Guar gum used as thickener and texture modifier
Throughout 2012 and looking into 2013, food manufacturers remain engaged with the dilemma of working…Throughout 2012 and looking into 2013, food manufacturers remain engaged with the dilemma of working with guar gum in their formulations. This proven hydrocolloid offers many advantages to food product designers who need texture, viscosity and stability in a wide variety of creations. Guar gum has a lot to offer; is naturally derived, performs well, and until recently, was an economical choice.
However, the guar gum market has experienced unprecedented demand from the energy industry during the last 24 months. Oil and gas industry demand has tripled in this time period because guar gum is an effective viscosifier of the fluids used in hydraulic fracturing (sometimes known as “fracking"), which has boomed in recent years. Along with increased demand, the price of guar gum soared as much as 1,600%.
According to a Dec. 5, 2012, article in The Wall Street Journal, guar gum pricing and demand have followed a classic boom and bust cycle. As the oil and gas industry used more guar, prices skyrocketed and supplies tightened significantly. But starting in mid-2012, guar prices began to retreat, and at year-end 2012, guar pricing has fallen from a May high of $27,000 a ton down to $7,000 a ton. Does that mean a return to old use patterns? Not really. Both the energy and food industries are learning to work with alternative materials to avoid the potential uncertainties about supply and pricing.
Guar functionality
The concern about guar gum availability has roots in this gum’s character and its broad applicability in a variety of food products. Derived from the seeds of the guar plant, Cyamopsis tetragonoloba, the majority of the world supply is grown in India and Pakistan. Unlike certain other common thickeners, such as modified food starch and cellulose gum (CMC), guar can even support some “all-natural" label claims. In the EU it is designated by the E number E 412.
Guar imparts viscosity and water-binding capacity even at low usage levels. It’s frequently used in stabilizer blends in combination with other gums. And, it can be used in many different product categories, including dairy products, sauces, soups, frozen desserts and bakery products.
Guar is the most widely used general purpose thickener and texture modifier in the food industry. It is this variety of functions that make it so attractive to food and beverage makers. Some of the features of guar include: thickens beverages, sauces, and gravies; binds water and controls ice crystal formation in ice cream; provides mouthfeel to dairy products; controls water and extends the shelf life of baked goods. Guar also has some emulsification properties.
The building blocks of the guar molecule, which like locust bean gum, is known as a galactomannan, are the carbohydrates mannose and galactose at a ratio of approximately between 1.5: 1 and 2:1, forming a chain-like structure with a molecular weight of 50,000 to 8,000,000. The backbone chain consists of (1,4)-linked β-D-mannopyranose. The fairly even distribution of the galatose-comtaining side chains helps guar form a stable solution. Commercial guar gum contains approximately 4% to 12% moisture and 2% to 6% protein.
Guar swells in hot or cold water and is one of the most efficient water-thickening agents used in the food industry. Because of its high molecular weight, it produces highly viscous, pseudoplastic (shear-thinning) solutions even at low concentrations. The viscosity of the solutions stays fairly constant in the typical pH range of foods and beverages. However it is not generally recommended for use in very acidic applications and is best used from ph 4 to 7. Exposure to high heat at low pH can degrade its viscosity. Guar’s performance depends on particle size—a smaller particle will hydrate more rapidly, while a larger particle size is more easily dispersible. The particle size can also influence viscosity. In solution, it provides a “long" texture with a translucent appearance.
