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Polysaccharides from Sunflower Stalk Pith: Chemical, Structural, and Partial Physicochemical Characterization

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dc.contributor.advisor Ming, Xu
dc.contributor.author Xu, Ming
dc.date.accessioned 2016-05-27T12:51:56Z
dc.date.available 2016-05-27T12:51:56Z
dc.date.copyright 2016-04
dc.date.created 2016-05-25
dc.date.issued 2016-05-27
dc.identifier.uri http://hdl.handle.net/10214/9734
dc.description.abstract Polysaccharides from sunflower stalk pith (SSP) were extracted by hot water and sodium hexametaphosphate (SHMP). The chemical analyses suggested both fractions dominated in galacturonic acids with small amount of neutral sugars, indicating their identity as pectins. The yield of water-extractable pectin (WEP) and SHMP-extractable pectin (SEP) were 1.8% and 11.0%, respectively. The detailed structure of each fraction was investigated by high performance size exclusion chromatography (HPSEC), FT-IR spectroscopy, methylation analysis and 1D & 2D NMR spectroscopy. The weight average molecular weight and intrinsic viscosity for WEP and SEP were 57.2 kDa, 0.48 dL/g and 23.1 kDa, 0.50 dL/g, respectively. FT-IR spectra confirmed WEP and SEP had characteristic pectin-like structures and the degree of esterification (DE) was calculated to be 92% and 64 %, respectively. Methylation analysis demonstrated that 1,4-GalpA residues dominated all the sugar linkages, while other linkage types including 1,2-Rhap, 1,2,4-Rhap, 1,4-Galp and 1,5-Araf were also present in WEP and SEP. NMR spectroscopy further revealed WEP and SEP mainly homogalacturonan (HG) structure and a small fraction of rhamnogalacturonan-I (RG-I) structure was also in evidence. WEP and SEP showed limited surface activity within a concentration up to 1 % (w/w), compared with commercial citrus pectin. Residue fraction (RF) after pectin extraction, which was mainly composed of insoluble cellulose and hemicellulose, had the best water holding and oil binding capacities among all the examined fractions. en_US
dc.language.iso en en_US
dc.rights Attribution 2.5 Canada *
dc.rights.uri http://creativecommons.org/licenses/by/2.5/ca/ *
dc.subject SSP en_US
dc.subject pectin en_US
dc.subject polysaccharides en_US
dc.subject structural characterization en_US
dc.subject WHC en_US
dc.subject OBC en_US
dc.title Polysaccharides from Sunflower Stalk Pith: Chemical, Structural, and Partial Physicochemical Characterization en_US
dc.type Thesis en_US
dc.degree.programme Food Science en_US
dc.degree.name Master of Science en_US
dc.degree.department Department of Food Science en_US
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