title: Evolution of amylopectin structure in developing wheat endosperm starch.
abstract: In this study, starches extracted from wheat grains harvested at 7, 14, 28, and 35 days after anthesis (DAA) were used as a means of examining the molecular structure of amylopectin (AP) from developing wheat grain. Scanning electron microscopy of wheat grain cross-sections revealed the presence of endosperm at 7 DAA and contained lenticular-shaped developing large (A-type) granules. From 14 DAA onward, spherical-shaped small (B-type) granules coexisted with large granules in the endosperm. During granule development, the fine structure of AP varied with maturity in both large and small granules. Towards the end of the pre-physiological maturity stage (28 DAA), AP in small and large granules had shortest external chain length (ECL), longest internal chain length (ICL) and lowest amount of A-chains. At physiological maturity (35 DAA), these changes in ECL, ICL and amount of A-chains were reversed when compared to 28 DAA. In both large and small granules, the external AP structure was apparently more organized at physiological maturity than at pre-physiological maturity.
authors.affiliation: Department of Food Science, University of Guelph, 116, Guelph, ON N1G 2W1, Canada.
authors.forename: Danusha N
authors.initials: DN
authors.lastname: Kalinga
authors.affiliation: Food Science and Nutrition, University of Minnesota, 225, 1334 Eckles Ave, St. Paul, MN 55108, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Bertoft
authors.affiliation: Department of Molecular and Cellular Biology, Science Complex, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Ian
authors.initials: I
authors.lastname: Tetlow
authors.affiliation: Guelph Food Research Centre, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, ON N1G 5C9, Canada.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Food Science, University of Guelph, 116, Guelph, ON N1G 2W1, Canada.
authors.forename: Rickey Y
authors.initials: RY
authors.lastname: Yada
authors.affiliation: Food Science and Nutrition, University of Minnesota, 225, 1334 Eckles Ave, St. Paul, MN 55108, USA. Electronic address: kseethar@umn.edu.
authors.forename: Koushik
authors.initials: K
authors.lastname: Seetharaman
mesh_terms: D000687:Amylopectin / Q000737:chemistry*; D002523:Edible Grain / Q000737:chemistry; D056625:Endosperm / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D012639:Seeds / Q000737:chemistry / Q000254:growth & development; D013213:Starch / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry*
chemical_list: D013213:Starch; D000687:Amylopectin
keywords: Amylopectin; Development; Endosperm; Starch; Wheat