Bakers can select from a variety of concentrated fiber ingredients to complement the natural fiber of whole grains. Many of these ingredients offer specific functional benefits, but they also may require some formula finesse.
Before the industrial revolution, milling flour to remove the fibrous bran layer and germ was a labor intensive and costly operation. White bread was reserved for the aristocracy, the refined folks, and thus the origin of the term “refined.” Over time, doctors and nutritionists realized that consuming the whole grain provided health benefits, and in the 1930s, the U.S. began replacing the lost vitamins and minerals through enrichment. Now, the industry realizes the fiber of whole grain is just as important as the vitamins and minerals, perhaps more so, and is putting fiber back in the form of whole grain from various sources.
Interestingly, some differences of opinion exist about what constitutes fiber. “There are over 20 separate ‘definitions’ of dietary fiber. Currently, work is being done to create a universal definition by Codex. Whether and when this will be complete is unknown,” notes Steven Young, principal, Steven Young Worldwide and North American tech advisor to Matsutani America, Houston. For food labeling purposes, the FDA defines fiber as material isolated by analytical methods approved by the Association of Official Analytical Chemists.
| Bakers are putting fiber back into bread in the form of whole grain and other sources. |
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| Fiber has proven a successful fat replacement in muffins. |
In the 1980s, fiber was identified as being either soluble or insoluble, based on emerging evidence on health benefits. Soluble dietary fibers positively impact blood cholesterol and blood glucose levels, whereas insoluble dietary fibers improve bowel function. Although the recommended dosage of fiber is 25 grams per day for women and 38 grams for men, most people consume only 14 to 15 grams per day, according to the American Dietetic Association. Thus, one or more servings per day of high-fiber bakery products could significantly improve the average diet.
Fiber from whole grain
Whole grains, such as wheat, oats and barley, are a natural source of fiber. Whole wheat, for example, contains 12.2 percent fiber, with less than 2 percent as soluble fiber, and whole oats contain 10 percent fiber, with 4 percent as soluble fiber. Certain grain varieties contain higher levels of naturally-occurring fiber. ConAgra Mills recently launched Sustagrain®, a proprietary waxy, hull-less barley variety, available in flour, thick and quick-cooking flakes and steel-cut and whole kernels. This product has three times more fiber than oats, and nine times more fiber than brown rice.
In late 2005, the FDA approved a heart health claim for barley, stating evidence that adding barley to the diet can contribute to lowering serum cholesterol. To qualify for the health claim, foods containing barley must provide at least 0.75 grams of soluble fiber per serving. Breads containing 25 percent (bakers percent) Sustagrain can qualify for this claim, as well as a “good source” of fiber claim.
Mike Veal, director of marketing for ConAgra Mills, offers the following tips. “Sustagrain is naturally very high in fiber so vital wheat gluten is needed when baked volume is important. It also absorbs more water than whole wheat flour, so more formula water is needed for optimal machinability. Sustagrain contains more fermentable sugars than wheat, so when replacing flour, yeast levels and proofing times should be adjusted.”
Because this ingredient retains water better than wheat flour, bread products are softer. Besides bread, barley can be used to boost the fiber content of muffins, cookies, pizza crust, tortillas and crepes. Sustagrain also can be used in combination with Ultragrain® to create bread that is an excellent source of fiber.
According to Rajen Mehta, senior manager, fiber applications & tech service for Hope, Minn.-based SunOpta Ingredients Group, choosing the optimal fiber blend is crucial to successful formulation. “You really have to look at how the different types of fibers behave in the food system and how they impact your product characteristics,” he says.
While many fibers may achieve the desired technical effect, “the issue is how do you still maintain the texture, mouthfeel, etc.,” Mehta says. “It’s very easy to change the nutritional profile but to deliver the taste is the tough part.”
Concentrated grain fibers
When bakers want to boost fiber, they can turn to several concentrated fiber ingredients. One example is a hydrocolloid blend derived from oat fiber and oat bran, which exhibits both lipophilic and hydrophilic functions.
“This ingredient can be used in as low as 3 percent of formula weight to provide functionality. It is primarily used to maintain water and fat in an emulsified form within a food system. It is also a crumb humectant, delaying staling to thereby improve shelf life in bakery products. This product also provides a stronger hinge in hamburger buns that have been frozen or thawed,” says Robert Serrano, vice president, product development at Grain Millers, Eugene, Ore.
Grain Millers has one of the only certified organic plants in the country producing organic oat fiber because they use no chemicals during processing. Oat fibers provide 90 percent insoluble fiber on a dry basis and can be used in reduced calorie bakery products. Regular oats contain 3 percent to 4 percent soluble fibers, which are primarily beta glucan gums and qualify for the heart health claim.
The company also produces an oat bran concentrate with 10 percent to 12 percent beta glucan. Insoluble oat fibers can increase water uptake in dough, allowing bakers to add 2-3 times the weight of the fiber in water for better dough yield. They can also be used in calorie-reduced products.
“In bread, oat fibers can be used at 5 percent to 10 percent. In tortillas, they might be used at 20 percent. In sweet goods, they also function to reduce water activity and act as mold inhibitors. A new application for oat fibers is to provide structure by complexing with starch and forming matrices within doughs for fried goods, such as corn chips,” Serrano says. Adding as little as 3 percent oat fiber will improve chip integrity during handling and packaging.
Resistant starch
In the newer, white whole grain breads, resistant starch can boost fiber content while maintaining the desirable white color. MGP Ingredients produces a resistant wheat starch that delivers 85 percent dietary fiber on a dry basis. Its recently renamed Fibersym™ RW has a neutral flavor and white color, resulting in a nearly invisible source of fiber. Its low water-holding capacity makes it ideal for flour replacement, as well as increasing the freshness of snack foods and batter products, and for maintaining crispness and increasing bowl life in breakfast cereals.”
“Hi-maize resistant starch allows a generous substitution of flour without the risk of incurring moisture management problems at any point in the bread production process. Its low water-holding capacity helps to support predictable performance, whereas fiber made from whole wheat flour or other insoluble forms will often take up water immediately, yet continue to absorb water long after the mixing process,” says Rhonda Witwer, business development manager, nutrition, National Starch Food Innovation, Monroe, N.J.
This can produce dough that becomes “bucky” and dry, leading to quality problems at the end of the production line. In contrast, Hi-maize resistant starch made from high amylose corn mixes well initially and maintains a constant moisture level over time. The absorption rate of Hi-maize is virtually the same as flour, allowing bread processors of bread and other baked products to maintain their standard and preferred manufacturing processes, Witwer adds.
Bakers can include up to 20 percent of Hi-maize 260 in fiber-enhanced formulas. Tests conducted by the American Institute of Baking have show that baking time can be reduced by as much as 20 percent to 27 percent for breads made with Hi-maize compared to traditional fiber sources.
Other fiber sources
Some fruits, such as dates, raspberries and dried plums, contribute fiber. Another novel fiber source is citrus fiber or dried orange pulp. Citri-Fi is about 70 percent fiber, says Brock Lundberg, vice president of technolgoy at Fiberstar Inc., Willmar, Minn. Citri-Fi can be used to block fat absorption in fried products, such as donuts, or to replace fat in baked products, such as muffins or brownies. The general formula to replace fat is one part Citri-Fi and seven parts water for one part fat.
Although fine tuning may be needed to optimize results, this formula applies to nearly all products, including white bread, donuts and muffins. In most products, this means that the usage level is 1 percent or less. Typical formula adjustments are minimal, beyond reducing the fat source and adding the citrus fiber and water to replace it.
“In certain applications where emulsified shortenings are used, bakers might add back the emulsifiers separately since they are reduced when the fat is reduced,” Lundberg says. Occasionally leavening might also need to be adjusted up or down.
Fibersol®-2 (FS2), another soluble dietary fiber, is derived from corn starch. “It can be used at almost any level necessary to achieve nutrient content or select structure/function claims,” Young says. Typically, this ingredient would be used to “top off” the dietary fiber content coming from other sources of dietary fiber, including flour and bran. Since it is 100 percent water soluble, it really doesn’t bind water and has minimal impact on the structure of the bakery product.
A definite challenge for bakers who use fiber is figuring out how to best manage the holding and release of liquid. The CreaFibe product line by Creafill Fibers Corp., Chestertown, Md., is comprised of three insoluble fibers: QC Bamboo, SC Alpha Cellulose, WC Wheat Fiber. All three products have different morphology, which effects how they hold and contain liquid.
The bamboo fiber is a thin, ribbon-like fiber with small fiber beads mixed with the threads. The unique morphology of these very thin fibers allows bamboo to bind with less liquid than other types of fibers, which makes it ideal for crisp baked products, such as ice cream cones, snacks and wafer-like cookies. The fibers can contribute to crispness by building structure, reinforcing the strength with minimal liquid retention.
Wheat fiber consists of thick strands with long fiber tendrils with a great deal of fibrillation, and falls at the opposite end of the morphology range from bamboo fiber. The water binding capacity is higher, which increases shelf life, retains moisture, or prevents moisture migration in moist baked products. The addition of wheat fiber can require increases in liquid, mix times and bake times. Up to 4 percent can be added with simple formula and process changes.
Fiber can be quite a workhorse–retaining moisture, replacing fat or adding crispness. Breads and tortillas are two products that are often enriched with added fiber, but as evidence of the health benefits of fiber continue to mount, consumers can expect to see more high-fiber bakery products in the market.
