Characterization of grape juice polysaccharides retained by microfiltration at three different transmembrane pressures

Abstract

Bioactive polysaccharides were isolated from commercial grape juice by a fractionation process via membrane microfiltration. An increase in transmembrane pressure during microfiltration achieved doubling the production of Fractions Enriched in Polysaccharides [FEPS] and the amount of total carbohydrates, and triplicate the protein content. Infrared spectroscopy showed that the initial samples and the concentrates were composed by acidic and neutral polysaccharides. FEPS fractionation by cetrimide precipitation confirmed the presence of arabinogalactan in the neutral fraction and an acidic fraction, as well as the decrease of protein content. Grape juices maintain the presence of bioactive polysaccharides associated with dietary fiber, which were concentrated by microfiltration operation in amounts that would make them a good source of fiber, postioning them as a healthy food.