[1]National Agricultural Research and Innovation Centre Food Science Research Institute Budapest H-1022 Hungary;
[2]Research Group for Technical Analytical Chemistry Hungarian Academy of Sciences Budapest University of Technology andEconomics Budapest H-1111 Hungary;
[3]Department of Inorganic and Analytical Chemistry Budapest University of Technology and Economics Budapest H-1111 Hungary;
[4]Department of Engineering University of Szeged Szeged H-6720 Hungary;
[5]Potato Research Centre University ofPannonia Keszthely H-8360 Hungary;