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AHPA Offers Tools for Identifying Adulterated Bilberry Products

The American Herbal Products Association (AHPA), the leading trade association in the United States dealing with herbal products, announced in December of 2007 that it has added new analytical tools and methods to its Web site to assist manufacturers in identifying materials labeled as powdered bilberry (Vaccinium myrtillus, Ericaceae) fruit extract that have been adulterated with Red Dye No. 2.1,2

Concerns over bilberry extract misbranding and adulteration were raised when researchers from the company MediHerb in Austra-lia found that the synthetic food dye Red No. 2, also known as "amaranth dye" (not related to the grain amaranth [Amaranthus spp., Amaranthaceae]) and banned from the US food supply since the 1970s, had been used to mimic the color of bilberries in ingredient samples labeled as powdered bilberry fruit extracts. The researchers published their findings in the Journal of Agricultural and Food Chemistry in 2006.3

The tools and methods that AHPA now provides on its Web site are intended to instruct and aid in the differentiation between genu-ine bilberry fruit extract and extracts adulterated with Red No. 2.1 AHPA offers methods for detecting the presence of anthocyanins normally present in bilberry through pH manipulation and by using high performance thin layer chromatography (HPTLC). AHPA further provides information on additional resources regarding bilberry.2

"AHPA is providing methods to help enable proper evaluations of materials where identity and quality issues are known to exist," said Steven Dentali, PhD, AHPA's vice president of scientific and regulatory affairs.1 "By providing these analytical methods, we will help companies make better ingredient purchasing decisions."

The methods and tools provided by AHPA should enable manufacturers to detect this known adulterant dye in bilberry products, but they may not necessarily detect all possible product defects. Proper implementation of HPTLC analysis of ingredients labeled as bilberry extract by qualified personnel, however, is likely to reveal significant variations from the normally expected chemical composition of bilberry fruit extract.

According to an article published by in October of 2007, unconfirmed reports have been made of mulberry (Morus spp., Moraceae) fruit and black bean (Phaseolus spp., Fabaceae) skin being used to enhance the anthocyanin content of extracts labeled as bilberry.4 These materials, or possibly some other misbranded ingredient, were the likely starting material for the "bilberry" samples analyzed by MediHerb.3

A study conducted by researchers from the Italian botanical extract manufacturer Indena and published in the Journal of AOAC Inter-national in 2007 found that only 15% of 40 finished bilberry products tested in the study (sold in Europe, Japan, and the United States) met their specifically-stated label claims for anthocyanin content.5 Moreover, 10% of the products were found to contain no anthocya-nins at all. In its study, Indena recommended a new liquid chromatography method for identifying and quantifying anthocyanins and anthocyanidins in commercial bilberry extracts and products, which has been included in European and Italian pharmacopeias and is under evaluation by the United States Pharmacopeia.4

AHPA's tools and methods for determining adulteration of bilberry extracts with amaranth dye are available on the organization's Web site at AHPA member companies MediHerb and the Swiss analytical equipment and methods supplier CAMAG assisted in the development of the tools and methods.1

AHPA similarly provided methods and tools for determining the purity of powdered Hoodia gordonii (Asclepiadaceae) stems in September of 2007.6 These tools and methods are also available on the AHPA Web site.

  1. AHPA provides industry tools for authentic bilberry [press release]. Silver Spring, MD: American Herbal Products Association; December 10, 2007.

  2. Bilberry. American Herbal Products Association Web site. Available at: Accessed January 22, 2008.

  3. Penman KG, Halstead CW, Matthias A, et al. Bilberry adulteration using the food dye amaranth. J Agric Food Chem. 2006;54(19):7378-7382.

  4. Daniells S. Indena reports new technique for bilberry purity standards. Available at: ng.asp?n=80637-indena-bilberry-hplc-anthocyanin. Accessed January 22, 2008.

  5. Cassinese C, DeCombarieu E, Falzoni M, Fuzzati N, Pace R, Sardone N. New liquid chromatography method with ultraviolet detection for analysis of anthocyanins and anthocyanidins in Vaccinium myrtillus fruit dry extracts and commercial preparations. Journal of AOAC International. 2007;90(4): 911-919.

  6. Hoodia Methods. American Herbal Products Association Web site. Available at: Accessed February 12, 2008.