Guar gum, a galactomannan from the seed kernel of the guar plant Cyamopsis tetragonolobus, is a cold and hot water soluble natural polysaccharide. It consists of a long polysaccharide chain made up of the sugars mannose and galactose.
A one-per-cent aqueous solution of guar has a viscosity of about 3,000 to 5,000 cps. Synergistic effects occur when guar gum is used in combination with xanthan or locust bean gum, with the resulting viscosity being greater than either gum produces alone. Guar gum is typically used as a thickener and stabilizer in a range of food products. Its functionalities include preventing synerisis or weeping of the water from fillings, interfering with formation of ice crystals in ice cream, and providing a fat-like mouth feel in reduced-fat foods. It also stabilizes and thickens baked goods; retains moisture, prolongs shelf life, and shortens batter mix time in baked goods; and increases volume and soft texture in rolls and breads.
With its emulsifying properties, guar gum is also a crucial ingredient in the oil and natural gas drilling industry, which uses 75 per cent of the total available supply. Because of the shortage and rising prices, guar gum is no longer the most cost-effective hydrocolloid for food applications. As a result, formulators are now looking for alternative ingredients to reduce or eliminate the requirement for guar gum without compromising the quality of finished products. Some of guar gum alternatives now available include:
• A blend of oat fibre/potato starch and psyllium has been successfully used as a 1:1 replacement for guar gum in bakery products like bread, buns, cookies, muffins, cakes and bagels. It can also improve dough machinability, eating quality, moistness and shelf life.
• Carrageenan is a high-quality ingredient for binding water, stabilizing and modifying texture in many foods. By using a low concentration of carrageenan, formulators can create water-based gel systems, ranging from free-flowing liquids to solid gels. Carrageenan can replace guar gum in shake mixes, hot cocoa, meal replacement and sports supplements, and in dairy products such as dessert creams, puddings, ice cream and yogurt.
• Xanthan gum is a heteropolysaccharide that exhibits a high viscosity in aqueous solutions at low concentrations. It has very strong pseudoplasticity, with no evidence of thixotrophy. Good hydration of conventional xanthan gum can be obtained by first mixing it with other dry ingredients, like sugar and salt. There is also an enhanced grade of xanthan gum available commercially that is designed to exceed performance of conventional xanthan gum today in terms of cost-in-use, productivity and superior stability. Its unique properties include enhanced hydration rate with the added benefit of complete hydration in the presence of salts, acids and high solids; rapid hydration in most hot and cold water-based systems; superior viscosity (10 times that of conventional xanthan gum, measured at low shear rate) and enhanced suspension properties. Xanthan gum can replace guar gum in a wide variety of fresh and frozen baked products and beverages, dips, dressings, soup mixes and condiments.
• Carboxymethyl cellulose gum is a highly purified, cold water-soluble polymer derived from cellulose and commonly used as a thickener, stabilizer or dispersant. Cellulose gums are a versatile, cost-effective way of creating a range of viscosity grades, with flow properties ranging from nearly Newtonian to pseudoplastic.
• Pectin is polysaccharides derived from naturally occurring structural components in fruits and vegetables. It is widely used in food for thickening and gelation; for mouth feel in beverages without impacting odour, taste or flavour release; as a protective hydrocolloid for proteins in acidic condition; to prevent fruit flotation in beverages; and to control synerisis. Pectin can replace guar gum in gluten-free baked products, fruit juice, dairy and non-dairy shakes, low-fat sour cream and low-fat mayonnaise.
Mary Lim is technical manager for L.V. Lomas Ltd. Contact her at [email protected]