Starches are used widely in all sorts of products, ranging from cheese sauces to cream or acidic sauces. Using a starch in conjunction with other hydrocolloids such as xanthan or guar gums can create stability and different textural aspects in sauces or reduce the caloric content when substituted for oils.
Gil Bakal, managing director of a rice-based food starch company, advises that when formulating sauces for mass distribution, application scientists should ask: How is it processed? To what conditions, including pH, will it be exposed? And, what are the shelflife or storage conditions of the sauce?
“It might be easy to get a sauce to look good initially but, over the course of time, the shelflife of the product starts to deteriorate,” says Bakal.
For one, starch-based sauces are subject to retrogradation, a crystallization process that is more or less severe, depending on the amount of amylose. In products that gel, syneresis occurs, and “formulators end up with a more-rigid product [in which water is expelled],” states Bakal.
The more highly branched a starch molecule (which is typical of amylopectin starch molecules), the more suitable it is for a processed sauce, because it does not retrograde easily. Typically, waxy starches are the least prone to retrogradation: they have very little amylose. They will stay stable over a longer period of time, and they also are more freeze/thaw stable.
Rice starch are highly branched starches. “Rice starches can be used in combination with other starches to help reduce their retrogradation,” suggests Bakal.
A lot of sauces use chemically modified starches because they are more freeze/thaw stable. Hydroxypropylation is a common chemical modification that adds branches to the starch to improve the food's freeze/thaw stability.
“A product's pH typically aggravates the whole thing,” says Bakal. “It is another stress on the starch, which causes it to be more prone to syneresis and, subsequently, retrogradation.” Tomato sauce is an example of a low-pH sauce that uses starches, which usually either are modified or are unique native starches that have a natural ability to withstand a low pH.
During processing, good control over the cooking process ensures the maximum stability of the finished product. Any deviations from batch to batch results in variations in the sauce's stability. Microwaving a food can add a lot of heat exposure without very good uniformity, says Bakal.
“Oxidental” Color
In frozen sauces, a high fat content or a good stabilizer system decreases the potential of a broken or grainy sauce after the freeze/thaw cycle. Color is a distinctive clue that a sauce was not formulated correctly, says Alberto Bruzzone, export area manager at Sacla Italia (Asti, Italy), a manufacturer of vegetable-based products. When pesto is overcooked, it results in a dark brown color.The color of a sauce will react to exposure to light. Extracted resin, such as oleoresins, and natural or--especially--artificial colors can help make sure color choices remain stable over time. Paprika oleoresin, a natural spice that produces a specific red color, can degrade upon exposure to the fluorescent lights used in retail stores.
Color degradation and flavor loss usually are not starch-related, but more about the balance of acidulants and antioxidants. In many cases, color is an oxidation issue. Kelators like citric acid and ascorbic acid primarily are used to protect a sauce from color deterioration. Prego's (Campbell Soup, Camden, N.J.) Three Cheese Marinara Pasta Bake uses citric acid and shrink sleeve labeling to maintain the color.
Oxidation is related directly to the fat content. Oxygen will attack higher polyunsaturated fat to create the peroxides of rancidity. So, the composition or the type of fat used is critical to both color and texture. For most heat-treated items, a highly stable oil is ideal.
Excluding air or oxygen in the product is one of the most important processing techniques used to increase shelflife and stability. This can be accomplished by minimizing shear or by using deaeration equipment. That involves passing the emulsion (which has to be a thin, pourable film) through a vacuum vessel. With thicker dressings, nitrogen gas is pumped into the mixing process to retard the oxidation of the oil present. And, of course, antioxidants help. For example, some naturally occurring rosemary extracts help provide protection against oil rancidity and oxidation.
In the Thick of It
One industry expert suggests that a pleasing mouthfeel is the most important attribute for a pourable sauce. It cannot be too slick and slimy; it must have some body to it.Some sauces are designed to be thick so they do not leak out of the package; they are heated and then thinned at a later time when the product is consumed. Such a sauce has elastic rheological properties and almost always will require a high-fat or gum stabilizer system.
Winterized oil produces liquid oil lower in saturated fat and less likely to oxidize: these oils may be labeled as partially hydrogenated. Unfortunately, the hydrogenation process produces trans isomers, which the industry is trying to reduce or eliminate.
The fatty acids in natural sunflower seed and canola oils have fewer double bonds (i.e., are more saturated) compared to soybean oil and, thus, are less likely to oxidize. However, there are times when saturated fats are necessary to achieve a firmer texture.
Sacla Italia primarily uses sunflower seed oil for its spoon-and-serve pasta sauces, because it is a mild oil that helps to enhance ingredient flavors. Sacla also adds extra virgin olive oil to its pesto. “The sunflower seed oil is best suited for an industrial operation, because it withstands temperature changes,” says Bruzzone. The extra virgin olive oil is good for that purpose but, on an industrial scale, it is quite expensive and increases costs dramatically.
Take a Dip
One of the first steps to developing a sauce is to determine how the sauce will be used. A marinade can be a thin sauce designed to be absorbed over several hours by a piece of meat or a vegetable. It also can be a slightly thicker sauce designed to be coated on the product and then cooked to provide an outside coating.A dipping sauce (like a ranch dip) has to be thick enough to coat the product and requires a water-in-oil emulsion, a starch or an emulsifier stabilizer.
If the product to be dipped already has a high fat content, like a chicken nugget, it is not necessary to have the fat in the dipping sauce to get the proper mouthfeel; a starch-based dipping sauce will do. If the product to be dipped is something like celery or a vegetable, a sauce needs a certain amount of fat dispersion to achieve the proper mouthfeel.
To control water activity, Bruzzone says his company uses fresh basil leaves as opposed to frozen leaves, which contribute excess water. Separation of the main ingredients from the oil may occur in the pasta sauce if too much water results from freezing.
Sacla's spoon-and-serve products are heat pasteurized. Many companies use preservatives or antimicrobials, such as sorbates and benzoates, to prevent bacterial growth. Lauric arginate is a new self-affirmed GRAS preservative just recently entering the U.S. marketplace.
Water activity is not a problem with dried sauces that are to be reconstituted. “The worst thing to worry about in regards to stability of dry mixed sauces is figuring out how they will be reconstituted,” says Bakal.
Formulating sauces correctly can mean the difference between a sauce that debuts with a limp reception or a product that is smothered with accolades.
Sidebar: Showcase: Modified and Granular Starches
EmTex[tm] modified starches from Cargill Food & Pharma Specialties address nutrition and cost issues by partially or fully replacing eggs in baked goods, sauces, gravies, soups, and both spoonable and pourable dressings. In a recent study involving a sauce with 30% and 50% levels of oil, the starches replaced all egg solids in the formulation with favorable results in both hot and cold processes. Studies also indicate that sauces formulated with EmTex have a stable shelflife for as long as six months. It also has excellent emulsifying properties, especially in acidic food systems. Cargill's Food and Pharma Specialties, Wen Shieh, 219-473-2512, wen-juin_shieh@cargill.comNational Starch Food Innovation and Omega Protein united to create NOVOMEGA[tm], an encapsulated, long-chain omega-3 fatty acid in powder form. Novomega utilizes Omega Protein's OmegaPure[r], the only marine source of essential long-chain omega-3 fatty acids directly affirmed by the FDA as a GRAS food ingredient for direct human consumption. Novomega can be added easily to baked goods without affecting their taste, texture or aroma. Two servings (4 slices) of bread per day made with NOVOMEGA contain roughly the same amount of long-chain omega-3 fatty acids as many popular fish dishes. National Starch Food Innovation, Ilya Zhivkovich, 908-685-2748, ilya.zhivkovich@nstarch.com, www.foodinnovation.com
A&B Ingredients introduces Remyline XS-DR-P, an instant, easily dispersible, all-natural rice starch that adds thickness and sheen to instant soups, sauces, dips, dressings, baby food and dairy desserts. Because it does not need to be cooked or heated and disperses instantly and completely in liquid, this rice starch can be used to add texture, flavor and shine quickly and inexpensively to foods that are cold-processed. It also is able to withstand multiple stress conditions such as high shear, acidity, syneresis and freeze/thaw cycles. A&B Ingredients, Gil Bakal, 973-227-1390, gbakal@abingredients.com
INSCOSITY[r] modified food starches from Grain Processing Corporation are cold water-swelling, granular, instant food starches. The starches are manufactured to retain the starch granule integrity to ensure smooth texture and stable viscosity over a range of formulations, processing procedures and storage conditions. These highly stabilized starches hydrate readily in cold or hot aqueous systems and maintain their functionality in both neutral and acid formulations, under conditions of prolonged heating and through long-term storage. Samples available. Grain Processing Corporation, Bob Bahn, 563-264-4265, sales@grainprocessing.com, www.grainprocessing.com
Paselli EZ Sperse[tm] agglomerated, cold water-swelling, modified potato starches from AVEBE are recommended for a wide variety of dry mix or cold prep sauce and marinade applications. Avoid viscosity creep and evade the lumps that plague other dry mix manufacturers. The potato starches attain >90% of their maximum viscosity in the first five minutes of mixing and hold their thick, rich texture for extended periods. Whether for a delicate Alfredo or a robust marinade, these high-quality potato starches provide significant advantages in flavor and texture over waxy maize or corn starches. AVEBE America Inc., Jane Petrolino, 609-520-1400, ext. 2044, petrolinoj@avebe.com, www.avebe.com
