Structural and mechanical characterization of k/i-hybrid carrageenan gels in potassium salt using Fourier Transform rheology

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Loic Hilliou (Author) FEUP; Manfred Wilhelm (Author) Other; Mikio Yamanoi (Author) Other; Maria P. Gonçalves (Author) FEUP

Journal

Title: Food Hydrocolloids

Vol. 23 No. 8

Pages: 2322-2330

ISSN: 0268-005X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 20 Citations

ISI Web of Science

Scopus - 27 Citations

Scientific classification

FOS: Natural sciences

CORDIS: Physical sciences

Other information

Authenticus ID: P-003-DX3

DOI: 10.1016/j.foodhyd.2009.06.008

Abstract (EN): The mechanical and structural properties of κ/ι-hybrid carrageenan gels obtained at various concentrations in the presence of 0.1 m KCl were studied with Fourier Transform rheology (FTR) and cryoSEM imaging. FTR data show that gels formed at concentration below 1.25 wt% exhibit a strain hardening behavior. The strain hardening is characterized by a quadratic increase of the scaled third harmonic with the strain and a third harmonic phase angle of zero degree. Both features are weakly depending on the concentration and conform to predictions from a strain hardening model devised for fractal colloidal gels. However, the phase angle of the third harmonic reveals that κ/ι-hybrid carrageenan gels obtained at higher concentrations show shear thinning behavior. Colloidal gel models used to extract structural information from the concentration scaling of gel equilibrium shear modulus G0 and the strain dependence of FTR parameters suggest that κ/ι-hybrid carrageenan gels are built from aggregating rod-like strands (with fractal dimension x = 1.13) which essentially stretch under increasing strain. The mechanically relevant structural parameters fairly match the gel fractal dimension (d = 1.66) obtained from the cryoSEM analysis. © 2009 Elsevier Ltd. All rights reserved.

Language: English

Type (Professor's evaluation): Scientific