COLORIMETRIC VS. CHROMATOGRAPHIC ANALYSES OF ALKALOIDS IN LUPIN SEEDS

Paulina Wilczura

Department of Genomics, Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60–479 Poznań, Poland; (Poland)

Wojciech Święcicki

wswi@igr.poznan.pl
Department of Genomics, Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60–479 Poznań, Poland; (Poland)

Katarzyna Kamel

Department of Genomics, Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60–479 Poznań, Poland; (Poland)

Wiesław Wasiak

Department of Analytical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89 b, 61-614 Poznań, Poland; (Poland)

Abstract

A characteristic trait of lupins is a production of alkaloids, which are a toxic and bitter taste compound of
seeds. Due to the lack of fast, sensitive and inexpensive screening techniques to identify and reject high alkaloid
plant material, development of suitable tools is important challenges for lupins breeding and seed production.
The aim of this study was to compare two alkaloid content estimation methods in Lupinus angustifolius
L. and Lupinus albus L.
During the Wagner’s colorimetric test, which is recommended by the UPOV, seed halves were stained on
four colors depending on the alkaloid content but only the level of 0.5% – 0.6% showed clear color change.
Gas chromatography allowed accurate quantification and qualification of alkaloid content.
Since safe alkaloid content for consumption is 0.02% of seed dry weight, colorimetric method is less useful
for dividing lupin cultivars into sweet and bitter, than gas chromatography but can be used as a screening
technique.

Keywords:

gas chromatography, Lupinus angustifolius L.;, Lupinus albus L.;, sweet/bitter lupins;, Wagner’s colorimetric test