Publications by authors named "Dasha A Koroteeva"

2 Publications

  • Page 1 of 1

Structural and thermodynamic properties of rice starches with different genetic background Part 2. Defectiveness of different supramolecular structures in starch granules.

Int J Biol Macromol 2007 Dec 19;41(5):534-47. Epub 2007 Jul 19.

Institute of Biochemical Physics, Russian Academy of Sciences, Kosygina str. 4, 119334 Moscow, Russia.

High-sensitivity differential scanning microcalorimetry (HSDSC), small-angle X-ray scattering (SAXS), light (LM) and scanning electronic (SEM) microscopy techniques were used to study the defectiveness of different supramolecular structures in starches extracted from 11 Thai cultivars of rice differing in level of amylose and amylopectin defects in starch crystalline lamellae. Despite differences in chain-length distribution of amylopectin macromolecules and amylose level in starches, the invariance in the sizes of crystalline lamellae, amylopectin clusters and granules was established. The combined analysis of DSC, SAXS, LM and SEM data for native starches, as well as the comparison of the thermodynamic data for native and annealed starches, allowed to determine the structure of defects and the localization of amylose chains in crystalline and amorphous lamellae, defectiveness of lamellae, clusters and granules. It was shown that amylose "tie chains", amylose-lipid complexes located in crystalline lamellae, defective ends of double helical chains dangling from crystallites inside amorphous lamellae ("dangling" chains), as well as amylopectin chains with DP 6-12 and 25-36 could be considered as defects. Their accumulation can lead to a formation of remnant granules. The changes observed in the structure of amylopectin chains and amylose content in starches are reflected in the interconnected alterations of structural organization on the lamellar, cluster and granule levels.
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http://dx.doi.org/10.1016/j.ijbiomac.2007.07.005DOI Listing
December 2007

Structural and thermodynamic properties of rice starches with different genetic background Part 1. Differentiation of amylopectin and amylose defects.

Int J Biol Macromol 2007 Oct 5;41(4):391-403. Epub 2007 Jun 5.

Institute of Biochemical Physics, Russian Academy of Sciences, Kosygina Str. 4, 119334 Moscow, Russia.

A combined DSC - HPAEC-PAD approach, gel permeation chromatography and mild long-term acidic hydrolysis were employed to study the effects of amylopectin chain-length distributional and amylose defects on the assembly structures of amylopectin (crystalline lamellae, amylopectin clusters) in A-type polymorphic starches extracted from 11 Thai cultivars of rice with different amylose level. Joint analysis of the data allowed determining the contributions of different populations of amylopectin chains to the thermodynamic melting parameters of crystalline lamellae. It was shown that amylopectin chains with DP 6-12 and 25or=37 could be related to chains stabilizing these structures. The total effect of amylose and amylopectin defects can be described by means of Thomson-Gibbs' equation. The increase of defects in the assembly structures is accompanied by rise of the rates of acidic hydrolysis of both amorphous and crystalline parts in starches.
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http://dx.doi.org/10.1016/j.ijbiomac.2007.05.010DOI Listing
October 2007