Changes in molecular weight and carbohydrate composition of cell wall polyuronide and hemicellulose during ripening in strawberry fruit

Abstract Polyuronides and hemicelluloses from the cell wall of developing strawberry fruit ( Fragaria ananasa , Duch. cv. Toyonoka) were examined for molecular weight distribution, and carbohydrate composition prior to and following gel filtration chromatography. In non-fractionated polyuronides, the galacturonic acid and arabinose concentrations decreased during development. The concentration of rhamnose markedly increased, whereas that of arabinose declined in low-molecular-weight polyuronides ( M r kDa ). A significant reduction of hemicelluloses was detected in the high-molecular-weight region ( M r >170 kDa ), whereas little change was observed in the sugar composition of these polymers. Polygalacturonase activity was consistently reduced during ripening.