Hydroxyl radical is involved in cell wall disassembly and aril breakdown in mulberry fruit during storage

The effect on hydroxyl radical ((OH)-O-center dot) on cellular wall disassembly and aril breakdown in mulberry fruit was investigated in vitro and in vivo. The in vitro experiment showed (OH)-O-center dot induced total sugar and uronic acid released from the cell wall material of mulberries in a dose-dependent manner. Then the harvested mulberries were treated with 5 mM (OH)-O-center dot to find out its effect in vivo. The results suggested that the application of exogenous (OH)-O-center dot induced degradation of cellular wall polysaccharides, especially water soluble pectin (WSP) and hemicellulose, which was associated with the higher incidence of aril breakdown in (OH)-O-center dot-treated mulberries. Meanwhile, the results of gel permeation chromatography analysis further demonstrated that (OH)-O-center dot enhanced depolymerization and structural modifications of polysaccharides of mulberries during storage as experienced by the downshift in molecular mass of WSP and hemicellulose fractions. These results indicated that as a consequence of the enhanced degradation of cell wall polysaccharides, (OH)-O-center dot could increase the incidence of aril breakdown in harvested mulberry fruit during storage. (C) 2016 Published by Elsevier B.V.