Açai Berry (Euterpe oleracea) Dietary Supplements: Variations in Anthocyanin and Flavonoid Concentrations, Phenolic Contents, and Antioxidant Properties.

Açai (Euterpe oleracea) is a palm plant that is native to South America and produces deep purple berry fruits. Despite açai's popularity as a dietary supplement, little is known about the phenolic composition and antioxidant properties of commercially available açai berry products. Therefore, twenty açai supplements in a variety of forms (e.g., capsule, powder, frozen pulp, and liquid) were analyzed for their total phenolic and anthocyanin contents, individual anthocyanin and other flavonoid concentrations, and antioxidant capacities. Hierarchical cluster analysis was then used to group açai supplements into categories based on similarities in their chemical profiles and antioxidant properties. Results showed that over half of the supplements contained little or no açai fruit or had sufficient amounts of water to substantially lower the concentration of açai chemical components. Additionally, two açai supplements contained unlisted ingredients that greatly altered the products' chemical properties. Chromatographic analysis of individual anthocyanins and other flavonoids was useful in identifying the presence of açai fruit within the dietary supplements while complimentary in vitro spectroscopic assays aided in detection of adulterants. This study highlights the complexity of the dietary supplement market while also showing the importance of collectively analyzing data from multiple complimentary techniques when evaluating açai berry products.