A rheological characterization of Kappa-carrageenan / galactomannan mixed gels: a comparison of locust bean gum sarnples

• Type: Article in International Scientific Journal
• Date: 1991

Authors

P. Fernandes (Author) Other; Maria do Pilar Gonçalves (Author) FEUP; J. Doublier (Author) Other

Journal

Title: Carbohydrate Polymers

No. 16

Pages: 253-274

ISSN: 0144-8617

Publisher: Elsevier

Indexing

ISI Web of Science

Scopus

Scientific classification

FOS: Engineering and technology > Other engineering and technologies

Other information

Resumo (PT): Mixed gels of kappa-carrageenann and locust bean gum (LBG) obtained from different varieties of Portuguese carob trees and commercial gums were compared the viscoelastic properties of the gels were measured using dynamic parallel-plate geometry. Mixed gels at 1.0% of total poly-saccharide concentration without addition of KCI showed whatever the LBG sample a synergistic maximum when the ratio of kappa--carrageenan to LBG was 80/20. The amplitude of this maximum varied with the LBG sample. The gels prepared at 0.3% total concentration with KCI added showed a synergistic maximum at the same mixing ratio and the amplitude varied in a similar manner. Each sample was fractionated into the fraction soluble at 25 °C and the fraction soluble at 90°C. Mixed gels of kappa-carrageenan with cold water soluble and hot water soluble fractions, and also with tara gum and guar gum were prepared at 80/20 ratio. It was found that the synergetic maxima were related to the intrinsic viscosity and the M/G ratio. A linear relationship between the storage modulus Gmax at the synergistic maximum and the product of the intrinsic viscosity and the square at the mannose to galatose ratio was found, suggesting that the synergestic mechanism can be ascribed to both the unsubstitued (galactose-free) regions of the galactomannan and the molecular weight.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 22