Challenges in Assessing Bioactive Botanical Ingredients in Functional Beverages

Abstract

Bioactive botanicals are used as functional ingredients in conventional foods to be marketed as functional foods. Among these functional foods, teas and non-alcoholic, non-carbonated bottled beverages are especially popular. The analytical assessment of these ingredients in functional foods and beverages presents a new challenge because of low levels of analytes and the matrix complexity. This article summarizes recent development of analytical methods for the determination of bioactive constituents from St. John's wort (SJW; Hypericum perforatum L.), ginkgo (Ginkgo biloba L.) and kava (Piper methysticum, Forst.) in functional beverages. The constituents selected as marker compounds were hyperforin, adhyperforin, hypericin and pseudohypericin for SJW, five terpene trilactones (ginkgolides A, B, C and J, and bilobalide) for ginkgo products, and six kavalactones (methysticin, dihydromethysticin, kavain, dihydrokavain, yangonin and desmethoxyyangonin) for kava products. The methods developed include improved sample preparation, liquid chromatography with ultra violet/photodiode array detection (LC/UV/PDA), LC with evaporative light scattering detection (ELSD) and LC with mass spectrometry (MS). The stability of SJW constituents in non-alcoholic, non-carbonated, fruit-flavored beverages was also discussed.