Modification of granular potato starch by multiple deep-freezing and thawing

Szymońska, Joanna; Krok, Franciszek; Komorowska-Czepirska, E.; Rębilas, Krzysztof

doi:10.1016/s0144-8617(02)00263-1

Cited by 74 publications

(37 citation statements)

References 21 publications

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“…Moreover, the total spectrum intensity, lost on dehydration at elevated temperatures, was fully restored (Tables I and II). These facts, in accordance with our previous observations, 21 indicated that some addi- tional amount of water released in the granules during freezing, most probably from their semicrystalline regions, became accessible to copper ions after migration on thawing within the amorphous background of the granules.…”

Section: Starch After Modificationsupporting

confidence: 93%

“…The applied oven drying did not induced the B-to A-type transition in the starch granules as was checked by an X-ray diffraction. 21 Total copper content in the samples, after their wet mineralization with HNO 3 , was determined using a standard procedure of the flame atomic absorption spectrometry method (AAS). 22 Freezing/Thawing Procedure Samples of granular starch (about 30 mg) containing incorporated Cu 2þ ions were frozen and thawed in the EPR quartz tubes with their original water content (13 and 8% w/w for potato and wheat, respectively) or after drying at 393 K for 2 h. Dried starch was also frozen/thawed in starch-water suspensions (starch/water ¼1:1 v/v) according to a formerly described procedure.…”

Section: Sample Preparationmentioning

confidence: 99%

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Electron paramagnetic resonance study of water distribution in starch granules

et al. 2006

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An electron paramagnetic resonance (EPR) study was performed for potato and wheat starch containing Cu2+ ions as a paramagnetic probe. Distribution of water in the starch granules as well as the interactions between the copper and starch matrix of different crystalline structures were determined. EPR spectra of the native starches consisted of two different centers of Cu2+. One of them, giving at 293 and 77 K an EPR signal of axial symmetry with a well-resolved hyperfine structure (HFS), was assigned to the Cu2+ -starch complex in which Cu2+ ions strongly interacted with oxygen atoms of the starch matrix. Another Cu2+ species, exhibiting an isotropic signal at 293 K and an axial signal with resolved HFS at 77 K, was attributed to a [Cu(H2O)6]2+ complex freely rotating at room temperature and immobilized at low temperatures. Interaction of Cu2+ with the starch matrix and the relative number of the particular copper species depended on the crystallographic type of starch. Dehydration at 393 K resulted in elimination of the rotating complex signal and decrease of the total intensity of the EPR spectrum caused by clustering of the Cu2+ ions. Freezing at 77 K and thawing led to restoring of the spectrum intensity and reappearing of the signal of the [Cu(H2O)6]2+ complex. This effect, related to liberation of water molecules from the granule semicrystalline growth rings on freezing/thawing, was especially visible for wheat starch, indicating differences in the water retention ability of starch granules of different crystallographic structure.

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Section: Starch After Modificationsupporting

confidence: 93%

Section: Sample Preparationmentioning

confidence: 99%

Electron paramagnetic resonance study of water distribution in starch granules

et al. 2006

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“…It is known that the surface morphology of potato starch granules can be disordered by freezing, the surface structure of the granules became perforated and noticeable surface crushing was observed when starch granules were exposed to multiple freezing and thawing cycles or deep freezing in liquid nitrogen. [41][42][43] The most noticeable disordering of starch granule surface morphology was observed for PEF + osmotic pre-treatment. In fact, the freeze-drying procedure resulted in effective damage of starch grains and rather homogeneous distribution of starch matter inside the cells.…”

Section: Resultsmentioning

confidence: 99%

Effect of a Pulsed Electric Field and Osmotic Treatment on Freezing of Potato Tissue

et al. 2010

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“…Nevertheless, blocklets were observed as protrusions on the surface of starch granules. The sizes of these blocklets on potato starch granules range between 50 and 300 nm according to Baldwin et al (1998) or are around 30 nm according to Szymonska et al (2003). On granules from sweet potato, maize, rice, and wheat, the blocklets were reported to have similar sizes of approximately 20-40 nm (Ohtani et al 2000).…”

Section: Blocklet Structurementioning

confidence: 99%

Fine Structure of Amylopectin

Bertoft

2015

Starch

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Starch granules consist of two major polyglucans, namely, branched amylopectin and essentially linear amylose. In all nonmutant starches, amylopectin is the major component and is responsible for the internal structure of starch granules, which is the native, semicrystalline form of starch. The granules, irrespective of the plant source, consist of granular rings of alternating amorphous and semicrystalline polymers. On a smaller scale, blocklets as well as crystalline and amorphous lamellae have been identified. Amylopectin is generally accepted as the contributor to the lamellar structure, but the nature of blocklets is only beginning to be resolved. Amylopectin consists of numerous chains of glucosyl units that are divided into short and long chains. These chains are organized as clusters that have been isolated by using endo-acting enzymes, and the fine structure of the clusters have been investigated. The clusters consist of still smaller, tightly branched units known as building blocks. The organization of the clusters and building blocks in the macromolecular structure of amylopectin is to date uncertain, and two schools exist at present suggesting that amylopectin either has a treelike branched cluster structure or a building block backbone structure. The structural features of amylopectin and the two models presently in debate are discussed in this chapter.

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Modification of granular potato starch by multiple deep-freezing and thawing

Cited by 74 publications

References 21 publications

Electron paramagnetic resonance study of water distribution in starch granules

Electron paramagnetic resonance study of water distribution in starch granules

Effect of a Pulsed Electric Field and Osmotic Treatment on Freezing of Potato Tissue

Fine Structure of Amylopectin

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