R&D: Ingredient Technologies to Tackle Textures -- May 2009
Protein as a Texture Improver in Reduced-fat Applications
Pea protein, a newly available, all-natural vegetable protein, provides unique opportunities for the food industry. Peas also are an alternative source to soy protein. Pea protein is a purified protein source with no residual complex sugars; therefore, it digests with no complications, offers clean labeling and is non-GMO. Pea protein has a high nutritional value and is rich in essential amino acids that are beneficial for growth, performance and recovery from stress, said Chandani Perera, Ph.D., project coordinator, Roquette America Inc., during a presentation titled, “Pea Protein as a Texture Improver in Reduced-fat Applications.”
Pea protein isolate is produced from yellow peas, through grinding it into flour and then removing the bran. The flour then goes through a wet separation into starch, internal fiber and pea protein. The anti-nutritional factors are very low, as tannins are removed by elimination of bran; complex sugars are reduced to 0.5-1%; and saponins are reduced during the wet process and in drying.
Pea protein isolate has approximately 85% protein on a dry weight basis. The protein is highly digestible because of sugar reduction and has a digestibility score of 98%, which is comparable to an animal protein. The proprietary extraction process maintains very functional properties.
The ability of pea protein to bind water provides excellent emulsification properties, thus imparting improved texture to reduced-fat applications. It has excellent flowability, is easily dispersed in liquids, contributes minimal foam formation and provides high stability. Because of its isoelectric point, pea protein has a higher solubility at lower pH than soy protein, noted Perera.
Pea protein offers many application possibilities for snacks, vegetarian and prepared meals, patés, sauces and dressings, soups, pasta, meal substitutes, sport mixes, cereal and protein bars, extrusion and baking. A “soluble grade” of pea protein is designed mainly for beverage applications, whereas “functional grade” could be used in many other applications. (See chart “Protein Solubility Relates to Isoelectric Point.”) In reduced-fat Thousand Island or Caesar dressings, for example, pea protein provides creamy texture. Its readily dispersible, free-flowing, low-dust formulation properties and neutral taste make it an overall functional and nutritional ingredient for new healthy foods.
“Pea Protein as a Texture Improver in Reduced-fat Applications,” Chandani Perera, Ph.D., project coordinator, Roquette America Inc., firstname.lastname@example.org
--Summary by Elizabeth Mannie, Contributing Editor
Alginate in Restructured Meat and Fish Products
Phosphates can play a critical role in restructured meat and fish products formed by binding together smaller pieces. One supplier discussed alginate chemistry and how a system consisting of alginate, calcium and phosphate sequestrants can be used for the production of these products.
Alginates are cold water-soluble, cold-setting hydrocolloids that form heat- and freeze/thaw-stable gels. Alginates are extracted from species of brown seaweed, such as Lessonia trabeculata (southwest coast of South America), Laminaria japonica (coasts around Southeast Asia) and Laminaria hyperborean (North Sea), said Hank Huang, Ph.D., senior technical scientist, FMC BioPolymer, during a presentation titled, “Alginate in Cold-set, Restructured Meat and Fish Products.”
An alginate’s hydrocolloid chain is composed of two monomers, (1,4) beta-D-mannuronate and/or (1,4) alpha-L-guluronate. The exact composition determines its functional properties, which include thickening, gelling and stabilizing. The viscosity of an alginate solution is determined by factors such as its molecular weight, concentration and hydration rate; the solution’s temperature and ionic strength; and the shear applied to the solutions, noted Huang.
Alginate gels are formed through ionic bonds between COO- groups on the alginate molecule and calcium ions (Ca++). Several key factors impact alginate gelation, said Huang. First, alginates must be properly dispersed and hydrated. In order to assist with hydration and control gelation, calcium availability can be controlled with sequestrants, buffering systems and/or heat. For example, calcium release can be controlled by diffusing a soluble calcium salt or by use of slow-release calcium salts. Also, an acid-soluble calcium salt can be used where it is released by addition of an acid. Cooling a solution below 70°C also can increase calcium availability.
These factors come into play in the formation of restructured and reformed fish and meat “steaks” or sausages made from smaller pieces of meat. Here, meat pieces are placed in a proprietary solution of hydrated sodium alginate molecules and calcium ions. (See chart “Calcium Sources.”) The meat or fish pieces are bound together in a gel, the formation of which is optimized through use of a sequestrant controlling the release of calcium. (See chart “Types of Sequestrants.”)
For example, a solution with only 0.3% of the sequestrant tetrasodium pyrophosphate (TSPP) allows for a faster forming and stronger gel than one with 0.5% TSPP (since TSPP binds calcium). Also, a very weak gel is formed with a solution of 0.5% sodium tripolyphosphate (STPP), noted Huang.
Huang provided formulations, processing steps and tips for several types of processed meat products. For example, in reformed steaks, a wide range of meat and fish ingredients can be used (e.g., beef, ham, pork, poultry, fish, etc.), and the piece size can vary from finely ground to coarsely cut (e.g., 2in). Also, 1-2% salt can slow the setting process and reduce the firmness, although the impact is small, when a solution with 3% of the proprietary alginate blend is used.
Overall, the benefits of the alginate system proposed by Huang include that it is a one-step, cold-process structuring agent that provides good finished product structure and heat stability. The system can reduce recipe costs, as well as allow the development of healthier meat products with reduced calorie and fat contents.
“Alginate in Cold-set, Restructured Meat and Fish Products,” Hank Huang, senior technical scientist, FMC BioPolymer, www.fmcbiopolymer.com
--Summary by Claudia D. O’Donnell, Chief Editor
Hydrocolloids are added to foods to control water and thicken. When two thickeners are used, the combination often offers synergies. For example, two thickeners may combine to form a gel, or they may combine to form a “super thickener.” A gellant and a thickener may combine to modify a texture. A protein and a hydrocolloid may combine to form a gossamer network in a liquid system. Kevin Johndro, lab manager, Ingredient Solutions Inc., and his group gave some examples of synergistic combinations and some suggestions for others to try during a speech titled, “Hydrocolloid Synergies: Their Applications in Foods.”
Carrageenan and locust bean gum (LBG) provide sparkling, crystal-clear gels of various textures and are excellent choices for gummies, dessert gels and fruit roll-ups, but the system is very expensive, and LBG is subject to supply problems.
To cut costs, tara gum [a major portion of which is a galactomannan polymer similar to locust bean gum.--Ed.] can be blended with natural-grade carrageenan to provide the same synergistic reaction as conventionally refined carrageenan and LBG, albeit slightly weaker. The tara/carrageenan combination can be used for high gel strength and elasticity.
Iota carrageenan and starch is a cost-effective system, allowing up to a 40% reduction in starch, significantly reducing the high process viscosity of 100% starch, said Johndro. Various combinations improve organoleptic qualities and resist shear degradation. In starch-based puddings, iota enhances texture at 0.04%, giving a cleaner mouthfeel. The texture is shorter and less sticky. For marinated whole chicken, iota carrageenan and starch allow for ease of injection into the muscle, maintaining natural texture without gumminess. These two promote excellent moisture retention, minimal drip loss, and the drippings resemble natural juices.
Xanthan/guar and xanthan/LBG are also synergistic combinations with xanthan guar, providing smoother flow, additional thickening and cling in barbecue sauce. In cheese spread, xanthan and LBG eliminate whey-off, reduce flavor masking and lower formulation cost at equivalent functionality, Johndro added.
Kappa carrageenan and konjac gels may be made to be both thermally reversible and thermally irreversible. They are primarily used in retorted pet foods, but also find use in noodles, retorted meats and heat-stable fillings. Konjac can be difficult to use in process, due to its high viscosity. Kappa carrageenan also has synergy with potassium chloride and with kappa casein protein. Iota carrageenan is synergistic with calcium ions. Other synergies to consider are xanthan with konjac or starch, konjac with starch, or pectin with alginate. Synergistic blends now make up about 30% of the hydrocolloid market.
Carrageenan has found some niches where it is virtually irreplaceable. Understanding the science of carrageenan helps scientists move forward in its applications, but the models are still incomplete, and much work remains to be done. There is plenty of room to capitalize on experimenting with synergies, but finding the right gums and the right ratio is not easy.
“Hydrocolloid Synergies: Their Applications in Foods,” Kevin Johndro, lab manager; Susan Therio, chemist; Scott Rangus, vice-president, sales; and Pete Bixler, Ph.D., founder; Ingredient Solutions Inc., email@example.com, www.isinc.to
--Summary by Elizabeth Mannie, Contributing Editor
Cross-linked Resistant Wheat Starch
Dietary fiber is one of the top ingredients for weight control and for diabetic foods. Resistant starch is recognized as dietary fiber by the definitions of the American Association of Cereal Chemists International, Institute of Medicine and Codex. The European Food Safety Authority also considers resistant starch as dietary fiber. Resistant starch is the sum of starch and products of starch degradation not absorbed in the small intestine of healthy individuals.
Resistant starch is classified into four groups: RS1: physically inaccessible starch; RS2: raw starch granule; RS3: retrograded; and RS4: chemically modified starch. Kyungsoo Woo, Ph.D., principal scientist, MGP Ingredients Inc., explained that the company’s “cross-linked resistant starch, which is classified as RS4, phosphated distarch phosphate, can be labeled as modified wheat starch with no use limitations under 21CFR 172.892,” in his speech titled, “Cross-linked Resistant Wheat Starch Properties and Food Applications.”
This resistant wheat starch (RWS) is manufactured from wheat starch by reacting with sodium trimetaphosphate and sodium tripolyphosphate, then either dried into an RS4 RWS (cook up) for fiber enhancement, or first treated with a hydrothermal treatment and then dried into an RS4 RWS for both fiber enhancement and fat replacement.
This RWS contains typically greater than 90% total dietary fiber content by AOAC method 991.43, noted Woo. Fortifying with this ingredient easily enables products to claim a good or excellent source of fiber, with minimum requirements of 2.5g or 5g fiber per serving, respectively. At less than 0.5Kcal/g, this resistant starch contains approximately 90% less calories than typical starch, by Atwater factor calculations.
Animal studies show consumption of RWS produces higher levels of beneficial short-chain fatty acids, lowers liver cholesterol and increases serum HDL cholesterol, when compared to a cellulose diet. Additional benefits included lower food consumption and weight gain, also in comparison with a cellulose diet. Human studies have shown reduced postprandial glucose and insulin responses in healthy younger adults. After consumption of a bar formulated with RWS, glycemic response was 19.9 (obtained by taking glucose control as 100). It is about an 80% reduction in glycemic response (59.9) after consumption of a bar formulated with puffed wheat.
This RWS possesses water-holding capacity of 0.7g water/g, which is lower than most other fiber sources, including other types of resistant starch. It promotes crispness in low-moisture, flour-based foods and improves shelflife regarding microbial activity and retrogradation, said Woo. RWS is process-tolerant during extrusion, pressure cooking and frying and contributes a smooth texture, white to invisible fiber source and neutral flavor. During five freeze/thaw cycles, RWS showed significantly less water loss than other starches, Woo added.
Nutritionally enhanced applications for RWS include wheat bread, muffins, buns, pasta, tortillas, pizza dough, breakfast cereals, cookies and waffles. In white pan bread, RWS provides an “excellent” source of fiber and reduces calories, while still having a regular “bread-like” texture and positive sensory attributes.
“Cross-linked Resistant Wheat Starch Properties and Food Applications,” Kyungsoo Woo, Ph.D, principal scientist, MGP Ingredients Inc., www.mgpingredients.com
--Summary by Elizabeth Mannie, Contributing Editor
Applications for Ancient Grains
Whole grains can enhance a variety of products, including baked goods, cereals, snacks, toppings, breaded products and more.
“Whole grains allow consumers to feel that they are doing something right for their health,” explained Elizabeth Arndt, R&D director, ConAgra Foods, during a speech titled, “Applications for Ancient Grains.” “In addition, whole-grain products have a healthy halo, making the timing right for new product introductions. An opportunity exists to increase utilization of minor and exotic grains, some of which are known as ancient grains.”
Ancient grains are typically considered grains that have survived intact for centuries, not altered by modern plant science. Common ancient grains include amaranth, millet, quinoa, teff and sorghum. Ancient grains offer unique flavors and provide visual interest to foods through their seed size, shape and color, along with a balance of nutrients.
When it comes to these exotic grains, the many considerations include type, color, size and what type of processing they will undergo, whether it be toasting, flaking or another process. Generally, ancient grains offer similar nutrients compared to other whole grains, such as fiber, protein, vitamins, minerals and other phytonutrients. Amaranth, quinoa, sorghum, millet and teff are ancient grains that do not contain gluten and are appropriate for use in formulating gluten-free foods.
Amaranth is a pseudo-cereal, with a history as a staple of the Aztec culture. It can be used as a popped snack food and in other grain-based foods, including cereals, breads, muffins, pancakes and crackers. Compared with other whole grains, amaranth is higher in protein and mineral content.
Millet is a cereal grain originating as a staple in India and is also common in Africa. The small, round seeds have a mild flavor and can be white, gray, yellow or red. In the U.S., millet is more common in animal foods, but also can be found in cereals and baked goods. Millet is notable for its relatively higher level of B vitamins.
Teff is an important food source in the Ethiopian diet, used to make injera flatbread, Arndt said. The seeds are very tiny, with a slightly sweet, molasses-like flavor, and are available in brown or ivory seed colors.
Quinoa is a pseudo-cereal that originated in the Andes and was first cultivated by the Incas. Today, the cooked whole grain often can be found in side dishes. The small seeds have a slightly nutty, earthy flavor and are primarily available in white, red or black seed colors. Quinoa is higher in protein and mineral content and has a comparably high Oxygen Radical Absorbance (ORAC) value.
Believed to originate in Ethiopia, sorghum can be used in many products, from baked goods to snack foods. Sorghum has a mild flavor and delivers important whole-grain nutrients.
Incorporating ancient grains often requires formulation and processing adjustments. Inclusion levels can range up to 100%. In baking, the addition of whole grains requires additional water and, often, added functional ingredients. The amount of whole grains in a product can be listed in grams or ounce-equivalents, in a factual statement. The Whole Grains Council Stamp is another option for labeling of whole grains. The FDA-approved whole-grain health claim stating, “Diets rich in whole-grain foods and other plant foods, and low in total fat, saturated fat and cholesterol, may reduce the risk of heart disease and certain cancers,” may be used for products with at least 51% whole grain by weight and that meet other claim criteria.
“Applications for Ancient Grains,” Elizabeth Arndt, director R&D, ConAgra Foods, firstname.lastname@example.org, www.conagrafoods.com
--Summary by Elizabeth Mannie, Contributing Editor
In the Format of Your Choice
The food industry changes more rapidly than many. Consumers can instantly change what they eat, as they are influenced by trendy cuisines to popular diets or emerging nutritionals. The food industry responds with new ingredients or ways to use old favorites in challenging new applications. Prepared Foods strives to keep its readers abreast with changes in applied food science and ingredient technology. Beyond these printed pages, past and future information is also available in the following formats.
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