Next Generation Fortification
UMass research team works to develop nutrient microgels for foods and beverages.
By Joanna Cosgrove
Food scientist David Julian McClements and his colleagues at the University of Massachusetts Amherst Center for Health & Wellness are investigating more economical and reliable ways to incorporate omega 3 fatty acids into foods. They’re developing new microgel capsules to trap the omega 3 fatty acids, chemically stabilize them to prevent spoilage, and allow them to be easily incorporated in beverages, yogurts, dressings, desserts and ice cream, without sacrificing taste, appearance or texture.
The project began in the fall of 2008 after the team received funding from the USDA and is an extension of research the group has been doing for the last decade in the area of lipid oxidation in microstructured systems.
“[Omega 3 oils] are being increasingly used in the food industry for their potential health benefits, but there are major problems incorporating them into foods because of their high tendency to oxidize and produce off-flavors (rancid smell) and potentially toxic reaction products,” said Dr. McClements. “There is therefore a pressing need to develop novel food-grade methods of encapsulating [omega 3 oils] to protect them against oxidation, without adversely affecting sensory properties of food (taste, smell, mouthfeel, appearance and shelf-life)
In previous studies, Dr. McClements, an expert in food-based delivery systems, and his co-workers found that certain milk and soy proteins were good at preventing omega 3 fatty acids from going rancid. The researchers are now working to find a way to economically produce large amounts of powdered omega 3 microgel particles rich in these antioxidant proteins from food-grade materials. To do this, they’re concentrating on new “structural” techniques for surrounding the delicate fish oils in a protective biopolymer microgel of water, antioxidant protein and dietary fiber. These microgel particles resemble the familiar gelatin dessert, Jell-O, except that they’re microscopic.
“We create tiny droplets of [omega] 3 oils (< 1 micron) by homogenizing the oil with water and a protein,” he explained. “The protein-coated [omega] 3 oils are then trapped inside a microscopic hydrogel particle comprised of another protein. The resulting system looks like a ‘plum pudding’ (i.e., lipid droplets trapped in a hydrogel sphere), rather like raisins trapped in a round cake. Proteins are used because they are often good antioxidants.”
The microgels, he said, could be used in a wide variety of products. If they were dried, they could also be used in breads, powdered soups and milk, and cookies.
The research, although promising, is still in its early stages. “We are really just demonstrating the scientific principle of forming and stabilizing these microgel capsules,” said Dr. McClements, adding that commercialization would need to be carried out by the food industry.
Dr. McClements and his forward-thinking team of food scientists hope their research will build on earlier successes to address modern public health problems, more widespread but perhaps no less disabling and costly to society—obesity, diabetes, heart disease, osteoporosis and cancer. Specifically, UMass Amherst researchers are not only looking at cheaper, more reliable ways to incorporate nutrients like omega 3 fatty acids in food, but also oat phytosterol molecules to help lower cholesterol, and orange peel flavonoids, which have shown promise in killing cancer cells.
Eric Decker, chair of the UMass Amherst food science department and co-director of its Center for Health & Wellness said the research team is buoyed by growing worldwide interest in functional foods and beverages. Europeans will readily pay more for food that promises to boost health, he said. And in the past 20 years Japan has launched one of the most far-reaching public health campaigns anywhere, to increase nutraceutical consumption to control heart-disease-related healthcare costs and other problems.
With recent new grants from the USDA, Dr. McClements is already looking ahead to the next big thing in nutraceuticals: time-release nanolaminated coatings around fat droplets for delivery at different levels in the human body. For example, he and colleagues are learning to coat droplets with dietary fibers so some will break down in the mouth to deliver flavor immediately while others break down in the stomach or small intestine to deliver peptides that signal fullness or satiety.
Still others might be designed not to break down until they reach the large intestine, where the laminated droplets would deliver anti-hypertensive or cancer-fighting food compounds that can’t survive digestive acids in the stomach. By manipulating food structure, Dr. McClements and other food scientists are also exploring ways to increase solubility in the small intestine so more of the nutrients are absorbed.
“More studies are needed before we can justify further work on tailoring foods to match an individual’s genetic makeup,” Dr. McClements added, but that’s coming as well.