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United States Department of Agriculture

Agricultural Research Service

Title: Method performance and multi-laboratory assessment of a normal phase HPLC/FLD method for the quantitation of flavanols and procyanidins in cocoa and chocolate containing samples

Authors
item Robbins, Rebecca - MARS, INC
item Leonczak, Jadwiga - MARS, INC
item Johnson, J - MARS, INC
item Li, Julia - MARS, INC
item Kwik-Uribe, Catherine - MARS, INC
item Prior, Ronald
item Gu, Liwei - UNIV OF FLORIDA

Submitted to: Journal of Chromatography A
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 3, 2009
Publication Date: June 12, 2009
Citation: Robbins, R.J., Leonczak, J., Johnson, J.C., Li, J., Kwik-Uribe, C., Prior, R.L., Gu, L. 2009. Method performance and multi-laboratory assessment of a normal phase HPLC/FLD method for the quantitation of flavanols and procyanidins in cocoa and chocolate containing samples. Journal of Chromatography A. 1216(24):4831-4840.

Interpretive Summary: Procyanidins are a large diverse group of compounds that exist in many foods, including chocolate. Quantitative methods are needed to be able to measure the content of these diverse compounds in different foods. We have developed such a method that involves separating procyanidins in chocolate and cocoa-containing food products and then quantifying them using fluorescence detection and external reference standards. This method produced excellent reproducibility and performance over three months using three separate secondary standards (cocoa powder, liquor, and chocolate). Accuracy was determined by comparison to the NIST Standard Reference Material 2384. The analyses of seven different cocoa-containing samples revealed that inter-lab variability was quite low for this measurement of less than 10% for the range of samples analyzed. These data demonstrate this method to be robust and transferable, suggesting the possibility for its standardization for the analysis of procyanidins in cocoa products. This will have significant impact on the food industry interested in providing a measure of these compounds in their foods.

Technical Abstract: The quantitative parameters and method performance for a normal-phase HPLC separation of flavanols and procyanidins in chocolate and cocoa-containing food products were optimized and assessed. The chromatographic separation based on degree of polymerization (DP) was achieved on a diol stationary phase column with a binary gradient of acidic acetonitrile and methanol-water. Quantitation was achieved with fluorescence detection (ex 230 nm/em 321 nm) using external reference standards giving linear responses over a wide range of concentrations. Method reproducibility and performance was examined over three months using three separate secondary standards (cocoa powder, liquor, and chocolate). Accuracy was determined by comparison to the NIST Standard Reference Material 2384. The analysis of seven different cocoa containing samples revealed that inter-lab variability was quite low for this measurement, with a RSD(R) of less than 10% for the range of samples analyzed. These data demonstrate this method to be robust and transferable, suggesting the possibility for its standardization for the analysis of flavanols and procyanidins in cocoa products.

Last Modified: 10/1/2014
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