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Molecular characterization of native and processed waxy maize starch in relation to the recrystallization behavior of model systems and starch microspheres

Elfstrand, Lidia LU ; Eliasson, Ann-Charlotte LU ; Jonsson, M; Reslow, M and Wahlgren, A (2004) 11th International Starch Convention In Starch: from polysaccharides to granules, simple and mixture gels p.203-214
Abstract
The recrystallization behavior of five starch materials, native waxy maize starch, and starches modified by acid hydrolysis and mechanical treatments, were investigated by DSC (differential scanning calorimetry) and electron microscopy (SEM). The starches were known to vary significantly in molecular weights but not in the degree of branching. Microspheres manufactured from one of these starches were also studied by both methods. The acid hydrolysis did not produce major breakdown of the granular structure of starch as evidenced by SEK or the amount of crystalline amylopectin, as measured by DSC, but broadened the melting temperature range compared to native starch. No crystallinity could be detected in the material after the mechanical... (More)
The recrystallization behavior of five starch materials, native waxy maize starch, and starches modified by acid hydrolysis and mechanical treatments, were investigated by DSC (differential scanning calorimetry) and electron microscopy (SEM). The starches were known to vary significantly in molecular weights but not in the degree of branching. Microspheres manufactured from one of these starches were also studied by both methods. The acid hydrolysis did not produce major breakdown of the granular structure of starch as evidenced by SEK or the amount of crystalline amylopectin, as measured by DSC, but broadened the melting temperature range compared to native starch. No crystallinity could be detected in the material after the mechanical treatment, which also seemed to destroy the granular structure. The crystallinity was regained after the material had been dispersed in 70 % water during heating followed by 20 hour storage at 6 degreesC, called as one-step temperature treatment, while within the set of samples stored at 20 degreesC only one of the starches showed presence of regained crystallinity. No significant differences could be observed with regard to endothermic transition temperature or temperature range between the samples of native starch and both the acid hydrolysed and the mechanically treated samples, as measured by DSC. Apparently from the enthalpy values and presence of endothermic transitions, amylopectin molecular weight and modification method seemed to affect the amount of starch crystallites formed and/or the recrystallization rates, with acid hydrolysed samples showing higher enthalpy values compared to mechanically treated samples. The same conclusion, as for one-step temperature treatment of starch materials, was done for a two-steps temperature treatment of the starch materials, regarding transitions temperatures within the set of experiment. The two-steps treatment with nucleation at a lower temperature and crystal growth and perfection at a higher temperature resulted in an increase in the melting temperatures and narrower melting intervals. This treatment is also similar to the actual microsphere manufacture process. DSC thermogram of placebo starch microspheres revealed that the crystallites, obtained in production process of the microspheres, melted at temperatures similar to melting temperatures of the starch dispersion after 14 days/6 degreesC- storage but showed higher enthalpy value and smaller melting interval. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
starch microspheres, SEM, recrystallization, DSC, waxy maize starch
in
Starch: from polysaccharides to granules, simple and mixture gels
pages
203 - 214
publisher
Nova Science Publishers, Inc.
conference name
11th International Starch Convention
external identifiers
  • WOS:000224157200014
ISBN
1-59454-013-6
language
English
LU publication?
yes
id
b303ac59-5f48-4188-98eb-d48e24473a97 (old id 1406744)
date added to LUP
2009-06-03 13:08:13
date last changed
2016-04-16 09:24:02
@misc{b303ac59-5f48-4188-98eb-d48e24473a97,
  abstract     = {The recrystallization behavior of five starch materials, native waxy maize starch, and starches modified by acid hydrolysis and mechanical treatments, were investigated by DSC (differential scanning calorimetry) and electron microscopy (SEM). The starches were known to vary significantly in molecular weights but not in the degree of branching. Microspheres manufactured from one of these starches were also studied by both methods. The acid hydrolysis did not produce major breakdown of the granular structure of starch as evidenced by SEK or the amount of crystalline amylopectin, as measured by DSC, but broadened the melting temperature range compared to native starch. No crystallinity could be detected in the material after the mechanical treatment, which also seemed to destroy the granular structure. The crystallinity was regained after the material had been dispersed in 70 % water during heating followed by 20 hour storage at 6 degreesC, called as one-step temperature treatment, while within the set of samples stored at 20 degreesC only one of the starches showed presence of regained crystallinity. No significant differences could be observed with regard to endothermic transition temperature or temperature range between the samples of native starch and both the acid hydrolysed and the mechanically treated samples, as measured by DSC. Apparently from the enthalpy values and presence of endothermic transitions, amylopectin molecular weight and modification method seemed to affect the amount of starch crystallites formed and/or the recrystallization rates, with acid hydrolysed samples showing higher enthalpy values compared to mechanically treated samples. The same conclusion, as for one-step temperature treatment of starch materials, was done for a two-steps temperature treatment of the starch materials, regarding transitions temperatures within the set of experiment. The two-steps treatment with nucleation at a lower temperature and crystal growth and perfection at a higher temperature resulted in an increase in the melting temperatures and narrower melting intervals. This treatment is also similar to the actual microsphere manufacture process. DSC thermogram of placebo starch microspheres revealed that the crystallites, obtained in production process of the microspheres, melted at temperatures similar to melting temperatures of the starch dispersion after 14 days/6 degreesC- storage but showed higher enthalpy value and smaller melting interval.},
  author       = {Elfstrand, Lidia and Eliasson, Ann-Charlotte and Jonsson, M and Reslow, M and Wahlgren, A},
  isbn         = {1-59454-013-6},
  keyword      = {starch microspheres,SEM,recrystallization,DSC,waxy maize starch},
  language     = {eng},
  pages        = {203--214},
  publisher    = {ARRAY(0x9f863a8)},
  series       = {Starch: from polysaccharides to granules, simple and mixture gels},
  title        = {Molecular characterization of native and processed waxy maize starch in relation to the recrystallization behavior of model systems and starch microspheres},
  year         = {2004},
}