title: Molecular rearrangement of waxy and normal maize starch granules during in vitro digestion.
abstract: The objective of the present study is to understand the changes in starch structures during digestion and the structures contributing to slow digestion properties. The molecular, crystalline, and granular structures of native waxy maize, normal maize, high-amylose maize, and normal potato starch granules were monitored using SEC, XRD, DSC, and SEM. The amylose and amylopectin molecules of all four starches were hydrolyzed to smaller dextrins, with some having linear molecular structure. Neither the A- nor B-type crystallinity was resistant to enzyme hydrolysis. Starch crystallites with melting temperature above 120°C appeared in waxy and normal maize starches after digestion, suggesting that the linear dextrins retrograded into thermally stable crystalline structure. These crystallites were also observed for high-amylose maize starch before and after digestion, contributing to its low enzyme digestibility. On the contrary, the enzyme-resistant granular structure of native normal potato starch was responsible for its low susceptibility to enzyme hydrolysis.
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: Anju
authors.initials: A
authors.lastname: Teng
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: Torsten
authors.initials: T
authors.lastname: Witt
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: Kai
authors.initials: K
authors.lastname: Wang
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: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: The University of Queensland, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, Brisbane 4072, QLD, Australia. Electronic address: jovin.hasjim@roquette.com.
authors.forename: Jovin
authors.initials: J
authors.lastname: Hasjim
mesh_terms: D000688:Amylose / Q000032:analysis; D002152:Calorimetry, Differential Scanning; D002850:Chromatography, Gel; D004063:Digestion; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010194:Pancreatin / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D010194:Pancreatin; D013213:Starch; D000688:Amylose; D005087:Glucan 1,4-alpha-Glucosidase
keywords: Amylose; In vitro digestion; Scanning electron microscopy; Size-exclusion chromatography; Starch granules; X-ray diffractometry