AMHERST, MASS. — Research being conducted at the University of Massachusetts may lead to the development of low-calorie foods that maintain their taste and texture.
"Our goal is to keep the fat in the food, but stop it from being digested by surrounding it with layers of dietary fiber," said Julian McClements, a professor of food science at the university. "Foods produced with these encapsulated fats should have the same qualities as conventional high-fat foods."
To make the encapsulated fats, small oil droplets are formed by mixing oil, water and a surfactant in a process similar to making salad dressing. The surfactant coats the droplets and keeps them separate from the water until fiber is added to the mix in the final step.
Controlling the electrical charges of the surfactant and the fiber molecules allows the oil to attract the fiber like a magnet. Droplets are usually coated with two to three layers of fiber, and other substances such as proteins may be incorporated to hold the fiber layers together or to provide additional benefits.
The process is suitable for encapsulating a range of fats and oils, everything from orange oil to olive oil, and uses fiber obtained from apples, oranges, seaweed or shellfish. All of the ingredients are food-grade, so this technology requires no Food and Drug Administration approval. Encapsulated fats may be used in emulsion-based foods such as beverages, sauces, desserts, yogurt and salad dressings. They remain stable in acidic foods and during freezing, thawing and cooking, and also handle large amounts of salt.
How much of the fat may be digested is controlled by the number of layers and the types of fiber used. The researchers are currently experimenting with ways to chemically link the fiber layers to enhance their ability to stay intact around the fat droplets.
Layers of fiber also may be used to encapsulate vitamins and antioxidants, enabling them to survive a trip through the stomach and be released in the small intestine for absorption by the body. The process may allow ingredients with proven health benefits, like omega-3 fatty acids, to be included in a variety of foods.
Future research by the team will focus on customizing the layers of fiber to respond to different environments, and testing to determine whether this method may be used as a delivery system for therapeutic drugs that dissolve in fats.
"It should be possible to develop coatings that release drugs at specific sites within the human body," Mr. McClements said.
The research team includes Mr. McClements and food science professors Eric Decker and Yeonhwa Park.