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By Frances Katz, Senior Technical Editor | 05/07/2007
In the U.S., starch usually means corn starch, either common or waxy, often chemically modified for extra functionality. In Europe, starches are more often wheat, potato or tapioca, with a different set of chemical modifications, or sometimes no chemical modifications at all. One reason is shelf-life priorities are different in different countries.
Lately, U.S. priorities are changing, triggered by changing dietary preferences of consumers. Today, starches may need to be appropriate for organic labeling or other carbohydrate combinations, such as “resistant” starches, or part of grain flours or other carbohydrate components of grains or tubers.
Starches are used to improve the functionality of mixed food systems, and one of the components that may cause problems is indigenous starches. These starches often are not well characterized, so overcoming “set-back” or syneresis caused by native starches may require the addition of modified starches or other ingredients.
When talking about the role of starch in food systems, there are two parts to the equation: starch added to improve function and starch that is naturally present and could cause interactions with added starch to the detriment of the food system.
The difference between a starch from corn or one from potato can depend on the structure of the starch, controlled by the kinds of polymers found in the grain or tuber and the way the polymers are packed into the starch granule. Polymers are characterized as amylose (linear starch) or amylopectin (branched starch). But there are many variations between one amylopectin starch (often called waxy starches) and another, as well as differences between the length and texture of amylose starches. These are governed by a set of enzymes that trigger branches and size.
A waxy rice starch produces foods that are different in texture and other attributes than a waxy potato or a waxy barley starch. If a consumer is accustomed to eating foods made with rice starch, the texture will be different when the food is made with another starch.
Some of the alternatives to corn starch have been around for decades, but because of shipment and handling, have been more expensive than corn or waxy corn starches. Potato starch generally is more expensive than corn but has different attributes, such as forming a gel and “set back” to form different textures unless it is chemically modified. The cost of chemical modification is variable, but highly modified starches can be very expensive. Recently, new starches in addition to potato, tapioca and rice starches are appearing in the marketplace.
When concerns about modified starches hit the baby food industry, at least one firm advertised they would “add more food” to baby foods, replacing the starches. The assumption by the consumer was starch added nothing to nutrition of baby foods.
Of course, in many cases the “more food,” especially vegetables, contain large amounts of starch. So, in adding more food, the primary action was to add pea or bean starch (or carrot or apple). Today, starch from peas and beans are being used to control the glycemic index of foods, as these starches resemble resistant starch and pass through the gut without being absorbed by the body.
“Use of the white bean starch reduces the glycemic index of white bread significantly,” according to Jay Udani, medical director for Medicus Research LLC (www.medicusresearch.com), Northridge, Calif.
One such product is Starchlite, the product of Pharmachem Laboratories Inc., (www.pharmachemlabs.com), Kearny, N.J., a standardized, all-natural extract of the common white bean (Phaseolus vulgaris). It has been clinically shown to delay the digestion and absorption of carbohydrates, reducing caloric impact, glucose impact and the glycemic index of starchy foods.
Starchlite may be used as an ingredient in a variety of foods and beverages, including baked goods, cereals, frozen foods, packaged meals, pasta, pizza crust, soups and confectionary. Sensory evaluations show Starchlite has no negative effect on the taste or texture of foods.
Affirmed GRAS in July 2006, Pharmachem received a letter last November from the FDA authorizing the following structure/function claim for Starchlite: "May reduce the enzymatic digestion of dietary starches" or "May assist in weight control when used in conjunction with a sensible diet and exercise program."
Nutri-Pea Ltd. (www.parrheim.com), Portage la Prairie, Manitoba, produces Accu-Gel, made from the kernels of golden Canadian peas. Field peas, as they are called in Canada, are a little higher in the linear fraction starch than common corn, so pea starch is about 35 percent amylose and 65 percent amylopectin.
Accu-Gel is made from non-GMO peas. With no chemical modification, the starch offers excellent heat-, shear- and acid-stability in food product formulations, the manufacturer claims. The product can be used in food products at 20-23 percent lower concentration than other starches.
The ingredient often is used in frozen desserts and similar products and is prized for its gelling ability. “It’s bland and is used in place of modified starches by companies that want a clean label. It forms a great gel and is widely used in low-fat sour cream products.” according to Jerry Kresnye of Norben Co. (www.norbencompany.com), Willoughby, Ohio, which markets the product in the U.S.
Potato starch has long been prized for its ability to maintain sheen and bind lots of water. National Starch Food Innovation (www.foodinnovation.com), Bridgewater, N.J., has a new product called N-Hance 59, a new functional native starch from potatoes. It retains moisture in poultry products while eliminating the need for modified starches, sodium phosphate or carageenan additives.
Introduced in March at the Natural Products Expo West , N-Hance 59 offers poultry producers serving the growing natural-food market a new clean-label option for preparing tumbled, injected, marinated, coated, par-cooked, frozen or otherwise packaged/semiprepared poultry products.
“What makes N-Hance 59 unique is its multifunctional role,” says Joe Lombardi, marketing manager for National Starch’s Wholesome Ingredients-North America, division. “N-hance 59 is both a highly functional moisture retainer and clean-label alternative to sodium phosphate and modified starches, additives traditionally used to retain moisture in meats. Our tests have shown N-Hance does remarkably well in retaining meat juiciness, increasing yield weight and improving visual and textural appeal. This is good news for poultry producers who want attractive, high-quality poultry that is free of sodium phosphates or modified starches.”
The product also binds moisture in vacuum packaged meats so they maintain high yields. It’s inherently bland and allows the flavors of meats and marinades to come through while delivering good mouthfeel. N-Hance 59 starch has a low gelatinization temperature and is relatively stable at low cooking temperatures, under neutral pH and in low-shear and stress conditions.
Rice, the most consumed food grain in the world, is available in many varieties. Both high-amylose rice and amylopectin rice are available, and two new micronized rice flours offer exceptionally fine particle sizes ideal for coatings, baked goods such as sponge cakes and rice paper wrappers.
These rice flours provide higher binding capacities than conventional rice flours. “The rice flours also emulsify oils and fats better than earlier rice flours and serve well as carriers for oils and fats,” says Gil Bakal, managing director of A&B Ingredients (www.abingredients.com), Fairfield, N.J. “Thorough emulsification permits consistent product taste and texture.”
The two types of rice flour include Remyflo R790T, based on a high amylose variety of rice, and Remyflo S90T, a waxy rice variety. As with other rice-based ingredients, these specialty flours are easy to digest, free of allergens and don’t contribute off flavors commonly associated with some other flours. The products are well suited for food systems in which delicate flavors are crucial to product success.
Another ingredient is Remyline AX-FG-P specialty rice starch, developed to reduce fat uptake in tortilla chips by up to 50 percent. The specialty starch also reduces breakage, improves machinability during processing and can increase the crispiness of the chips. It replaces 2-5 percent of the corn flour. It is labeled as “rice starch” on the package.
Another grain that has grown popular is barley, especially waxy barley, an ingredient that combines the effect of the insoluble fiber beta glucan with the effect of the starch, a dense amylopectin. Barley Balance, made by Crookston, Minn.-based PolyCell Technologies (www.poly-cell.com) and marketed by DKSH, Baltimore, Md., is a concentrate of waxy barley made by dry milling and separation, producing a product with about 23 percent beta glucan and 35 percent waxy starch.
The combination produces a bland, viscous gel with a low glycemic index that enhances functional foods and beverages. “In baked foods, the barley starch helps to hold water and prevent staleness,” according to Tom Jorgens, president of PolyCell. “Products that contain enough beta-glucan can carry a cardiovascular claim. The viscosity and water holding helps increase satiety, making the combination carbohydrate product ideal for diet foods.”
Sources of starch added to improve functionality have broadened in recent years. There are starches processed to retain the “native starch” designation that offer most of the functionality of chemically processed starches.
For instance, National Starch’s Novation line of products is available from potato, waxy rice, organic waxy maize and organic tapioca. They’re processed by a technology that results in properties similar to modified starches, while meeting the labeling criteria of native starches. This allows the product developer to formulate with native starches, maintaining the quality and texture of modified cook-up starches.
National Starch’s system for producing grains under identity preservation aids organic food processors in other ways. The company recently added some pregelatinized flours that can be used with starches. These products, made from wheat, provide functions such as thickening and stabilizing for food systems that require high freeze-thaw stability. They are suited for applications in which a natural, home-style appearance is desired, lending the opacity, texture and flavor balance typical of a flour.
Starches and other combination carbohydrates continue to expand in variety. From the large number of technical papers on the functionality and healthy characteristics of new starches, it wouldn’t be surprising to see starch from yams, apples, blueberries, buckwheat, and mung beans on American tables. As corn is increasingly used for other purposes, such as fuel, there may be new uses for fruit and vegetable starches to thicken, alter textures and improve flavor of foods.
The native starches, whether from rice, potato, barley or other grains, are best used in systems with carefully regulated shear and heat. They may also have more variability triggered by variety, year and handling than modified starches.
Be sure you can measure the amount of shear and heat applied when manufacturing products using these native starches. Overmixing, for instance, can cause shear thinning in a final product, or may cause shear thickening and difficulties in pumping.
There may not be tests available that demonstrate differences, so think about how to control the amount of shear and heat, and reassess each batch of starch when the seasons or suppliers change.
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