Studies on Degradation Characteristic of Cell-wall Polysaccharide during Postharvest Fruit Ripening and Softening of Winter Jujube (Zizyphus jujube Mill)
This paper studied the changes of Winter jujube fruit in firmness,respiratory intensity and the cell wall material (CWM) and cell wall polysaccharides fractions during storage.The cell wall material (CWM) and eight cell wall polysaccharides fractions were extracted from Winter jujube during storage at different time (0 and 60 days).The sugar composition characteristics of each fraction were determined by Ion chromatography.The results showed that,during storages,the firmness of Winter jujube decreased slowly and respiratory intensity increased gradually.During storage the cell wall polysaccharides fractions decreased,especially the amount of CDTA-soluble、Na2CO3-soluble and KOH-1-soluble pectic polysaccharides fractions showed significant difference between storage at 0 day and 60 days (P<0.01).Those decreases suggested the degradation of polysaccharides during storage,fruit softening was associated with degradation of cell wall polysaccharides(CDTA and Na2CO3 pectic polysaccharides fractions),Compare to other cell wall polysaccharide fractions,the decrease of pectic fractions was shown most significantly in Na2CO3-1 fraction during storage.Monosaccharide components in CDTA and Na2CO3 pectic polysaccharides fractions mainly contained arabinose,which degradated obviously during storage at 0 day and 60 days,it showed that the branched-chain degradation to promote fruit softening.KOH-1,KOH-2 and KOH-3 fractions decreased,it showed they may promote fruit softening too.