Production of a food grade blueberry extract rich in anthocyanins: selection of solvents, extraction conditions and purification method

Blueberries are recognized, by the scientific community and consumers, for their health promoting potential. This fact makes blueberries, and blueberry derived products, prime candidates to aid in the development of healthier foodstuffs that are easily recognized as such by consumers. As blueberries health promoting properties are frequently associated with their phenolic, particularly anthocyanins, composition the present work aimed to establish a simple, food safe, approach to extract these compounds. One that, while being food safe also allowed for a relatively easy scale up process. To accomplish this, four different solvents (water, ethanol, methanol and acetone) acidified or not, were evaluated for their extraction capabilities. The results obtained demonstrated that ethanol acidified with 0.01% HCl was an effective extractant of both phenolic compounds and anthocyanins. Acetone was significantly more effective in extracting phenolic compounds but it was almost unable to extract anthocyanins, with the addition of acid allowing for an increase of anthocyanin yield but reducing the overall phenolic yield. The extraction of anthocyanins may be further improved with the addition of an ultrasound treatment to the extraction process, though no significant differences were observed when considering the overall phenolic content. Furthermore, if seeking a condensed extract, purification using solid phase extraction columns allowed the production of an extract comprised of ca. 40% (w w−1) anthocyanins. © 2017, Springer Science+Business Media New York.