Question

How does locust bean gum impart spreadability, I.e., chemical reaction?

Is it when it is used with xantham gum because they're synergistic?

Answer 1

Locust bean is a thickening agent and a gelling agent used in food technology

In many polysaccharide systems, the combination of a gelling polymer with a nongelling one gives rise to strong synergistic effects, as a consequence of interaction among different chain polymers and formation of mixed junction zones.

the most exploited mixed gels, especially by the food industry, are those involving the microbial polysaccharide xanthan gum (XG) and the plant galactomannans, like locust bean gum (LBG). Concentrated aqueous systems of LBG and XG display quite different rheological properties

Interestingly, when mixed together these macromolecules interact to form a firm, thermoreversible gel with synergistic effects.

we report the results of a thorough investigation of both polymer concentration and temperature effects on the rheological properties of mixed LBG-XG systems in 20 mM KCl under continuous and oscillatory flow conditions. Under continuous shear at 25 degrees C, pure LBG shows the flow properties of a macromolecular solution, with a shear-thinning behaviour and a Newtonian region at low shear rates, whereas the rheological behaviour of XG and all LX mixed systems is that typical of weak-gels. Furthermore, in the mixed systems the viscosity values do not increase monotonically with increasing xanthan concentration, but the synergistic effect has a maximum in accordance with the XG:LBG ratio 1:1. As the temperature is increased from 25 degrees C to 85 degrees C, whilst the LBG system do not show any qualitative change but there is only a parallel, downward shift of viscosity values, in the case of xanthan there is a dramatic change in the corresponding curve profiles, due to the thermally induced helix-coil conformational transition

yes.it is used with xantham gum because they are synergetic.