Dietary fiber can play a positive role in helping to control cholesterol, blood glucose and body weight (the latter through appetite regulation). Regular consumption also may help reduce the risk of colon cancer, cardiovascular ailments and other diseases.
Fruit Fibers: Nutrition and Functionality
Plant-derived dietary fibers are resistant to digestive enzymes in the stomach and small intestine. However, they are broken down completely or partially into catabolites by fermentation in the large intestine—for example, butyrate, which the human body absorbs and utilizes. Cereals, fruits and vegetables are the primary sources of fiber, said Frank Mattes, president of Herbstreith & Fox Inc., in his presentation on fruit fibers. The American Dietetic Association recommends a daily dietary fiber intake of about 1oz (20g-35g) per day, but average consumption is only half an ounce.
Fiber addition can be based purely on physiological aspects, but fibers also offer technological benefits. In addition, fruit fibers can influence food rheological properties.
Three factors "plant type, specific plant tissue and manufacturing process" strongly influence the physical and chemical properties of dietary fiber ingredients, such as water and ion binding, solubility, swelling, flavor and nutritional benefits. Depending on the refinement process, fruit fibers are characterized by the flavor of the source fruit. Additionally, these fiber products also carry high amounts of secondary plant substances, such as flavonoids. Research indicates these compounds may strengthen capillary resistance, prevent oxidation of low-density lipoprotein (LDL) cholesterol, chelate heavy metals and prevent ascorbic acid oxidation.
Fruit fibers derived from apple, citrus and other fruits with a high content of soluble fiber have relatively good water-binding and -swelling properties. They can help provide a smooth mouthfeel in products. Greater purification of these ingredients increases fiber content and produces products with a more neutral taste. Their higher water-binding capacity means they can thicken and stabilize products.
Their cold-swelling properties mean they are readily dispersible and easy to handle in production. The fibers are shear-stress stable, and the texture formed has good heat and freeze/thaw stability. With their extraordinary swelling capability, fruit fibers are an ideal base for beverage powders or fiber bars that promote weight reduction. It also is possible to produce reduced-calorie ice cream with a pleasant mouthfeel and enhanced stability. Replacing fat with fruit fiber ingredients can result in low-calorie sausages. Other application areas include dairy foods such as low-fat cheese products. In bakery products, calorie reduction and water-binding are of interest, resulting in extended shelflife.
"Fruit Fibers: Nutrition and Functionality,"? Frank Mattes, Herbstreith & Fox Inc., f.mattes@herbstreith-fox.com, www.herbafood.de
A Glycemic Index-reducing Prebiotic
Acacia gum can be used to create healthful products of increasing interest to consumers. A greatly expanded growing region in sub-Saharan Africa has resulted in a consistent supply of this all-natural fiber, noted Sebastien Baray, U.S. technical manager with Colloides Naturels Inc., in his presentation "Fiber Fortification with Acacia Gum."
Baray recounted a variety of nutritional trends: One third of U.S. adults consider their diets deficient in fiber, and there is a strong understanding of the link between fiber and overall health. Also, insulin resistance and diabetes are approaching epidemic status, with diabetes cases expected to increase 19% between 1999 and 2010 worldwide. Four out of 10 consumers are aware of dietary fiber's role in prevention and management of diabetes, and 18% of U.S. consumers say they look for a Glycemic Index (GI) on food labels, he said.
An ideal nutritional ingredient is of relevant nutritional interest to consumers, is supported by scientific data, has a natural origin, is compatible with industrial processing and results in an enjoyable food with no negative side effects. Acacia gum is an all-natural, non-genetically modified (GM) fiber that meets all of these criteria.
The molecular structure of acacia gum consists of polysaccharide sub-units attached to a proteinaceous core. This complex structure explains the low viscosity and high resilience of the fiber. Acacia gum can be used to fiber-fortify products with no negative impact on their texture.
Research (C. Cherbut, et al., 1999) with 10 human subjects consuming increasing amounts (10g-70g/day) over 100 days showed lowered negative symptoms such as bloating, flatulence and cramping compared to fructo-oligosaccharides, with symptoms generally not appearing until doses neared 50g/day. The same study demonstrated acacia fiber's prebiotic benefits—at 10g and 15g/day, there was a four-fold increase in "friendly bacteria." Another study (Rochat, et al., 2001) showed acacia gum had a prebiotic effect at only 6g/day.
Lately, acacia gum has been proven to decrease significantly the GI of some products in which it is added. A study at the University of Sydney in 2004 with 12 healthy volunteers showed the addition of 6% acacia gum reduced crisp bread's GI by 11.5% and its insulin index by 19%.
"Fiber Fortification with Acacia Gum," Sebastien Baray, Colloides Naturels Inc., sbaray@cnius.com, www.cniworld.com
Formulating with Inulin, the Invisible Fiber
The "invisible" fibers inulin and oligofructose offer the perfect solution to formulating many healthful foods. Extracted from the root of the Belgian endive plant (chicory root), inulin and oligofructose offer a host of functional and nutritional benefits, explained Hilary L. Hursh, technical project leader with Orafti Active Food Ingredients.
Inulin is a broad term for polymers of 2-60 fructose units, while oligofructose (OF) is a more specific term for chains of 2-10 fructose units. The chains of fructose are linked by b 2-1 bonds, which cannot be broken down by the body's enzymes. Inulin and oligofructose arrive in the colon intact and are fermented by beneficial bacteria. Overall, they contribute only 2kcal/g and do not influence blood glucose levels or the secretion of insulin. These properties make inulin and oligofructose safe for diabetics and also ideal for people looking to maintain a healthy body weight.
Inulin and OF also stimulate bifidobacteria growth and activity in the colon, which in turn helps decrease risk of digestive illness, recovery time after diarrheal disease and colon cancer risk. Additionally, enriched inulin has been proven clinically to boost the body's absorption of calcium in the colon and to increase bone mineral density.
Because chicory root fiber is soluble, it is very easy to incorporate it into a wide range of products, including baked goods, bars, beverages, cereals, confections and dairy products. OF replaces the bulk of sugar, while contributing 30% of the sweetness of sucrose and also contributes to Maillard browning and masks off-notes often associated with artificial sweeteners. These flavor-masking properties also can be used to cover the bitter flavor of vitamin/mineral mixes, the sour flavor of yogurt and the beany flavor of soy. Additionally, inulin can act as a healthy replacement for fat. Long-chain inulin contributes a creamy mouthfeel to low- and no-fat products by forming a particle gel that has a short fat-like texture. This texture is particularly useful for low-fat table spreads, cream cheeses and frozen desserts.
"Formulating with Inulin, the Invisible Fiber," ? Hilary L. Hursh, Orafti Active Food Ingredients, hhursh@ orafti-us.com, www.orafti.com
Flaxseed: Is it a Whole Grain?
Flaxseed is one of nature's most complete whole-grain ingredient packages, and is composed of omega-3 fatty acids, dietary fibers, lignan phytoestrogens, antioxidants and other phytonutrients. This nutrient-dense whole food can be used in many ways to enhance the value of baked goods. "Flaxseed:Omega-3, Fiber and More. Is it a Whole Grain?" by Linda Pizzey, president of Pizzey's Milling, highlighted components in flaxseed, their role in human nutrition, and what the marketplace is saying.
To date, the Whole Grains Council does not accept flaxseed as a whole grain, and the FDA has not ruled on it. However, flaxseed contains the three components needed by a seed to be a whole grain—a bran, endosperm and germ. Pizzey quoted a July 2005 Baking Management article in which Lynn Gordon, president of Meadow Bakery, noted, "The benefits of whole grains are in the whole grains and not the claims."
The rich soluble-fiber component of flaxseed, added to its oils, makes it a solution for the replacement of trans fats in many bread and roll applications. Some 28% of flaxseed is dietary fiber in which 30%-40% is soluble fiber and 60%-70% is insoluble fiber
This fiber also contributes to the anti-staling effect of flaxseed. The inclusion of up to 8% flaxseed in a bread formulation will completely replace all other oils, helping to bind moisture, giving the smooth mouthfeel of soluble fiber and mimicking the properties of the oil it has replaced.
Structure function claims, or claims that describe the effect a food product has on the normal structure or function of the body, have been shown to be the most widely read and understood of all label claims on food products. These types of claims now can be used on products that incorporate flaxseed. Such statements as "alpha-linolenic acid (ALA) omega-3s support cardiovascular health" are acceptable on a food label that incorporates as little as 1.3g of flaxseed per serving.
Recent testing has shown flaxseed to be oxidatively stable for more than 10 times as long as other refined sources of omega-3, arguably because of its powerful cocktail of antioxidants and other phytonutrients. This strengthens the argument for using the whole foods approach to adding nutrients to bakery goods.
"Omega-3, Fiber and More. Is it a Whole Grain?" Linda Pizzey, Pizzey's Milling, linda@pizzeys.com, www.pizzeys.com
Dietary Fiber: A Food Technologist's Perspective
Unlike other nutrients, "dietary fiber" (for nutrition labeling purposes) is defined by the method(s) used to measure it, noted Steven Young, principal, Steven Young Worldwide. Over 20 definitions were proposed between 1987 and 2001, with the American Association of Cereal Chemists (AACC) in 2000 and National Academy of Science (NAS) in 2001 proposing the two most recent descriptions. However, none are recognized for nutritional labeling purposes. Definitions and methods of analysis are evolving, as is ingredient science and technology, application technologies and marketplace demands.
The number of foods, beverages and dietary supplements containing dietary fiber has been growing at an annualized rate of 8% (by volume) since 1996. This translates to ~$20 billion (U.S. retail value) in products for 2006. Also by 2006, an estimated 25% of this volume will be attributed to "carbohydrate modified" products, i.e., fiber-enhanced, low-/no-sugar, low-/no-"net carb," low-calorie, medical foods, foods for special dietary purposes (diabetes, weight loss, etc.), dietary supplements, etc.
In the U.S. alone, over 60 individual ingredients are sold primarily as sources of dietary fiber. From a product developer's perspective, selection and use of any dietary fiber ingredient is related to composition (dietary fiber content, accompanying nutrients), functionality (e.g., flavor, color, texture, etc.), nutritional efficacy, labeling, availability and cost. Composition including composition of "minor" nutrients can vary significantly ingredient to ingredient.
Also important are nutritional efficacy and labeling considerations. The availability of sound nutrition science, the amount and type of any given dietary fiber, and the specific application to be considered dictate what can and cannot be said about the finished food product. Labeling considerations include front panel declarations, nutrient content claims, ingredient listings and any implied, structure/function or full or qualified health claims that might be available.
Economics also plays a role. (See chart "Cost of Dietary Fiber.") When properly selected and used, dietary fiber ingredients can lead to new, novel application opportunities. Such applications include dairy foods (fluid, frozen, cultured, fermented), baked goods (yeast raised, chemically leavened, sweet goods), beverages (dry/liquid, still/carbonated, cold/hot filled, pasteurized, ultra hot temperature, aseptic), cereals (ready-to-eat, hot, flaked, extruded), snack foods (fried, baked, cold extruded), confections (hard and soft candies, bars) and even processed meats (ground, emulsion types, coarse ground, whole muscle).
"Dietary Fiber: Issues & Opportunities, A Food Technologist's Perspective," L. Steven Young, PhD, steve@stevenyoung.net, www.stevenyoung.net
