imati razvijenu metodologiju i dobru analitiku za njegovo određivanje. Metode koje se najčešće koriste za određivanje aspartama su obično dugotrajne, skupe i zahtevaju značajna ulaganja u opremu, kao i komplikovan pred-tretman uzoraka. Stoga je neophodno razviti brz, ekonomičan, osetljv i precizan test za njegovu detekciju. U ovom radu je predložen test za određivanje aspartama koji se zasniva na nizu reakcija katalizovanih upotrebom tri enzima: α-himotripsin, alkoholna oksidaza i peroksidaza iz rena. Tokom reakcione kaskade dolazi do transformacije aspartama u tri reakciona koraka, od kojih je svaki enzimski katalizovan, α-himotripsinom, alkoholnom oksidazom i peroksidazom iz rena, redom. Preko nekoliko reakcionih međuproizvoda (methanol i vodonik-peroksid) aspartam se transformiše do obojenog produkta, čije se formiranje prati spektrofotometrijski, a zatim se na osnovu apsorbance obojenja dalje preračunava koncentracija aspartama prisutna u ispitivanom uzorku. Eksperimentalni postupak je jednostavan i efikasan, a njegova preciznost dobra. Optimizacija predloženog testa izvršena je u cilju određivanja optimalne: i) aktivnosti α-himotripsina; ii) vremena pre-inkubacije; iii) temperature pri kojoj se odvija reakcija. Predloženi test ocenjen je određivanjem sadržaja aspartama u dijetalnim pićima (Coca-Cola Diet) i veštačkim zaslađivačima (Candarel tablete), kao i procenom njegovog praga osetljivosti. Dobijeni rezultati ukazuju na neophodnost optimizacije metode detekcije, u cilju omogućavanja određivanja nižih koncetracija aspartama prisutnih u uzorku.
PB  - Association of Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Enzymatic spectrophotometric reaction rate determination of aspartame
T1  - Enzimatsko-spektrofotometrijski test za određivanje aspartama
EP  - 359
IS  - 4
SP  - 355
VL  - 69
DO  - 10.2298/HEMIND140526049T
ER  - 
@article{
author = "Trifković, Kata T. and Łękawska-Andrinopoulou, Lucyna and Bugarski, Branko and Georgiou, Constantinos A.",
year = "2015",
abstract = "Aspartame is an artificial sweetener of low caloric value (approximately 200 times sweeter than sucrose). Aspartame is currently permitted for use in food and beverage production in more than 90 countries. The application of aspartame in food products requires development of rapid, inexpensive and accurate method for its determination. The new assay for determination of aspartame was based on set of reactions that are catalyzed by three different enzymes: α-chymotrypsin, alcohol oxidase and horseradish peroxidase. Optimization of the proposed method was carried out for: i) α-chymotrypsin activity; ii) time allowed for α-chymotrypsin action, iii) temperature. Evaluation of the developed method was done by determining aspartame content in 'diet' drinks, as well as in artificial sweetener pills., Aspartam je veštački zaslađivač niske kalorijske vrednosti, približno 200 puta slađi od saharoze. Aspartam se trenutno koristi u industriji hrane i pića kao zamena za šećer u preko 90 zemalja u svetu, pa je stoga nužno imati razvijenu metodologiju i dobru analitiku za njegovo određivanje. Metode koje se najčešće koriste za određivanje aspartama su obično dugotrajne, skupe i zahtevaju značajna ulaganja u opremu, kao i komplikovan pred-tretman uzoraka. Stoga je neophodno razviti brz, ekonomičan, osetljv i precizan test za njegovu detekciju. U ovom radu je predložen test za određivanje aspartama koji se zasniva na nizu reakcija katalizovanih upotrebom tri enzima: α-himotripsin, alkoholna oksidaza i peroksidaza iz rena. Tokom reakcione kaskade dolazi do transformacije aspartama u tri reakciona koraka, od kojih je svaki enzimski katalizovan, α-himotripsinom, alkoholnom oksidazom i peroksidazom iz rena, redom. Preko nekoliko reakcionih međuproizvoda (methanol i vodonik-peroksid) aspartam se transformiše do obojenog produkta, čije se formiranje prati spektrofotometrijski, a zatim se na osnovu apsorbance obojenja dalje preračunava koncentracija aspartama prisutna u ispitivanom uzorku. Eksperimentalni postupak je jednostavan i efikasan, a njegova preciznost dobra. Optimizacija predloženog testa izvršena je u cilju određivanja optimalne: i) aktivnosti α-himotripsina; ii) vremena pre-inkubacije; iii) temperature pri kojoj se odvija reakcija. Predloženi test ocenjen je određivanjem sadržaja aspartama u dijetalnim pićima (Coca-Cola Diet) i veštačkim zaslađivačima (Candarel tablete), kao i procenom njegovog praga osetljivosti. Dobijeni rezultati ukazuju na neophodnost optimizacije metode detekcije, u cilju omogućavanja određivanja nižih koncetracija aspartama prisutnih u uzorku.",
publisher = "Association of Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Enzymatic spectrophotometric reaction rate determination of aspartame, Enzimatsko-spektrofotometrijski test za određivanje aspartama",
pages = "359-355",
number = "4",
volume = "69",
doi = "10.2298/HEMIND140526049T"
}
Trifković, K. T., Łękawska-Andrinopoulou, L., Bugarski, B.,& Georgiou, C. A.. (2015). Enzymatic spectrophotometric reaction rate determination of aspartame. in Hemijska industrija
Association of Chemical Engineers of Serbia., 69(4), 355-359.
https://doi.org/10.2298/HEMIND140526049T
Trifković KT, Łękawska-Andrinopoulou L, Bugarski B, Georgiou CA. Enzymatic spectrophotometric reaction rate determination of aspartame. in Hemijska industrija. 2015;69(4):355-359.
doi:10.2298/HEMIND140526049T .
Trifković, Kata T., Łękawska-Andrinopoulou, Lucyna, Bugarski, Branko, Georgiou, Constantinos A., "Enzymatic spectrophotometric reaction rate determination of aspartame" in Hemijska industrija, 69, no. 4 (2015):355-359,
https://doi.org/10.2298/HEMIND140526049T . .

Hydrotreating of straight-run gas oil blended with FCC naphtha and light cycle oil

Dukanović, Zoran; Glišić, Sandra; Jancić-Cobanin, Vesna; Niciforović, Miroslav; Georgiou, Constantinos A.; Orlović, Aleksandar

(Elsevier Science Bv, Amsterdam, 2013)

TY  - JOUR
AU  - Dukanović, Zoran
AU  - Glišić, Sandra
AU  - Jancić-Cobanin, Vesna
AU  - Niciforović, Miroslav
AU  - Georgiou, Constantinos A.
AU  - Orlović, Aleksandar
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2486
AB  - In order to expand diesel fuel processing capacity an option to co-hydrotreat straight run gas oil blended with fraction containing FCC naphtha and light cycle oil was investigated. Industrial test run was performed under pressure of 40 bar in the catalytic reactor with two layers of conventional Co-Mo/gamma-Al2O3 catalyst, by increasing volume content of FCC naphtha and light cycle oil fraction in the reactor inlet to 20%vol. Reactor inlet temperature was also increased during the test run from 327 to 334 degrees C. Liquid hourly space velocities between 1.05 and 1.32 h(-1) have been used with H-2/oil ratios of 908-1135 Nm(3) hydrogen/m(3) oil. Sulphur inlet concentrations of 6500-8200 ppm were reduced to 36-72 ppm in the hydrotreated oil. GC-MS analysis of the sulphur compound's sub-families has shown that most of the sulphur was present in more reactive classes like alkyl substituted benzothiophenes. High conversion of sulphur was achieved by a combination of the following process parameters: high reaction temperature, low space velocity, presence of FCC naphtha in the feed and distribution of inlet sulphur dominantly concentrated in more reactive benzothiophenes. The activation energy of 33.2 kcal/mol was determined for this type of feedstock using power law kinetic expression.
PB  - Elsevier Science Bv, Amsterdam
T2  - Fuel Processing Technology
T1  - Hydrotreating of straight-run gas oil blended with FCC naphtha and light cycle oil
EP  - 165
SP  - 160
VL  - 106
DO  - 10.1016/j.fuproc.2012.07.018
ER  - 
@article{
author = "Dukanović, Zoran and Glišić, Sandra and Jancić-Cobanin, Vesna and Niciforović, Miroslav and Georgiou, Constantinos A. and Orlović, Aleksandar",
year = "2013",
abstract = "In order to expand diesel fuel processing capacity an option to co-hydrotreat straight run gas oil blended with fraction containing FCC naphtha and light cycle oil was investigated. Industrial test run was performed under pressure of 40 bar in the catalytic reactor with two layers of conventional Co-Mo/gamma-Al2O3 catalyst, by increasing volume content of FCC naphtha and light cycle oil fraction in the reactor inlet to 20%vol. Reactor inlet temperature was also increased during the test run from 327 to 334 degrees C. Liquid hourly space velocities between 1.05 and 1.32 h(-1) have been used with H-2/oil ratios of 908-1135 Nm(3) hydrogen/m(3) oil. Sulphur inlet concentrations of 6500-8200 ppm were reduced to 36-72 ppm in the hydrotreated oil. GC-MS analysis of the sulphur compound's sub-families has shown that most of the sulphur was present in more reactive classes like alkyl substituted benzothiophenes. High conversion of sulphur was achieved by a combination of the following process parameters: high reaction temperature, low space velocity, presence of FCC naphtha in the feed and distribution of inlet sulphur dominantly concentrated in more reactive benzothiophenes. The activation energy of 33.2 kcal/mol was determined for this type of feedstock using power law kinetic expression.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Fuel Processing Technology",
title = "Hydrotreating of straight-run gas oil blended with FCC naphtha and light cycle oil",
pages = "165-160",
volume = "106",
doi = "10.1016/j.fuproc.2012.07.018"
}
Dukanović, Z., Glišić, S., Jancić-Cobanin, V., Niciforović, M., Georgiou, C. A.,& Orlović, A.. (2013). Hydrotreating of straight-run gas oil blended with FCC naphtha and light cycle oil. in Fuel Processing Technology
Elsevier Science Bv, Amsterdam., 106, 160-165.
https://doi.org/10.1016/j.fuproc.2012.07.018
Dukanović Z, Glišić S, Jancić-Cobanin V, Niciforović M, Georgiou CA, Orlović A. Hydrotreating of straight-run gas oil blended with FCC naphtha and light cycle oil. in Fuel Processing Technology. 2013;106:160-165.
doi:10.1016/j.fuproc.2012.07.018 .
Dukanović, Zoran, Glišić, Sandra, Jancić-Cobanin, Vesna, Niciforović, Miroslav, Georgiou, Constantinos A., Orlović, Aleksandar, "Hydrotreating of straight-run gas oil blended with FCC naphtha and light cycle oil" in Fuel Processing Technology, 106 (2013):160-165,
https://doi.org/10.1016/j.fuproc.2012.07.018 . .
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Bioluminescent whole-cell biosensors

Georgiou, Constantinos A.; Bugarski, Branko

(Association of Chemical Engineers of Serbia, 2004)

TY  - JOUR
AU  - Georgiou, Constantinos A.
AU  - Bugarski, Branko
PY  - 2004
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/655
PB  - Association of Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Bioluminescent whole-cell biosensors
EP  - 91
IS  - 6a
SP  - 89
VL  - 58
UR  - https://hdl.handle.net/21.15107/rcub_technorep_655
ER  - 
@article{
author = "Georgiou, Constantinos A. and Bugarski, Branko",
year = "2004",
publisher = "Association of Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Bioluminescent whole-cell biosensors",
pages = "91-89",
number = "6a",
volume = "58",
url = "https://hdl.handle.net/21.15107/rcub_technorep_655"
}
Georgiou, C. A.,& Bugarski, B.. (2004). Bioluminescent whole-cell biosensors. in Hemijska industrija
Association of Chemical Engineers of Serbia., 58(6a), 89-91.
https://hdl.handle.net/21.15107/rcub_technorep_655
Georgiou CA, Bugarski B. Bioluminescent whole-cell biosensors. in Hemijska industrija. 2004;58(6a):89-91.
https://hdl.handle.net/21.15107/rcub_technorep_655 .
Georgiou, Constantinos A., Bugarski, Branko, "Bioluminescent whole-cell biosensors" in Hemijska industrija, 58, no. 6a (2004):89-91,
https://hdl.handle.net/21.15107/rcub_technorep_655 .