Effects of added galacto- and gluco-mannans on the NMR spectra of 133CS ions in kappa-carrageenan gels
✍ Scribed by Lennart Piculell; Wei Zhang; Tristan Turquois; Cyrille Rochas; François-René Taravel; Peter Anthony Williams
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 837 KB
- Volume
- 265
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
NMR chemical shifts and line-widths of 13?Cs ions were measured in kappa-carrageenan gels containing galacto-or gluco-marmans, and compared with measurements on kappa-carrageenan alone. In the mixed gels, as in pure kappa-carrageenan, large changes in the NMR parameters were found to accompany the onset of helix formation for kappa-carrageenan, as obtained independently from polarimetry or differential scanning calorimetry. The shift changes on helix formation in the mixed gels were very similar to those in kappa-carrageenan alone, indicating that the ordered conformation of kappa-carrageenan, and its degree of specific ion binding, was the same in all systems. A much enhanced line-broadening was seen in gels containing carob galactomannan or konjac glucomannan, which are known to form synergistic gels in the mixtures with kappa-carrageenan, while other additives (guar galactomannan or agarose) had a small or insignificant effect. The observations are interpreted in terms of an association between mannans and (aggregated) kappa-carrageenan helices in the synergistic gel mixtures.