Food and physics go together like oil and water. That can be an excellent thing if you know how to mix the two. Food Science professor Julian McClements knows. He wrote the definitive text, Food Emulsions: Principle, Practice and Technique, and has authored more than 250 peer-reviewed papers. His work has been cited more than 1,300 times - enough for Thomson Scientific to name Julian the eighth most influential agricultural researcher in the world.

"There is no question that Dr. McClements is unrivaled in the field of food emulsions - in understanding what they do and how they can be effectively utilized to process novel kinds of food products," says Dr. Gilbert Leveille, executive director of the Wrigley Science Institute.

Think milk or mayonnaise or salad dressing. They are all emulsions: mixtures of oily and watery ingredients that don't mix well by themselves. You can shake oil and vinegar together relentlessly, only to watch the oil-in-water emulsion immediately separate back into two distinct layers. Food companies run into this problem all the time. So they add substances that surround and stabilize the droplets, preventing emulsified foods from morphing back into blobs of oil and water. But even stabilized emulsions are notorious for breaking down. For example, few emulsions take well to freezing. Julian's research could change this.

"We work on the interface between fundamental and applied research," Julian says. "We take ideas from physics and chemistry and apply them in ways that people have not done before." He and his colleagues are designing novel ways of strengthening oil-in-water emulsions by encapsulating the droplets they contain in invisibly thin layers of biopolymers, giving fickle food emulsions newfound stability.

They are developing emulsified food products that not only survive all of the varied environmental assaults encountered during processing and preparation but that also have improved function inside the body. "As food scientists, we've always been interested in what happens to the food up until you put it in your mouth," he says. "But I think now, people are really interested in the physics and chemistry of what happens when food's actually in your body. We are trying to design foods that have all the characteristics that make somebody want to buy them, but also all the characteristics that, once you eat them, perform some kind of benefit."

Those benefits range from better taste to improved nutritional value. For example, to much acclaim, Julian and fellow Food Science Professor Eric Decker figured out how to stabilize omega-3 oil droplets so that the 'good fat' can be added to foods without affecting flavor.

Now, Harvard researchers are taking that work one step further, evaluating the health effects of omega-3-fortified yogurt. Julian is collaborating with another departmental colleague, Yeonhwa Park, to build protective barriers around 'bad fat' droplets to reduce their digestibility. That research, while still being tested in animals, could potentially evolve into a weight loss strategy for humans.

Researchers are particularly excited about the multi-tasking capacity of Julian's emulsion technology. He has figured out how to coat emulsion droplets with not just one but many layers, each serving a different function. As he explains, "The big advantage of doing this is that you can create multi-functional coatings. You could build a layer that is antimicrobial, a layer that is antioxidant, a layer that gives mechanical strength, and a layer that restricts specific molecular diffusion. If you want, you could keep doing this process over and over again."

Now consider the apple, a definitively non-emulsified food. Imagine dipping an apple into a series of solutions, each of which coats the fruit with a naked-to-the-human-eye layer of functional material (e.g., protein). This layer could have any of a number of features, like antibacterial, antioxidant, or structural properties. Or it might slow down the diffusion of carbon dioxide and other gases, lengthening shelf life. Visiting scientists from Spain and France have joined Julian's lab to do just that: make a better apple. They are exploring ways to confer on apples and strawberries novel properties that make them more attractive to consumers.

That his work has attracted foreign scholars to Amherst is a measure of Julian's success in the world of physics and food. Gil says, "I don't think there'd be any argument in terms of his recognition and the ripple effect that his research has. Other scientists are continually expanding his contributions to the world of food science and food emulsions."