Using both soluble and insoluble fibers together in baked foods will offer several formulation benefits in high-fiber items.

“Using a combination of soluble and insoluble fibers is often a good strategy because each type has positive and negative properties and using a blend can minimize the downside,” said Julia DesRochers, PhD, principal scientist, technical service, Tate & Lyle. “For example, in bread applications, high levels of soluble fiber can delay dough development and produce a slack dough. In contrast, high levels of insoluble fiber can compete with flour for water resulting in a tight inextensible dough and a chalky, mouth-drying texture in the finished product. A combination of both really helps reduce those problems.”

Both soluble and insoluble fiber ingredients may be added to offer technical properties and health benefits, said Kyle Krause, regional product manager, functional fibers and carbohydrates, North America, Beneo. 

“Soluble fibers are more common for sugar reduction and replacement,” he said. “Inulin and oligofructose are soluble fiber ingredients that can provide technical benefits like sugar-like sweetness and moisture retention while improving overall nutritional profile as prebiotic dietary fiber.  Chicory root fiber is therefore a versatile ingredient in sugar and fat-reduced baked goods, without sacrificing taste and texture.”

Understanding how each fiber will affect individual products will help formulators decide which to use.

“For crispy and crunchy products, insoluble fiber can contribute to that texture and sometimes help prevent breakage, and on the other hand, for chewy and moist products, soluble fiber may be a better fit,” said Liyi Yang, senior associate, global applications, bakery, snacks and confectionary, Ingredion.

A blend of fibers, even if they’re both soluble, can help reduce gas and bloating in users, which can be a problem when a significant portion of fiber is added to baked goods.

“A common challenge is adding too much fiber that triggers gastrointestinal (GI) issues,” said Thom King, chief executive officer, Icon Foods. “In a baked good, I would not add more than 10% to 11% of the total weight of the solution in added fibers. And that’s only if you’re stacking fibers. If you’re using a single fiber, 5% to 6% of the total solution weight can trigger GI response like gas, bloating. But stacking different types of fibers, like an inulin or FOS, fructooligosaccharides, with soluble tapioca fiber can overcome that pitfall.”

Because fiber impacts the moisture in a bakery formulation, shelf life can also become an issue when adding fiber to baked goods.

“The amount of water that is baked out or free in the system can impact shelf life,” said Brook Carson, vice president, R&D, Manildra Group USA. “Even the rate at which that water is released post-bake can impact shelf life.”

A fiber that competes for water may cause undesirable textural changes, DesRochers said. 

“The solubility of a selected fiber may help to prevent some of this issue, for example using a highly soluble fiber,” she said. 

Because dry ingredients compete for water in a formulation, bakers need to optimize the ingredient blend to ensure that water is bound by the most functional ingredients, said Cynthia Machado, PhD, senior technical and business development manager, global ingredients, Blue Diamond Growers. Otherwise, the product will lose its soft texture and dry out more rapidly.

“For example, if a fiber that has poor water binding properties is used, it can negatively impact the shelf life of the product,” she said. “This can occur because a fiber with poor water-holding capacity will only hold the water temporarily, consequently keeping it from other ingredients that have superior water binding capacity.”

Packing fiber into baked goods is beneficial for Americans, but formulators must be aware of the formulation challenges. Weighing the options and understanding the benefits of each will help bakers find the best solutions and produce products that are tasty and healthful.

This article is an excerpt from the February 2024 issue of Baking & Snack. To read the entire feature on Fiber, click here.