Formulating Cheese Sauces

April 2003

Formulating Cheese Sauces

By Kimberlee J. BurringtonContributing Editor

Vegetables taste better with it, macaroni and cheese isn’t complete without it, and Swiss fondue would not exist without cheese sauce. Even tortilla chips at the movie theater wouldn’t be the same without that spicy nacho cheese poured on top.Whether served in an upscale restaurant or on a frozen entrée, cheese sauces are more than just melted cheese. A cheese sauce can serve as a flavor enhancer or a dipping sauce, act as the main attraction in a pasta dish, or help intensify or round out an entrée’s flavor profile.

But no matter what their use, it takes some technical tricks to formulate cheese into a sauce while maintaining a smooth texture, cheesy flavor, and even freeze/thaw stability. One look at the ingredient legend for a typical nacho-cheese sauce should give you a clue about all of the ingredient technologies needed: water, cheese (Cheddar [milk, cheese culture, salt, enzymes], enzyme-modified cheese [milk, water, milkfat, sodium phosphate, cheese culture, salt, enzymes, vitamin A palmitate]), soybean oil, whey, dried corn syrup, sodium phosphate, jalapeño peppers, salt, lactic acid, sodium alginate, vinegar, sorbic acid as a preservative, artificial color and natural flavor.

“The most important factor when formulating a cheese sauce is knowing the food application it will be used in,” says Mike Gordy, president, Food Ingredients Division, Sargento Foods Inc., Plymouth, WI. So, once you understand the requirements of your application, what it takes is some of your favorite cheese, a little knowledge of cheese chemistry and a few other key ingredients, and you are ready to begin formulating.

Understanding cheese chemistryTraditional alfredo sauce made fresh in an upscale restaurant will contain heavy cream, grated Parmesan cheese, butter, salt and pepper. Typically, the chef might heat the cream, butter and salt to a boil and, after removing this from the heat, add the pepper and cheese. Adding the cheese last preserves its full, nutty flavor, allows the cheese to melt without excessive heat and lets it develop into a smooth sauce.

When saving the aforementioned alfredo sauce and reheating it the next day, it likely will not gain back the same smooth texture it originally achieved. The cheese structure will become curdy or lumpy upon reheating, and some syneresis of moisture will occur, leaving a very undesirable lump of alfredo sauce to add to the pasta. Regardless of the chosen cheese variety, the same lack of stability will happen. The ingredient legend for a typical prepared alfredo sauce found on the grocery shelf shows what it takes to formulate a shelf-stable sauce; the first requirement is to understand some basic cheese chemistry and emulsification properties.

Cheese consists of an oil phase (containing fats and oil-soluble components) and a water phase (containing a solution of water-soluble proteins and minerals). These two phases are not compatible without some help. The surface-active proteins in cheese are soluble in the oil and in the water phases, and collect at the interfaces between the two phases, creating an emulsion. Phase separation is prevented if the emulsion has large droplets of one phase floating within the other phase. Emulsification improves as the droplets get smaller, increase in surface area and eventually reach a state of total homogenization.

Emulsification is closely related to cheese texture. Modifying the emulsion helps achieve the desired textural properties in a cheese sauce. Variables — such as cheese type, age and pH, amount of calcium, and the temperatures experienced during processing — all affect emulsification properties.

Just as in formulating a process cheese, an important factor in formulating a cheese sauce is determining the relative casein content (RCC) or intact casein content of the cheese. The RCC is the ratio of the amount of casein nitrogen divided by the total nitrogen in the cheese.

“The more intact protein in a cheese, the better emulsification it provides for a cheese sauce,” says Kristi Jankowski, group director of research & development, Sargento Food Ingredients. Swiss cheese provides better emulsification than Cheddar because it has a higher intact protein or RCC.

“The age of the cheese, cheese type and chemical composition of the cheese will affect the flavor and taste, as well as sauce functional attributes, such as viscosity, texture and mouthfeel,” says Khalid Shammet, Ph.D., category director, sauces, Sargento Food Ingredients. Ages of cheese, such as Cheddar, are classified by days of aging or ripening; a mild Cheddar ages less than 60 days, a medium Cheddar from 60 to 120 days and an aged Cheddar 150 to 210 days.

As cheese ages, fats and proteins break down into shorter units due to bacterial and/or fungal action. These units have an increased solubility over those in a young cheese, increasing the strength of their flavor. An insoluble compound will have no flavor because it has no ability to react with taste receptors in the mouth. Aging cheese also decreases its RCC, reducing its emulsifying ability. Protein associations at a given level of emulsification determine the texture of cheese sauce. Short proteins have less opportunity than long proteins to interact with each other. Using an aged cheese will result in a shorter, more curdy texture. Proteins become more water-soluble as protein-protein interactions weaken, temporarily enhancing emulsification. As proteins continue to break down, the decrease in protein-protein interactions leads to a general loss of structure and poor emulsification. To solve this problem, developers could add young cheese or casein.

The pH of a cheese also affects protein configuration. Individual proteins change their configuration into spheres at specific pH values, corresponding to their isoelectric points, which further reduces their interactions with other phases. Heating can also damage proteins and decrease their emulsifying ability. Cheesemakers can’t be expected to control all of these variables. Heating occurs during pasteurization and cooking, while aging is necessary to develop cheese flavor. Formulators can control variables — such as pH and calcium levels — by selecting the appropriate cheese, combined with other ingredients, including emulsifying salts, starches, hydrocolloids, vegetable oils and water, to achieve the desired texture of a cheese sauce.

The processing profileA walk through cheese-sauce manufacture will give some understanding of the heating and mixing conditions that these ingredients will have to endure. Cheese sauces are divided into categories according to the heat process used in their manufacture. Hot-fill and refrigerated products will undergo pasteurization (155º to 180ºF for 30 seconds to a few minutes), while aseptic (250º to 280ºF for 4 to 20 seconds) and retort (250º to 260ºF for 15 to 30 minutes) products will receive a higher-heat treatment.

Food scientists can formulate asceptic or retorted sauces with higher moisture and less cheese because the sauces are subjected to a higher-heat treatment and, thus, do not have the shelf-stable safety issues of a hot-fill product. “Generally, a hot-fill product will have a higher cheese content, giving it a better mouthfeel, flavor profile and cling than other products,” says Gordy.

One other processing step that often differentiates types of sauces is homogenization. “Homogenization of refrigerated or room-temperature products creates smaller fat globules, resulting in a richer flavor, and stability against fat separation and change in product viscosity,” says Shammet.

These specially designed process steps ensure product quality but also have some importance in product safety. The formulation of a cheese sauce can be designed to ensure product safety, as well. N. Tanaka et al. has extensively researched the product safety of shelf-stable and refrigerated process-cheese sauces. “The Tanaka guidelines for shelf-stable process-cheese products, published in 1986 in the Journal of Food Protection, 49, 526-531, were developed to establish a moisture content, salt content and pH level to protect against the growth of Clostridium botulinum,” says Jankowski. A high-moisture sauce (60% moisture) requires a high salt content and a low pH to ensure adequate product safety, according to Tanaka.

These guidelines would not apply to all products. “Higher moisture levels in frozen sauces can be tolerated because you don’t have the same safety issues associated with a shelf-stable product,” says Jankowski. After establishing the processing requirements and end use of the sauce, ingredient selection can begin.

Changing the chemistryEmulsifying salts control cheese properties through their ability to bind calcium. Phosphoric- and citric-acid salts, including sodium citrate, sodium aluminum phosphate (SALP), monosodium phosphate (MSP), disodium phosphate (DSP) and trisodium phosphate (TSP) — are used in cheese-sauce applications. “Phosphates and citrates, or combinations of both, are typically used in cheese sauces,” says Jankowski. “One side benefit of phosphates is their bacteriostatic effect on sauces, which does not support the growth of Clostridium botulinum.”

Phosphates vary in chain length, and this directly affects the firmness of the cheese structure. Generally, the longer the chain, the more strongly the phosphate binds calcium. Choosing the right emulsifying salt or blend of emulsifying salts takes into account the amount of calcium needed to be replaced by sodium, the changes in pH that may occur and the amount of “creaming” that will take place.

Creaming results from the splitting of the large hydrophobic casein aggregates into smaller units during the cooking and stirring process. Surface area and water-binding ability of the casein increases during creaming. Typically, a cheese sauce requires a low amount of creaming because of the lack of a firm texture. “A blend of different phosphates can provide a low- to medium-creamed structure for the desired cheese-sauce functionality,” says Stephan Lihl, Ph.D., business unit manager food, Chemische Fabrik Budenheim, Budenheim, Germany, the parent of Budenheim/Gallard-Schlesinger Industries, Inc., Plainview, NY.

Emulsifying salts will only influence available protein, independent of whether the source is natural cheese or added casein. Therefore, dosage level must be adjusted to the protein content. The lower the protein content, the lower the dosage level. Phosphates do have an influence on the pH of a cheese sauce, thus there is a minimum dosage required, depending on the formulation. “Our phosphate blends are added directly to the other ingredients at the initial melting stage of the process at usage levels between 1.8% to 2.4% of the finished product,” says Lihl. Flavor problems due to emulsifying salts only arise when the pH is too alkaline or too acidic. Optimum flavor is achieved at target range of pH 5.7 to 6.0.

“To achieve the desired functionality of a cheese sauce — high viscosity in the hot stage, lower viscosity in the cold stage — it is necessary to develop the right formulation, in addition to the selection of emulsifying salts,” continues Lihl. “The addition of caseins and caseinates are useful to maintain structure. Premelting in lower dosages, along with a specified mechanical treatment and a short cooling period is also very important for maintaining structure.”

Keeping it stableJust as important as selecting the right emulsifying system is selecting the right stabilizer to fit the sauce application. Cheese sauces require additional ingredients to bind extra water added to the formula. Starches and hydrocolloids (especially alginates, xanthan gum, carrageenan and guar gum) bind water, control viscosity and contribute to the finished texture of a sauce. Proteins, such as whey proteins, provide similar functionalities and can prove very cost-effective. Whey proteins add body and develop a smooth, creamy texture, but do not melt, stretch or spread like caseins do. Starches and hydrocolloids are essential in a sauce requiring freeze/thaw stability. Hydrocolloids and starches have unique functional benefits.

Starches contain high-molecular-weight branched-chain amylopectin and straight-chain amylose. Amylopectin and amylose function differently when heated, so the relative quantities of each will dictate the functionality of the starch in a sauce. Typically, a developer will choose a waxy-type starch for a sauce because of its high amylopectin content. Amylopectin aligns itself in a less-rigid structure than amylose, retaining more moisture and creating a smooth texture.

Waxy starches are available from most grain sources, but some may provide more benefits than others. Native rice starches, when used at 2% to 4%, provide a fat-like mouthfeel, clean flavor release, less-structured viscosity, good freeze/thaw stability and reduced syneresis in a cheese sauce. “One advantage of using rice starches in applications that require smooth textures, like a cheese sauce, is their small particle-size range of 2 to 8 microns,” says Gil Bakal, managing director, A&B Ingredients, Fairfield, NJ. Rice starch allows a sauce to retain a smooth texture in a product such as macaroni and cheese or pasta, even as the pasta absorbs some water after reheating.

The composition of the starch is an important factor for determining the stability necessary for a frozen application. Typically, higher-amylopectin starches provide the best freeze/thaw stability because amylopectin does not leach out like amylose. This leaching causes retrogradation of the amylose and the development of a rigid structure, squeezing out the water.

“A standard waxy rice starch contains highly branched-chain amylopectin structures, which give great mouthfeel, even under high-shear and high-temperature conditions,” Bakal comments. “A waxy native rice starch provides enhanced stability for a cheese sauce used in a frozen product. A waxy rice starch also provides a silky sheen and better flavor release than modified starches.”

Rice starch has no functional limitations in a sauce; in fact, it can have positive synergistic effects with other ingredients. “Rice starches exhibit good synergy with carrageenan and xanthan gum by extending the starch functionality and enhancing the stability of the cheese sauce,” says Bakal. He adds that a clean label is another advantage of using a rice starch, noting his company’s native rice starches, which are all-natural, GMO-free and hypoallergenic, as an example. One factor to consider when choosing to formulate with a starch is whether manufacturing requires additional equipment in process to prehydrate the starch prior to incorporation into the sauce.

Hydrocolloid helpA number of factors are important for the evaluation of hydrocolloids in a cheese sauce, such as heating conditions, pH, dispersibility and even price. For example, xanthan gum provides more acid-tolerance than carrageenan. Most gums are available in agglomerated forms for improved dispersability, at an added cost. Guar gum is often chosen for its low cost.

Most developers may associate alginates with ice cream because it was the gums’ first food application; however, sodium alginate has some of the most unique properties available for cheese-sauce applications. Alginates are the salts of alginic acid, which derives from brown kelp. Two basic components — mannuronic acid and guluronic acid — make up alginic acid. The properties of alginate salts are affected by and by their block structure and chain length. An alginate can be classified as “high-M” or “high-G,” based on its relative M:G ratio.

Calcium ions can crosslink alginate molecules. A solution may thicken or gel, depending on the ratio of calcium ions to alginate in the system. When forming a calcium-alginate gel, a high-G alginate will produce firm, brittle gels, while a high-M alginate will produce softer, more elastic gels. By selecting an appropriate calcium salt for a specific application, or by using calcium sequestrants, developers can control the extent of calcium interaction that occurs. “In order to allow hydration of the alginate in most dairy applications, phosphates are typically used to help sequester any calcium,” says Jennifer Heyer, applications specialist, ISP Food Ingredients, San Diego. “Since most process-cheese products already contain phosphates as emulsifying salts, there is a natural fit for alginates in existing process-cheese-sauce processes and formulations.” Because alginate selection and control of calcium interaction easily modifies viscosity and texture, alginates offer extreme versatility and find use in a wide range of applications.

Levels and types of phosphates used as emulsifying salts will also affect alginate use level. Because phosphates help control the release of calcium ions in dairy systems, they limit the amount of calcium that is available to interact with alginate molecules. Calcium ions that are not sequestered will interact with the alginate, and may contribute additional viscosity. “Some of our current alginate products contain phosphates, which act as calcium sequestrants, and were formulated to allow gum hydration in the presence of calcium ions,” says Heyer.

Because sodium alginates come in a broad range of viscosities, typical usage levels can range from 0.3% to 1.0% in a cheese sauce. “Our alginate products can be added to the cheese upfront with other dry ingredients, prior to the addition of water,” adds Heyer. “This will sufficiently disperse the gum, which will allow for complete hydration once the water is introduced.” There is no need to prehydrate the gum.

One of the primary economic benefits of using alginates in a process-cheese sauce is that it enables the manufacturer to reduce the natural-cheese level and increase the moisture level in the product without compromising texture, body or mouthfeel. Alginates can usually replace a significant portion of starch, in addition to other hydrocolloids in the formulation. “One important functional benefit that alginates provide in process-cheese sauce is improved shelf-life stability,” says Heyer. “Alginates will help stabilize the emulsion in a cheese sauce, reducing breakdown and fat loss.”

Another excellent potential application for alginates is an acidified cheese sauce, as alginates are stable at a relatively low pH. “This application could provide an economic benefit for the manufacturer as well, as an acidified product would not require retort temperatures,” says Heyer.

Adding alginates to retorted cheese sauces offers great potential too. Some of the phosphates currently used in process-cheese sauces can control the release of calcium in such a way that the calcium is sequestered while the product is hot and released as the product cools. “As the cheese sauce cools and the phosphate releases calcium ions, they are free to cross-link alginate molecules, which will build structure in the jar,” says Heyer. This would allow the manufacturer to maintain a low in-process viscosity, yet still get the desired body in the finished cheese sauce.

Dry cheese-sauce mixes can also benefit from alginates. They provide body, sheen and a fat-like flow in cheese sauces that contain little or no natural cheese. In addition, alginates are relatively easy to use; they are both hot- and cold-water soluble, and some products come in fine mesh particle sizes that will hydrate quickly, all beneficial attributes when formulating a cheese sauce dry mix.

“We are preparing to introduce a brand-new line of Macrocystis-based alginate blends specifically for process-cheese applications,” says Heyer. “These blends were formulated with the right balance of carefully selected alginate and phosphate ingredients to give enhanced functionality in a range of process-cheese applications.”

Cheesy flavorOnce formulators address stability and functionality in the formulation, cheese flavor requires consideration. It’s natural to expect that cheese sauces get most of their flavor from their namesake ingredient, but these sauce formulations may contain anywhere from 50% cheese to virtually no cheese at all.

Cheese flavor development during aging or ripening is very complex. “The type of starter culture and enzymes used in the manufacturing of natural cheese impact the aging process and, thus, flavor development, due to the degradation of proteins during proteolysis and changing fat during lipolysis,” says Jankowski.

Aged cheese is often used to provide the desired flavor, but flavor impact and cost are important factors for designer’s to consider. For this reason, formulators use enzyme-modified cheeses (EMCs) made from the cheese type the EMC is trying to replace. “Depending on the desired flavor profile, common cheese types used in sauces are Cheddar, Swiss, Italian cheeses, bleu cheese and smoked Cheddar,” she says. “However, all these flavors can be enhanced by EMC products.”

EMC development is very similar to the technology behind accelerated cheese ripening. Incubation impacts the cost and flavor development of an EMC. An aged Cheddar may provide a smoother, more-natural cheese flavor than an EMC, but the economics of the sauce may dictate more use of EMC than cheese.

Cheese-sauce flavor may prove the last variable designers play with, but it is a very important one. Besides EMCs, a myriad of other flavor options exist. Added flavors, seasonings and particulates all are available, from garlic to basil to sun-dried tomatoes.

If, at the end of the day, balancing the chemistry, stability and flavor becomes too much, there is an easier way for manufacturers to make a cheese sauce. “If formulating cheese sauces is not your expertise, concentrated cheese sauces are available that only require the addition of water, heating and mixing to the desired consistency,” says Gordy.

Sounds like a good alternative.

Kimberlee J. Burrington is the whey applications program coordinator for the Wisconsin Center for Dairy Research in Madison, WI. She received her B.S. and M.S. degrees in food chemistry from the University of Wisconsin-Madison. Her industry background is in bakery and dairy.

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