Variation in crystalline type with amylose content in maize starch granules: an X-ray powder diffraction study

Cheetham, Norman W.H.; Tao, Leping

doi:10.1016/s0144-8617(98)00007-1

Cited by 958 publications

(627 citation statements)

References 13 publications

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“…This approach has frequently been used in starch analyses, although the background and scattering from amorphous regions are not precisely defined. The relative crystallinity estimated for maize and potato tuber starches was similar to published data (Cheetham and Tao, 1998;Nara and Komiya, 1983). Interestingly, MD cryst exhibited the highest degree of crystallinity of all measured samples (Table 1).…”

Section: Physicochemical Properties Of the Crystallized Maltodextrinssupporting

confidence: 85%

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Hejazi¹,

Fettke

Haebel

et al. 2008

The Plant Journal

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SummaryStarch phosphorylation by glucan, water dikinase (GWD; EC 2.7.9.4) is an essential step in the breakdown of native starch particles, but the underlying mechanisms have remained obscure. In this paper, the initial reactions of starch degradation were analyzed using crystallized maltodextrins as model carbohydrates. As revealed by X-ray diffraction analysis, the crystallized maltodextrins represent the B-type starch allomorph. Recombinant GWD phosphorylated crystalline maltodextrins with a high specific activity (55-60 nmol mg )1 protein min )1 ), but exhibited very little activity with the same maltodextrins that had been solubilized by heat treatment. Recombinant phosphoglucan, water dikinase (PWD; EC 2.7.9.5) utilized the crystalline maltodextrins only when pre-phosphorylated by GWD. Phosphorylation of crystalline maltodextrins, as catalyzed by GWD, initiated solubilization of neutral as well as phosphorylated glucans. In both the insoluble and the soluble state, mono-, di-and triphosphorylated a-glucans were observed, with wide and overlapping ranges of degree of polymerization. Thus, the substrate specificity of the GWD is defined by the physical arrangement of a-glucans rather than by structural parameters, such as the distribution of branching points or degree of polymerization. Unlike GWD and PWD, recombinant b-amylase isozyme 3 (BAM3), which has been shown to be essential for plastidial starch degradation, preferentially degraded soluble maltodextrins rather than crystallized glucans. In summary, two conclusions were reached. Firstly, carbohydrate targets of GWD are primarily defined by the molecular order of glucan helices. Secondly, GWD-catalyzed phosphorylation mediates the phase transition of glucans from a highly ordered to a less ordered and hydrated state.

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Section: Physicochemical Properties Of the Crystallized Maltodextrinssupporting

confidence: 85%

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Hejazi¹,

Fettke

Haebel

et al. 2008

The Plant Journal

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“…4(a) and (b) show the XRD curves of G50 and G80 before and after hydrothermal treatment for different time periods. It can be seen that native G50 showed the strongest diffraction peaks at 2θ of around 17°, with a few smaller peaks at 2θ of around 5°, 14.5°, 15°, 20°, 22°, 23°, 26°, 30.5°, and 34°, which were indicative of B-type crystalline structure [42][43]. After treatment for 0.5 h, these peaks were largely depressed, with some peaks (5° and 14.5°) becoming invisible.…”

Section: Structural Changes Of High-amylose Starch After Hydrothermalmentioning

confidence: 97%

Understanding the structural features of high-amylose maize starch through hydrothermal treatment

Yang

Xie

Wen

et al. 2016

International Journal of Biological Macromolecules

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Understanding the structural features of high-amylose maize starch through hydrothermal treatment, International Journal of Biological Macromolecules http://dx.doi.org/10.1016/j.ijbiomac. 2015.12.033 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Abstract:In this study, high-amylose starches were hydrothermally-treated and the structural changes were monitored with time (up to 12 h) 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 (0.5 h) 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.

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“…While the small angle X-ray scattering provides information about the sizes of repeating lamellar structure (10 to 50 nm) within the starch granules (Lopez-Rubio et al 2009), the wide-angle X-ray scattering throws light on the structure of the nanoparticles of the condensed matter with a special resolution ranging from angstroms to hundreds of nanometer (1 to 10 nm) whether they are in liquid or solid form. This aspect has been studied in the case of rice and it has been reported that, rice starch exhibits a typical A-type pattern of diffraction with peaks at 15, 23 and an unresolved doublet at 17,18 A° (Cheetham and Tao 1998), which changes into V-type pattern after parboiling (Priestly 1976). In case of finger millet also it has been reported that the millet starch exhibits a typical A-type pattern with strong peaks at 15.…”

Section: Introductionmentioning

confidence: 99%

Effect of processing on the microstructure of finger millet by X-ray diffraction and scanning electron microscopy

et al. 2011

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Finger millet is one of the important minor cereals, and carbohydrates form its major chemical constituent. Recently, the millet is processed to prepare hydrothermally treated (HM), decorticated (DM), expanded (EM) and popped (PM) products. The present research aims to study the changes in the microstructure of carbohydrates using X-ray diffraction and scanning electron microscopy. Processing the millet brought in significant changes in the carbohydrates. The native millet exhibited A-type pattern of X-ray diffraction with major peaks at 2θ values of 15.3, 17.86 and 23.15°, whereas, all other products showed V-type pattern with single major peak at 2θ values ranging from 19.39 to 19.81°. The corresponding lattice spacing and the number of unit cells in a particular direction of reflection also reduced revealing that crystallinity of starch has been decreased depending upon the processing conditions. Scanning electron microscopic studies also revealed that the orderly pattern of starch granules changed into a coherent mass due to hydrothermal treatment, while high temperature short time treatment rendered a honey-comb like structure to the product. However, the total carbohydrates and non-starch polysaccharide contents almost remained the same in all the products except for DM and EM, but the individual carbohydrate components changed significantly depending on the type of processing.

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Variation in crystalline type with amylose content in maize starch granules: an X-ray powder diffraction study

Cited by 958 publications

References 13 publications

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Understanding the structural features of high-amylose maize starch through hydrothermal treatment

Effect of processing on the microstructure of finger millet by X-ray diffraction and scanning electron microscopy

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