title: Small differences in amylopectin fine structure may explain large functional differences of starch.
abstract: Four amylose-free waxy rice starches were found to give rise to gels with clearly different morphology after storage for seven days at 4°C. The thermal and rheological properties of these gels were also different. This was remarkable in light of the subtle differences in the molecular structure of the amylopectin in the samples. Addition of iodine to the amylopectin samples suggested that not only external chains, but also the internal chains of amylopectin, could form helical inclusion complexes. It is suggested that these internal helical segments participate in the retrogradation of amylopectin, thereby stabilising the gels through double helical structures with external chains of adjacent molecules. Albeit few in number, such interactions appear to have important influences on starch functional properties.
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave, St Paul, MN 55108, USA. Electronic address: eric.bertoft@abo.fi.
authors.forename: Eric
authors.initials: E
authors.lastname: Bertoft
authors.affiliation: Department of Nutrition and Food Science, University of Ghana, P.O. Box LG 134, Legon-Accra, Ghana.
authors.forename: George A
authors.initials: GA
authors.lastname: Annor
authors.affiliation: Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, 745 Agricultural Mall Dr., West Lafayette, IN 47907-2009, USA; Novozymes North America Inc., 77 Perry Chapel Church Rd., Franklinton, NC 27525, USA.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Shen
authors.affiliation: Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, 745 Agricultural Mall Dr., West Lafayette, IN 47907-2009, USA.
authors.forename: Pinthip
authors.initials: P
authors.lastname: Rumpagaporn
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave, St Paul, MN 55108, USA.
authors.forename: Koushik
authors.initials: K
authors.lastname: Seetharaman
authors.affiliation: Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, 745 Agricultural Mall Dr., West Lafayette, IN 47907-2009, USA.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Hamaker
mesh_terms: D000687:Amylopectin / Q000737:chemistry*; D007455:Iodine / Q000737:chemistry; D012275:Oryza / Q000737:chemistry; D012212:Rheology; D013213:Starch / Q000737:chemistry*; D013696:Temperature
chemical_list: D013213:Starch; D000687:Amylopectin; D007455:Iodine
keywords: Amylopectin gel; Functional properties; Starch gel structure; Starch retrogradation; Waxy rice starch