Is used as a thickener in sauces, salad dressings, as a stabiliser in ice cream that prevents ice crystals from forming, and as a fat substitute that adds the “mouth feel” of fat.
In pastry fillings, it prevents “weeping” (syneresis) of the water in the filling, keeping the pastry crust crisp. It has a very high viscosity (thickness) even when very little is used.
When mixed with xanthan gum or locust bean gum, the viscosity is more than when either one is used alone, so less of each can be used.
| Application | Function |
|---|---|
| Soups, sauces and marinades | Viscosity control. |
| Pastry fillings | Viscosity and syneresis control. |
| Ice Cream | Ice crystal and Viscosity control. Fat mimetic. |
Guar gum (E412) is a polysaccharide (a long chain made of sugars) composed of galactose and mannose.
Guar gum comes from the endosperm of the seed of the legume Cyamopsis tetragonolobus, which is an annual plant grown in arid regions of India.
Guar gum is an economical thickener and stabiliser. It hydrates fairly rapidly in cold water to give highly viscous, pseudoplastic solutions of generally greater low-shear viscosity when compared with other hydrocolloids and much greater than that of locust bean gum. High concentrations (~ 1%) are very thixotropic but lower concentrations (~ 0.3%) are far less so.
Guar gum is more soluble than locust bean gum. Unlike locust bean gum, it does not form gels but does show good stability to freeze-thaw cycles. Guar gum shows high low-shear viscosity but is strongly shear-thinning. Being non-ionic, it is not affected by ionic concentration or pH but will degrade at pH extremes at temperature (e.g. pH 3 at 50°C). It shows viscosity synergy with xanthan gum. With casein, it becomes slightly thixotropic forming a biphasic system containing casein micelles.
When guar gum is dissolved in hot or cold water, it takes around 4 hours to reach maximum viscosity.
It is not advisable to use more than 0.4% w/w Guar gum in a formulation as it can give a “mealy” taste to the finished product.