title: Understanding the structural features of high-amylose maize starch through hydrothermal treatment.
abstract: In this study, high-amylose starches were hydrothermally-treated and the structural changes were monitored with time (up to 12h) using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). When high-amylose starches were treated in boiling water, half-shell-like granules were observed by SEM, which could be due to the first hydrolysis of the granule inner region (CLSM). This initial hydrolysis could also immediately (0.5h) disrupt the semi-crystalline lamellar regularity (SAXS) and dramatically reduce the crystallinity (XRD); but with prolonged time of hydrothermal treatment (≥2 h), might allow the perfection or formation of amylose single helices, resulting in slightly increased crystallinity (XRD and DSC). These results show that the inner region of granules is composed of mainly loosely-packed amylopectin growth rings with semi-crystalline lamellae, which are vulnerable under gelatinization or hydrolysis. In contrast, the periphery is demonstrated to be more compact, possibly composed of amylose and amylopectin helices intertwined with amylose molecules, which require greater energy input (higher temperature) for disintegration.
authors.affiliation: School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China.
authors.forename: Jianing
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane, Qld 4072, Australia. Electronic address: f.xie@uq.edu.au.
authors.forename: Fengwei
authors.initials: F
authors.lastname: Xie
authors.affiliation: School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China.
authors.forename: Wenqiang
authors.initials: W
authors.lastname: Wen
authors.affiliation: Ministry of Education Engineering Research Center of Starch and Vegetable Protein Processing, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Shang
authors.affiliation: School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China. Electronic address: liu_peng@gzhu.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
mesh_terms: D000688:Amylose / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D006868:Hydrolysis; D013213:Starch / Q000737:chemistry* / Q000648:ultrastructure; D013696:Temperature; D013816:Thermodynamics; D014961:X-Ray Diffraction; D003313:Zea mays / Q000737:chemistry*
chemical_list: D013213:Starch; D000688:Amylose
keywords: Granule structure; High-amylose starch; Hydrothermal treatment