title: Effect of a small amount of sodium carbonate on konjac glucomannan-induced changes in thermal behavior of wheat starch.
abstract: The effects of konjac glucomannan (KGM) on thermal behavior of wheat starch have been studied in the presence of low concentrations of Na2CO3 (0.1-0.2 wt% of starch). Confocal laser scanning microscopy (CLSM) allows the visualization of the starch gelatinization process and granule remnants in starch pastes. Heating the starch dispersion in KGM-Na2CO3 solution significantly delays granule swelling and inhibits amylose leaching, whereas Na2CO3 alone, at the same concentration, has little effect. Na2CO3 assists KGM in producing the extremely high viscosity of starch paste, attributing to a less remarkable breakdown of viscosity in subsequent heating, and protecting starch granules against crystallite melting. The distinct partially networked film around the surface of starch granules is evident in the CLSM images. We propose that Na2CO3 could trigger the formation of complexes between KGM and starch polymers, which exerts a protective effect on granular structure and modifying gelatinization characteristics of the mixtures.
authors.affiliation: Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Division of Food Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.
authors.forename: Charles G
authors.initials: CG
authors.lastname: Winkworth-Smith
authors.affiliation: Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Jianfen
authors.initials: J
authors.lastname: Liang
authors.affiliation: Division of Food Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Foster
authors.affiliation: Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China. Electronic address: chengyq@cau.edu.cn.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Cheng
mesh_terms: D002254:Carbonates / Q000737:chemistry*; D008351:Mannans / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry*
chemical_list: D002254:Carbonates; D008351:Mannans; C022901:(1-6)-alpha-glucomannan; C005686:sodium carbonate; D013213:Starch
keywords: CLSM; Konjac glucomannan; Na(2)CO(3); Thermal behavior; Wheat starch