Food hydrocolloids offer significant functionality to the food scientist, but options are impacted by marketing's working definition of clean label and perceptions of quality implied by the ingredients used in a formulation. This discussion is limited to food gums, defined as non-starch, hydrocolloid ingredients that are soluble or form colloidal suspensions in water. Thus, ingredients which are a source of insoluble fiber are not included. (Starches were addressed in an article titled “Retro Starches…Back to the Future?” in the September 2006 issue of Prepared Foods.)
Culinary Perceptions of GumsGum quality perceptions are undergoing a rapid change, led by trendsetting chefs. Chefs Heston Blumenthal of London's The Fat Duck Restaurant, Ferran Adria of Barcelona's El Bulli and Wylie Dufresne of WD50 in New York City are three very vocal, award-winning chefs who recognize and promote the fact that properly applied food gums can enhance food quality rather than diminish it. Other trendsetting chefs, namely Homoro Cantu of Chicago's Moto and James George Sarkar of Venue in Hoboken, N.J., have been labeled “progressive” because they use ingredients like xanthan gum and alginate.
The 2006 IFT/RCA-sponsored Product Development Competition echoed these trends. Common themes included the use of gums to replace labor-intensive procedures and to provide freeze/thaw stability. While these hydrocolloid uses are by no means new, the chef community's endorsement of them is, says Catherine Proper, executive chef of Target Corporation. Classic culinary sauces are transformed into stabilized emulsions with the assistance of these functional wonders. Who ever thought chefs would be able to put hollandaise under a heat lamp for two hours in a banquet setting? As gum manufacturers continue to provide easy-to-use forms and educate chefs about their benefits, culinary uses of gums will continue to increase.
Benefits of GumsNutritional studies clarifying the benefits of soluble fiber are also altering the perceptions of food gums. Marketers are learning that using hydrocolloids to solve technical problems is quite acceptable to consumers, as long as consumers understand that food gums are also a significant source of soluble dietary fiber. A negative can be repositioned as a positive if consumers are reminded of the dual function of the stabilizer ingredient, says Greg Andon, president of a gum supplier. “Locust bean gum (a stabilizer)” is perceived quite differently than “locust bean gum (soluble dietary fiber)” in an ice ingredient declaration.
Hydrocolloids are used in food products to thicken, gel and/or stabilize. Desirable properties permit formulators to improve formulation cost (hydrophilic/water binders allow higher yield), “processability” (improving textures to permit high speeds, consistent packaging performance), shelflife performance (recrystallization control, syneresis control, emulsion/foam stabilization, freeze/thaw performance) and reconstitution performance (reheating, microwaving).
The chart “Sources of Edible Hydrocolloids” shows these ingredients by source. Of those listed, only the chemically modified group is incompatible with a clean label formulation strategy. Some chemically modified gums may be acceptable for use in some companies because they are labeled with more consumer-friendly names, such as cellulose gum and pectin.
Gum FunctionalityNon-starch hydrocolloids can be first thought of as either non-gelling or gelling ingredients. When clean label formulation requires a new approach to thickening and texture delivery, this is the first question used to narrow the bewildering array of gum options. However, this simple distinction quickly begins to blur, depending on usage conditions. The selection of a hydrocolloid to modify texture requires consideration of the final gel character and the properties of the food product (pH, ionic strength, acidity, temperature and a variety of processing conditions).
When thickening is required, the non-gelling gums are usually the first place to start. Guar and locust bean gums are options, providing relatively high viscosity at low use levels. The viscosity contribution is quite stable, recovering fully after application of shear. Viscosity is significantly reduced by increasing temperature and recovers during cooling.
Xanthan gum is another option offering very high viscosity and pseudoplasticity; that is, the viscosity of xanthan solutions decreases as the applied shear rate increases. Xanthan is very pH-, enzyme- and temperature-stable. It has a bland flavor and forms clear solutions. It is compatible with high concentrations of either sugar or salt. Like guar or locust bean gum, it provides a “longer” texture than many starches, which may impact consumer texture preferences or processing efficiency, limiting its use level in a food.
Jim Carr, principal for a custom ingredient blending company, explains that blends of high-viscosity gums often are used to tailor textures and maximize benefits while minimizing cost and texture negatives. Blends are sometimes formulated to use the maximum economical amount of a particular gum that does not impart a textural negative. As with other ingredients, blends may permit higher viscosity contributions than could be achieved with any single gum. In addition, there are well-known synergies between various gums.
Other Viscosity ApproachesIf the viscosity requirements are not met by standard approaches, greater innovation may be required. Barb Chinn, applications manager for a gum manufacturer, suggests that some gelling hydrocolloids can be used in alternate ways to provide viscosity with little or no gel character. One of the most difficult textures to deliver is short-textured, full-bodied viscosity. Physically modified pectin has been designed to meet this need. Where gums contribute their high viscosity efficiency via their long molecular chains, this same factor can contribute to long textures at high use levels. The shorter texture from starch derives partly from its macro particulate nature provided via the intact starch granule. This pectin material is processed to simulate granule functionality, providing desirable short textures.
Traditional gelling gums can provide viscosity by processing the finished product so that the gel structure is not allowed to form or is broken in a controlled manner. Suitable gums for this approach would include those that do not form brittle gels. See chart “Textures of Gelling Agents.” For example, fruit preparations made in the U.S. frequently are thickened with modified starch, explains Wanda Jurlina, technical applications manager for a gum manufacturer. In other countries, pectin or gellan gum is used to provide similar viscous textures, with improved flavor release and a clean label. The process is essentially modified to shear the material during cooling through the set point of the gel. An apparently viscous material is the result, rather than a “cuttable” gel.
The concept of a fluid gel is useful here. Sometimes viscosity is not actually required, but is a means of suspending particles or conveying mouthfeel. A gel may be the best means to accomplish this task. A familiar example is chocolate milk. The cocoa particles are suspended in the milk, not by viscosity, but by a fluid gel network formed by the interaction of milk protein, carrageenan and cocoa particles. Another example is a beverage sold several years ago called Orbitz. It was a low-viscosity, clear beverage with suspended colored gelled spheres. If viscosity had been used to suspend the spheres, the liquid would have been too thick to be considered a beverage, according to Jurlina. However, using a fluid gel approach based on gellan gum, the spheres are effectively suspended in a low-viscosity, refreshing beverage with a clean mouthfeel.
Gelling ApproachesThe list of gelling hydrocolloids is longer, each with its own specific considerations for gel type, conditions of gelling, stability and other functional properties. Identifying applications analogous to a product can help narrow the list of gums to consider. The technical support staff of suppliers can provide specific guidelines to achieve the full functionality of the gum in a system. When using gums, it is very helpful to provide the most complete information possible about the formula, process and performance expectations. Small changes can mean the difference for excellent gum performance in a system.
Syneresis control and freeze/thaw tolerance are important functions delivered by food gums. All of these gums interact strongly with water; however, the preferred gums are likely to result from the group of non-gelling gums or gelling gums that form soft, flexible gels. Film formation is useful as a structural agent in some foods, like tortillas. Emulsion and foam stabilization are also major functions provided by hydrocolloids in foods.
Since gums provide significant performance at low use levels, it is critical to provide that functionality consistently over time. As a relatively expensive ingredient on a per-pound basis, gums often are targeted in cost saving efforts. This is one category of ingredients where changing sources may drive significant production problems.
Specifications often are written for these ingredients describing viscosity at a low use level, such as a 1% solution. However, the actual use in a product may be at a very different concentration or in a water-limited system. Two products with the same viscosity at 1% may perform quite differently in a system. Also, some gums are provided preblended by the supplier. Since a number of gums have synergistic reactions with other gums, gum suppliers often are best equipped to identify the most cost-effective combination for a system. However, it is important to agree to specifications that describe the performance of the gum or blend into the food product and process. A change of source of one of the gums may yield the same performance in a standardized test, but yield a significant difference in the food system.
Gums and High-quality, Clean Label FoodsAs scientists learn more about the effects of food ingredients on health, gums lose their negative association with cheap ice cream and gain stature as beneficial, clean-label ingredients. As chefs learn the power technical food ingredients can bring to their arsenal of culinary tools, we may see more of this crossover between the culinary and food science worlds.
Leslie Skarra is president of Merlin Development, which provides high-quality, cost-effective research and development services. Merlin specializes in all technical aspects of food product development from concept through commercialization, including prototype development, formulation, scale-up, quality system design and production start-up. Skarra can be contacted at 763-475-0224 or Lskarra@merlindev.com www.merlin development.com.
Sidebar: Suspended in OrbitzClearly Canadian's Orbitz beverage made a splash several years ago with colored gelled spheres “suspended” in a beverage. If viscosity had been used to suspend the globes, the product would have been very thick and not likely considered a beverage. Instead, a fluid gel approach, based on gellan gum, was used.
Sidebar: What Makes a “Clean Label”?1. A preference for constituents that are natural, organic or wholesome.
2. Constituents that have names with which the consumer will be familiar either with their names (not chemical sounding) or their reason for being in a formulation (e.g., not “stabilizer” or “emulsifier”).
3. Constituents that are perceived as contributing to a healthy lifestyle.
4. A preference for constituents that are considered ingredients rather than additives; food rather than chemicals.
5. Fewer total ingredients.
6. Lack of constituents that are perceived as contributing to an unhealthy lifestyle (fat).
7. Constituents for which there are no known or perceived health risks.
Source: National Starch Food Innovation