Guar Gum Basics

By Maureen Akins and Harold Nicoll, Contributing Editors

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 gums 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. Its 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. Guars performance depends on particle sizea 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.

Using enzymes to break up the chain length of guar results in  partially hydrolyzed guar gum (PHGG) This greatly reduces the viscosity to about 10 mPas in 5% aqueous solution, vs. about  2,000 to 3,000 mPas  in a 1% solution of regular guar. This ingredient is typically used in nutritional products as a soluble fiber.

Guar and other gum blends

As one approach, the food industry is trying blends. Guar itself shows a viscosity synergy particularly when combined with xanthan gum, but with tara gum, gum tragacacanth, gum karaya, as well as several cellulosic gums. It also exhibits viscosity synergy with starch pastes and might slow starch retrogradation.

A number of alternatives contain some guar, but also include other gums with the properties of guar. These other gums are in more abundant supply and not subject to the same demand or price variations as  guar gum. Blends of gums often provide added benefits to end users that a single gum cannot.

What does the future hold for guar gum? Its a tricky question, because as a crop-based material, supply of guar is subject to the uncertainty of the weather, rapid demand swings and unforeseen events in the supply chain. But, new replacement products and innovative approaches to using them will help food formulators navigate through periods of uncertainty.

Maureen Akins is the technology manager for TIC Gums, White Marsh, MD. She has 10 years experience in R&D focusing on the applied use of hydrocolloids across the food industry.

Harold Nicoll is the marketing manager for TIC Gums. He spent the first 23 years of his career in marketing communications and public affairs for The Dow Chemical Company and the last two with TIC Gums. For more information, visit ticgums.com.

Click here to read more about guar gum and more in the January/February 2013 issue of Food Product Design, available for download in the SupplySide Store.