Study of Capsaicin Content in Various Parts of Pepper Fruit by Liquid Chromatography with Electrochemical Detection

Veronika Supalkova,a,b Helena Stavelikova,c Sona Krizkova,b Vojtech Adam,b Ales Horna,d Ladislav Havel,a Pavel Ryant,e Petr Babula,f Rene Kizekb,*

a Department of Plant Biology, b Department of Chemistry and Biochemistry, and e Department of Plant Nutrition, Mendel University of Agriculture and Forestry, Zemedelska 1, CZ-613 00 Brno, Czech Republic.
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c Department of Gene Bank in Olomouc, Research Institute of Crop Production, Slechtitelu 11,CZ-783 71 Olomouc-Holice, Czech Republic
d Department of Food Engineering and Chemistry, Faculty of Technology, Tomas Bata University, T.G. Masaryka 275, CZ-762 72 Zlin, Czech Republic
f Department of Natural Products, University of Veterinary and Pharmaceutical Sciences,Palackeho 1-3, CZ-612 42 Brno, Czech Republic

Paper based on a presentation at the 12th International Symposium on Separation Sciences, Lipica, Slovenia,
September 27–29, 2006.

The burning taste of pepper is induced by six chemically related compounds derived from phenylalkylamide alkaloid (capsaicinoids) group. Capsaicin and its derivative dihydrocapsaicin have the strongest burning effects from them. The aim of this work was to determine capsaicin content in different fruit parts (ovary, lower flesh, upper flesh and seeds). For these purposes, we optimized high performance liquid chromatography with electrochemical detection. The most suitable conditions for capsaicin determination were as follows: working electrode potential of 750 mV, mobile phase of acetate buffer (pH 4) and methanol in ratio 40:60 (ν/ν, %). At these conditions we were able to detect picomoles of capsaicin per injection. Finally, we utilized this technique to determine capsaicin in various cultivars of peppers. The highest content of capsaicin (227 mg per 100 g of fresh weight) was found in ´Takanotsume’ cultivar.

Keywords: capsaicin, cyclic voltammetry, adsorptive transfer stripping technique, pepper