July 1, 2003
Health and nutrition experts all agree that eating a good breakfast is important. A traditional breakfast of cereal or other grain-based foods, such as pancakes or waffles, with fruit can easily begin ones journey toward an optimum fiber intake something that most Americans do not achieve. Too frequently in our convenience-oriented and eat-on-the-go culture, breakfast just doesnt happen, or if it does, it consists of high-sugar, high-fat foods with little, if any, dietary fiber.
Fibers role in achieving health and preventing disease is not entirely clear. For example, in recent months, a number of studies examining the relationship of high-fiber foods and colorectal cancer yielded contradictory results. However, viscous fibers, such as the soluble fibers in oats and psyllium, are recognized as cholesterol-lowering agents and are associated with lower glycemic response and insulin demand, thus indicating a role in diabetes prevention and management. In terms of gastrointestinal health, the part fiber plays in normal laxation is indisputable, leading to its importance in management and treatment of constipation and diverticulosis. Based on epidemiological and observational studies, other potential benefits from fiber include protection against duodenal and breast cancers, and improvement of immune function.
The nutrient that isnt
For many years, fibers contribution to health wasnt recognized because, in reality, fiber is not a nutrient. It never enters the body, per se, and no direct blood or biochemical markers identify its presence or impact. Its significance is derived from observations or associations with good or bad health outcomes. Thus, identifying just what constitutes a fiber and what it does physiologically is not an easy task.
The most basic definition for fiber is based on what it isnt digested or absorbed. Many compounds in foods may meet this definition, but what makes a substance a fiber is its ability to change the environment in the gastrointestinal tract through viscosity and/or fermentation. Measuring fiber in food has evolved over the years from analyzing plant foods for crude fiber (essentially what was left after extraction with a dilute acid or alkali solvent) to the more current methods that quantify remnants of plant cells, polysaccharides, lignin and other substances that resist digestion by the enzymes in the alimentary canal. This means that the analytical chemist must mimic the actions of mastication and digestion on a food in the laboratory and then measure what is left.
Current research and labeling regulations recognize total dietary fiber, soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) based on AOAC methodology. Both SDF and IDF use an aqueous enzyme solution, with IDF being an insoluble fraction and SDF being precipitated by alcohol addition. The most common IDFs are cellulose, hemicellulose, lignin and resistant starch. The most common SDFs are pectins, beta-glucans and galactomannan gums. Polyfructans, such as inulin and fructooligosaccharides (FOS), and resistant maltodextrins do not fully precipitate in alcohol other methodologies quantify their contribution to dietary fiber in a food.
Recently, two scientific bodies proposed new definitions for fiber that differ in how they name and classify fiber. In 2001, the American Association of Cereal Chemists (AACC) Dietary Fiber Technical Committee adopted the following definition:
Dietary fiber is the edible parts of plants or analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin, and associated plant substances. Dietary fibers promote beneficial physiological effects including laxation, and/or blood cholesterol attenuation and/or blood glucose attenuation.
In 2002, the Food and Nutrition Board (FNB) of the Institute of Medicine, Washington, D.C., developed the following definitions for fiber:
Dietary fiber consists of nondigestible carbohydrates and lignin that are intrinsic and intact in plants. Functional fiber consists of isolated, nondigestible carbohydrates that have beneficial physiological effects in humans. Total fiber is the sum of dietary fiber and functional fiber.
Based on current scientific data, the FNB established a requirement for total fiber for the first time, expressed as Adequate Intake (AI). This is based on grams per 1,000 kcal and the usual daily intake of energy to determine a grams-per-day value. Because it is based on energy consumption, the AI varies for different age groups and genders. For adult men, 19 to 50 years old, it is 38 grams per day, while for women in the same age group, the AI is only 25 grams per day. In the 51-plus age group, the AI goes down to 30 grams per day for men and 21 grams per day for women.
Intended as the basis for new FDA labeling regulations, FNB developed the definitions of fiber and the AI for total fiber to help consumers and scientists identify fibers based on physiological functions and health benefits. Much of the research conducted on the value of high-fiber diets evaluates consumption from high-fiber-containing foods and not specific fibers. Additionally, research has identified properties such as being viscous and fermentable as beneficial, but these properties are not exclusively associated with the fibers solubility.
According to Dan Gallagher, a member of the FNB committee on fiber, and professor in the department of food science and nutrition at the University of Minnesota, St. Paul, dietary fiber exists in a complex matrix and it is not always clear which part of the matrix provides the physiological benefit. He adds that under the current definitions of dietary fiber, it is possible to add naturally occurring fibers that are not that beneficial, such as cellulose, and qualify a product for a dietary-fiber claim. He further explains that because a functional fiber must demonstrate efficacy to be included in the total fiber value, consumers will get real benefits from consuming fiber-enriched foods and beverages.
In the May-June 2003 issue of Cereal Food World, the AACC Dietary Fiber Technical Committee published a report that takes to task the FNBs definitions of fiber. Major objections include the separation of dietary fiber into two components as arbitrary, the use of intrinsic and intact as being inadequate descriptors and unquantifiable, and the lack of continuity with current research and composition databases. It views the end results of adopting the FNB definitions as leading to consumer confusion, delays in research, and a disincentive for the food industry to develop and market high-fiber ingredients and foods.
Additionally, manufacturers would have to change all food labels to reflect the new terminology, but without a well-defined analytical method to measure the components. The goal is to get high-fiber foods to taste good and the FNB definitions limit a manufacturers ability to do this, says Bryan Tungland, a member of the AACC Dietary Fiber Technical Committee and vice president, scientific and regulatory affairs, Sensus America LLC, Monmouth Junction, NJ.
Current label claims
While the debate on how to update the definition of fiber and labeling regulations is just beginning, existing labeling regulations allow a number of claims that consumers as well as the food industry comprehend. The current Daily Reference Value (DRV) for dietary fiber is 25 grams. Low-fat foods that contain 20% or more of the DRV (5 grams) for dietary fiber qualify for a high-fiber claim and those with 10% to 19% (2.50 to 4.75 grams) can claim to be a good source of fiber. Foods that contain at least 10% more of the DRV either naturally or through fortification can claim this advantage when they are compared to a similar food.
FDA allows a health claim for fiber-containing grain products, fruits and vegetables and the prevention of some cancers. There are two claims for soluble fiber and the reduction of risk for cardiovascular disease one that only requires the presence of soluble fiber, and a stronger claim for the presence of soluble fiber from oats, psyllium, and alpha-amylase hydrolyzed oat bran or whole oat flour. Fruits and vegetables that are a good source of dietary fiber can also make a claim for reducing the risk of some types of cancer. Whole-grain foods that contain 51% or more wholegrain ingredients by weight, are low-fat, and contain a minimum amount of dietary fiber per serving specified in the regulation can claim the following: 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 some cancers.
Traditional breakfast fibers
A traditional breakfast commonly contains a number of high-fiber grain products. Whole wheat, oats and barley all contain significant fiber, but the form used to make a cereal or other grain-based food can dramatically lower the contribution of dietary fiber. Consumers cite color, texture and taste of wholegrain products as barriers to choosing them.
Not all grains are created equal in the type and quantity of fiber. Wheat bran is mostly insoluble fiber while oats and barley are mostly soluble, or viscous fibers. Whole-grain-based cereals, such as bran flakes, bulgur, oatmeal and barley, range from 2 to 8 grams of total fiber per serving; whole-wheat bread or a bran muffin is worth about 2.0 to 2.5 grams.
The dietary-fiber content of wheat flour varies from 1.7 grams per 100 grams in cake flour and 12.2 grams per 100 grams in whole wheat. Adding bran to pancakes, muffins and lower-fiber cereals is an easy way to up the fiber in a breakfast meal. Substituting whole-wheat flour for half of the all-purpose flour is also a simple way to increase fiber, but 100% whole-wheat substitution may require some modifications in the amount of flour used and the addition of gluten flour and water to achieve a lighter texture.
A variety of oat products are available for use in hot and cold cereals, breads and muffins, beverages and as a meat extender. Whole-oat groats are dehulled and heat-treated to stabilize enzymes that cause rancidity. Grinding whole-oat products through a hammer mill or rollers results in whole-oat flour of various granulations. By lightly grinding groats, millers create a meal-type product called crushed oats. Rolling whole-oat groats results in flakes as well as quick, baby and instant rolled oats.
Adding various oat products to breakfast cereals achieves the desired texture, taste and cooking qualities. Granola cereals could use large-flake rolled oats, quick rolled oats, baby rolled oats and/or oat flour. In a hot cereal, a thinner, large rolled oat or quick rolled oats are the forms of choice. Since extruded cereals can use whole-oat flour or low-bran oat flour, whole-oat flour works best for higher-fiber products. In bread and muffins, oat bran, quick and old-fashioned rolled oats, crushed oats and steel-cut groats are mixed with wheat flour. Currently, quick and baby rolled oats are used as meat extenders. Bran, a higher-fiber option once used in meats, is not an economical choice.
One possibility for expanding the availability of oat fiber at breakfast is creating oat-based beverages, made from a powder mix added to milk or juices; these are common in South America and Asia. The addition of small-sized oat particles in a convenient, easy-to-prepare, liquid meal-replacement product could provide dietary fiber in a smooth-textured beverage designed to appeal to todays consumer.
Defatted soy flour and textured-soy-protein products can supply additional sources of fiber in breakfast foods. Cereals and baked goods can mix soy flour with whole grains, while sausage patties or links might contain textured soy-protein products. Furthermore, the soy fiber that is removed during processing of other soy products can help increase fiber content when added to a variety of foods.
Other whole grains and seeds that appeal to the organic and health-conscious consumer include quinoa and flaxseed. Quinoa is a seed grain that originates from South America. According to Marjorie Leventry, R.D., vice president of marketing, Inca Organics, Chicago, organic-grown quinoa from Ecuador contains 14.5% dietary fiber, with 3% being soluble fiber. A typical serving cooked into a cereal with apple juice starts with 45 grams dry grain to yield about 3/4 cup. Currently available as flour, developers are working on a flake product. While quinoa flour has potential as an ingredient in breakfast bars, cost remains a barrier.
Mostly recognized today as a source of omega-3 fatty acid, ancient Egyptians first used flaxseed as a laxative. It contains about 28% dietary fiber with one ounce providing 32% of the Daily Value for fiber. A number of cold cereals now contain whole flaxseed, but ground flaxseed supplies the maximum nutritional benefit. According to Dennis Wiesenborn, professor in the departments of agricultural engineering and cereal and food sciences at North Dakota State University, Fargo, this can present a problem for processors, because the highly unsaturated omega-3 fatty acids quickly become rancid when exposed to air. He cites possible applications for using flaxseed in breakfast-type products as nutrition bars, due to their air-tight packaging, and beverages with a creamy texture, because of the soluble fiber in the hull. It is also possible to use ground flaxseed in baked products like muffins and bagels to achieve fiber content in the range of 5 to 10 grams. However, the presence of gums and fatty acids necessitates modifications in ingredients such as water, shortening and yeast, as well as in processing.
As natural sources of beneficial fibers, such as pectin, fresh and minimally processed fruits represent the other major category of high-fiber food at breakfast time. Dried plums are eaten by some in the morning for regularity. But many people will not consume them on a regular basis. Dried plums, which contain about 7% to 8% dietary fiber with 60% pectin, can add fiber to food products as a paste, puree, powder, juice concentrate, or very-low-moisture form. Their multifunctional properties make them ideal as an ingredient for a number of breakfast foods, but practical usage levels normally will not meet requirements for a dietary-fiber claim. Currently, some breakfast bars use the puree as a humectant. Jim Degan, advisor to the California Dried Plum Board, Temple, CA, says, It is best to blend dried-plum products with other high-fiber ingredients to get the desired taste and texture and the high-fiber claim. In bakery products, dried plum can serve as the base in fruit fillings, a fat replacer in batters and doughs, and a natural sweetener and colorant. Recently, the California Dried Plum Board introduced a new application idea for bakery products that utilize a Fit for Life Mix Formula a combination of dried-plum powder or puree with crushed wheat, flaxseed meal, and oat fiber to produce light, moist, tasty bread and rolls that are low in fat and high in fiber and other micronutrients. Another potential application for dried-plum products are breakfast meats, where a paste or puree adds fiber, texture and moisture to leaner cuts of meat, creating a tasty low-fat product.
Many cereals, muffins, bars and other breakfast foods on the market today contain fruit in low-moisture forms or as purees, but do not meet requirements for a fiber claim. Potential barriers to increasing the fruit content of these products include moisture control and cost, as well as consumer taste preferences. Tree Top, Selah, WA, makes a full line of apple ingredients that contribute fiber, including evaporated, freeze-dried, puffed, infused, pureed and frozen. In addition, they produce frozen cherries and plums, and blended fruit flakes and powders. Colored and puffed apple pieces, manufactured to mimic the texture and flavor of other fruits, make an economical choice for many breakfast products. Scott Summers, director, technical services at Tree Top, says, The product we sell with the highest dietary fiber is apple fiber powder which has about 47% dietary fiber. This is currently being used in an RTE cereal that is touting fiber. Functionally it is being used to coat sticky fruits in the cereal matrix. It is very difficult to get a fiber claim on fruit alone and usually necessitates an additional fiber-laden ingredient. Low-moisture apple has about 6% dietary fiber....Apple fiber, if used to coat other fruit, is limited to surface areas available and its gritty physical nature limits the amount you can add without negatively changing mouthfeel.
A number of ingredients commonly used in foods for processing and product functionality classify as dietary fibers. Some, such as traditional gums, cannot typically be added in quantities that would qualify for a fiber label claim without adversely affecting product quality and desirability. However, others present some real opportunities for increasing fiber in foods that consumers prefer.
Resistant starches (RS) are nondigestible by intestinal enzymes and occur naturally as physically inaccessible starch in plant cells (RS1); native granules found in some foods, like bananas and high-amylase maize starch (RS2); and retrograded, or crystalline, nongranular starch found in cooked and cooled starch-containing products, like potatoes, bread and cereal flakes (RS3). Resistant starch analyzes as dietary fiber under accepted AOAC methods and is estimated to be about 10% of starch consumption. The nutritional attributes of resistant starch have been widely studied. Some of its benefits derive from partial fermentation in the colon, where it contributes to the production of short-chain fatty acids and has prebiotic properties, as well as aids in laxation. Other observed benefits include a low glycemic response.
Resistant starches are produced commercially from various starch sources. Made from high-amylose cornstarch, Novelose and Hi-maize brands of resistant starch from National Starch and Chemical Company, Bridgewater, NJ, are GRAS and have proven functionality and benefits. A natural, mild proprietary process that uses only heat produces these white RS2-type granules with 40% to 60% dietary fiber and a bland taste. The company also manufactures an RS3-type retrograded nongranular maltodextrin with 30% dietary fiber through enzymatic processing. These products contribute functional properties that aid processing due to their low water-holding capacity, resulting in high-quality, good-tasting products that can meet dietary-fiber content claims. They can also withstand the rigors of most processing conditions.
Resistant starch can help add fiber to breakfast foods such as breads, muffins, lightly extruded cereals, bars and even a smoothie-type beverage if used at a low level. Rhonda Witwer, business development manager, nutrition, National Starch, says, There is a lot of science behind the health claims for our resistant starch. It is more natural than other resistant starches on the market. However, there is not one magic fiber. There are many benefits from fiber naturally found in the diet, and it appears that a mixture of fibers may have benefits beyond single fibers. It is clear, however, that resistant starch contributes benefits beyond that delivered by soluble fibers or other insoluble fibers.
Maltodextrin as fiber
Chemical processing of starch to create indigestible starch esters, ethers and cross-bonded starches produces resistant maltodextrins, which are referred to as RS4. Matsutani America, Inc., Decatur, IL, has manufactured and sold a digestion-resistant maltodextrin, Fibersol-2, since the early 1990s. Produced by a proprietary heat and enzyme hydrolysis of cornstarch, it analyzes as 90% soluble dietary fiber under an AAOC method approved in 2001 and is GRAS as maltodextrin.
About 50% of digestion-resistant maltodextrin is fermented in the large intestine, with 10% being absorbed in the small intestine and the rest excreted. While its true caloric value is less than the 4 calories per gram used for labeling purposes, it is still possible to create low-calorie and high-fiber foods, according to Steve Young, technical advisor for Matsutani America. He adds that it can be used in a variety of breakfast foods, including flaked or extruded cereals, breakfast bars, meal-replacement products (both liquid and dry), baked goods (bagels, breakfast pastries, etc.), and breakfast beverages, such as fruit/vegetable juices, fortified beverages, milk and other dairy drinks, coffee, etc. This also includes foods for diabetic and weight-management diets, as well as diet supplements.
This digestion-resistant maltodextrin offers many processing and formulation advantages. The off-white powder has a clean, neutral flavor, is highly soluble and yields a clear, transparent solution. It also disperses rapidly, binds water, and has low hygroscopicity and freeze/ thaw stability. According to Young, its primary advantage is that it is fully stable to heat and acid. This is not the case with resistant starches. Many resistant starches can vary in analytical fiber content in response to specific process and product applications. Fibersol-2 never varies in its fiber content no matter what product or process it is used in. Because this product is a refined fiber, formulators can use a high level in many applications without impacting desirable sensory properties.
Fortifying with fructans
Fructans, such as long-chain inulin and the shorter chain fructooligosaccharides (FOS), provide another opportunity to add fiber to common breakfast foods. Inulin is a natural component of many plants, such as chicory, artichokes, leeks and bananas. It classifies as a soluble dietary fiber and is partially fermented in the colon. Commercially, it is extracted from chicory roots and marketed as native inulin with a mix of long-, medium- and short-chain units, or hydrolyzed to contain only shorter-chain FOS. Both inulin and FOS are available in powder and liquid forms.
A number of health benefits are associated with inulin improved laxation, lower blood-lipid levels, prebiotic properties, enhanced calcium absorption and improved immune function. In general, these ingredients have low viscosity and are easy to incorporate in various food systems. Additionally, FOS has a low level of sweetness and can replace sugar in foods.
Most inulin/FOS products are self-affirmed as GRAS. But recently, after a review of data submitted by Sensus America, LLC, Monmouth Junction, NJ, FDA and USDA issued a nonobjection letter for the GRAS status of the companys inulin and FOS. This gives the green light for its use in all food categories, including nonstandardized meats, with the sole exception of infant formula. This creates many opportunities to add fiber to cereals, bars, beverages, baked goods and restructured meat. Tungland explains that inulin/FOS functionality in products is related to the balance of long-, medium- and short-chain FOS. Native inulin works in most products. In some, like a nutrition bar, the shorter-chain FOS acts as a humectant and increases shelf life. He goes on to cite the functional attributes of inulin/FOS in different breakfast foods: In cereal, it manages moisture migration and increases bowl life and shelf life; in beverages, it adds body and mouthfeel and allows for a smooth flow; and in a restructured poultry product, such as sausage patties, it makes a very effective binder and adds lubricity and snap. He adds that many of these foods can incorporate significant fiber up to 9 grams per serving in cereals, 10 grams per serving in restructured meat and in fortified water, up to 50% of the Daily Value for fiber.
Following the sugar beat
The dietary fiber in many naturally occurring food sources is a mix of soluble and insoluble fiber, and the fiber extracted from sugar beets is no exception. Marketed by International Fiber Corporation, North Tonawanda, NY, sugar-beet fiber contains 73% dietary fiber, of which one-third is soluble. Specific fractions include hemicellulose (29%), pectin (22%), cellulose (18%) and lignin (4%). Residual protein, sugar and minerals account for the other 27%. Because the company uses only water to extract the product, it is considered a natural fiber, and even comes in an organic version.
According to Jit Ang, executive vice president of research and development and business development at International Fiber Corporation, in addition to its dietary-fiber health benefits, sugar-beet fiber offers technological benefits in many breakfast foods due to its water-holding capacity of 3.5 to 5 times its weight. It can bulk up dietary fiber in all types of cereals, cereal bars, breads, bagels, sweet goods, and sausages that are nonstandardized meat products. In baked goods, formulators will need to adjust the amount of water and/or flour. Currently, the company is developing a high-fiber bread mix for bread machines to target the weekend time slot when families have more time for breakfast. He goes on to say that it is easy to add enough fiber to make a health claim in breads, muffins or cereals, yet still have moist and tasty products. Fat reduction is an added benefit in many typical high-fat foods, such as doughnuts and sausage.
Cellulose use grows
Available for decades, cellulose, the insoluble structural fiber in many plants, was perhaps the original fiber used for food fortification. The International Fiber Company markets a number of brands of powdered cellulose. Cellulose is extracted from trees, its most economic source, using acid or alkali under high-temperature, high-pressure conditions. After washing and bleaching, the purified cellulose is then made into cellulose powders, gels and gums. Powdered cellulose works well in baked goods and powdered drinks. With a 99% dietary-fiber content, low-level additions in many products can result in a fiber claim with functional and economical benefits. Ang points out: Fibers are more expensive than fat, sugar or flour.
Therefore, the ingredient cost of a food product may go up when you add fiber. However, fibers can provide many functional benefits other than fortification. These added benefits (that lead to improved quality) are often more than enough to offset any ingredient cost differential.
Research has shown the presence of antioxidant activity and demonstrated a cholesterol-lowering effect from carob-fiber consumption. As an insoluble fiber with high water-binding capacity, it also contributes to improved intestinal motility and bowel function. Potential applications include bars, cereals, baked goods, chocolate-containing products and beverages. Bill Riha, manager, food technology at Nutrinova, says that this product is GRAS because it is considered a carob product, a part of the human diet for centuries. He points out that its major limitation is its color, it has to be used in brown (products). An insoluble fiber, carob can give a gritty feel to beverages that gums and thickeners can help overcome.
In general, viscous fibers tend to lower blood cholesterol levels, especially LDL-cholesterol. Purified fibers found in foods include guar gum, karaya gum, konjac mannan, locust-bean gum, pectin and xanthan gum. Of these, clinical studies with guar gum and pectin provide sufficient evidence of improved lipid profiles and attenuation of blood-glucose responses, and the FNB cites both as functional fibers associated with reduced risk of coronary heart disease. In normal food and beverages, it is generally difficult to add sufficient quantities of these gums alone to reach a fiber claim. Currently, partially hydrolyzed guar gum is the basis for a series of medical foods, which include a basic powder, ready-to-use juice drinks and cereals, aimed at adding fiber to the diets of those with special medical needs. Pectin is added to jams and low-calorie gelled products, such as sugar-free jams and yogurts.
Potential high-fiber applications
The creation of high-fiber foods and beverages for breakfast consumption can easily encompass todays trends for nutritious, quick-to-prepare and easy-to-eat products. Obvious options include cold cereals and instant hot cereals in individual packets, breads, muffins and other baked goods, cereal/nutrition bars, dairy products and meal-replacement beverages. Dried plums, inulin or sugar-beet fiber offer new opportunities in nonstandardized meat products.
Product developers should strive to incorporate more traditional breakfast fibers from grains and fruits in processed foods and beverages. They should also take advantage of the wide variety of high-fiber ingredients to design products that meet consumers sensory expectations and need for dietary fiber, recognizing that each type of fiber offers a different physiological and technical benefit. A successful high-fiber product might encompass the use of multiple fibers, woven together in formulation to help consumers find the breakfast foods that will lead them towards better dietary health.
Angela M. Miraglio is a registered dietitian and Fellow of the American Dietetic Association from Des Plaines, IL. She has extensive experience in trade communications, public and consumer affairs and technical communications, as well as product development and nutritional assessment. Her firm, AMM Food & Nutrition Consulting, provides food and nutrition communications and technical-support services to food and beverage companies, and trade and professional associations. She can be reached via e-mail at [email protected].
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