October 1, 1998

19 Min Read
Secrets to Sauce Success

Secrets to Sauce Success
October 1998 -- Applications

By: Kimberly J. Decker
Contributing Editor

  Remember those gravies Grandma used to whip up using nothing but flour, a little milk, and some meat drippings? They seem a far cry from all the processed sauces and gravies on the market today, and for good reason. The wide variety of ingredients and processing conditions available to product developers has turned sauce- and gravy-making into a much more complicated and technological endeavor than anything Grandma could have imagined.

Sauces and gravies 101

  In terms of processing, handling, and ultimate serving conditions, hundreds of sauce permutations exist, from retorted cream sauces and dry meat-gravy mixes to institutional frozen cheese sauces and fresh-herb pasta toppers sold in grocer dairy cases. But whatever sauce product developers choose to make, they had better know how they expect it to perform. Only then can they set themselves on the path to building a successful formulation.

  Among the most common pitfalls formulators encounter is an inadequate understanding of the product's performance requirements, according to Christine Carr, senior director of marketing of soups, sauces and gravies, Griffith Laboratories U.S.A. Inc., Alsip, IL. "That's where you will definitely fail, if you don't understand everything that they're going to do with your sauce," she says.

  Although these different parameters complicate the formulation process, product developers need only build upon a few basic functionalities to create a typical sauce or gravy. First, the formulation needs a thickening agent. On a basic level, flour does the trick, providing opacity and viscosity. Take that a step further and use a starch to fine-tune the viscosity. Liquids, often water, hydrate thickening agents and dry materials, developing the sauce's viscosity, and permitting flavor release. Processors also can choose from dairy ingredients such as cream and milk, or meat and vegetable stocks; the former adds a sweet dairy flavor and rich texture, while the latter lends complex flavor notes and additional solids. Most of a sauce's flavor, however, has traditionally come from either animal or vegetable fats, herbs, spices and vegetables, or meat flavor notes. Besides contributing to the sauce's "savory" character, these components add color and visual appeal, and particularly in the case of fats and meats, mouthfeel. Processors wanting their products to withstand retorts and kettle systems, freezers and freeze-dryers, and hours on a steam table as well as minutes in a microwave, must add to this functional trilogy other ingredients, such as gums and emulsifiers.

Laying the foundation

  The most important part of a processed sauce or gravy is the base, usually composed of hydrated starches at levels typically between 2% and 5%, according to Celeste Sullivan, applications scientist, Grain Processing Corporation, Muscatine, IA.

  The base formula has a strong influence on the sauce's overall sensory character - even its flavor, explains Tom Rieman, business manager of cheese powders, Kraft Food Ingredients, Memphis, TN. Without a well-prepared white-sauce base, subtle flavor nuances get lost. "Basically, you're going to make a white sauce, and the white sauce is just a thickening system," he says. "And you're going to build into that thickening system any special functionality you need, including flavor. But if you're building a decent white sauce, it's going to have just about all the functionality you need."

  Bearing in mind starch's hallowed position in a sauce formulation, product developers must carefully evaluate the choices. "It's very important for you to know how that end product is going to be processed, how it's going to be handled, and the other ingredient interactions which you may have, such as whether there would be fat in the system,"
Sullivan says, "because fat has a tendency to coat starch granules and inhibit granule hydration." And the considerations do not stop there; she stresses the importance of also knowing the sauce's intended applications, desired texture, final pH, shelf life, storage conditions, total solids, and cost constraints.

Staying stable

  To understand why these parameters have such an impact on starch choice, the food formulator first must examine the important thickening role this ingredient plays in a sauce or gravy.

  To develop viscosity, starch molecules must absorb water. Hydration depends on the starch used, its amylose-to-amylopectin ratio, and its gelatinization temperature range. For example, starches from grains such as corn, wheat and rice have a higher amylose-to-amylopectin ratio than root or tuber starches. This ratio allows grain starches to thicken upon cooling, withstand high temperatures and shear, and reheat without much viscosity loss.

  Native starches exhibit these characteristics only up to a point. Raise the temperature too high, lower the pH too much, and pump the solution through three miles of tubing at high speeds, and that viscosity rapidly decreases along with the sauce's stability.

  Starch gelatinization requires heat, as undercooked starches can appear cloudy, taste starchy, lack stability, and possess low viscosity. And some agitation is required to increase speed of heat penetration: "You can lower your processing time, which everyone wants to do," Carr notes. But most heat-processing techniques, such as retorting, HTST or aseptic processing, take sauces to temperatures anywhere from 230° to nearly 300°F. Exposing starches to such high temperatures makes them fragile, and increases their chances of swelling to the point where they rupture and significantly decrease the sauce's viscosity. Combine that heat with shear, and the starch granules fragment and become stringy, with disastrous effects on sauce viscosity. Furthermore, starch molecules are particularly susceptible to acid and enzyme hydrolysis, frustrating designers of low-pH sauces and gravies.

  With obstacles like these, product designers must turn to modified food starches - in particular, cross-linked ones. Cross-linking chemically modifies starches with certain compounds, reinforcing the associations between the starch molecules and rendering the granule more resistant to heat and acid hydrolysis or breakdown via shear.

  Freezing also affects starch viscosity. As the kinetic motion of starch molecules decreases in response to lowered temperatures, the molecules retrograde, reassociating with one another through hydrogen bonding. This squeezes water out of the solution - syneresis - and causes the sauce to set into a nonflowing gel. Furthermore, as ice crystals form, they essentially "stab" the starch granules, allowing even more syneresis to occur. Stabilized starches overcome this problem by using anionic groups - traditionally acetyl groups and, more recently, hydroxypropyl groups - dispersed throughout the granules. These create an ionic repulsion and steric hindrance that prevents the molecules from retrograding. With this modification, the sauces last through several freeze/thaw cycles without weeping.

  While cross-linking and stabilization preserve sauce viscosity and stability in the face of processing and storage conditions, certain salts, macromolecules, and even the foods that the sauces coat, can interfere with starch hydration and sauce viscosity in ways those modifications can't address. Fats can coat starch granules to the exclusion of water. Some proteins - those in flour, for example - have a similar effect. Salts, when ionized in the sauce's liquid medium, raise the starch's cookout temperature, and sugars can inhibit starch hydration to an even greater extent. Pregelatinized starches can combat these problems - as can adding sugars or salts after gelatinization.

  Additionally, designers must understand how much moisture the substrates are going to give off once they're cooked, and what that means to the finished product. This exudation occurs most often with frozen foods. Aside from the sauce's own level of freeze/thaw stability, the frozen product's quality - the integrity of cell walls or the state of muscle fibers, for example - impacts the sauce's viscosity.

  Increased viscosity can spell trouble, too. Just imagine macaroni topped with a cheese sauce: that macaroni can absorb water from the sauce until the latter seems dry and too thick. The water is still in the system, but not in the sauce. Overly viscous sauces can be a trouble spot with consumers and processing equipment alike. For example, tubing or filling systems often require a thinner sauce to facilitate deposition.

  To reconcile some of these problems, heat- and shear-thinning starches allow processors to achieve one level of viscosity in the plant and another on the plate. And while they have gained popularity, Sullivan notes that, for the most part, processors can get the same effect by manipulating "regular" modified starches. "You want them to be thin, but they're going to be thin when they're hot," she says. "And there are acid-thinned starches. You may want to use a small amount of an acid-thinned starch that is designed to give you a thin, hot-paste viscosity and that sets back to a very rigid gel. Now you may use a small amount of something like that in combination with a traditional starch for stabilization to give you a little shorter texture, a little more cling in a barbecue sauce or cheese sauce."

Mixing and matching

  Once a sauce leaves the processing plant and ends up in a consumer's cupboard or foodservice stockroom, it faces a whole new set of challenges. Microwaving sauces can result in non-uniform heating and, therefore, non-uniform granule gelatinization. Cross-linked or pregelatinized starches can help a sauce withstand not only uneven microwave heating, but too much time in the oven as well.

  Convenience has long made dry sauce and gravy mixes one of the most popular forms. In dry mixes that require a cook step, a cross-linked starch can give the mix tolerance to abuse. For instant dry mixes, pregelatinized starches with moderate cross-linking come in handy, developing viscosity almost upon contact with liquid, while still having heat, acid and shear resistance.

  Not all instant starches perform equally. Smaller particle sizes give a smooth texture, but they can hydrate too quickly, leading to lumps. And while coarser starches lump less often, their grainy texture makes them more suited to applications such as tomato sauces. New advances in instant starch technology have given processors the best of both worlds - smooth texture and even dispersion. Traditional drum-drying techniques often produced grainy, fragmented granules that yielded coarse-textured sauces with reduced processing flexibility. Newer techniques leave the granules intact. This is the key to a smooth sauce, according to Sullivan: "If you can have an instant starch that has an intact granule, then you have the stability of a cook-up system and the ease of instant hydration." And, if lumping is still a problem, agglomerated starches undergo a more controlled hydration and have greater resistance to clumping.

  But despite processors' best-laid plans, consumers can still find ways to foil them by not following a package's directions closely - or at all. Carr advises giving a sauce some "freedom," so consumers will get consistent results. "You have to think: 'How are consumers going to use that?' because they're not going to follow directions exactly. So, you have to make sure when you're developing your product that you've done the stress-testing that you need to do." For example, allow a temperature range of maybe 10% or 20% for the gelatinization to take place.

  Processors also must consider foodservice conditions. Steam-table temperatures might promote viscosity loss via starch hydrolysis. Once again, cross-linking can provide the solution. Another problem foodservice sauces face involves skinning or drying out. "We know they're going to hold it in a steam table for four to six hours," Carr says. "For the most part, everything's going to skin. It's just the nature of the product. However, you can formulate it so that if it skins, then you blend it and the skin goes right back into the sauce. And you do that through using starches and gums."

Where starches leave off

  From guar, locust bean and xanthan gums, to the carrageenans and carboxymethylcellulose (CMC), formulators have a wide variety of gums and hydrocolloids from which to choose to supplement and strengthen a sauce or gravy's starch base. But along with that wide range comes equally wide variability, particularly in terms of pH and shear requirements.

  Gums hydrolyze under adverse conditions in much the same manner as starches. "A pH lower than 3.5 combined with heat - about 1808F - will degrade some gums except xanthan gum," explains Florian Ward, Ph.D., vice president, R&D, TIC Gums, Belcamp, MD. Shear's effect on hydrocolloids also varies depending on the gum. Although some gums need high shear to reach hydration, many, such as guar and locust bean gums, exhibit pseudoplasticity: As shear forces on them increase, their viscosity drops. In some cases, this drop is fortunately reversible, but product designers still should know a gum's properties before abusing it.

  Side chains and substitutions along the backbones of CMC and xanthan and guar gums prevent them from associating too closely. As a result, they dissolve readily at low temperatures, which makes them ideal for instant applications. Furthermore, "agglomerated gums hydrate faster than regular powders and may be preferred for use in dry mixes or instant sauces," Ward says. Agglomerated gums tend to incorporate more evenly, reducing lumping.

  In contrast, the low degree of substitution along the backbones of locust bean gum and kappa carrageenan make them soluble solely at high temperatures. Such gums also are more likely to form gels, which might be unwanted in a sauce. Even xanthan/locust bean gum blends can gel after cooling, according to Ward. However, processors can manipulate gum levels, type of hydration, and percent solids, among other factors, to control gel formation.

  All gums - xanthan, locust bean, guar and CMC, for example - improve freeze/thaw stability due to their water-binding properties and ability to retard the formation of large ice crystals. Hence, these work well in frozen sauces and gravies.

  For consumers who prefer not to have a congealed layer of fat at the top of an opened can of gravy, formulations combining starch and gum emulsifiers can win consumers' loyalty. "Some gums, like gum acacia and propylene glycol alginate, are 'true' emulsifiers, due to their hydrophilic-lipophilic character," Ward says. "They can replace the lecithin in eggs as emulsifiers, provided the oil-to-gum ratio is appropriate and that proper homogenization techniques are employed." Combining gums with appropriately modified starches also provides product formulators with a powerful combination for keeping sauce emulsions stable. "There are types of starches that can be utilized for emulsification where you have an octanyl succinate, or an OS, modification, and that just helps to tie up that fat within the system," says Sullivan.

  Indeed, synergies between gums and starches and among gums themselves increase their utility in sauces and gravies. Designers can reduce the level of starch in a recipe by two-thirds simply by using a suitable gum system with heat stability and strong rheology and viscosity characteristics.

Things to come

  Once product developers have made a stable, viscous sauce base, they can begin the business of flavoring it. In doing so, they must once again consider processing's effects on the flavors, as well as consumers' preferences. But fortunately, "the options when it comes to flavors are really endless right now," Carr says.

  For products that must withstand a lot of heat, reaction or process flavors provide a stable flavoring option. Product formulators can use thermohydrolysis reactions, including the Maillard reaction, to produce critical flavor notes. And while food processors typically want to avoid oxidation, limited lipid oxidation contributes to the flavor in cooked meats. "A little bit adds that roundness to the flavor profile," says Michelle Mani, food technologist, McCormick & Company, Hunt Valley, MD. "For most reaction flavors, there are a blend of products. There are usually proteins and amino acids. There is either fat or a variety of fatty acids. You're using some carbohydrates and certain sugars. You could be adding salt and herbs or spices, depending on what you're looking for."

  Formulators can work these precursors into a sauce, subject it to retorting, and let the heat activate the flavor-producing reactions. But Mani says better results might be achieved by going at the process from a different angle: "Typically, they react the flavors beforehand and then put them in, because that way you can be sure you're going to get more consistency over time."

  Consistency is an important issue with reaction flavors. While they might help reconcile the bad relationship between heat and flavors, they can open up a host of other problems. For example, food designers must consider the effects of taking flavor-producing reactions too far or not far enough, as consumers may do in their homes. But Mani says that processors have little to fear. "Typically, what the consumer's going to be doing in preparing the product isn't going to have a lot of effect on changing it. They're not using high enough temperatures for a long enough time."

  In addition to reaction flavors, monosodium glutamate, yeast and vegetable extracts, and 5( nucleotides can provide essential savory notes to a sauce. If product designers want a "cleaner" label, ingredients exist that produce similarly powerful flavors without containing monosodium glutamate or compounds like it. "We do have what we call 'clean' or 'super-clean' products that don't contain those ingredients," Mani says. "It's just using other technology in order to produce an enhanced savory flavor." They contain some of the same components common to reaction flavors - peptides, fatty acids, carbohydrates - but the difference lies in how they react with one another in the combinations in which they appear.

  Fresh herbs and spices - more widely embraced flavoring alternatives - can give a sauce an appearance that often translates into upscale status with consumers. But the bright colors that make fresh herbs so attractive do not always withstand processing. "In the case of herbs, they are a lot more delicate than spices are, so you would tend to get color changes," Mani says. "So while they can be put in a sauce and hold up somewhat, they won't have the impact that people would expect if they were mixing a sauce up fresh."

  The popularity of cheese-flavored and cheese sauces continues growing with consumers, and Rieman has some simple advice for formulators looking to cash in on that popularity. "My message is that cheese sauces are simple," he says. "The thickening system can be any one you like that delivers the texture you want, and any special kind of functionality you want, and you just add cheese to flavor it. And you have a million options of how you're going to flavor it. You can use cheese powders. You can use just natural block cheese. You can use EMCs (enzyme-modified cheeses). You can use natural and artificial flavors. So you can do just about anything in the world you want." EMCs represent an exciting flavoring option for sauces. Their production involves adding to a "young" cheese a combination of enzymes that, Rieman says, "try to duplicate in a few hours what nature takes six months to do" - that is, they accelerate cheese aging, breaking down the fat and protein in the cheese curd to release smaller peptides and volatiles that give the "finished" cheese its flavor.

  While this process produces some very flavorful cheeses, the enzymes used can work somewhat indiscriminately, breaking proteins and fats down to the point where bitter peptides, soapy notes, and off-flavors evolve. For this reason, EMCs are better-suited to bolstering a cheese's flavor in a sauce application, rather than replacing it altogether. High-impact cheese concentrates are another option. These are not EMCs, but rather are very flavorful cheeses. "They would make terrible eating cheeses," says Rieman. "But by using them as ingredients in a process cheese, or in a cheese sauce, or in a cheese powder, they really deliver a lot of flavor. This is real cheese, but it's just that we've developed more flavor in it than you would in a natural, traditional process."

  Given that sauces can run the gamut from high-fat cheese-based and cream-based sauces to nonfat gravies, processors must choose between using an oil- or water-soluble flavor. Using an oil-based flavor in a nonfat sauce, for example, won't yield the same flavor delivery as using a water-soluble one. But product designers have a bit more leeway when using water-soluble flavors in cream-based or fatty sauces. A cream sauce may be able to use either a water- or oil-soluble flavor depending on the ratios of fat to water.

  Even in retort situations, where the can traps any volatilized flavors, high temperatures can change flavors. With nonreaction flavors, Mani stresses that "You've got to make sure that either they don't continue to react or, if they do, that it's in a positive way." When retorting cheese sauces, Rieman notes that the heat can simply destroy important flavor compounds. "You're going to get some changes, and retorting tends to be one of the more difficult applications," he says. "And then you also have to be careful about browning. I would not recommend a cheese powder that has a lot of lactose in it for that application."

  To develop the more heat-stable flavors that work best in steam-table situations, flavorists simply include in the formulation higher amounts of those flavor notes that volatilize more easily. "More often, these flavors will just be blown off," Mani says. "They'll just volatilize while they're being cooked. So you want to make sure that you have enough in there so that if some of them blow off, there's still enough left to give you the flavor characteristics."

  Processors can encapsulate flavors in fats or starches to reduce volatility and increase storage stability. While refrigeration helps to slow flavor loss and deterioration, refrigerated sauces do not have as long a shelf life as retorted ones, so the flavor's stability cannot outlast that of the sauce itself. And in the case of oil-soluble flavors, preservatives can help extend a flavor's impact. The preservative acts not so much on the flavor as on the fat itself - halting oxidative rancidity. But it has the same end effect: It protects the diluent and, as such, the flavor contained within it.

  A sauce's starch and gum base can actually interfere with, or change, the sauce's flavor. Certain starches sequester flavors and render them ineffective. "Starch can be a problem because it is hard to mask the starchy flavor," Mani says. Properly cooking the starch helps with that problem. Ward also notes that some gums can mask tastes or flavors while others can enhance them, depending on the flavor components' threshold values. As a solution, Mani suggests using the best combinations of starches and gums at the lowest usage levels.

  Indeed, the technology and variability in starches, gums and flavors give product developers ample opportunities to create processed sauces and gravies that were unheard of on such a large scale not long ago. Furthermore, the high demand for a wide variety of sauces - ethnic and otherwise - has opened up the doors for food product designers to experiment with new flavor and texture combinations. Sure, the sauces might not be like what Grandma made, but they could prove even better.

  Kimberly Decker, a California-based technical writer, has a bachelor's degree in consumer food science with a minor in English from the University of California-Davis. She lives in the San Francisco Bay Area, and enjoys cooking and eating food in addition to writing about it.

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