Hamide Z. Şenyuva

Immunoaffinity column clean-up techniques in food analysis: A review.

This review provides a critical assessment of the applications of immunoaffinity columns for sample clean-up in the field of food safety. The performance of immunoaffinity columns are compared in terms of specificity, binding capacity and recovery, and commercial disposable columns are contrasted with home-made columns. Areas covered include multiple-use of columns, multiple-analyte columns, use with automated systems and validation of IAC methods. Publications illustrating the many varied applications of IAC for sample clean-up in the areas of mycotoxins, veterinary drug residues, pesticide residues, environmental contaminants and vitamins have been compiled, comparing extraction methods, achievable recovery, and illustrating the variety of end-detection methods that have been employed.

Study of acrylamide in coffee using an improved liquid chromatography mass spectrometry method: Investigation of colour changes and acrylamide formation in coffee during roasting

An improved analytical method for the determination of acrylamide in coffee is described using liquid chromatography coupled to mass spectrometric detection (LC-MS). A variety of instant, ground and laboratory roasted coffee samples were analysed using this method. The sample preparation entails extraction of acrylamide with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and clean-up with an Oasis HLB solid-phase extraction (SPE) cartridge. The chromatographic conditions allowed separation of acrylamide and the remaining matrix co-extractives with accurate and precise quantification of acrylamide during MS detection in SIM mode. Recoveries for the spiking levels of 50, 100, 250 and 500 µg/kg ranged between 99 and 100% with relative standard deviations of less than 2%. The effects of roasting on the formation of acrylamide and colour development were also investigated at 150, 200 and 225°C. Change in the CIE (Commission Internationale de l’Eclairage) a* colour value was found to show a good correlation with the change in acrylamide. CIE a* and acrylamide data was fitted to a non-linear logarithmic function for the estimation of acrylamide level in coffee. Measured acrylamide levels in commercial roasted coffees compared well with the predicted acrylamide levels from the CIE a* values.

A simplified approach for the kinetic characterization of acrylamide formation in fructose-asparagine model system

The potential of acrylamide formation and degradation was studied in fructose-asparagine reaction system at different temperatures (120–200°C). Kinetic data for concurrent formation and degradation of acrylamide was analysed based on a simplified form of chemical reaction in series in which acrylamide occurred as an intermediate. Experimental results revealed that the reaction proceeds zero order and first order with respect to asparagine and fructose, respectively. The thermal degradation of acrylamide was determined to be first order in fructose-glycine reaction system. The concurrent formation and degradation of acrylamide followed a typical kinetic pattern at the temperatures studied. Thermal degradation was observed within 60 min at T > 150°C, while only the accumulation was noted at T < 150°C. The mathematical model fitted to experimental data very well within temperature range of 120–200°C. The temperature dependence of both acrylamide formation and degradation were found to obey Arrhenius law, and the activation energies were 52.1 kJ/mol and 72.9 kJ/mol, respectively.

Analysis of furan in foods. Is headspace sampling a fit-for-purpose technique?

Headspace GC-MS has been opitimized for the determination of furan in foods. The conditions of sample preparation, headspace sampling and GC separation were optimized to enhance sensitivity during GC-MS analysis. Green coffee was used to prepare a matrix matched calibration curve for furan. However, it was unexpectedly found that a green coffee sample was not blank. GC-MS analysis performed after equilibration for 30 min at 40°C showed the presence of 4.2 ng/g furan in green coffee. In order to understand whether furan was naturally present or formed during headspace sampling, green coffee was investigated in time-dependent manner at headspace equilibration temperatures of 40 and 70°C. It was observed that furan response continued to increase in a way similar to first order formation kinetics. The same behavior was found for freshly squeezed tomato and orange juices leading to the suspicion of furan formation during headspace equilibration. It is concluded that a matrix matched calibration for each particular food matrix is necessary to compensate for furan formation during headspace sampling, and thus, to quantify furan more accurately.

Bioactive compounds in foods

Introduction. Professor John Gilbert , Central Science Laboratory, Sand Hutton, York, UK and. Dr Hamide Z. Senyuva , Ankara Test and Analysis Laboratory, Scientific and Technical Research Council of Turkey, Ankara, Turkey. Part 1 - Natural toxicants . 1. Pyrrolizidine alkaloids . Colin Crews , Central Science Laboratory, Sand Hutton, York, UK and. Professor Dr Rudi Krska , Christian Doppler Laboratory for Mycotoxin Research, Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Applied Life Sciences, Tulln, Austria. 2. Glucosinolates . Dr Ruud Verkerk and Dr Matthijs Dekker, Department of Food Technology and Nutrition Science, Agricultural University Wageningen, The Netherlands. 3. Phycotoxins in seafoods . Dr John Leftley Scottish Association for Marine Science, Oban, Argyll, Scotland, UK and Integrin Advanced Biosystems Ltd., Marine Resource Centre, Barcaldine, Argyll, Scotland, UK and. Dr Fiona Hannah , University of London, University Marine Biological Station, Millport, Isle of Cumbrae, Scotland, UK. 4. Mushroom toxins. Professor Jana Hajslova , Institute of Chemical Technology, Prague, Czech Republic. 5. Mycotoxins . Mr Keith Scudamore , KAS Mycotoxins, Taplow, Berkshire, UK. 6. Phytoestrogens . Dr Don Clarke , Central Science Laboratory, Sand Hutton, York, UK. 7. ss-Carboline alkaloids . Dr T. Herraiz , Spanish Council for Scientific Research, Madrid, Spain. 8. Naturally-occuring Nitrates and Nitrites in foods. Dr M. Reinik , Estonian Health Protection Inspectorate, Tartu Laboratory, Tartu, Estonia. Dr T Tamme , Estonian University of Life Sciences, Department of Food Science and Hygiene, Tartu, Estonia. Dr M. Roasto , Estonian University of Life Sciences, Dept. of Food Science and Hygiene, Tartu, Estonia. Part II Man-made components . 9. Acrylamide in heated foods . Dr Hamide Z. Senyuva , Ankara Test and Analysis Laboratory, Scientific and Technical Research Council of Turkey, Ankara, Turkey. Dr Vural Gokmen , Food Engineering Department, Hacettepe University, Ankara, Turkey. 10. Furan in processed foods . Dr Imre Blank , Science Department Head, Nestle Product Technology Center, Orbe, Switzerland. 11. Chloropropanols and chloroesters. Dr Colin Hamlet , RHM Technology Ltd, The Lord Rank Centre, High Wycombe, Bucks, UK. 12. Hetrocyclic amines . Dr M. Knizel , University of California, Lawrence Livermore National Laboratory, Biology & Biotechnology Research Program, Livermore, CA, USA. 13. Polycyclic Aromatic Hydrocarbons . Dr M. Rose , Central Science Laboratory, Sand Hutton, York, UK. Dr Laura Cano-Lerida , Johnson Matthey Catalysis, Belasis Avenue, Chilton, Billingham, UK. Dr P. Walton , Department of Chemistry, University of York, Heslington, York, UK.

Rapid analysis of fungal cultures and dried figs for secondary metabolites by LC/TOF-MS.

A liquid chromatography-time-of-flight mass spectrometry (LC/TOF-MS) method has been developed for profiling fungal metabolites. The performance of the procedure in terms of mass accuracy, selectivity (specificity) and repeatability was established by spiking aflatoxins, ochratoxins, trichothecenes and other metabolites into blank growth media. After extracting, and carrying out LC/TOF-MS analysis, the standards were correctly identified by searching a specially constructed database of 465 secondary metabolites. To demonstrate the viability of this approach 11 toxigenic and four non-toxigenic fungi from reference collections were grown on various media, for 7-14 days. The method was also applied to two toxigenic fungi, A. flavus (200-138) and A. parasiticus (2999-465) grown on gamma radiation sterilised dried figs, for 7-14 days. The fungal hyphae plus a portion of growth media or portions of dried figs were solvent extracted and analysed by LC/TOF-MS using a rapid resolution microbore LC column. Data processing based on cluster analysis, showed that electrospray ionization (ESI)-TOF-MS could be used to unequivocally identify metabolites in crude extracts. Using the elemental metabolite database, it was demonstrated that from culture collection isolates, anticipated metabolites. The speed and simplicity of the method has meant that levels of these metabolites could be monitored daily in sterilised figs. Over a 14-day period, levels of aflatoxins and kojic acid maximised at 5-6 days, whilst levels of 5-methoxysterigmatocystin remained relatively constant. In addition to the known metabolites expected to be produced by these fungi, roquefortine A, fumagillin, fumigaclavine B, malformins (peptides), aspergillic acid, nigragillin, terrein, terrestric acid and penicillic acid were also identified.