The aim of this study was to investigate the occurrence and stability of free radicals in freeze-dried samples of cow milk, pineapple and banana after irradiation (10 kGy dose), using the ESR spectroscopy, as well as to assess possible changes in their protein structure by means of electrophoresis.The Conference is dedicated to the 100th Anniversary of the academician Pavle Savić birthday and 20th Anniversary of the Society of Physical Chemists of SerbiaPhysical chemistry 2010 : 10th international conference on fundamental and applied aspects of physical chemistry; September 21-24, Belgrade, 2012

Ignjatović, A,

Mojović, M.

Rogić, Zorana

Spasojević, I.

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       PHYSICAL CHEMISTRY 2010  10th International Conference on Fundamental and Applied Aspects of Physical Chemistry  Proceedings      The Conference is dedicated to the 100th Anniversary of the academician Pavle Savić birthday and 20th Anniversary of the Society of Physical Chemists of Serbia         21-24 September 2010 B E L G R A D E                            ISBN 978-86-82475-17-0 Title: Physical Chemistry 2010. (Proceedings) Editors: S. Anić and Ž. Čupić Published by: Society of Physical Chemists of Serbia, Studentski trg 12-16 P.O.Box 47, 11158 Beograd, 218, Srbija Publisher: Society of Physical Chemists of Serbia For Publisher: S. Anić, President of Society of Physical Chemists of Serbia Printed by: “Jovan” Printing and Publishing Company; 200 Copies; Number of pages 16 + 388, Format: B5; Printing finished in September 2010.  Text and Layout: “Jovan”  200 - Copy printing    II  CONTENTS   VOLUME I Organizers .............................................................................................................IV Committees ............................................................................................................. V Sponsors ............................................................................................................... VII Twenty years of Society of physical chemists of Serbia..................................VIII Plenary lectures....................................................................................................... 1 Chemical Thermodynamics ................................................................................. 35 Spectroscopy, Molecular Structure and Physical Chemistry of Plasma.......... 55 Kinetics and Catalysis........................................................................................... 91 Nonlinear Dynamics............................................................................................ 191 Electrochemistry ................................................................................................. 263 Biophysical Chemistry, Photochemistry and Radiation Chemistry............... 299  VOLUME II Radiochemistry and Nuclear Chemistry........................................................... 389 Material Science .................................................................................................. 397 Solid State Physical Chemistry .......................................................................... 451 Macromolecular Physical Chemistry ................................................................ 471 Environmental Protection,  Forensic Sciences and Pharmaceutical Physical Chemistry ........................... 525 Phase Boundaries ................................................................................................ 621 Complex Compounds.......................................................................................... 633 General Physical Chemistry............................................................................... 647 Education............................................................................................................. 683 Author index........................................................................................................ 695 Participating Institutions.................................................................................... 703               III   The Society of Physical Chemists of Serbia  in co-operation with   Institute of Catalysis, Bulgarian Academy of Sciences  Boreskov Institute of Catalysis, Siberian Branch of  the Russian Academy of Sciences  Faculty of Physical Chemistry, University of Belgrade, Serbia  Institute of Chemistry Technology and Metallurgy, University of Belgrade, Serbia  Vinča Institute, University of Belgrade, Serbia   Institute of General and Physical Chemistry, Serbia                         IV  International Organizing Committee  Chairman:             S. Anić (Serbia) Vice-chairman:     N. Stepanov (Russia)                                B. Adnađević (Serbia)  Members: M. Gabrovska (Bulgaria), N. Cvijetićanin (Serbia), T. Grozdić (Serbia),  D. Jovanović (Serbia), M. Lalić (BiH), D. Marković (Serbia), B. Milosavljević (USA), N. Miljević (Serbia), M. Mojović (Serbia), N. Ostrovski (Serbia), C. Pona (Italy), B. Simonović (Serbia), D. Stanisavljev (Serbia), A. G. Stepanov (Russia), V. Vasić (Serbia), N. Vukelić (Serbia), V. Vukojević (Sweden)   International Scientific Committee  Chairman:              Ž. Čupić (Serbia) Vice-chairmans:     V. N. Parmon (Russia)                                 M. Franko (Slovenia)  V. Vasić (Serbia)  Members: A. Antić-Jovanović (Serbia), G. Bačic (Serbia), R. Cervellati (Italy), R. Compton (United Kingdom), V. Gaspar (Hungary),  M. Jeremić (Serbia), A. L. Kawczyñski (Poland), Lj. Kolar-Anić (Serbia), S. Kuchanov (Russia), R. Leblanc (USA),  S. Mentus (Serbia), S. Milonjić (Serbia), Lj. Morozova-Roche (Sweden),  D. Moscone (Italy), J. Nedeljković (Serbia), Z. Noszticzius (Hungary), M. Perić (Serbia), V. Petruševski (Macedonia), M. Plavšić (Serbia), G. Smulevich (Italy),  G. Schmitz (Belgium), I. Schreiber (Czech), P. Ševčik (Slovakia), N. Stepanov (Russia), M. Trtica (Serbia), D. Veselinović (Serbia)  Local Executive Committee  Chairman:              B. Adnadjević Vice-chairmans:    S. Blagojević                                 A. Ivanović  Members: A. Abu Rabi-Stanković, P. Banković, N. Begović, S. N. Blagojević,  N. Cvjetičanin, M. Daković, A. Đerić, A. Ignjatović, Lj. Ignjatović, A. Jović,  J. Krstić, S. Kuprešak, D. Lončarević, J. Maksimović, V. Marković, M. Milenković, M. Milojević, Z. Mojović, B. Nedić, I. Pašti, N. Pejić, A. Popović-Bjelić, M. Petković, N. Potkonjak, D. Ranković, R. Ranković, M. Stević,  I. Stojković, B. Šljukić, M. Vujković    V     Honorary Committee  Nikola Hajdin,  President of Serbian Academy of Sciences and Arts Branko Kovačević,  Rector of University of Belgrade Paula Putanov,  Member of Serbian Academy of Sciences and Arts Momčilo Ristić,  Member of Serbian Academy of Sciences and Arts Ankica Antić Jovanović,  Honorary President of Society of Physical Chemists of Serbia Ivan Draganić,  Honorary Member of Society of Physical Chemists of Serbia Roger M. Leblanc  (Canada) Honorary Member of Society of Physical Chemists of Serbia Preben Graae Sørensen  (Denmark) Honorary Member of Society of Physical Chemists of Serbia Guy Schmitz (Belgium)  Honorary Member of Society of Physical Chemists of Serbia Miroslav Kopečni,  Honorary Member of Society of Physical Chemists of Serbia Vladimir Petruševski  (Macedonia), Honorary Member of Society of Physical Chemists of Serbia Biljana Minčev Šukarova  (Macedonia), Honorary Member of Society of Physical Chemists of Serbia Ljiljana Kolar-Anić,  Honorary Member of Society of Physical Chemists of Serbia Milorad Jeremić,  Honorary Member of Society of Physical Chemists of Serbia Čedomir Radenović,  Honorary Member of Society of Physical Chemists of Serbia             VI       SPONSORS  Ministry of Science and Technological Development  University of Belgrade, Belgrade  The Faculty of Physical Chemistry, University of Belgrade  Institute of Chemistry Technology and Metallurgy, University of Belgrade  Vinča Institute, University of Belgrade  Institute of General and Physical Chemistry, Belgrade  NovoLab, Belgrade  MOL, Belgrade  Gradski zavod za zaštitu zdravlja, Belgrade                    VII              On the occasion of the hundredth anniversary of the birth of Academician Pavle Savić and twentieth anniversary of founding Society of Physical Chemists of Serbia, instead of the usual introduction, here is given translation of the text 20 years of Society of Physical Chemists of Serbia 1989 – 2009, published in a special Issue of Chemical Industry Vol. 63 (5a).   Editors                        VIIITHE APPLICATION OF PHYSICOCHEMICAL METHODS FOR THE ANALYSIS OF RADIATION PROCESSED FOOD PRODUCTS  Z. Rogić1, I. Spasojević2, A. Ignjatović1 and M. Mojović1  1Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12–16, 11158 Belgrade, Serbia 2Institute for Multidisciplinary Research, Kneza Višeslava 1, 11000 Belgrade, Serbia milos@ffh.bg.ac.rs  Abstract The aim of this study was to investigate the occurrence and stability of free radicals in freeze-dried samples of cow milk, pineapple and banana after irradiation (10 kGy dose), using the ESR spectroscopy, as well as to assess possible changes in their protein structure by means of electrophoresis.  Introduction The application of irradiation in order to preserve food quality has been neglected for a long time in comparison to other methods, mainly due to prejudices. However, the attitude of consumers towards food irradiation is now becoming more positive due to spreading of information and knowledge of this process as well as to the availability of a number of analytical methods to detect aftermath of radiation treatment [1]. ESR spectroscopy due to its ability to reveal the presence of minute amounts of free radicals generated by irradiation plays a leading role in such studies [2]. The procedure for food samples used in these experiments is based on the fact that non-irradiated samples give poor signals, while in irradiated samples the significant increase of amplitude of EPR signal is noticed. Although the nutrient proprieties of irradiated food are no longer in question, there is a need for irradiation control in the international food trade in order to enhance consumer confidence in the regulation [3].  Experimental Samples of cow milk, pineapple and banana were cryogenically dried, pulverized and then freeze-dried. The ESR spectra of irradiated and non-irradiated samples (control) of the same mass were obtained using X-band EPR spectrometer, and standard SDS-PAGE electrophoreses was used for detection of radiation induced protein degradation products.  Results and Discussion The difference in the EPR peak heights of free radicals of the control and irradiated samples is obvious (Fig.1). Radiation induced signal decay with time (banana sample week II shows aberration most likely due different orientation of the sample in the EPR cavity), but clearly indicate that radiation treatment can be detected long after its application.  361  Fig.1. Typical ESR spectra and calculated absolute EPR peak heights of different food samples Pineapple0 250 500 750 1.000 I week II week IV week V weekPeak height Banana050100150Peak height 200250I week II week IV week V weekCow milk02004006008001.0001.200I week II week IV week V weekPeak height  In the second part of the experiment samples were subjected to SDS electrophoresis in order to detect any changes in the concentration of proteins.    Fig.2. SDS-PAGE gels of: P - pineapple, P '- irradiated pineapple, B - banana, B' - irradiated banana, M - milk, M '- irradiated milk.    Pineapple (Fig.2.P, P’) sample shows very small number of low molecular weight proteins, but also no change in the concentration of proteins. Banana (Fig.2.B, B’) shows different molecular weight proteins, as well as the loss of some higher molecular mass proteins during radiation. Milk sample (Fig.2.M, M’) is extremely sensitive to radiation. Gel presents proteins in a wide range of molecular weight, as well as many proteins of similar molecular weight. Reduction of the intensity and of the number of strips on gel of irradiated milk sample is present. Tested samples of banana and cow milk showed the destruction of proteins, while a change in the sample of pineapple is negligible. Changes in the number and width of protein fragments in gel are a clear proof that during the radiation degradation of existing protein molecules into smaller molecular fragments occurred. 362Conclusion Based on the results obtained by ESR spectroscopy and electrophoresis, we demonstrated that the tested samples suffered a series of changes after the application of 10 kGy ionizing radiation which is commonly used for food preservation. Electrophoresis shows that radiation treatment undoubtedly breaks peptide links affecting the decomposition of certain proteins, reducing their concentration, and decays polypeptide chains of high molecular weight proteins into smaller fragments. EPR spectra showed that ionizing radiation enhances cellulose and sugar radical EPR signal in tested samples of cow milk, banana and pineapple. By investigating EPR signal attenuation in time it can be reliably determined whether any of these groceries had been treated by radiation even after longer periods of time after the radiation. Furthermore, we concluded that sample of cow milk powder could potentially be used as radiation dosimeter since free radicals generated under the influence of ionizing radiation showed a weak recombination in time.  Acknowledgments  The authors acknowledge their gratitude to the Ministry of Science of Republic of Serbia for the financial support (Project #143016).  References [1]  M. P. Esteves, M. E. Andrade, J. Empis, Radiation Physics and Chemistry, 1999, 55, 737-742. [2]  O. G. Duliu, R. Georgescu, S. I. Ali, Radiation Physics and Chemistry, 2007, 76, 1031-1036. [3]  J. Raffi, N. D. Yordanov, S. Chabane, L. Douifi, V. Gancheva, S. Ivanova, Spectrochimica Acta Part A, 2000, 56, 409-416.   363

The application of physicochemical methods for the analysis of radiation processed food products

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The application of physicochemical methods for the analysis of radiation processed food products

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