Studies on κ-carrageenan/locust bean gum mixtures in the presence of sodium chloride and sodium iodide
✍ Scribed by M. P. Gonçalves; C. Gomes; M. J. Langdon; C. Viebke; P. A. Williams
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1997
- Tongue
- English
- Weight
- 251 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
The solution properties of k-carrageenan and k-carrageenan/locust bean gum mixtures have been studied by small deformation oscillation measurements and differential scanning calorimetry (DSC) in the presence of sodium chloride and sodium iodide. Both salts induced the k- carrageenan to undergo a coil-helix conformational change as noted by an increase in the storage and loss moduli (G, GЉ) and by an exothermic peak in the DSC cooling curves. The enthalpy DH c-h and temperature of the conformational transition T c-h were higher in NaI compared to NaCl and T c-h increased with increasing the concentration of both electrolytes. Gelation was not observed for carrageenan or carrageenan/locust bean gum mixtures in the presence of up to 200 mM NaI. Although carrageenan alone did not gel in the presence of 100 mM NaCl, a weak gel was obtained for a mixture containing 0.9%/0.1% carrageenan/locust bean gum. Furthermore, the mixture showed hysteresis in both the rheological and DSC cooling and heating curves. A strong gel was produced for carrageenan alone in the presence of 200 mM NaCl and the gel strength increased on adding a small proportion of locust bean gum (0.9%/0.1%).