New microgel capsules trap omega-3 fatty acids

Mar 4 2009

Nutritionists are nearly unanimous in recommending that Americans should eat significantly more omega-3 fatty acids and consume them in foods, not in vitamin pills.

The health-promoting fats are found in fish and some other food sources. But if we don't like fish, can't prepare it well, can't afford it more often, or all of the above, what are we to do?

Food scientist Julian McClements and colleagues at the University of Massachusetts Amherst Center for Health & Wellness are now 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, for example. All this without sacrificing taste, appearance or texture. Among other things, omega-3s are essential for normal growth in children and a recognized aid to heart health in adults.

In previous studies, McClements, an expert in food-based delivery systems, and his co-workers found that certain milk and soy proteins are good at preventing omega-3 fatty acids from going rancid. The researchers now want to find a way to economically produce large amounts of powdered omega-3 microgel particles rich in these anti-oxidant 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.

Food as medicine is an unfamiliar concept to many American consumers, according to McClements and Eric Decker, chair of the UMass Amherst food science department and co-director of its Center for Health & Wellness. Many don't remember the first wave of nutraceuticals introduced in the 1940s and 1950s when vitamin-fortified flour, cereals and milk were "unbelievably successful" in eliminating once-common diseases such as goiter and rickets caused by vitamin deficiencies, Decker notes.

While it's becoming more common to hear of consumers picking up blueberry juice as a hedge against memory loss or whole-grain bread to ward off colon cancer, the United States remains one of the least receptive societies to the idea of food as preventive medicine compared to places like Japan and New Zealand. Nevertheless, because of their public health value, nutraceuticals are becoming a "hot topic" among North American nutritionists and food scientists.

The new generation of food scientists hopes to build on the earlier successes to address modern public health problems, more widespread but perhaps no less disabling and costly to society - obesity, diabetes, heart disease, osteoporosis, cancer. Specifically, UMass Amherst researchers like McClements are not only looking at cheaper, more reliable ways to incorporate nutrients like omega-3 fatty acids in food, but at molecules known as phytosterols from oats, for example, that can lower cholesterol, and flavonoids in orange peel that show promise for killing cancer cells.

With recent new grants from the USDA, 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, 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," McClements adds, but that's coming, as well, he predicts.

Europeans will readily pay more for food that promises to boost health, Decker observes. 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 health care costs and other problems. Watch for international food companies to team up with food science programs like the Health and Wellness Center at UMass Amherst to do the same.