Aqueous dissolution of crystalline and amorphous amylose-alcohol complexes.
Int J Biol Macromol
; 11(6): 339-44, 1989 Dec.
Article
em En
| MEDLINE
| ID: mdl-2489102
ABSTRACT
Complexes of amylose, the linear starch polysaccharide, with linear alcohols having chain lengths varying from 4 to 8 carbon atoms, were prepared. Either crystalline or amorphous complexes could be formed depending on preparation conditions. Crystalline complexes gave sharp X-ray diffraction patterns, characteristic of the VH form of amylose, whereas no observable pattern was obtained from the amorphous form. Thermal dissociation of the complexes occurred at increasing temperatures with increasing alcohol chain length. Crystalline complexes dissociated at temperatures approximately 23 degrees C higher than their amorphous counterparts and the enthalpy of dissociation was also greater for the crystalline samples. Enthalpy values were independent of alcohol chain length. Differences in thermal behaviour of the two types of complex may be described in terms of the polymer crystal lattice energy and may explain the variability of reported results for complex dissociation in the literature.
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Base de dados:
MEDLINE
Assunto principal:
Álcoois
/
Amilose
Idioma:
En
Ano de publicação:
1989
Tipo de documento:
Article