Nanofiltration helps recover blueberry polyphenols from residues

The use of nanofiltration membranes enable the recovery of substantial amounts of phenolic compounds in waste residues from processed blueberries, according to a recent study in Food and Bioproducts Processing. Blueberry skins are normally considered as a residual waste product (known as blueberry pomace), after processing has removed the juice. However, the skins of blueberry fruits contain the highest concentration of anthocyanins, a class of polyphenols, by weight. The use of nanofiltration membranes, by researchers at the University of Arkansas, Fayetteville enabled recovery of between 73% and 99% of these anthocyanins. The use of crossflow filtration mode also minimised membrane fouling during the process. “The present investigation clearly demonstrated that the nanofiltration technology of membrane based separation can be suitably used for the efficient recovery of total polyphenols (anthocyanins, flavonols and chlorogenic acid) from the blueberry pomace in the class flow mode of filtration,” wrote first author, Dr. Alexandru Avrama. Although this initial study was of pilot-plant scale, the establishment of a larger facility could potentially transform the pomace, previously considered as a waste product, into a commercially valuable source of anthocyanins.