title: Two-dimensional macromolecular distributions reveal detailed architectural features in high-amylose starches.
abstract: Two-dimensional (2D) structural distributions based on macromolecular size and branch chain-length are obtained for three maize starches with different amylose contents (one normal and two high-amylose varieties). Data were obtained using an analytical methodology combining chemical fractionation, enzymatic debranching, and offline 2D size-exclusion chromatography with multiple detection. The 2D distributions reveal novel features in the branching structure of high-amylose maize starches. Normal maize starch shows well-resolved structural topologies, corresponding to the amylopectin and amylose macromolecular populations. However, high-amylose maize starches exhibit very complex topologies with significant features between those of amylose and amylopectin, showing the presence of distinct intermediate components. These have the macromolecular size of amylose but similar branching structure to amylopectin, except for a higher proportion of longer branches. These structural features of the intermediate components can be related to a less tightly controlled biosynthesis of the branching structures in high-amylose maize starch mutants, which may prevent these molecules from maturing into full-size amylopectin. This altered macromolecular branched architecture of high-amylose starches probably contribute to their better nutritional properties.
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China; KTH Royal Institute of Technology, Division of Glycoscience and Wallenberg Wood Science Centre (WWSC), AlbaNova University Centre, SE-106 91 Stockholm, Sweden; The University of Queensland, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane 4072, QLD, Australia.
authors.forename: Francisco
authors.initials: F
authors.lastname: Vilaplana
authors.affiliation: The University of Queensland, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane 4072, QLD, Australia.
authors.forename: Di
authors.initials: D
authors.lastname: Meng
authors.affiliation: The University of Queensland, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane 4072, QLD, Australia.
authors.forename: Jovin
authors.initials: J
authors.lastname: Hasjim
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China; The University of Queensland, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane 4072, QLD, Australia. Electronic address: b.gilbert@uq.edu.au.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Gilbert
mesh_terms: D000687:Amylopectin / Q000737:chemistry; D000688:Amylose / Q000737:chemistry* / Q000648:ultrastructure; D002850:Chromatography, Gel; D015394:Molecular Structure; D013213:Starch / Q000737:chemistry* / Q000648:ultrastructure; D014783:Viscosity; D003313:Zea mays / Q000737:chemistry*
chemical_list: D013213:Starch; D000688:Amylose; D000687:Amylopectin
keywords: Amylopectin; Amylose; Branching; Intermediate components; Size-exclusion chromatography; Starch