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Galactomannans - Viscosity and gelation

4 important questions on Galactomannans - Viscosity and gelation

What can decrease the viscosity of galactomannans?

When galactomannans would be heated at rather low pH values, the viscosity will drop with decreasing Mw.

Do galactomannans give a good viscosity?

Yes, they have a high water-binding capacity forming highly viscous solutions at low concentrations.

How do galactomannan and xanthan interact?

Non-substituted parts of locust bean gum (so no galactosyl residues) interacts via cations(+) with the helical xanthan structure
Backbone of galactomannan can interact with xanthan despite being substituted.

Why is the degree of substitution important for the interaction between galactomannan and other polysaccharides?

Guar gum (2:1) + xanthan gum --> increase in viscosity
Guar gum (2:1) + gelling polysaccharide (agar, carrageenan) --> gel strength increased

Locust bean gum (4:1) + xanthan gum --> gelling agent, while both are not gelling agents when used alone, but only increase the viscosity

Tara gum (3:1) + xanthan gum --> gel, but weaker compared to LBG