Structural, rheological and functional properties of galactose-rich pectic polysaccharide fraction from leek. (1st February 2020)

• Record Type: Journal Article
• Authors: Ognyanov, Manol; Remoroza, Connie; Schols, Henk A.; Georgiev, Yordan N.; Petkova, Nadezhda Tr.; Krystyjan, Magdalena
• Is Part Of: Carbohydrate polymers. Volume 229(2020)
• Publication Date: 2020-02-01
• Subjects: Leek -- Pectic polysaccharides -- Enzymatic fingerprinting -- HILIC-MS -- Rheology; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2019.115549
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: An acid-extracted pectin from leek consisted of a high Mw population (10–100 kDa). The pectin is mainly built up by HG segments with different blocks of ester distributions. RG-I segments were substituted with galactan side chains with varying length. The pectin exhibited higher water holding capacity than oil-holding capacity. Interaction between pectic segments may control the rheological properties. Abstract: An acid-extracted polysaccharide from alchohol-insoluble solids of leek was obtained. The sugar composition indicated that galactose and galacturonic acid were the major sugars, followed by small amounts of rhamnose and arabinose. The fraction contained a relatively high methyl-esterified homogalacturonan next to rhamnogalacturonan type I decorated with galactose-rich side chains. The fraction consisted of three high Mw populations, covering the range of 10–100 kDa. Enzymatic fingerprinting was performed with HG/RG-I degrading enzymes to elucidate the structure. The oligomers were analysed using LC-HILIC-MS, HPAEC, and MALDI-TOF MS. The data revealed the presence of GalA sequences, having different patterns of methyl-esterification, RG-I composed of unbranched segments and segments heavily substituted with β-(1→4)-linked galactan chains of varying length. The rheological study showed the shear-thinning, weak thixotropic, anti-thixotropic, and non-Newtonian behavior of the polysaccharide. The pectin exhibited higher water holding capacity than oil-holding capacity and the fraction did form stable foams at high concentration.