Concerns were raised last year when Australian scientists discovered that azo dyes were used to mimic the colour of bilberries in a commercial product (J. Agric. Food Chem 2006, Vol. 54, Issue 19, pp. 7378 -7382). This has since expanded to reports of mulberry or black bean skins being used to increase the anthocyanin content of the extracts.
Christian Artaria, marketing director for Italian botanical derivatives supplier Indena, told NutraIngredients.com: "Based on our routine analysis, at least 15 to 20 per cent of the bilberry samples we collect on the market and analyse are adulterated."
"The adulteration with azo-dyes, that we also found in the past, is much less present then the sophistication with other fruits," he added.
The anthocyanins content is used as the standard for bilberry, and UV spectrometry is needed to verify the 25 per cent anthocyanins. However, according to unconfirmed reports, this has led to extracts masquerading as bilberry but actually containing mulberry (22-24 per cent), or black bean skin (20 per cent).
The Australian study from 2006 reported that, when high-performance liquid chromatography (HPLC) was used, one extract was found to contain nine per cent anthocyanins that were "probably not derived from [bilberry]".
A simple test using high performance liquid chromatography (HPLC) is needed to verify the anthocyanin profile as well as the concentration of these polyphenols, Bo Ahlstedt, director of Olle Svennson AB, Sweden's largest supplier of wild harvested blueberries, told NutraIngredients.com.
The HPLC method was first developed by Indena, and has been included in several Pharmacopoeias, including the European and Italian editions, and is under evaluation in the USA.
Indena have drawn parallels between the deliberate addition of azo dyes to powdered chilli (recently discovered in Europe), and what is happening now with bilberries. However, while the EU was quick to react to the illegal Sudan 1 food colouring adulteration, they have been deafeningly silent over bilberry adulteration, said the company.
"While EU now requires a mandatory assay for the presence of azo dyes in chilli and curry imported in powdered form (J. Chromatographic Sci. 2005, 43, 461), the implication of the addition of azo dyes to bilberry products has so far been substantially ignored by health authorities," stated Indena.
With the price per kilo now estimated at around €600, there have been companies offering lower-price extracts that are said to be cleaning out the market.
Tony Jacobs, sales and marketing director of Artemis Nutritionals Europe AG, told NutraIngredients.com that the fake product is priced around €400-450 per kg, and it is "impossible to produce bilberry at this price."
"Anyone buying for less that €500 is most likely getting a fake bilberry," he said.
