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Prague, Czech Republic

Gregrova A.,Institute of Chemical Technology Prague | Cizkova H.,Institute of Chemical Technology Prague | Mazac J.,Customs Technical Laboratory Prague | Voldrich M.,Institute of Chemical Technology Prague
Journal of Food and Nutrition Research | Year: 2012

A set of authentic spirit vinegars and mixtures of vinegars with synthetic acetic acid was analysed. Isotopic ratios, 2H/ 1H (SNIF-NMR; site-specific natural isotopic fractionation-nuclear magnetic resonance) and 13C/ 12C (IRMS; isotope ratio mass spectrometry), were determined and compared with the already published data. Gas chromatography analyses of volatiles and sensory analyses were applied to distinguish spirit vinegars, synthetic acetic acids and their mixtures. Concentrations of minor volatiles such as acetaldehyde and acetone were very low and too variable to be used as authenticity markers. The samples of authentic spirit vinegars contained ethanol and ethyl acetate, the indicators of the fermentation process, in concentrations ranging from 0.50 g·l -1 to 3.40 g·l -1 and from 0.10 g·l -1 to 0.50 g·l -1, respectively. Both the sensory assessment and the chromatographic method were found to be useful for fast screening of suspicious samples or for the detection of highly adulterated samples. However, these methods do not allow quantification of added synthetic acetic acid or confirmation of mixtures. In such cases, only the coupled SNIF-NMR and IRMS methods are able to authenticate the contents of the samples credibly with the estimated detection limit of 15% of synthetic acid addition. © 2012 VÚP Food Research Institute, Bratislava.

Gregrova A.,Institute of Chemical Technology Prague | Neradova E.,Institute of Chemical Technology Prague | Kruzik V.,Institute of Chemical Technology Prague | Mazac J.,Customs Technical Laboratory Prague | And 2 more authors.
European Food Research and Technology | Year: 2014

Possible adulteration of canned products containing spirit vinegar pickle by adding synthetic acetic acid is a significant problem of the food industry. Isotope analyses, which determine botanical origin of acetic acid and also can detect synthetic acid, were applied to detect undeclared addition of synthetic acetic acid to canned products. The aim of the study was to improve the extraction technique for the SNIF-NMR (2H/1H; site-specific natural isotopic fractionation-nuclear magnetic resonance) and IRMS (13C/12C; isotope ratio mass spectrometry) isotope methods and for an atypical matrix and to determine isotope ratios in canned vegetables pickle to prove their adulteration or authenticity. The following set of canned products was analysed: pickled cucumbers (n = 16) and one vinegar pickle purchased in the Czech market and six model (cucumber) pickles. The determined ratios of 2H/1H and 13C/12C for the pickled cucumbers proved to be authentic ranged from 89.4 to 107.0 ppm and from -28.7 to -15.6 ‰, respectively; for the synthetic acetic acids diluted with water they ranged from 114.2 to 129.0 ppm and from -44.9 to -33.4 ‰, respectively. Isotope analyses were confirmed as a reliable tool for assessing authenticity of canned products. The method enables detection of synthetic acetic acid addition into vinegars and canned vegetables containing vinegar pickle up from 20 % (of total acidity). © 2014 Springer-Verlag Berlin Heidelberg.

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