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Linear and Nonlinear Rheology of Mixed Polysaccharide Gels. Pt. I. Young's Modulus, Ring Extension and Uniaxial Compression Tests

Authors

  • Tom Brenner,

    1. Graduate School of Human Life Science, Osaka City University, Sumiyoshi, Osaka, Japan
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  • Piyada Achayuthakan,

    1. Graduate School of Human Life Science, Osaka City University, Sumiyoshi, Osaka, Japan
    2. Biotechnology Program, Faculty of Science and Technology, Suan Sunandha Rajabhat University, Dusit, Bangkok, Thailand
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  • Katsuyoshi Nishinari

    Corresponding author
    • Graduate School of Human Life Science, Osaka City University, Sumiyoshi, Osaka, Japan
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Corresponding author. TEL: +81-66605-2818; FAX: +81-66695-2818; EMAIL: katsuyoshi.nishinari@gmail.com

Abstract

Abstract

Small and large deformation tests were performed on polysaccharide-based gels containing konjac glucomannan, locust bean gum and κ-carrageenan. Low pH degradation of κ-carrageenan during heating led to lower gel strength. When κ-carrageenan degradation was avoided, the linear-regime rheology was dominated by the κ-carrageenan content, and the storage Young's modulus (E′) was found to decrease with decreasing κ-carrageenan concentration. The large deformation behavior, however, was dominated by the konjac glucomannan concentration, and the rupture strain increased strongly with increasing konjac concentration. These two opposing trends led to a maximum in rupture stress in extension tests. No rupture was observed in compression of the gels at the polysaccharide concentrations tested. The compression force of konjac-rich gels was lower than that observed for gels without konjac at low-compression degrees, but it was similar to or higher at high-compression degrees, above 60–80%, indicating the higher degree of strain hardening of konjac-rich gels.

Practical Applications

Mixing of different polysaccharides has been used for widening the texture range, and it was shown in this report that the mixture of konjac glucomannan, locust bean gum and κ-carrageenan in the presence of sucrose and acid can produce jellies with various textures.

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