Impact of full range of amylose contents on the architecture of starch granules.
The effects of amylose deposition on crystalline regions of barley starch granules were studied in granules containing zero to 99.1% amylose using "waxy" (WBS, 0% amylose), normal (NBS, 18% amylose) and amylose-only barley lines (AOS, 99.1% amylose). The effects were probed after hydrolysis of amorphous regions of starch granules in dilute HCl generating lintners, which typically represent the crystalline lamella of starch granules. Compared to NBS and WBS, AOS granules exhibited an irregular, multilobular morphology with a rough surface texture. AOS displayed lower rates of acid hydrolysis than WBS, and AOS reached a plateau at ∼45wt% acid hydrolysis. High-performance anion-exchange chromatography of lintners at equivalent levels of hydrolysis (45wt%) revealed the average degree of polymerization (DP) of AOS lintners was 21, substantially smaller than that of NBS and WBS (DP 42). AOS lintners contained the lowest number of chains (NC) per molecule (1.1) compared to NBS (2.8) and WBS (3.3) and the average chain length of AOS, NBS and WBS lintners was 19, 15 and 13, respectively. Hence, both NC and the average chain length correlated with amylose content. The size distribution profile of AOS lintners revealed a repeat motif in the molecules corresponding to 5-6 glucose residues.
Department of Food Science and Nutrition, University of Minnesota, USA. Electronic address: golds333@umn.edu.
Avi
A
Goldstein
Department of Nutrition and Food Science, University of Ghana, Legon-Accra, Ghana.
George
G
Annor
Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble, France; CNRS, CERMAV, F-38000 Grenoble, France.
Jean-Luc
JL
Putaux
Department of Molecular Biology and Genetics, Aarhus University, Denmark.
Kim H
KH
Hebelstrup
Department of Plant and Environmental Sciences, University of Copenhagen, Denmark.
Andreas
A
Blennow
Department of Food Science and Nutrition, University of Minnesota, USA.
Eric
E
Bertoft
D000688:Amylose / Q000737:chemistry*; D003460:Crystallization; D001467:Hordeum / Q000737:chemistry*; D006868:Hydrolysis; D013213:Starch / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D013499:Surface Properties
D013213:Starch; D000688:Amylose
Acid hydrolysis; Amylose; Barley; Crystalline polysaccharides; Lintnerization; Starch