engleski

Determination of stable isotope ratios of 13C/12C in honey samples by LC/EA-IRMS – preliminary results

Stable isotope analysis has become indispensable for verifying the authenticity of honey. As part of the project “Center for Safety and Quality of Food”, we analysed the 13C/12C stable isotope ratio (δ13C) in samples of multifloral honey harvested from small stationary beekeepers. Honey samples were collected in different Croatian regions, including north (Zagorje), east (Slavonia), west (Istria), and south (Dalmatia). To determine the smallest differences between isotopes in compounds produced by physical and biochemical isotope fractionation in nature, we used the technique of liquid chromatography/elemental analysis-isotope ratio mass spectrometry (LC/EA-IRMS). Bulk stable isotope analysis of honey was performed using EA- IRMS. For separation and isotopic analysis of individual sugars in honey, including glucose, fructose, disaccharides, and trisaccharides, LC- IRMS was used. Several physicochemical analyses (according to the Council Directive EC 2001/110/EC on honey) and pollen analyses confirmed that all of the honey samples were of excellent quality within the botanical varieties. No honey sample showed signs of adulteration, as no extraneous sugars were detected. This was also confirmed by LC/EA- IRMS. The preliminary results of δ13C analyses from LC-IRMS and EA-IRMS showed that there were differences between honey samples from the continental and Mediterranean parts of Croatia. These preliminary results indicate good possibilities to determine the authenticity of honey from different parts of Croatia. These results are very important for the creation of a unique database of stable isotopes for Croatian honey. To obtain more accurate results, honey samples from the same area would have to be studied in the coming years to confirm the above stated thesis.

Croatian honey ; food fraud ; geographical origin ; honey authenticity ; stable isotope analysis

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