³ÉÈËÊÓƵ

Researchers in South Dakota State University's Department of Dairy and Food Science, led by associate professor Srinivas Janaswamy, have created a novel type of bread by pocketing healthy compounds inside of starch granules. Early findings show this "functional food" may help with blood sugar management and disease prevention.

To the human eye, starch — a complex carbohydrate that is one of the greatest sources of energy for humans — appears to be a very fine, white powder. But underneath a microscope, starch granules emerge as seemingly imperfect tennis balls. Some are oval, some are round, and some are in-between — but all have that same general "round-ish" shape.

This gave South Dakota State University associate professor Srinivas Janaswamy an interesting idea. Over the past few years, Janaswamy had noticed a growing demand for "functional foods" — food that has health benefits beyond basic nutritional value — and wanted to develop his own novel functional food.

With a background in food science, Janaswamy had ideas of what types of could be developed but ran into various problems along the way. What he really needed was a carrier system that, for example, could provide the body with healthy compounds needed to fight diseases.

Starch granules, Janaswamy hypothesized, could be the perfect carrier for his novel idea.

Healthy compounds 
Fruits and vegetables are considered healthy foods because of the compounds found in them. , with their antioxidant and anti-inflammatory properties, are particularly notable due to their potential in disease prevention. These compounds are found abundantly in almost all fruits and vegetables. 

But the challenge with polyphenols is their bioavailability in the body. Polyphenols have low bioavailability for a variety of reasons, some of which are related to digestion. A good example of this is , a compound found in the roots of the turmeric plant that has proven beneficial to diabetes complications. But for curcumin to provide these benefits to the body, it needs to make it to the gut — which it rarely does.

In the field of food science, researchers have been using a process called "encapsulation" to control the stability and release of polyphenols during the digestive process. Janaswamy had also previously utilized this process in his work. In the early stages of his research, he found that oriented polysaccharide fibers could be used to encapsulate different polyphenols.

"The combination of both the functional ingredient and the carrier system is highly important to creating a functional food," Janaswamy said.

The roundish shape of starch granules, Janaswamy thought, would make for the perfect carrier system to encapsulate, or "pocket," compounds in by creating pores on them.

A novel functional food 
After researching many different food and compound combinations, Janaswamy and , a doctoral candidate at ³ÉÈËÊÓƵ, decided to develop a wheat bread made with porous starch loaded with curcumin or resveratrol — an antioxidant polyphenol found in red grapes.

"Porous starch has demonstrated significant potential due to its capacity to safeguard encapsulated polyphenols, which enables a gradual release during the digestive process," Janaswamy explained. "The holes and concavities increase the absorption rate of polyphenols into the starch granules."

In the experimental phase of the research, Janaswamy and Wahab prepared seven different types of breads: a white bread without any added compounds and six other breads with varying levels of curcumin or resveratrol. Previous research has shown that adding certain polyphenols to white bread can cause bitterness and "off flavors." However, encapsulating them in porous starch granules can alleviate these concerns, Janaswamy says.

"The incorporation of curcumin and resveratrol impacted the physical characteristics of bread," Janaswamy said. "These findings further highlight the significance of carefully determining the concentration of bioactive compounds in food formulations to achieve optimal nutritional and physical properties."

One of the key findings during the experimentation phase was the antioxidant activity of the breads. The curcumin and resveratrol variations showed much higher antioxidant activity than white bread. Antioxidants have proven to help reduce risk of disease, including heart disease and certain cancers.

The higher concentrations of polyphenol-loaded starch granules were also found to reduce the rate of starch hydrolysis of breads. Starch hydrolysis is the process of breaking down starch into smaller sugars, like glucose. Slowing down starch hydrolysis implies a slower starch digestion process, which will aid in lowering the glycemic response when consuming polyphenol-enriched breads. This could lead to a more gradual release of glucose and could potentially alleviate diabetes complications. Janaswamy notes that further research must be conducted to verify these concepts, however.

But the encapsulation of polyphenols is the key to the development of the team's novel functional bread, Janaswamy said. The starch granules act as a physical barrier, which allows the compounds to have greater bioavailability over a longer period of time in the body.

"The results of this research suggest that our approach has the potential to enhance the nutritional value and functional properties of bread products," Janaswamy said. "They also provide the scientific fundamentals necessary for creating more nutritious bread options for consumers."

The research team's bread improves antioxidant retention and better controls starch digestion, both of which will help blood sugar management and prevent chronic diseases. While more research needs to be completed before this novel functional food reaches the shelves of local grocery stores, this study, published in the academic journal Food Hydrocolloids is a significant step toward increasing the healthy properties of bread through the addition of fruit- and vegetable-derived compounds.

In the future, this novel functional food could contribute to the global functional food market, which is projected to reach $237.8 billion by 2033.

Funding for this study, titled ," was provided by the U.S. Department of Agriculture's