title: Effects of reactive oxygen species on cellular wall disassembly of banana fruit during ripening.
abstract: Fruit softening is generally attributed to cell wall disassembly. Experiments were conducted to investigate effects of various reactive oxygen species (ROS) on in vitro cellular wall disassembly of harvested banana fruit. The alcohol-extracted insoluble residue (AEIR) was obtained from the pulp tissues of banana fruit at various ripening stages and then used to examine the disassembly of cellular wall polysaccharides in the presence of superoxide anion (O2(-)), hydrogen peroxide (H2O2) or hydroxyl radical (OH) and their scavengers. The presence of OH accelerated significantly disassembly of cellular wall polysaccharides in terms of the increase in contents of total sugars released and uronic acid, and the decrease in molecular mass of soluble polysaccharides, using gel permeation chromatography. However, the treatment with H2O2 or O2(-) showed no significant effect on the disassembly of cellular wall polysaccharides. Furthermore, the degradation of the de-esterified AEIR was more susceptible to OH attack than the esterified AEIR. In addition, the effect of OH could be inhibited in the presence of OH scavenger. This study suggests that disassembly of cellular wall polysaccharides could be initiated by OH as the solublisation of the polysaccharides increased, which, in turn, accelerated fruit softening.
authors.affiliation: South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China; Graduate School, Chinese Academy of Sciences, Beijing 100039, PR China.
authors.forename: Guiping
authors.initials: G
authors.lastname: Cheng
authors.affiliation: South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China. Electronic address: xwduan@scbg.ac.cn.
authors.forename: Xuewu
authors.initials: X
authors.lastname: Duan
authors.affiliation: Food Research Center, Agriculture and Agri-Food Canada, Guelph ON N1G 5C9, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Shi
authors.affiliation: College of Horticultural Science, South China Agricultural University, Guangzhou 510642, PR China.
authors.forename: Wangjin
authors.initials: W
authors.lastname: Lu
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Haidian 100083, PR China.
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Luo
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Haidian 100083, PR China.
authors.forename: Weibo
authors.initials: W
authors.lastname: Jiang
authors.affiliation: South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China.
authors.forename: Yueming
authors.initials: Y
authors.lastname: Jiang
keywords: Banana; Cellular wall disassembly; Fruit; Polysaccharides; Reactive oxygen species