Just add starch
November 1, 2012
by Laurie Gorton
No two starches are created equal, and that’s good for bakery and snack product developers seeking to differentiate their products and solve formulating problems. Food starches provide “go to” answers that address structure, moisture, shelf life, yield and even cost issues. And they make a crucial difference when preparing the gluten-free and clean-label products that attract so much consumer buzz these days.
Since flour, the main ingredient of carbohydrate-rich baked foods, contains plenty of starch already, why add more? The simple answer is, starches work. “Starches are cost-efficient functional ingredients,” said Carl Jaundoo, PhD, associate program coordinator, Roquette America, Inc., Keokuk, IA. “They influence appearance, texture, taste and shelf life.”
In many cases, not much starch is needed. For example, deep-fried snack foods benefit from Midsol Krisp or Midsol 1 modified cook-up wheat starches when added at 5 to 10%, according to Ody Maningat, PhD, vice-president of applications technology and technical services, MGP Ingredients, Inc., Atchison, KS. He said the starch reduces fat absorption and increases the crispness of the finished snack, including extruded corn curls.
Bakery and snack food formulators can choose among native and modified starches as well as pregelatinized styles. Physically modified starches joined the roster as an alternative to chemically modified types.
“Starches play an increasing role in baking today,” said Mel Festejo, COO, American Key Food Products,Closter, NJ. “Starches are viable and practical ingredients that can address these needs because of their robust properties.”
Addressing mega trends
Suppliers point to two specific application challenges that starches can meet: clean label and gluten free.
“Modified and clean-label starches allow bakers to address mega market trends, including increased ingredient and formulation costs, nutrition — by either addition or reduction — as well as gluten-free and unique textures,” said Patrick O’Brien, marketing manager, bakery, Ingredion, Inc., Westchester, IL. “Starches help bakers address these trends in a cost-efficient manner.”
Describing clean label as a major driver of innovation in the baking industry, Dr. Jaundoo observed, “This trend will influence the choice between modified and native starches. More bakeries are looking for native starches with the same functionality as modified starches.”
Clean label drives innovation by starch manufacturers, too. Mr. Festejo described starches without chemical modification to include Empure physically modified cook-up and cold-swelling starches from potato and pea sources. “We expect increasing preference for natural and clean-label ingredients,” he said.
In its recent white paper about novel starches, Ingredion cited the 2012 North American CPG Trend Prediction Report from market researcher Mintel, Chicago, IL, that noted, “Natural (clean-label) formulations appear at all price points, making them available to all consumers.” The white paper went on to state, “Delivering these products on an industrial scale can be challenging. From processing and transportation through to storage and preparation, prepared foods are put through their paces.”
When formulations go gluten-free, starches help make up for its absence. “Starch blends such as PenTech GF will continue to play an important role in gluten-free formulating since they provide structure, crumb formation and moisture retention,” said Bryan Scherer, director of R&D, Penford Food Ingredients Co., Centennial, CO.
Gluten-free formulating is constantly evolving, Mr. Scherer added. “In the next few years, starches will offer new and expanded functionalities including allergen replacement, fiber enhancement, and sugar and fat reduction,” he said.
Although wheat gluten is banned from gluten-free foods, wheat starch is not. Dr. Maningat described gluten-free native and modified wheat starches that stay under the 20-ppm limit, the de facto standard for gluten-free labeling. Wheat starch, he said, has unique functionality in baked foods. “This attribute is primarily due to the similarity in granule size, shape, size distribution and surface characteristics of added wheat starch compared to the naturally occurring wheat starch in the flour,” he explained.
By stabilizing texture and shelf life, starches enhance convenient use of baked foods. Mr. Festejo observed that the rapid development of convenience foods and strong growth in the c-store, in-store bakery and bakery chain channels put a premium on stability and shelf life. Products for these customers can also reflect consumer preferences for shorter ingredient lists and greater use of natural or clean-label ingredients.
And let’s not forget economic issues. “Cost reductions could be achieved by use of starches as egg replacers to meet the current high cost of eggs,” Mr. Festejo said. Emfix modified starch, he noted, mimics the processing and emulsifying properties of eggs, providing essential structure and texture in cakes, muffins and other baked foods.
PenTech NG, a blend of native starches with a gum and leavening system, can replace dry or liquid whole eggs and/or egg yolks in baked goods while maintaining great product integrity, according to Mr. Scherer.
Food starches come from many sources, but the most common are cereal grains (wheat, corn, rice), tubers (potato, tapioca) and legumes (pea). Plants form starches to store energy for later use, but they do so in different ways — hence, the functional differences between them.
Starches contain two basic molecules: linear-chain amylose and branched-chain amylopectin. Their ratios vary by source. For example, corn starch carries 25 to 28% amylose, while high-amylose corn contains 50 to 70% amylose, but waxy maize has virtually none.
“The ratio of amylose to amylopectin influences the functionality including gelatinization temperature,” Dr. Jaundoo explained. “When starches are heated, the linear amylose molecules solubilize and leach into solution. Then follows reassociation, aggregation and finally precipitation at low concentrations. Waxy maize, with no linear molecules, remains flowable and clear.”
The functionality of native starches varies from heavy bodied pastes (corn) to high viscosity, long texture, creamy consistency and low temperature stability (waxy maize). “Native starches are most suitable for products that are freshly prepared and used without prolonged storage,” Dr. Jaundoo explained. Roquette produces more than 300 native and modified starches.
Native starches, those offered in purified but not otherwise modified form, differ in the way they work in baked foods and snacks.
“In snacks, native starches offer various features and functionalities, depending on the base material,” said Leanna Long, starch product line technical specialist, Texturizing Solutions, Cargill, Wayzata, MN. She cited the company’s Tex and StabiTex high-amylose starch’s ability to provide expansion and texture control, uniform surface characteristics, structural stability and increased crunchiness.
Formulators seeking freeze-thaw stability turn to native tapioca starch, also an aid to shelf life of refrigerated goods, Mr. Festejo noted.
When working on gluten-free products, formulators often choose native starches because they are more label-friendly than “food starch, modified” — the usual way of reporting modified starches in the ingredient listing on consumer packaging. Native starches from potato, rice and tapioca improve volume, crumb formation and moisture retention in such uses, according to Mr. Scherer.
“PenPure clean-label native starch functionalities, including puffing, reduced breakage and adhesion, are key attributes in making extruded snacks,” Mr. Scherer added.
Sometimes it helps to match the starch source with the formulation’s flour source. “Native corn and wheat starch are the most similar,” observed Joe Carmosino, technical director, Manildra Group USA, Shawnee Mission, KS. The company offers Gemstar 100 native, Gemgel pregelatinized and Gemstar 2000-4000 modified wheat starches.
“In many applications, wheat and corn starches can be used interchangeably without negatively impacting the final product, but not in all,” Mr. Carmosino said. “Some baked products require the superior whiteness, soft texture or flavor of wheat starch in their mix to achieve a suitable finished product.”
Native starches also differ in how they thicken and texturize fillings, toppings and glazes. “The high level of amylose in native pea starch is a plus, given its excellent gelling properties,” Mr. Festejo said. “Different starches can also enhance shear resistance, as well as acid and heat stability in varying degrees.”
There’s a taste factor involved, too. “Some starches can contribute a cereal note when cooked. Potato and tapioca starches possess less flavor and are used in more delicately flavored products,” Mr. Festejo said. “If one is using a grain-based starch, typically salt is added to mask the flavor that can come with it. Use of a potato or tapioca starch can help reduce the amount of salt.”
Native starches must be cooked to get their full benefits. “This requires critical process controls because there is often a narrow range of tolerance between undercooked and overcooked,” Dr. Jaundoo said. “The functionality of native starches is also affected by processing conditions such as mixing, shear, pH and baking time and temperature.”
Other ingredients may change the performance of native starches, Dr. Jaundoo added. “With sugar and fruits, pH conditions will affect adversely the thickening power of native starches,” he said.
Modified starches are made by chemically treating native starches to change their properties, typically through hydrolyzing bonds or crosslinking parts of the starch molecule, thus shortening or lengthening its chain length.
Bakery formulations gain benefits through use of modified starches. According to Mr. O’Brien, these include viscosity control and management of moisture during baking. Also, starches enable control over texture, cell structure and finished product shape and size. In fillings, they optimize viscosity, texture, appearance, bake stability and shelf life. And they help with cost control.
The more specialized the job, the more a modified starch is needed. “Modified starches benefit bakery formulations by addressing specific needs within the product,” Mr. Carmosino said. These requirements might be freeze-thaw stability, batter adhesion, moisture control or viscosity stability.
Batter viscosity and moisture retention, for example, are important in sweet goods such as cakes, muffins and cookies, which depend on aeration for finished product texture and volume, Ms. Long noted.
In breads, cakes, muffins, wafers and bakery mixes, modified starches will improve the final texture, according to Mr. Festejo. “They also work well in refrigerated or frozen yeast doughs for pizza crusts and sandwiches by retaining moisture, contributing softer crumb, extending shelf life as well as improving texture,” he said.
The low viscosity and high solids levels provided by N-Tack, a specialty starch derived from waxy corn starch, is especially useful for formulating low-fat products, Mr. O’Brien explained. It acts as a binder to adhere nuts, fruits and seasonings to snacks. The film-forming characteristics of some starches such as Crisp Film modified high-amylose corn starch create protective barriers. Ingredion’s Hylon VII native high-amylose corn starch functions in a similar fashion.
The low pH value of Emflo modified cook-up potato starches suits their use in hot preparation of fruit fillings, marmalades and jams, providing good binding of juices and adding sheen and high viscosity to finished products, according to Mr. Festejo.
Just add water
Pregelatinized starches address another set of needs: They provide high viscosity, creamy texture and short bite with no cooking required. Also described as “cold water swelling,” pregelatinized starches do not contain the added covalent bonds created when chemically modifying starches. They are made by heating native starch in an alcohol-water mixture, removing the solvent and drying the starch. The starch crystals melt during this process but do not swell until the treated dried starch is added to cold water.
“Pregelatinized potato starches such as PenPlus 300 and PenPlus 2760 provide excellent cold viscosity for batters and improve dough handling in gluten-free baked foods,” Mr. Scherer said. They also manage viscosity and texture in bakery fillings.
Bread yield can be improved by adding just 1.5 to 2.0% of Pregel 40 or Pregel 46, both pregelatinized wheat starches, to the formula, according to Dr. Maningat. Like MGP Ingredients’ modified wheat starches, its pregelatinized types serve as batter viscosifiers, moisture retention agents, crumb softeners and shelf-life extenders in chemically or yeast-leavened bakery products.
Adding pregelatinized potato starches also benefits snack products. “Functionalities include puffing and reduced breakage,” Mr. Scherer said. When dissolved and used as a topical spray, these starches help adhere spices, seeds and other particulates to finished products.
The texture of snack foods can be improved through use of Baka-Snak modified pregelatinized waxy maize starch and Ultra-Crisp CS, a cold-water-swelling waxy maize starch. Mr. O’Brien noted that these Ingredion products contribute to volume control and uniform cell structure and reduce breakage.
Because their high efficacy allows a little starch to go a long way, these ingredients in their many forms have become popular choices for product developers. They can make the difference between a just-adequate product and a truly appealing one, thanks to their ability to modify structure, moisture, texture and shelf life qualities.