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Introduction of Gellan Gum |
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Properties of Gellan Gum |
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Application of Gellan Gum |
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 Comparing with other gums |
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Comparison with other Hydrocolloids
Form the foregoing discussion, the similarity between gellan gum and agar and k-carrageenan is apparent. This similarity is true not only in textural terms but, for agar, in terms of the large hysteresis in setting and melting. The ion dependence of the properties of gellan gum and k-carrageenan is striking. Another similarity is the ability of cold solutions of both gellan gum and carrageenan to gel upon the addition of ions. Ion-induced gelation is a phenomenon more commonly associated with alginate and formation of alginate gels in the cold by the conrolled release of Ca2+ is well known and widely used industrially. There are indications that the techniques used for preparing alginate gels may be appropriate for gellan gum in certain applications. Alginates also have a strong interaction with hydrogen ions and precipitation of sodium alginate form solution by conversion to the acid form through acid addition can be used in the manufacture of alginates. Likewise, acid precipitation is an effective and alternative means of isolating gellan gum. The gels produced form gellan gum by the addition of hydrogen ions are extremely strong. The fact that gelation of gellan gum is induced by ions both upon cooling like carrageenan and in the cold like alginate has led to its being described as the’ missing link’ in gelling hydrocolloids. The application of this statement is that understanding the molecular baisi of gellan gum gelation may help resolve the mechanism of carrageenan gelation, which is generally, although not universally, in contrast to alginate, where the accepted mechanism is ion-induced dimeric association of polymer chains in the cold.
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