Gel breakthrough gets rid of the grittiness in fiber-rich foods

COPENHAGEN, Denmark — People need 25 to 30 grams of fiber daily, yet many of us have a hard time reaching this mark through our current diets. One way to entice people to eat more fiber is to make it tastier. In a study published in the journal Food Hydrocolloids, researchers have found a way to disguise the dry, gritty mouth feel people often associate with eating fiber-rich foods.

Fiber is vital for human health and has been shown to help lower the risk of heart disease, diabetes, and colon cancer. Low levels of fiber contribute to nearly one million deaths annually. Despite its importance, people often avoid fiber-rich foods, such as wheat bran, vegetables, and whole grains. Insoluble dietary fibers often contain an unpleasant, gritty sensation that make them less appealing to eaters.

“If we don’t like it, we don’t eat it. It’s that simple. And no one would enjoy eating grainy flour – but that’s roughly what the sensation of insoluble dietary fibers often produces, especially added to more liquid foods like yogurt, juices, and beverages,” says study corresponding author Lilia Ahrné, a professor at the University of Copenhagen’s Department of Food Science, in a statement.

The team notes that insoluble fibers often go well with bread but not with many other foods.

“This is why there is such a limited selection of fiber-rich foods and beverages. And that’s why it’s important to figure out how to incorporate fibers into more foods without causing a bad eating experience,” Ahrné continues. “The more variety there is in fiber-rich products, the greater the likelihood that people will increase their fiber intake. And now, we have a potential solution.”

The current study devised a method to hide the gritty mouth feeling when eating fiber-rich food to get more people to increase their fiber intake. The structure of chia seeds and their soft, gel-like layer surrounding the food inspired them to make pea cell-wall fibers in a gel to form a coating around fiber particles. 

The gel is both flavor and odor-free. It is made of gellan gum created by bacteria and is already used in other food sources. The process of creating the gel capsules is feasible but involves precise steps like temperature control and viscosity management.

Instead of a gritty feeling in the mouth, the gel-encased fiber particles create a velvety texture — similar to cream on the tongue. The soft gel layer stops the fiber particles from being sensed by the eater’s tongue.

“Since the gel is at least as soft as tongue tissue, it doesn’t trigger the sensory receptors, and we don’t perceive the gritty texture,” says study first author Gabriele D’Oria, a former PhD student in the Department of Food Science at the University of Copenhagen.

The researchers recruited people to taste test the gel-coated fiber particles and asked them to describe the taste. With the gel coat, participants reported a 52% reduction in the perception of fiber particles in their mouths. Additionally, the gel helped lower the sensation of grittiness by 42% and mouth dryness by 36%.

“We have now demonstrated that gel coating works. The gel can be refined and adjusted depending on the purpose. And in principle, the method can be used for all types of foods and beverages,” adds D’Oria.

Researchers hope the findings help with a global nutrition issue where people of all ages lack fiber by creating more appetizing fiber-rich food options. While the study did not specifically target elderly populations, its findings could help address fiber-related health concerns in older adults, such as digestive issues and frailty. The gel capsule method could complement efforts to create more sustainable, plant-based dietary options by utilizing fiber-rich by-products.

“We are all aware of the need to shift to more plant-based diets,” Ahrné concludes. “If we can understand how to address the negative experiences of eating dietary fibers, we can better utilize fiber-rich by-products, such as bran from grains, in a sustainable way.”