Rheology and DSC of Gellan-Agarose Mixed Gels
The rheological and thermal properties of mixed gels of gellan and agarose were studied by dynamic viscoelastic measurement and differential scanning calorimetry (DSC). E’ increased slightly up to a certain temperature To and then began to decrease with increasing temperature. This temperature To shifted to higher temperatures with increasing gellan content. The critical concentration for gelation Co becomes higher with increasing gellan content. Two endothermic peaks were observed in DSC curves for mixed gels. The higher temperature peak was attributed mainly to the melting of gellan gum network whilst the lower temperature peak was mainly attributed to the melting of agarose network. In the phase separated gels, gellan forms at first a network on cooling, and then agarose forms another network at lower temperatures.
KeywordsDifferential Scanning Calorimetry Junction Zone Gellan Content High Temperature Peak Lower Temperature Peak
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- 1.G.R. Sanderson, Gellan gum, in: “Food Gel”s P.Harris Ed., Elsevier Applied Sci., London, pp. 201–232 (1990).Google Scholar
- 2.T. Matsuhashi, Agar, in: “Food Gel”s P.Harris Ed., Elsevier Sci., London, pp. 1–50 (1990).Google Scholar
- 3.D.A. Rees, E.R.Morris, D. Thorn & J. K. Madden, Shapes and interactions of carbohydrate chains, in: “The Polysaccharide”s G. 0. Aspinall Ed., Academic Press, New York, Vol. 1. pp. 195–290 (1982).Google Scholar
- 4.P. A. Williams and G.O. Phillips, Interactions in mixed polysaccharide systems, in: “Food Polysaccharide”s A.Stephens and I.C. M. Dea Eds., Marcel Dekker, in press.Google Scholar