A sensitive and selective method for the quantitative determination of fatty acid tryptamides as shell indicators in cocoa products

Michael Münch, Peter Schieberle

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Tetracosanoyl-2-(3-indolyl)ethane amide (lignocerinic acid tryptamide; LAT) and docosanoyl-2-(3-indolyl)ethane amide (behenic acid tryptamide; BAT) were identified as the most prominent tryptamides in cocoa shells based on electrospray ionisation mass spectrometry and 1H NMR measurements. The structure of LAT, which is reported for the first time in cocoa shells, and also that of BAT were confirmed by synthesis. By using synthesised heptadecanoyl-2-(3-indolyl)ethane amide as the internal standard, a sensitive and reproducible method was developed for the quantification of LAT and BAT in the picogram range by means of HPLC/fluorescence detection. The detection limit was determined to be 30 pg/run. In authentic shell samples, 50-fold higher concentrations of both tryptamides were determined compared to the cocoa cotyledons. In 15 commercial chocolate samples, concentrations of 23.1-63.0 μg of the tryptamides (sum of both) per gram of fat were found. A first experiment attempted to correlate the tryptamide content with the amounts of shells in a model chocolate showed that the method is a promising tool to determine the shell content in the quality assessment of cocoa products.

Original languageEnglish
Pages (from-to)39-46
Number of pages8
JournalZeitschrift fur Lebensmittel -Untersuchung und -Forschung
Volume208
Issue number1
DOIs
StatePublished - 1999
Externally publishedYes

Keywords

  • Behenic acid tryptamide
  • Chocolate
  • Cocoa products
  • Electrospray mass spectrometry
  • Lignocerinic acid tryptamide

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