Chemistry – Guar Gum
Stabilizers are hydrocolloids that are water-soluble, they disperse in water, and are commonly used in ice cream making. Stabilizers extensively used in the ice cream industry include guar gum. (Goff & Hartel, 2013) Stabilizer are derived from plants, bacteria, and animal by-products. Although derived from natural sources, stabilizers are considered food additives under European law.( Goff & Hartel ,2013) The purposes for using stabilizers in ice cream are to influence the viscosity or gelling behaviour of solutions. Stabilizers play many roles, supporting increase mix viscosity, retarding ice crystal and lactose crystal growth during storage. It helps prevent shrinkage of the ice cream during storage, reduces the rate of meltdown and stronger stand-up properties. Without stabilizer, ice cream products are likely to lack the resilience they’ll need to cope with the journey to the consumer’s table.
Guar gum, also called guaran, is a substance made from guar beans which has thickening and stabilizing properties in industries, traditionally the food industry, but increasingly the hydraulic fracturing industry. The guar seeds are dehusked, milled and screened to obtain the guar gum. It is typically produced as a free-flowing, off-white powder. It is classed as a galactomannan. Its E number is E412. Chemically, guar gum is a polysaccharide composed of the sugars galactose and mannose. The backbone is a linear chain of β 1,4-linked mannose residues to which galactose residues are 1,6-linked at every second mannose, forming short side-branches. Guar gum is more soluble than locust bean gum, as it has more galactose branch points. Unlike locust bean gum, it is not self-gelling. High concentrations (~ 1%) are very thixotropic but lower concentrations (~ 0.3%) are far less so. Guar gum shows high low-shear viscosity but is strongly shear-thinning. Being non-ionic, it is not affected by ionic strength or pH but will degrade at pH extremes