While the optimal amount of daily fiber intake varies by age and gender, the Dietary Guidelines for Americans 2015-2020 recommends 14 grams for every 1,000 calories of food consumed. For an average adult, this is about 25 grams for women and 38 grams for men. Unfortunately, most Americans consume about half of that and have been in this shortfall for some time. That’s why the U.S. Food and Drug Administration considers fiber a “nutrient of public health concern.” Deficits in consumption are associated with potential health risks.
To shore up the difference between recommendations and actual intake by the typical American who eats too many processed foods or may have a diet trending high in protein, many would need to significantly increase their daily calorie intake. With obesity at such high levels, this is not wise. That’s where fiber enrichment of everyday foods such as baked goods, a traditional source of grain-based intrinsic fiber, help bridge the gap.
Developing the definition
The F.D.A. defined fiber — for the first time — on May 27, 2016, as “non-digestible soluble and insoluble carbohydrates (with three or more monomeric units), and lignin that are intrinsic and intact in plants; or isolated or synthetic non-digestible carbohydrates (with three or more monomeric units) determined by F.D.A. to have physiological effects that are beneficial to human health.” On June 14, 2018, the agency published final guidance on the second type of fibers, growing the toolbox of ingredients available to bakers.
“Reaching a final decision on fiber sources that count toward fiber labeling helps manufacturers develop products with higher fiber content,” said Troy Boutte, principal scientist, DuPont Nutrition & Health. “Fibers add cost to products and are usually added as a selling point. So, most fiber products would not be added if they don’t contribute to fiber claims.”
Because fiber ingredients contribute fewer calories and health benefits, they will remain a mainstay in product development efforts, said Mike Buttshaw, vice-president of ingredients sales and marketing at MGP Ingredients.
Benefits recognized by the F.D.A. include lowering blood glucose and cholesterol levels, lowering blood pressure, improving laxation, increasing mineral absorption, and bolstering satiety. These often are recognized as being specific to the fiber’s solubility.
Soluble fibers include beta-glucan, fructooligosaccharides (FOS), galactooligosaccharides (GOS), gums, inulin, pectin, polydextrose, psyllium, some hemicelluloses and resistant maltodextrin. Many absorb water and form a viscous gel that traps dietary cholesterol and bile acids and carries them out of the body. This viscous solution also has been shown to trap carbohydrates, slowing their digestion and absorption. This may help prevent wide swings in blood sugar level during the day as well as impact the development of adult-onset diabetes.
Some soluble fibers such as inulin, FOS and GOS are not viscous; rather, they are fermentable. They function as prebiotics to promote the growth of beneficial intestinal bacteria.
Non-viscous insoluble fibers include such as lignin, cellulose and some hemicelluloses. Many vegetables and cereal grains are rich in insoluble fiber, with the highest amounts in wheat and corn.
There’s a third type of fiber known as resistant starch and, as its name suggests, is a starch that resists digestion in the small intestine. It is not soluble in water yet is fermented like a soluble fiber in the colon.
Dietary guidelines recommend a mix of these types of fibers, which makes the growing toolbox of fiber ingredients attractive to bakers. Some impact product formulations; others may be added seamlessly at defined usage rates.
“Qualifying more sources of fiber will help diversify consumer diets, which in turn will promote wellbeing,” said Jennifer Stephens, vice-president of marketing, Fiberstar, Inc. “However, not all fibers are the same. Each has its own functional role when incorporated into food.”
Including a larger number of fibers makes it easier to develop products that meet fiber claims. Products with 2.5 grams or more per serving may claim they are a “good source of fiber.” Those with 5 grams or more may be described with a high-fiber claim.
Intrinsic and intact
Whole grains and the flours made from them are natural sources of dietary fiber. They meet the F.D.A.’s definition of “intrinsic and intact” dietary fiber.
“While dietary fibers are mostly concentrated in the bran layer, they are also present in the endosperm of grains,” said Sumana Chakrabarti-Bell, principal scientist, Ardent Mills. “Both whole grains and the bran qualify as dietary fiber.”
One such example is high-amylose wheat flour from Bay State Milling Co. This is a whole food source of resistant starch dietary fiber. It is 100% wheat flour that delivers up to 35% dietary fiber.
“It was automatically approved as a source of fiber under the new definitions,” said Colleen Zammer, senior director of marketing and product development. “It is fiber that comes directly from the farm; it is a special variety of wheat that contains substantially higher levels of amylose starch in the endosperm than common wheat varieties. It is milled into flour in the same manner as common wheat and delivered to bakeries and manufacturers as wheat flour.”
The high-amylose flour functions exactly the same as common wheat flour in terms of gluten strength and stability, while absorbing more water, which reduces bowl costs for the baker, Ms. Zammer said.
Whole grain ingredients are familiar to most bakers, and new forms allow for creativity.
“A baker may take an artisanal or holistic approach when adding fiber in the form of whole grains,” said Laurie Scanlin, R.&D. culinary manager, Ardent Mills. “The broad array of grains, flours and flakes available allows for limitless culinary versatility.”
Ardent Mills offers black, blue and purple barleys that provide bursts of color in what might be traditionally beige-colored foods.
“We have a proprietary identity-preserved, hull-less barley that delivers three times the fiber of oats and 10 times that of brown rice,” said Don Trouba, senior director, go-to-market, The Annex by Ardent Mills. “Dietary fiber makes up more than 50% of the carbohydrates in this high-fiber barley and 40% of that is in the form of cholesterol-lowering soluble fiber that can be used to increase the thickness in fillings and can impart texture and visual appeal.”
Corn bran is another concentrated source of intact and intrinsic dietary fiber.
“It’s allergen-free, gluten-free and familiar, appearing on ingredient statements as simply ‘corn bran,’” said Keith Smith, regional technical service lead, Cargill.
The company offers a Non-GMO Project-verified corn bran.
Citrus fiber, with the lignin intact from the citrus source, aligns with the F.D.A.’s definition. This product can be labeled as citrus fiber, dried citrus pulp or citrus flour. Fiberstar works with citrus juice processors to reclaim the fibrous residuals from their process.
But not all citrus fibers are the same. Some are byproducts of the pectin extraction process. Fiberstar’s citrus fiber is about 75% total dietary fiber, with half being soluble and the other half insoluble. It also contains about 8% protein. The composition assists with moisture retention, improved emulsification and stabilization of water and oil through challenging conditions such as freeze/thaw and baking. Because this citrus fiber contains pectin, it is also applicable for fruit-based bakery fillings.
Greg Dodson, vice-president, fiber, at ADM, explained that as consumers seek out foods with clean labels, fewer added sugars and better-for-you ingredients, the company expects fiber to remain a trusted ingredient among developers and consumers.
This article is an excerpt from the March 2019 issue of Baking & Snack. To read the entire feature on fiber, click here.