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 cross 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.
“There is an incentive to further process the blueberry pomace and extract those remaining polyphenols for applications as natural colourants, encapsulated supplements or added nutraceuticals,” explained the researchers.
Source: Food and Bioproducts Processing
Volume 106, pp 91-101 DOI: 10.1016/j.fbp.2017.07.006
“Concentrations of polyphenols from blueberry pomace extract using nanofiltration”
Authors: Alexandru M. Avram, Pauline Morin, Cindi Brownmiller , Luke R. Howard, Arijit Sengupta, S. Ranil Wickramasinghe