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Modification of Pectin and Hemicellulose Polysaccharides in Relation to Aril Breakdown of Harvested Longan Fruit
Key Lab of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
Guangzhou No.6 Middle School, Guangzhou 510300, China
These authors contributed equally to this work.
* Author to whom correspondence should be addressed.
Received: 9 October 2013; in revised form: 19 November 2013 / Accepted: 21 November 2013 / Published: 27 November 2013
Abstract: To investigate the modification of cell wall polysaccharides in relation to aril breakdown in harvested longan fruit, three pectin fractions (WSP, water soluble pectin; CSP, CDTA-soluble pectin; ASP, alkali soluble pectin) and one hemicellulose fraction (4 M KOH-SHC, 4 M KOH-soluble hemicellulose) were extracted, and their contents, monosaccharide compositions and molecular weights were evaluated. As aril breakdown intensified, CSP content increased while ASP and 4 M KOH-SHC contents decreased, suggesting the solubilization and conversion of cell wall components. Furthermore, the molar percentage of arabinose (Ara), as the main component of the side-chains, decreased largely in CSP and ASP while that of rhamnose (Rha), as branch point for the attachment of neutral sugar side chains, increased during aril breakdown. Analysis of (Ara + Gal)/Rha ratio showed that the depolymerization of CSP and ASP happened predominantly in side-chains formed of Ara residues. For 4 M KOH-SHC, more backbones were depolymerized during aril breakdown. Moreover, it was found that the molecular weights of CSP, ASP and 4 M KOH-SHC polysaccharides tended to decrease as aril breakdown intensified. These results suggest that both enhanced depolymerization and structural modifications of polysaccharides in the CSP, ASP and 4 M KOH-SHC fractions might be responsible for aril breakdown of harvested longan fruit.
Keywords: aril breakdown; cell wall degradation; pectin; matrix glycan; depolymerization
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MDPI and ACS Style
Wang, D.; Zhang, H.; Wu, F.; Li, T.; Liang, Y.; Duan, X. Modification of Pectin and Hemicellulose Polysaccharides in Relation to Aril Breakdown of Harvested Longan Fruit. Int. J. Mol. Sci. 2013, 14, 23356-23368.
Wang D, Zhang H, Wu F, Li T, Liang Y, Duan X. Modification of Pectin and Hemicellulose Polysaccharides in Relation to Aril Breakdown of Harvested Longan Fruit. International Journal of Molecular Sciences. 2013; 14(12):23356-23368.
Wang, Duoduo; Zhang, Haiyan; Wu, Fuwang; Li, Taotao; Liang, Yuxiang; Duan, Xuewu. 2013. "Modification of Pectin and Hemicellulose Polysaccharides in Relation to Aril Breakdown of Harvested Longan Fruit." Int. J. Mol. Sci. 14, no. 12: 23356-23368.