Bilberry fruit extract laboratory guidance document

Market demand for bilberry (Vaccinium myrtillus, Ericaceae) fruit extracts, combined with high prices and falling profit margins have resulted in unscrupulous manufacturers selling various ingredients labeled “bilberry extract.” Adulteration predominantly occurs with anthocyanin-rich extracts from other species, e.g., bog bilberry (V. uliginosum), lingonberry (V. vitis-idaea), European elder (Sambucus nigra, Adoxaceae), and Chinese mulberry (Morus australis, Moraceae). Additional adulterants reportedly include black soybean (Glycine max, Fabaceae) hull or black rice (Oryza sativa, Poaceae) extracts, and synthetic colorants like amaranth dye, an azo dye prohibited for use by the United States Food and Drug Administration (FDA) as a suspected carcinogen, and/or charcoal. This Laboratory Guidance Document presents a review of the various analytical technologies and methods used to differentiate between authentic bilberry extracts and potential adulterants.