Authors:E. Schall, Zs. Bugyi, L. Hajas, K. Török, and S. Tömösközi
. , Török , K. , Hajas , L. , Adonyi , Z. , Popping , B. & Tömösközi , S. ( 2013 ): Comparative study of commercially available gluten ELISA kits using an incurred referencematerial . Qual. Assur. Saf. Crop. , 5 , 79 – 87
A GC-FID method for major volatile analysis in cider and wine was validated under the requirements of the ISO/IEC 17025 regulation using a split mode injection. This method presented a good linearity (R2>0.999, Cm>99%), a wide range of calibration, the maximum random errors for repeatability and intermediate precision were 5% and 8%, respectively, and the maximum limit of quantification and limit of detection were 14.1 mg l–1 and 4.6 mg l–1, respectively. Trueness, expressed as recovery (%), was successfully validated by means of two different methods, standard addition (92–110%) and comparison against reference materials (93–115%). Expanded uncertainty estimated at 95% confidence level ranged between 11% for methanol and 7% for allyl alcohol. The validated method was successfully applied for the analysis of major volatiles in ciders and wines, and to detect yeast and lactic acid bacteria spoilage.
Authors:K. Ladó, M. Then, Z. May, and K. Szentmihályi
) is frequently used for making tea and it is also applied as spice. Since the digestion of oils is relatively difficult and the undigested oil may greatly alter the element data, three different acid mixtures (nitric acid and hydrogen peroxide; nitric acid, hydrochloric acid and hydrogen peroxide; nitric acid, hydrochloric acid and hydrofluoric acid) were tested for determination of element content in fennel. Inductively coupled plasma optical emission spectrometry (ICP-OES) and polarography were applied for the determination of elements (Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, P, S, Se and Zn). The extraction was realised by using microwave digestion technique under low and high pressure. Lucerna p-alfalfa as reference material was used for the accuracy and precision of the analytical procedures. According to the results, it can be stated that the digestion of medicinal plants containing oil could be realised by aqua regia.
Authors:A. Györey, A. Gere, Z. Kókai, P. Molnár, and L. Sipos
In the field of product development and quality assurance flavour lexicons are widely used. These systems include the definition of all attributes and the relevant reference materials or reference samples. With the application of these lexicons more reliable results can be acquired and it can be very helpful to the assessors in sensory analysis. The main purpose of our further research was to establish a flavour language for table margarines. A well-trained margarine expert panel was already established and also an appropriate sensory method (QDA) was chosen. However, the applied sample presentation design also has a strong influence on the results. In this study the effect of two types of test protocols were compared on the performance of the expert panel. The results of the sensory panel were monitored using univariate (F-plot, MSE-plot, p*MSE-plot) and multivariate statistical methods (Tucker-1 correlation loading plot) by PanelCheck. With application of the side-by-side protocol (SBS) the panel agreement and the ability to discriminate the samples and the repeatability of the panel were considerably improved against using the sequential monadic presentation protocol (SM). The explained variance of the first occasion was 74.8% and in case of the application of SM was 55% for PC1.
The aim of this study was the comparison of different sample preparation methods for multielemental ICP-MS analysis of wine samples. All investigated methods were previously published for the same purpose, but the comprehensive comparison was carried out in the frame of this study for the first time. Five wine samples of different residual sugar content (2 dry, 2 sweet and one extra fine quality dessert wine) were used from Hungarian wine districts. Due to the lack of certified reference materials method validation and cross-checking was carried out by using two different types of inductively coupled plasma mass spectrometers (ICP-MS), namely a quadrupole based ICP-MS equipped with a collision cell (ICP-CC-MS) and a high resolution sector field ICP-MS (ICP-SF-MS). The measured elements were Li, Mg, B, Al, Cu, Rb, Sr, Zr, Cd, Ba, Tl, Pb, Bi, U, Cr, Fe, Mn, Co, Ni, Zn, As, Mo and Ga.Sample preparation procedures were based on sample dilution, microwave digestion using nitric acid (in combination with and without evaporation prior to ICP-MS analysis) and a mixture of nitric acid and hydrogen peroxide. The investigation resulted that the optimal digestion method for the above-mentioned purpose is microwave digestion using nitric acid without evaporation. The advantages and disadvantages of the investigated methods are critically discussed.
Authors:E. Alpözen, G. Güven, Ö. Özdestan, and A. Üren
A rapid and reliable liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was developed for the determination of acrylamide in three different local bread types; wheat bread, bran bread, whole wheat bread. Acrylamide analyses were made in crust parts of the 85 bread samples. The method was linear up to 750 μg kg–1 food with a determination coeffi cient of 0.999. Recovery rate was found 99.3% with limit of detection and limit of quantifi cation values of 1.5 μg kg–1 and 5.0 μg kg–1, respectively. Certifi ed reference materials of crisp bread were analysed and acrylamide contents of these samples were found in the range cited in the certifi cates. Statistical correlations were investigated between acrylamide contents and protein contents, reducing sugar contents, moisture contents, pH, and colour parameters (L*, a*, b*) of bread samples. Sample preparation procedure and chromatographic conditions of acrylamide analysis were investigated in more detail, and a rapid, accurate, precise, and reliable analysis method was developed.
Authors:L. Hajas, K. A. Scherf, Zs. Bugyi, K. Török, E. Schall, P. Köhler, and S. Tömösközi
, Z. , Diaz-Amigo , C. , Popping , B. , Poms , R. , Kerbach , S. & Tömösközi , S. ( 2012 ): Development of incurred referencematerial for improving conditions of gluten quantification . J. AOAC Int., 95 , 382 – 387
Authors:K. Török, L. Hajas, V. Horváth, E. Schall, Zs. Bugyi, and S. Tömösközi
): Investigation of the effects of food processing and matrix components on the analytical results of ELISA using an incurred gliadin referencematerial candidate . Acta Alimentaria , DOI:10.1556/AAlim.2014.0018, 44 , 390 – 399