June 7, 2011
by Laurie Gorton
Americans don’t eat enough dietary fiber. Every formulator working on health-and-wellness products knows that fact. Now, the 2010 Dietary Guidelines for Americans have called even more attention to the situation, naming dietary fiber as one of four underconsumed nutrients. (The others are potassium, calcium and vitamin D.) The guidelines recommend 14 g of dietary fiber per 1,000 Cal consumed, with 25 g per day for adult women and 38 g per day for adult men. Yet current intake levels average just 15 g per day.
While both insoluble and soluble dietary fiber benefit health, the soluble form especially promotes a healthy cardiovascular system and helps maintain blood sugar and cholesterol levels within normal limits. If Americans are to reduce their risks of heart problems and diabetes, they have to eat more fiber.
But consumers can be fickle in food choices, and they are less likely to take dietary supplements. They want their nutrients to come via foods they already like and eat.
IN THE TOOLBOX.
Formulators wanting to add dietary fiber to baked foods can pick among many sources, including cereal bran and whole-grain ingredients, but they may be overlooking something that has long been part of their toolbox: the food gums typically used to stabilize and modify texture.
“As a matter of fact, food gums are synonymous with soluble fiber,” said Mar Nieto, PhD, principal scientist, TIC Gums, White Marsh, MD.
Gums can be more appropriately defined as all water-soluble tree saps/exudates and all other mucilages that are complex polysaccharides and form colloidal suspension in water but are not digestible by human enzymes, he explained. That nondigestibility qualifies them as fiber. Ingredients that qualify as soluble fiber include those with the word “gum” in the name (guar gum, xanthan gum, locust bean gum, tara gum, gum Arabic), plus inulin, pectin, agar, CMC and other cellulose derivatives as well as konjac, gellan, carrageenan, resistant starch, resistant maltodextrin, arabinoxylans and lignin.
Most food gums are 80% soluble dietary fiber on a dry weight basis, higher than other sources such as oat or wheat bran. “Remember that soluble fiber includes only the polysaccharide portion of the gum,” Dr. Nieto said. Gums contain some water, minerals or salts and, in a few cases, protein. These components vary from gum to gum and account for 10 to 35% of the weight.
IN THE RANGE.
Gums range from slightly viscous to very viscous, from thin to thick, thus allowing selection according to finished product performance needs.
“Product formulators need to understand that some gums have compatibility issues with gluten-containing products such as breads,” Dr. Nieto said. “Furthermore, even if a gum is not compatible with gluten, it may be too viscous, which will limit its usage to a level below the functional dose for fiber.”
In the US, fiber content claims are based on the Daily Reference Value (DRV) of 25 g. To claim to be a high” source of fiber, the food must deliver 5 g or more per serving, which is 20% of DRV, while “good” source describes foods with 2.5 g to 4.9 g per serving, or greater than 10% of DRV.
“Those doses are difficult to achieve using viscous gum fibers, but [such hurdles] are easily overcome with fiber blends composed of thick and thin gum ingredients,” Dr. Nieto explained.
Many low-viscosity gums are incompatible with gluten, but cookies, cakes, crackers and so forth — products that do not rely on gluten for their structure — are much easier to fortify with fiber using gums. TIC Gums offers proprietary blends (Ticaloid LC-SR 5 and Ticaloid LC-SR 6) that can replace up to 20% of flour in high-fiber bread with minimal effect on the gluten structure. For cookies, cakes and crackers, low-viscosity gums such as gum Arabic, inulin, resistant maltodextrin, resistant starch, arbinoxylans, low-viscosity CMC, methylcellulose and guar may be used in combination with one another.
Formulators should also be aware that soluble dietary fiber is a prebiotic, a source of energy for beneficial bacteria living in the human gut. This extra functionality supports additional positive label implications.
TIC Gums publishes application advice, reports, newsletters and blogs about its food gums at www.ticgums.com/innovation-center/soluble-fiber.html