Alañón et al. at the UK university analyzed the flavanol content of 41 commercial chocolate brands available in Reading, UK, including Galaxy, Cadbury Dairy Milk, Divine 70% as well as Lindt and Green & Black’s products.
Bean origin and processing effect
The researchers found dark chocolate samples tended to have more flavanols than milk chocolate, but the highest cocoa solid samples were not the richest in cocoa flavanols.
“This evidence suggests that not only the inherent flavanol concentration associated with the diverse origins of cocoa beans, but also the diversity of manufacturing methods, may be able to influence loss of or epimerization of flavanols in finished products,” the researchers wrote in the journal Food Chemistry.
Milk versus dark chocolate
The study team assessed 41 commercially available dark and milk chocolate brands. These samples ranged from 20-90% cocoa solids and included 24 dark chocolates and 17 milk chocolates.
“In general, clear differences were found amongst milk and dark chocolate samples,” they wrote. “The flavanol content of milk chocolates was considerably lower than those found in dark chocolates.”
Results showed the mean flavanol content of the milk chocolates was 0.703 mg g-1 versus 1.156 mg g-1 in dark chocolate samples.
But the authors found no correlation between the cocoa solid percentage and total flavanols, epicatechin or catechin content of chocolate samples.
Why are flavanols important?
Cocoa is rich in polyphenols from flavanols, which some studies suggest offer cardiovascular health benefits and improved cognition.
The main flavanols in cocoa are (-) epicatechin and (+) catechin. A 2006 paper by Hagen Schroeter et al. identified (-) epicatechin as the most active compound for heart health, while a study by Javier Ottaviani et al. in 2011 said (-) epicatechin’s vascular response was six times that of catechin (-).
But (-) epicatechin can be converted to other types of flavanols such as (+) epicatechin and (-) or (+) catechin during chocolate processing and cocoa fermentation, said the researchers at the University of Reading.
Barry Callebaut has an EU-approved health claim to say dark chocolate with 200 mg of total flavanols contributes to normal blood flow.
Varying flavanol content
Their results showed milk chocolate did have lower (-) epicatechin content due to the presence of milk.
However, the dark chocolate sample with the highest cocoa percentage, 90%, did not have the most (-) epicatechin and had similar levels to a sample with just 50% cocoa solids.
They also found chocolates with the same labelled cocoa solid percentage often had varying (-) epicatechin levels.
The study team specified the 41 brands analyzed but kept the findings on cocoa flavanol levels per brand anonymous. Therefore, we cannot say which commercial brand contained the most or least flavanols.
Epicatehin: the most prevalent flavanol
The researchers found flavanol content ranged from 0.095 to 3.264 mg g-1 among the 41 brands and said epicatechin was the most predominant flavanol, accounting for 32.9% of flavanols.
They said epicatechin was a reliable predictor of polyphenol content, contrary to catechin.
The flavanol composition was assessed using high-performance liquid chromatography (HPLC-DAD).
They found samples with added ingredients such as chilli extracts and crystalized ginger contained more catechin than those without inclusions.
The study authors encouraged clearer on-pack labeling of flavanol and specifically epicatechin content for chocolate brands. A recent paper in the journal Phytotherapy Research also called for total flavanol and epicatechin levels to be labelled on pack when chocolate is marketed on a healthy platform.
Visit ConfectioneryNews' Cocoa Flavanol Science portal for more news on the topic.
Food Chemistry, Vol. 208, 1 Oct 2016, pps 177–184
‘Assessment of flavanol stereoisomers and caffeine and theobromine content in commercial chocolates’
Authors: M.E. Alañón , S.M. Castle, P.J. Siswanto, T. Cifuentes-Gómez, J.P.E. Spencer