Texturizing and Stabilizing, by Gum!
What is it that entices us to put a new food or beverage in our mouths for the first time? The appearance, smell and anticipated sensory rewards of a food experience. The real seal of approval, however, is our willingness or desire to try it a second time. It is not surprising, therefore, that the ingredient categories responsible for flavor and texture/stabilization, hydrocolloids, rank first and second, respectively, in importance in the food and beverage industry, as measured by U.S. market value.
Increased usage and growth rates of these ingredient categories are expected to continue in the coming years, according to Business Communications Co. (Norwalk, Conn.). Hydrocolloids encompass a range of polysaccharide- or protein-based ingredients that react with water and, for the most part, form networks to achieve their functionality. Food formulators like their versatility, and an increased use of hydrocolloids has been driven by the need for increased product variety, sensory enhancement, increased convenience, calorie reduction, shelflife extension, cost reduction, and the introduction of new ingredient technologies into traditional products (e.g., soy-based analogues).
Starch, particularly modified starch, is the most widely used hydrocolloid in food systems, accounting for over 85% of total hydrocolloid use by volume, according to Dennis Seisun of IMR International (San Diego, Calif.) an organization that monitors the worldwide food hydrocolloid industry. “Gelatin ranks second only to starch in terms of hydrocolloid volume and value, but is used in a limited number of applications. Together, starch and gelatin account for over 50% of hydrocolloid value in North America.”
As a protein, gelatin has been unique in this ingredient category dominated by polysaccharides. However, other functional proteins are being recognized for their textural contributions and are becoming part of tailored stabilizer systems.
The relative importance of individual hydrocolloids in North America is outlined in the accompanying table (See chart “Hydrocolloids in North America”). Non-starch polysaccharides commonly are referred to as “gums,” and are the primary focus of this article.
Gum Control in a Starch World
Gums serve as the texturizer or stabilizer of choice in many applications. In starch-containing products formulated with lower soluble solids (e.g., soups, sauces, gravies, etc.), gums often are used as a partial starch replacement. In some medium- and high-solids systems, gums frequently are used instead of starch (e.g., high-solids fruit fillings).
The ability of gums to thicken and gel foods efficiently, at a fraction of the starch concentration, is a key advantage. Other benefits are improved flavor and significantly reduced calorie contribution (some gums add no calories). Their ability to provide a range of variety and flexibility in textures is noteworthy. Rheological differences also provide benefits as processing aids. Gums commonly are used to enhance the functionality and stability of starches, such as during the baking process, and they help minimize retrogradation during storage.
Determining which gum to use in an application greatly depends on the type of functionality needed and the application's processing parameters. The related functionality and benefits of other ingredients also must be factored in. Other considerations include: proven technical viability and versatility, consumer familiarization and acceptance (on the label), and its availability through a wide selection of suppliers.
Texturizing. From thickening liquids to forming semi-solids via gelation, gums enhance texture and mouthfeel, and duplicate textural properties after the reduction of calorie, solids and/or costs (e.g., reduced-fat dressings, juice-based beverages, poultry products, soy-based meats, dairy analogues, etc.).
In gelled applications such as fillings or desserts, enhanced flavor release is associated with harder, brittle gels (though syneresis also increases with brittleness, and is addressed with viscosifiers). The benefits of gelation include improved cutability, sliceability, scoopability, moldability and structure (e.g., pie fillings, poultry products, gelled desserts, frostings and icings, respectively).
Common thickening agents include xanthan gum, carboxymethylcellulose (CMC), and guar gum, although forms of carrageenan, pectin and alginates also are used (each differs in rheological and other properties). Carrageenan, pectin, alginate, agar and gellan gum are gelling agents, though a xanthan/ locust bean gum combination also is used; these will vary in texture and other properties (e.g., hydration requirements, conditions for gelling, heat and acid stability, etc.).
Stabilizing. As mentioned earlier, stabilization is a key function of gums. Moisture stabilization translates into many benefits. Uniform water distribution may prevent cracking, or increase pliability. Moisture loss can be minimized at many temperatures, protecting against: freeze/thaw cycles, moisture migration during baking and subsequent storage (e.g., farinaceous), moisture loss during extended periods of heating (e.g., sauce on a steam table), or boilout during baking (e.g., fillings). When selecting gums, some important attributes to consider include: uniform viscosity across temperatures, pseudoplastic behavior, gelation with high melting points and the ability to gel with heat.
By thickening the continuous water phase, air can be indirectly stabilized to enhance creaminess and/or volume (e.g., whipped toppings, soft serve, cakes).
The stabilization of the water phase is important in stabilizing oil emulsions (e.g., dressings, spreads). The pseudoplasticity of xanthan gum, manifested by high at-rest viscosity, has been a reason for its widespread use in such applications. Propylene glycol alginate offers limited emulsification (e.g., dressings), while gum arabic is used directly for emulsion stability (e.g., flavors).
In the case of acidified dairy and soy beverages, specialized high methoxyl (HM) pectin products have been used for protein stabilization (counteracting reactivity below isoelectric pH values).
Suspension and Cling. Particle suspension (e.g., spices in dressings, pulp in beverages, nuts in batters, vegetables in soups, etc.) is another highly sought after function. A viscosifying gum exhibiting high pseudoplastic rheology (characterized by high at-rest or low-shear-rate viscosity, e.g., xanthan gum) provides this capability with little to no additional impact on mouthfeel or viscosity during swallowing. In dairy products (e.g., cocoa suspension), carrageenan's reactivity with casein creates an efficient network.
Fluid gels (from continuous shearing of gelling hydrocolloids through their set point as they cool after heating and hydration) are very pseudoplastic solutions, exhibiting high suspension with minimal viscosity. Gellan gum has demonstrated applicability, but other candidates could be considered. Enhancing a product's “cling” (e.g., dressings on lettuce, brine in relish, sauces on particulates, syrups, etc.) is another useful application of pseudoplasticity.
Other. Additional functions include forming films to limit oil migration, assisting in the application of glazes, and enhancing the sheen on product surfaces. The range of set point and melting point temperatures provided by gelling agents can be utilized as processing aids, as can their stability against melting in products that are further processed (e.g., fruit fillings). MC and hydroxypropyl methylcellulose (HPMC) are interesting examples, as they exhibit a “reverse thermal gelation,” gelling when heated and melting when cooled.
In shelflife extension, a gum's functionality is exhibited through its ability to prevent phase separation, maintain product homogeneity, or control moisture. (Polysaccharides do not significantly lower water activity [Aw].)
Processing ParametersWhether the product is an instant, cold make-up dry mix, or a heat-processed entrée, a gum is chosen for its functionality and processing properties. Cold hydration (e.g., xanthan gum, CMC, etc.) and hot hydration (e.g., locust bean gum, etc.) options are available for thickening or viscosifying gums. The majority of gel-forming gums require heat for hydration; subsequent ion addition and cooling result in gelation. Alginates are the exception, however, as they allow cold hydration and subsequent gelation via the addition of a calcium source.
In gum lingo, “dispersion” describes gum particle separation upon water contact; hydration describes complete water association on a molecular level (usually requiring mixing beyond when particles appear dissolved).
For gums that hydrate in cold systems, good dispersion lays the foundation for good hydration. Lumps are formed when particle hydration occurs faster than particle separation. However, there are mechanical, physical and procedural techniques to optimize dispersion: careful selection of particle size and physical conformation, particle separation prior to water introduction (dry mixing with other powders or slurrying with non-aqueous liquids), eductors for slight wetting of particles, and ultra high shear mixing equipment. Overcompensating on dispersion, however, impacts hydration efficiency by requiring longer mixing times.
When lumping does occur, the resulting aggregation is difficult to separate, and lowers functional gum concentration. Cold-hydrating gums are more susceptible to lumping in hot water.
Gums that require heat for hydration are minimally affected by dispersion when added to cold water. However, it is then very important to achieve the necessary hydration temperature under shear. For gelling agents hydrated with heat, packaging the product above the temperature at which the gel sets is critical for maximum gel strength.
Mixing procedures that offer high shear or pressure are ideal for gum hydration (though extreme homogenization pressures can have degradative effects on polysaccharide structural integrity, directly impacting functionality).
Influential OthersIons, pH. Salts or acids negatively impact a gum's hydration rate. Gelling gums commonly require the addition of ions for intermolecular crosslinking and network development; however, their presence must be controlled until hydration is complete.
Gums develop networks depending on the length (molecular weight) of their polymer chains. For viscosifying or thickening agents, adjacent chains join together via hydrogen bonding, whereas gelling agents rely on cations to crosslink chains into a network.
Protecting chain integrity from acid hydrolysis is critical in maintaining functionality over time. Therefore, the pH of a product application has direct bearing on gum selection, particularly for thickening. Some gelling agents susceptible to acid hydrolysis prior to gelation possess enhanced resilience after network formation. The three-dimensional molecular structure of some gums confers resilience (e.g., xanthan gum, gellan gum).
Low-pH conditions help to facilitate gelation for some gelling agents (e.g., high methoxyl pectin, gellan gum). Manipulating a product's pH is a useful tool in controlling the release of cations in systems for gelling polysaccharides that rely on ionic crosslinking of polymer chains.
Solids level. Sugars or low molecular weight carbohydrates bind water strongly enough to control water activity. Sugars compete for available moisture, making gum hydration difficult; they should be added after the gum is hydrated (though some sugar or corn syrup can be used for dispersion). In high solids environments, heat facilitates hydration. For gelling hydrocolloids, high solids typically raise the set temperature.
Other polysaccharides. Systems composed of more than one gum capitalize on unique hybrid textures from more than one gelling agent, synergies that result in thickening efficiency, or hybrid rheologies and textures with sensory and processing advantages.
The use of multiple gums offers a range of suitable solutions. The best gum decision may be the choice of a service-oriented supplier truly focused on offering solutions.
Website Resources:www.hydrocolloid.com — IMR International
www.bccresearch.com/press — Business Communications Co. Inc.
www.lsbu.ac.uk/water/hydro.html — Hydrocolloid info. from London South Bank University
Michael P. Wanous, Ph.D., M.B.A., possesses several years of domestic and international experience in the ingredient industry, and is a consultant specializing in strategies for ingredient and services technologies. Phone: 630-668-8820, e-mail: MPWPHDMBA@aol.com
Cutline 1: Pseudoplastic behavior is an important attribute when selecting which gum to use. That is, when shear is applied, for example by mixing or pumping, the viscosity of a gum solution can fall dramatically.
Sidebar: A focus on health has made fiber content more valuable to consumers. TIC Pretested® Pre-Hydrated® Nutriloid® 010 Powder was created for high-usage applications, including high-fiber beverages. With a low-viscosity level of typically less than 50cps at a 2.0% concentration, Nutriloid 010 is an excellent source of all-natural soluble dietary fiber for nutritional beverages and other similar products. Additionally, the company supplies a complete line of gums and gum systems. TIC Gums Inc., 410-273-7300, www.ticgums.com
Showcase: Gums and Starches
This highly functional resistant starch enhances fiber content and can reduce carbohydrate levels in foods such as breads, pastas, muffins, waffles, breakfast cereals and nutritional bars. A wheat derivative, FiberStar 70™ can partially replace flour in bakery products and delivers a minimum 70% of total dietary fiber. It possesses a clean flavor, is extremely white in color, and imparts a smooth, creamy texture in contrast to traditional fiber, like bran. In breads, these qualities produce a whiter crumb and potentially increased loaf volume. Depending on the level of use, FiberStar 70™ can provide finished product claims such as “Good Source of Fiber,” or “High Source of Fiber.” MGP Ingredients Inc., Food Ingredients Division, 800-255-0302, ext. 3276, firstname.lastname@example.org
These resistant starches are functional food ingredients that are completely natural and rich in fiber. Hi-maize and NOVELOSE starches are white, bland-tasting and an easy way to add fiber to carbohydrate-based foods such as breads, pastas, cereals and nutritional bars without impacting the taste or texture of the food. They significantly lower the glycemic response and are ideal for use in foods for the "carbohydrate conscious" market. As prebiotic fibers, they also are well-suited for use in gluten-free foods. National Starch's resistant starches are supported by more than 120 published studies substantiating their health benefits and nutritional value. National Starch & Chemical Co., Rhonda Witwer, 800-797-4992, Rhonda.Witwer@nstarch.com
Cold water-swelling potato starches give lump-free dispersibility in both cold and hot liquids. Paselli™ EZ Sperse starches display a smooth short appearance and texture with excellent clarity and surface sheen. In addition, the starches are specifically designed to have a quick hydration rate, offering minimum viscosity changes over time. They have intact granules and, hence, give a product texture similar to premium “cook-up” starches without heat. Their very bland flavor and high viscosity can provide cost savings through reduction of flavoring components and/or tomato solids. All AVEBE starches are kosher and GMO-free. Samples are available. AVEBE, 609-734-9155, email@example.com
Emulsification starch can be used to replace gums in beverages. Staley Mira-Mist® 662 is a cold-water soluble starch designed to stabilize oil-in-water emulsions. It is recommended as a replacement for gum arabic in beverage concentrates, yielding a stable emulsion consisting of small flavor oil droplets that disperse uniformly in both carbonated and non-carbonated drinks. The starch often can be used at a lower rate than the gum for a more economical formulation with comparable quality. Tate & Lyle Food Ingredients, 800-526-5728, www.TLNA.com
With today's "low-carb" craze, the use of gums offers some clear advantages. Gums can be used at a much lower level than starch—more than 10 times less—to achieve the same results. Gums also help resolve the negative textural issues in low-carb foods by replacing mouthfeel lost in sauces and ice cream, and by increasing volume in baked goods. The lower use level of gums may also provide a lower cost formula. Texturant Systems offers solutions to your low-carb needs with custom gum blends. Degussa Food Ingredients, 800-241-9485, firstname.lastname@example.org
Custom-designed stabilizer formulations for a variety of applications are available from this international supplier. For over 35 years, David Michael's proprietary Michtex® stabilizer formulations have been used in products such as pumpkin pie, cottage cheese, low/no fat processed cheeses, low/no fat coffee creamers, salad dressings, low/no fat frozen desserts, sorbets, low/no fat meats, bakery fillings, pie crusts, low/no fat icings, low/no fat cakes, low/no fat candies, sauces, gravies and beverages. The company's textural experts also can design a custom stabilizer that meets specific requirements. David Michael & Co., Total Customer Satisfaction Department, 215-632-3100, email@example.com
Premium high-quality native and modified food starches that are GMO-free and kosher certified are available at a significant cost savings. American Key Food Products' starches are available in cook-up and cold swelling varieties, with great freeze-thaw capabilities. They can be used in many food applications such as bakery, meat and snack products, soups, sauces, canned foods and pasta products. An extensive line of potato flakes, granules and flours also is available. American Key Food Products, 877-263-7539, www.AmericanKeyFood.com
A manufacturer of custom-designed stabilizers, texture systems and flavor and seasoning systems, Advanced Food Systems has been doing business for more than 20 years. The company's expertise in problem-solving and creating new products with fast turnaround times is available to customers in the processed meat and poultry, dressing and sauces, frozen foods, snacks and bakery industries. Advanced Food Systems Inc., 732-873-6776, firstname.lastname@example.org
Keeping snack coatings on is easier with a modified food starch that does not require the use of conventional vegetable oil-based formulations. Using INSTANT PURE-COTE® B792, the manufacturer can apply a clear, aqueous-based coating to snacks such as extruded cereals or nuts. Some benefits of using this coating include excellent surface sheen, improved adherence of seasoning particulates and an overall reduction of the snack's fat and calorie content. Grain Processing Corp., Bob Bahn, 563-264-4265, email@example.com
A commercially available, high-performance xanthan gum offers superior rheology, stabilizing and thickening properties, heat stability, pH stability, and excellent cling. Xanthan gum is ideal for salad dressings, baked goods, dairy products, low-calorie foods, syrups, and more. ADM offers xanthan gum customers dependable supplies of consistent, high-quality ingredients, along with outstanding technical support and worldwide distribution. ADM Specialty Ingredients' established line of products includes citric acid, NutriSoy® soy protein, Ultralec™ ultra-filtered lecithin, Fibersol-2™ soluble dietary fiber, and GDL. ADM, 217-451-4492, Ken Inman, firstname.lastname@example.org
This supplier of rice-based starches for the food industry is committed to working as a partner with its customers. Founded in 1990, A&B Ingredients is based on a tradition of research and development to help customers develop prototypes of new and improved food products. A&B maintains full applications labs with consumer testing capabilities and provides sales and marketing, importing, distribution and applications development services. A&B Ingredients, 973-227-1390, www.abingredients.com
Synergistic composites of certain hydrocolloids (xanthan gum with selected galactomannans), these products offer a range of effective food stabilizers. ISP's Textureze UB products provide a choice of flow properties and gel characteristics for use in foods such as fruit toppings, puddings, processed cheese, dough conditioners, dressings, sauces, and cottage cheese. The Textureze UB family (100, 110, 120, and 130) can be used in cold and hot processing, and helps modify the brittle textures of some other gums; it also helps adjust viscosity and mouthfeel. Further benefits include structure over a wide pH range, reduced syneresis, and emulsion and suspension stability. International Specialty Products, Customer Sales & Service, 800-622-4423
Many food companies have come to rely on this company for a wide variety of quality food ingredients. The Ashland Distribution Co. provides more than 1,500 food and beverage ingredients, including a wealth of innovative new specialty ingredients. The company offers local distribution from more than 80 distribution centers nationwide and has sourcing alliances with more than 100 suppliers worldwide. It offers technical support to all major suppliers. Ashland Distribution Co., Jim Holdrieth, 614-790-4306, email@example.com