Soluble polysaccharides isolation and characterization from rabbiteye blueberry (Vaccinium ashei) fruits

Abstract

Five soluble polysaccharide fractions were sequentially extracted with water, EDTA, Na2CO3, 4% KOH, and 14% KOH solutions at room temperature for 4 h from cell wall material of rabbiteye blueberry (Vaccinium ashei) fruits, and their physicochemical properties were examined. The sequential treatments yielded a total 36.02% soluble polysaccharides of the dry cell wall material. HPAEC and spectroscopy (FT-IR, NMR) analyses indicated that water-, EDTA-, and Na2CO3-soluble polysaccharide fractions were mainly composed of pectins, followed by lower amounts of arabinogalactans and glucans, while the two KOH-soluble fractions were mainly composed of hemicelluloses. Homogalacturonan was proven to be the predominant component in the isolated blueberry fruit pectic substance. The isolated blueberry fruit hemicelluloses could be defined as a linear β-(1→4)-linked-xylopyranosyl, in which xylose was the predominant neutral sugar (69.98 to 77.16%), followed by lower amounts of galactose, glucose, arabinose, and mannose.