Titre :
|
Steady flow and viscoelastic behavior of crosslinked waxy corn starch-kappa-carrageenan pastes and gels
|
Auteurs :
|
A. Tecante ;
J. Doublier
|
Type de document :
|
article/chapitre/communication
|
Année de publication :
|
1999
|
Format :
|
p. 221-231
|
Langues:
|
= Anglais
|
Catégories :
|
CHIMIE
|
Mots-clés:
|
VISCOELASTICITE
;
AMIDON
;
MELANGE
;
TEMPERATURE
|
Résumé :
|
The steady and small-deformation shear behaviors of 2-4 wt.% cross-linked waxy corn starch (CWCS) and 0.5 wt.% K-carrageenan (KC) mixtures have been studied. In some cases kappa C gelation was induced by the addition of 20 mM KCl and cooling to 25 °C. Rheological behavior was interpreted considering swelling-solubility as well as laser diffraction particle size and size distribution data. CWCS was chosen because it lacks amylose and its granules can swell without disruption under appropriate thermal conditions; thus the condition of particles dispersed in a continuous phase can be best fulfilled. Dispersions were heated (1.5 °C/min) to 96 °C, held for 10 min, then cooled (1.5 °C/min) to 80 °C. Steady tests were carried out at 60 °C and oscillatory tests were carried out at 60 and 25 °C. Only more concentrated dispersions displayed an anticlockwise up-down shear loop, which was enhanced by KC and KCI. Hysteresis disappeared with continuous shearing, and shear-thinning was observed with CWCS + kappa C being more viscous than CWCS + kappa C + kappa Cl and CWCS. Oscillatory tests at 60 °C showed that dispersions exhibited a predominantly solid-like behavior which was attenuated at lower starch concentrations and when KC and KCI were added. At 25 °C, trends were similar but with slightly greater G' and accentuated elastic character at higher starch concentrations.
|
Source :
|
Carbohydrate Polymers, vol.40
|