Titre :
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Effects of amylopectin branch length and amylose content on the gelatinization and pasting properties of starch
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Auteurs :
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J. Jane ;
Y. Chen ;
L. Lee ;
AL Et
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Type de document :
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article/chapitre/communication
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Année de publication :
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1999
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Format :
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p. 629-637
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Langues:
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= Anglais
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Catégories :
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PHYSIQUE ETAT DE LA MATIERE
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Mots-clés:
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AMIDON
;
COMPOSITION
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Résumé :
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Structures and properties of starches isolated from different botanical sources were investigated. Apparent and absolute amylose contents of starches were determined by measuring the iodine affinity of defatted whole starch and of fractionated and purified amylopectin. Branch chain-length distributions of amylopectins were analyzed quantitatively using a high-performance anion-exchange chromatography system equipped with a postcolumn enzyme reactor and a pulsed amperometric detector. Thermal and pasting properties were measured using differential scanning calorimetry and a rapid viscoanalyzer, respectively. Absolute amylose contents of most of the starches studied were lower than their apparent amylose contents. This difference correlated with the number of very long branch chains of amylopectin. Studies of amylopectin structures showed that each starch had a distinct branch chain-length distribution profile. Average degrees of polymerization (dp) of amylopectin branch chain length ranged from 18.8 for waxy rice to 30.7 for high-amylose maize VII. Compared with X-ray A-type starches, B-type starches had longer chains. A shoulder of dp 18-21 (chain length of 6.3-7.4 nm) was found in many starches; the chain length of 6.3-7.4 nm was in the proximity of the length of the amylopectin crystalline region.
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Source :
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Cereal chemistry, vol.76, n°5
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