Ustav konzervace potravin

Prague, Czech Republic

Ustav konzervace potravin

Prague, Czech Republic
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Prusova P.,Ustav konzervace potravin | Kruzik V.,Ustav konzervace potravin | Seidl J.,Ustav fyziky a merici techniky | Cizkova H.,Ustav konzervace potravin
Chemicke Listy | Year: 2017

Measuring electrical impedance enables characterisation of the studied matrix non-invasively and in real time. Our work was aimed to verify the method of electrochemical impedance spectroscopy for quick confirmation of orange juice authenticity. For the purpose of the experiment, the tested samples of orange juice were diluted with water and enriched by sugars and citric acid, as this type of adulteration and the chosen concentrations of the added substances correspond to the most likely means of misleading customers in the case of fruit juice. The analysis of the electrochemical parameters of the tested samples was carried out in an impedance cell with planar electrodes at a voltage of 0.5 V and the frequency ranging from 50 Hz to 1 MHz. The results of the measurements show that the method enables quick and simple screening of the quality of orange juice made from concentrate; more specifically, it enables one to detect dilution of 100 % juices with 20 or more per cent of water or the sugar addition. As such, the method can be recommended as another procedure of consumer protection and prevention of unfair competition among manufacturers. © 2017, Czech Society of Chemical Engineering. All rights reserved.


Sistkova I.,Ustav konzervace potravin | Haubeltova A.,Ustav konzervace potravin | Pohunek V.,Ustav konzervace potravin | Cizkova H.,Ustav konzervace potravin
Chemicke Listy | Year: 2017

The aim of this study was to investigate aroma active compounds of 5 samples of mineral water with lemon flavour. A total of 63 volatile compounds of lemon aroma were identified using solid phase microextraction in combination with gas chromatography-mass spectrometry, of which 20 were determined as aroma active by gas chromatography- olfactometry. The occurrence and representation of the identified substances varied within measured samples. The most abundant compounds that occurred in all samples were D-limonene, isocineole, eucalyptol, linalool, and α-terpineol. However, compounds represented in large amounts should not be overestimated at the expense of minor compounds. As indicated in the literature and proved by the results of gas chromatography-olfactometry, e.g. the most abundant D-limonene was not detected by evaluators who, however, were able to detect minor compounds such as octanal, isoborneol and nerol. These compounds can be described as key aroma active ingredients. © 2017, Czech Society of Chemical Engineering. All rights reserved.


Cizkova H.,Ustav konzervace potravin | Sevcik R.,Ustav konzervace potravin | Rajchl A.,Ustav konzervace potravin | Pivonka J.,Ustav konzervace potravin | Voldrich M.,Ustav konzervace potravin
Chemicke Listy | Year: 2012

The brief history of food adulteration in Czech towns from the Middle Ages, from the beginning of systematic approach (F. Accum, A. H. Hassall), to recent situation in the Czech Republic, is given. The examples of health consequences in some recent cases are summarized. The activities of the title Faculty in detection of food adulteration are described. The detection is based (a) on determination of selected markers or (b) on chemometric analysis, by statistical processing of analytical results for a large group of samples. New methods such as metabolomics and proteomics can also be used. The trends in food adulteration are described using the respective databases. The most important methods of food adulteration detection are described including the recent trends. The following methods are used: stable isotope analysis, DNA analysis, proteomics, spectroscopic and chromatographic methods.

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