RHEOLOGICAL BEHAVIOR OF KAPPA-CARRAGEENAN GALACTOMANNAN MIXTURES AT A VERY-LOW LEVEL OF KAPPA-CARRAGEENAN

• Type: Article in International Scientific Journal
• Date: 1994

Authors

FERNANDES, PB (Author) Other; Maria do Pilar Gonçalves (Author) FEUP; DOUBLIER, JL (Author) Other

Journal

Title: Journal of Texture Studies

Vol. 25

Pages: 267-283

ISSN: 0022-4901

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 12 Citations

Scopus - 13 Citations

Other information

Authenticus ID: P-001-JHV

DOI: 10.1111/j.1745-4603.1994.tb00760.x

Abstract (EN): The rheological behaviour of kappa-carrageenan/galactomannan blends, at ratios ranging from 1/99 to 5/95 in the presence of KCl, was investigated by means of viscosity and oscillatory shear measurements. These experiments were performed at 1% total polymer concentration and at 15C. The results were compared to those of the galactomannans alone (locust beam gum or guar gum). The mixtures exhibited gel-like properties provided the KCl content was high enough to induce stabilisation of the kappa-carrageenan molecules in the helical conformation. This limiting KCl content for gelation was of the order of 0.02% and did not depend upon the kappa-carrageenan concentration under these experimental conditions. The mixtures exhibited similar tendencies overall irrespective of whether the galactomannan was guar gum or locust beam gum. However, the phenomena appeared somewhat less pronounced with guar gum than with locust bean gum. The results are discussed on the basis of a model assuming the formation of a biphasic system, one phase being enriched with the galactomannan, the other phase consisting of kappa-carrageenan. Since the galactomannan remains the major component, the properties are primarily governed by this polysaccharide in solution. The gel-like properties of the mixture result from gelation of the kappa-carrageenan, this having a dominating effect upon the rheological behaviour of the galactomannan.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 17