Chemistry and Function of Gums
C. Ronnie Yuan, principal scientist at a leading hydrocolloid gum supplier explains, “Gums function either as gelling agents or thickeners (viscosifiers). In both cases, gum polymers can interact with each other through hydrogen bonds, electrostatic attraction, or hydrophobic interaction to thicken texture by controlling water.”Gum choice is determined by the properties desired in a particular product. “For example,” Yuan explains, “xanthan gum is a much better stabilizer than guar gum in salad dressings because of its desirable rheology and acid stability. And in regular chocolate milk, carrageenan is a preferred choice due to its unique interaction with milk protein (casein). But in soy-based chocolate beverages, a gellan gum ‘fluid gel’ is a better choice in providing the structure needed to suspend cocoa particles.”
“The primary function of gums in cheese products is water stabilization. This provides the desired viscosity and influences the final body and texture in finished cheese products and sauces. Gums also aid in firming cheese products to the point of being easily shredded or sliced. They are available in different particle sizes to aid in dispersion in different processing systems. As hydrophilic colloids, gums disperse very well, are soluble in water and bind well with casein. Gums can also be used as a full or partial replacement for fat in reduced- or no-fat products,” offers John Vojtech, senior scientist at Land O’Lakes Inc., a large supplier of consumer dairy products.
Gum Facts to Chew On
Guar gum and carrageenan are not very stable in low-pH environments, and under similar conditions, xanthan gum can cause flocculation of protein. Protective hydrocolloids such as pectin and carboxymethyl cellulose (CMC) can be used to prevent protein flocculation in acidified protein drinks. However, they only work in a pH range typically between 3.8 and 4.2. Some gums require high shear for activation, whereas others require heat to hydrate.“For cheese products, the standards of identity determine whether gum is allowed in the finished product. For example, gums are allowed in cheese spreads, but not in cheese food or process cheese. This scenario can be overcome by calling the final cheese ‘pasteurized process cheese product’ which has no standard of identity,” adds Vojtech.
“Certain gums have synergistic interactions that result in very different textures than the individual gums alone,” adds Yuan. “For example, xanthan and locust bean gums, which are not typically considered as gelling agents, can form a rubbery gel when used together.” Other synergistic combinations include xanthan and guar gum (used to enhance viscosity in sauces or beverages), xanthan and konjac glucomannan (rubbery gels), carrageenan and locust bean gum or konjac glucomannan (used for gelling in water dessert gels).
Combining two different textural components, such as elastic and brittle gels, to create new textures can also be an interesting approach used by food formulators. A water dessert gel with a very desirable gel texture can be formulated using xanthan gum, locust bean gum (which form a rubbery gel together) and low acyl gellan gum (which has a brittle texture).
Pectin Uses
Pectin is used as gelling agent in a variety of food products such as fruit spreads, desserts, and confectionery products. Pectin also acts as a thickener in fruit preparations, dairy products like ice cream, bakery fillings, glazes, dressings and condiments. In sorbet, pectin controls ice crystal growth and melting behavior. When used in beverages, pectin provides good mouthfeel and body and enhances pulp stability.“Apple pectin gives a smooth gel structure with a lot of mouthfeel and enhanced flavor transfer, while brittle textures are obtained with citrus pectin,” offers Frank Mattes, sales manager for a top pectin manufacturer. It is possible to create different textures with different types of pectin, including a stretchy and tailing structure similar to starch. However, it is also possible to produce confectionery products with short and chewable textures.
“The gelling properties of pectin depend on soluble solids present in the product,” states Mattes. In confectionery products, 99% of the soluble solids are sugar. “Pectin can also be used as a thickener or gelling agent in products with almost no soluble solids, but different pectin types may need consideration depending on the soluble solids content.” Like soluble solids content, pH is also a consideration for choosing the appropriate pectin type. Pectin works best in products with a pH lower than 4.5. Above pH 5.0, pectin very quickly degrades.
“Pectin is a polyelectrolyte,” Mattes explains. “Ionic strength and ion type influence the gelling behavior of pectin. Because of their molecular structure, low methyl ester pectin and citrus pectin have increased affinity to cations, especially calcium ions. For confectionery products, increased affinity to ions can be problematic, as it leads to faster gelling behavior.” In this case, apple pectin can be utilized for its enhanced tolerance to cations. Pectin also sometimes interacts with proteins, such as casein and soy proteins, so pectin can be used to stabilize protein-containing beverages like smoothies.
Singling Out Starches
In cheese products and sauces, starches provide body and textural attributes to the final product through gelation. “Starches are typically more economical than gums, can be used as bulking agents and usually have little or no flavor influence on the final cheese sauce or product,” offers Vojtech. Starches also can be effective replacements for cheese solids, providing sensory and performance characteristics in a more cost-effective manner than oils and dairy powders. “It is critical to consider all aspects of the requirements for the final product, plus processing and storage when choosing a starch,” he states. Key starch attributes to consider are fast hydration and gelation during processing, final viscosity, storage and freeze/thaw stability, texture/mouthfeel and cost.“In baked goods, lipophilic starches are a great addition to the line-up,” says Wendy Erickson, technical manager of the Bakery, Snacks & Cereal Category at a leading supplier of bakery ingredients. “They provide improved shelflife because of their ability to complex with fat and increase freezer stability.”
Resistant starches can help dilute the calorie contribution from carbohydrates in baked goods. There are four classifications of resistant starches. One and two are naturally found in plants, but typically not in high quantities. Class three are retrograded starches, and class four are chemically modified starches. “While all resistant starch products have overall lower caloric content, a class four resistant starch which is high in dietary fiber has the greatest impact in a finished baked good, contributing negligible calories," adds Erickson.
Starch properties vary, depending on their source. Tapioca starch has approximately 17% amylose, which allows for some retrogradation and soft gel formation at high enough concentrations. At 20%, potato starch has slightly more amylose, which in combination with its large granule size, produces a salve-like consistency. “Potato starch inherently offers higher viscosity than other starches in a native state or at equal modification levels,” offers Judy Turner, advanced technical resource at a supplier of potato and tapioca starch.
Tapioca starch has a clean flavor and tends to be used in mild flavored products such as those with a dairy base. “In vanilla flavored dairy products such as yogurt, pudding, cream and cheese sauces, tapioca starch does not hide the delicate dairy flavor notes,” Turner adds.
Both tapioca and potato starches improve mouthfeel and body of reduced fat and sugar foods. Potato starches, because of their large granule size, do not give as smooth and shiny a texture as other starch types. “For this reason, potato starches are found in barbecue sauces or other tomato-based sauces where the texture does not detract from the final appearance,” Turner explains.
Emulsifiers and Texture
Emulsifiers are another group of ingredients often crucial to the texture of products. In baking, emulsifiers can help “mix oil and water” by exhibiting both lipophilic and hydrophilic properties. The hydrophilic/ lipophilic characteristics of emulsifiers are described by their HLB (Hydrophilic/ Lipophilic Balance). A low HLB indicates an emulsifier with strong lipophilic character, while a high HLB emulsifier has more hydrophilic tendencies.“Emulsifiers such as mono and diglycerides or lecithin not only tenderize the finished cake but also contribute to cake batter viscosity. Emulsifiers reduce surface tension and allow greater incorporation of air into the batter. In breads, emulsifiers complex with protein and starch portions and strengthen the extensible gluten-starch film and delay the setting of the dough during baking,” contributes Erickson.
“In the cheese industry, the most commonly used emulsifiers are orthophosphates and citrates. Phosphates are used in loaf and block products, since they do not react well in quick cool processes. Citrates act well in processes that call for quick cooling, such as cast slices. In this process, the cheese is cooled before packaging and storage and needs a quick-acting emulsifier,” states Vojtech.
Both phosphates and citrates emulsify by exchanging sodium ions for calcium ions in the casein portion of the cheese. “Simply stated, this allows the casein strands to unwrap and become more receptive to linking with the fat globules in natural cheeses, increasing the ability for the protein/water matrix to hold fat,” explains Vojtech. Mono and diphosphates are lower in pH than trisodium phosphate (TSP), and therefore impart more firmness to the final product. TSP has the highest pH, and the resulting product is not as viscous during processing or as firm when cooled as are products using other phosphates.
Sodium hexametaphosphate (Hex) is a condensed orthophosphate that has greater emulsification ability than orthophosphates or citrates. Hex helps hold the fat in the cheese structure better and creates a firm body and high degree of melt restriction in the final product. “This is very desirable for products that need to withstand high temperatures during further processing or use by consumers,” Vojtech adds.
Synergistic Texturants
In baked goods, texturants are used alone and in synergistic combination to achieve the desired processing and finished baked product quality. “All baked products benefit from the addition of a texturant of some type. For example, cakes typically use an instant modified starch, gums and emulsifiers. This combination optimizes batter viscosity impacting the finished baked texture, internal crumb structure, eating quality and shelflife,” contributes Erickson. Optimized batter rheology helps retain the gases released from the chemical leavening system. If the batter viscosity is too thin, the gases are released, resulting in dense, lower volume cakes.“Cross-linked, substituted starches in combination with various hydrocolloids have excellent bake stability in bakery jams or acidic fillings,” contributes Andrea Peck, food scientist at a baking ingredient supply company. While pectins and alginates may contribute a firmer gel texture to fillings, combinations with modified starches can add a softer, shorter texture. In addition, modified starches aid in reducing boil-out and moisture management during the extra thermal process step. Together, the blends may have low viscosity during processing for ease of pumping and depositing, but form a set when applied to the product,” she says.
When in doubt, suppliers have lots of good information to help with specific texture issues. It is even possible to customize blends of texture ingredients and achieve the perfect mix to meet specific needs.
Showcase: Gums, Starches and Emulsifiers
A new stabilizer provides the structure that gluten-free products lack and is both affordable and easy to use. Gum Technology’s Coyote Brand Stabilizer ST-101’s blend of xanthan and guar gums works synergistically, allowing them to be used at a much lower concentration (about half) than that of straight xanthan alone. For a sample and gluten-free brownie recipe, call 800-369-GUMS. Gum Technology Corporation, 800-369-4867, info@gumtech.com, www.gumtech.comRebuild texture and improve consumer acceptance of low-fat and fat-free milk products with a new beverage texturizer. TEXTRA® provides the dairy industry with the tools to create a whole milk sensory experience without the fat by adding 1.5% and effectively delivering a rich, creamy mouthfeel. TEXTRA performs well in many beverages, including products typically considered too low in viscosity to suspend with other texturizers. National Starch Food Innovation, Marshall Fong, 908-685-5000, Marshall.Fong@nstarch.com, www.nationalstarch.com
A natural extract of the white bean may assist in weight and blood sugar control by slowing enzymatic starch digestion. StarchLite™, also known as Phase2®, is a dietary ingredient that is self-affirmed GRAS and can be incorporated into food or beverages without a standard of identity. Consumer acceptance tests of baked goods showed statistical parity for all measures at both 90% and 95% confidence levels, and the StarchLite sample scored numerically higher for overall taste. Pharmachem Labs, Gregory Drew, 800-526-0609, gdrew@pharmachemlabs.com
A very effective and versatile rheology modifier is now available. ADM’s NovaXan™ xanthan gum provides stability and improved textural qualities, pouring characteristics and cling. It is ideal for salad dressings, sauces and marinades as well as baked goods and dairy products. NovaXan offers unique flow behaviors, instantaneous, reversible shear-thinning and high viscosity, even at low
concentration. For customers looking to create products with high quality
textural characteristics, stability and aesthetic appearance, look no further. ADM, 800-637-5843, info@admworld.com, www.admworld.com
A custom-designed dry ingredient systems company can solve many of the baking industry’s texture and stability challenges. Advanced Food System’s TexRite® bakery systems can be used in the dough or as a glaze to significantly improve texture in fresh par-baked and frozen baked goods. The benefits include consistent baking and reduction in freezer burn, cracking and chewy post-freeze problems. TexRite offers “home-baked” quality to large-scale operations without sacrificing quality or shelflife. Advanced Food Systems Inc., Anton Dodel, 732-873-6776, lab@afsnj.com
A leading developer and manufacturer of specialty starches and dextrin for all segments of the food industry has introduced products that enhance the taste, texture and performance of foods. Penford Food Ingredients Co. has expertise in leveraging the inherent characteristics from potato, tapioca, rice and corn to help improve product quality. Their PenBind®, PenPlus®, PenCling® and PenTech® products help provide crispy texture in coated applications, moisture in meats, structure in gluten-free breads, shredability in imitation cheeses and smoothness in sauces, gravies and bakery fillings. Penford Food Ingredients Co., Andrea Gaebe, 303-643-1687, agaebe@penx.com
Some new data provides a better understanding of the relation between mouthfeel in beverages and various hydrocolloids. In breakthrough research, CP Kelco has developed texturizing agents such as GENU® pectin, CEKOL® cellulose gum, KELTROL® xanthan gum and KELCOGEL® gellan gum. Each contributes in different ways to the sensory perception of drinks due to differences in viscosity and density. To learn more about what hydrocolloids can do for your product or to learn more about the research, contact the company. CP Kelco, Jane Schulenburg,
jan.schulenburg@cpkelco.com, www.cpkelco.com
As an excellent film former, native and oxidized pea starch acts as a barrier for water or fat uptake, thus providing many application possibilities. Pea Starch N735, from Roquette America Inc., with a higher amylase content (35%) and derived from yellow pea, provides unique characteristics to finished products. It gives crispiness to cereals and French fries, maintains integrity of transparent noodles during cooking and preserves crispness of microwaveable battered food items. Custards, confectionary and meat substitutes are among the other applications of this unique starch. Roquette America Inc., Chandani Perera, 800-553-7035, www.roquette.com
When grain and fiber are added to baked goods, the gluten and dough matrix become stressed. Overcome these processing challenges in whole-grain products with Danisco’s PANODAN® DATEM, which strengthens the gluten matrix, so that the dough can handle the addition of grains and fibers without sacrificing quality. Whole-grain products can include many types of grain lipids. PANODAN emulsifies the flour and added fat in whole-grain dough, resulting in a finished product with better crumb structure and eating qualities. Danisco USA Inc.,
800-255-6837, ext. 1173, www.danisco.com
Reducing fat does not have to mean loss of texture. METHOCEL™ food gums add just the right amount of texture to baked goods, sauces, salad dressings, confections and other low-fat favorites. Salad dressings are smooth and pourable, microwaveable treats do not lose their shape, puddings stay rich and creamy and cupcakes still have that just-baked mouthfeel and crumb structure. Derived from naturally occurring cellulose, METHOCEL is odorless, tasteless and is available in a wide range of viscosities for easy formulating. Dow Food Group, Diane Brown, 800-488-5430, foodgroup@dow.com, www.methocelfoodgums.com
Ground-breaking nutritional and functional properties are available with a new soluble, all-natural fiber. Beneo™ (inulin, oligofructose) and Beneo Synergy 1 from ORAFTI provide many healthy benefits, including improved calcium absorption, “invisible” fiber enrichment, improved mouthfeel and enhanced gastrointestinal health through prebiotics. Beneo replaces fat and sugar in foods, beverages and nutraceuticals without affecting taste. Synergy 1 promotes bone mineral density at lower use levels. ORAFTI Active Food Ingredients, Joseph O’Neill, 610-889-9828, joneill@orafti-us.com, www.orafti.com
A full range of co-processed ingredients is based on a balanced ratio between two all-natural dietary fibers: acacia gum (a soluble fiber) and wheat fiber (an insoluble fiber). Equacia™, by Colloides Naturels International (CNI), not only offers the numerous proven nutritional and health benefits of those two fibers, but also helps mimic the rheological properties of fat in many applications such as bakery, sauces and processed meat. Colloides Naturels International, Sébastien Baray, samples@cnius.com
