Thirteen global labs took part in the evaluation HPLC (high-performance liquid chromatography) method with fluorescent detection (FLD) with results from 12 of them delivering consistent results.
Based on these results, Mars said the method filled a cocoa flavanol measurement void and should be used, “for the determination of flavanols and procyanidins in chocolate, cocoa liquors, powder(s), and cocoa extracts.”
Other chocolate makers have not indicated whether or not they would subscribe to that view.
The method, published in the Journal of AOAC International, was useful to consumers, industry and regulators alike, said the study’s lead author and R&D director at Mars Botanical, Dr Catherine Kwik-Uribe.
“This multi-laboratory collaborative study represents a critical breakthrough in the field by demonstrating that a method to measure these complex phytonutrients in cocoa can be reliable, robust, and easy-to-use,” said Dr Kwik-Uribe.
“Excitingly, in the not too distant future, this could lead to more uniform numbers on product labels that will help consumers compare and contrast flavanol-containing products, and help regulators evaluate claims.”
Under the system, flavanol and procyanidin content ranged from 1.35 to 4.39 across chocolate, cocoa liquors, powders, and cocoa extracts.
The study utilised 14 different products provided by Mars and tested for flavanols and procyanidins between 2mg and 500mg per gram. The results between the labs varied by between 4-10%. When tests were repeated variability was 13%.
Mars said existing analysis methods had, “left the field plagued by a variety of non-specific methods that provide no details about the types and mixtures of flavanols and procyanidins in foods and typically overestimate the true levels of these compounds in foods, including cocoa products.”
The HPLC-FLD method, Mars said, would also go a long way toward, “establishing a causal relationship between the intake of the specific phytonutrients and their health benefits.”
“Previous methods for the analysis of flavanols were able to reliably detect flavanols but the resolution decreased with a higher degree of polymerisation,” said the head of nutritional business consulting Inga Koehler, PhD, from German contract research organisation and consultancy, analyze & realize.
“Hence, some may argue that this new method is a breakthrough in the quantitative determination of flavanols in different cocoa products and intermediates. However, it would be interesting to understand whether the new validation method is also applicable for oligomeric proanthocyanidins (OPCs) in other sources like grape seed extracts.”
“Developing assays that can be applied to other OPC matrices such as those compiled in the USDA Database for the Proanthocyanidin Content of Selected Foods would be THE REAL breakthrough and help the food industry, consumers and regulators to get a clearer picture of different flavanols and their claimed health benefits.”
Journal of AOAC International
July/August 2012, Vol. 95, No. 4
‘Determination of Flavanol and Procyanidin (by Degree of Polymerization 1–10) Content of Chocolate, Cocoa Liquors, Powder(s), and Cocoa Flavanol Extracts by Normal Phase High-Performance Liquid Chromatography: Collaborative Study’
Authors: Catherine Kwik-Uribe1 and Harold H. Schmitz, Rebecca J. Robbins, Jadwiga Leonczak, Julia Li, J. Christopher Johnson, Tom Collins