Carboxymethyl Chinese yam starch: synthesis, characterization, and influence of reaction parameters.
Carbohydr Res
; 344(13): 1764-9, 2009 Sep 08.
Article
en En
| MEDLINE
| ID: mdl-19665107
Carboxymethyl starch (CMS) was obtained as a product of the reaction of starch and monochloroacetic acid (MCA) in the presence of sodium hydroxide. The influence of the molar ratio of NaOH/AGU, the molar ratio of MCA/AGU, the reaction time, reaction temperature, and the water content on the degree of substitution (DS) was studied. The optimal molar ratio of NaOH/AGU and MCA/AGU is 2.4 and 1.0, respectively. Increase of the ratio of NaOH/AGU or MCA/AGU leads to an increase in DS, but only to certain extent. The highest values of the DS were obtained when the carboxymethylation was performed at 60 degrees C for 2.5 h. The water content in the reaction media ethanol was optimal at 20% (v/v). The scanning electron micrographs (SEMs) revealed that the carboxymethylation affected the structural arrangement of the starch and caused granular disintegration. The particle size distribution (PSD) also displayed that the average particle diameter increased greatly after modification from 37.37 microm to 72.88 microm. Wide angle X-ray diffractometry (XRD) revealed that starch crystallinity was obviously reduced after carboxymethylation. The new bands at 1600 cm(-1) and 1426 cm(-1) in FT-IR indicated that the starch granules were substituted.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Almidón
/
Dioscorea
Idioma:
En
Revista:
Carbohydr Res
Año:
2009
Tipo del documento:
Article
País de afiliación:
China
Pais de publicación:
Países Bajos