Food scientist Robert Roberts' research on lactic acid-producing bacteria could yield useful food ingredients and help lead to market growth for milk and yogurt producers.

Dairy products show great potential as ingredients in food manufacturing. Researchers focusing on ingredient functionality are looking for new ways to differentiate and add value to dairy products and expand markets for the state's dairy farmers and food processors. Food scientist Robert Roberts is studying how the lactic acid-producing bacteria (LAB) used in fermented dairy products, such as yogurt, can be manipulated to create useful compounds. "These beneficial microorganisms produce polymers that have desirable characteristics as food ingredients," he explains. "But in order to make full use of these compounds, we have to learn more about their properties and how they are produced, so we can control their production and end up with the characteristics we want.

"In one study, we're looking at how we can use lactic acid bacteria to develop yogurts with different textures," Roberts says. "Some of these LAB by-products can function as stabilizers by binding water to give a product a desired consistency without adding carrageenan or other stabilizing ingredients. This would satisfy consumer preference for all-natural products with fewer added ingredients. These bacteria also produce compounds that mimic fat. When you remove fat from a product, you often lose some of the desirable sensory characteristics. If we can use bacterial strains to produce some of the same characteristics in low-fat products, we can make them more acceptable to consumers."

Roberts' work has positive implications for the state's dairy industry. Annual yogurt consumption in the United States has increased nearly 1,700 percent to more than 4 pounds per capita in the last 20 years. Yet per capita yogurt consumption in some European countries is about 20 times greater, indicating a potential for substantial growth in the U.S. market. "If we were to achieve yogurt consumption similar to that in some areas of eastern Europe, we would significantly increase the market for milk," Roberts says.

Roberts also is studying bacterial compounds that have antimicrobial properties that could improve food safety. "Minimally processed and convenience foods with extended shelf lives are typically stored at low temperatures to keep them fresh," he says. "But a failure in refrigeration, or even a slight increase in temperature, can result in bacterial growth and spoilage. Antimicrobial substances produced by lactic acid bacteria might be useful as natural preservatives in these foods."

In addition, lactic acid bacteria can grow on whey, a by-product of cheese manufacturing. Pennsylvania produces a million tons of whey annually, some of which is discarded through wastewater treatment. The development of LAB products could create new uses for excess whey and convert part of this waste stream into a valuable by-product, benefiting both the dairy industry and the environment, says Roberts.