TRIMMING THE FAT Judith Zwolak, Tulane Publications Staff
A Tulane chemical engineer hopes to make cookies, crackers and french fries a little healthier. Peter Pintauro, professor of chemical engineering-with the assistance of chemical engineering graduate student Weidong An and postdoctoral researcher Jin-Ki Hong-has devised a new process to manufacture partially hydrogenated vegetable oils such as shortening and margarine, which are found in many popular processed foods. The new method reduces the amount of trans fatty acids, a particularly unhealthy fat usually found in high quantities in these products.
"When you want to make a margarine or some kind of shortening for baking purposes, you add hydrogen to a liquid oil," Pintauro says. "In the traditional way to do this, you form trans fatty acids." Recent research published in the New England Journal of Medicine has found that trans fatty acids are harmful because they not only raise bad cholesterol, but also lower good cholesterol. The Food and Drug Administration is close to requiring food companies to report the quantities of trans fatty acids on their labels, says an FDA spokesperson. Shortly after English chemist William Normann invented the process in 1901, food manufacturers have used hydrogenation for a wide variety of products. Adding small amounts of hydrogen to oil keeps it fresher longer, while adding more hydrogen turns liquid oil into a solid the consistency of butter.
Pintauro's new process uses electricity to hydrogenate the oil, rather than oil manufacturers' current techniques, which employ high temperature and high pressure. "As a consequence, we don't produce nearly as much of these undesirable trans fatty acids," he says. "With this method, we think we can reduce the amount of trans fatty acids, which is as high as 30 to 40 percent in some of these processed foods, to 5 percent."
Pintauro's team accomplishes this reduction by using fuel-cell technology. A typical fuel cell acts like a battery and allows hydrogen and oxygen to react over a metal surface, which results in electrical energy. Reversing the process, Pintauro adds electricity to the fuel cell and produces hydrogen on the metal, which then contacts the oil and hydrogenates it. So far, Pintauro has produced only a few cups of this oil on a small scale in his laboratory. The next step is to produce oils on a pilot scale-"something in between a laboratory-scale reactor like we have here at Tulane and very large reactors in a commercial plant," Pintauro says.
Samples of the oils produced in Pintauro's laboratory are currently at the U.S. Department of Agriculture's National Center for Agriculture Utilization Research in Peoria, Ill. Here, researchers are studying the oils' chemical composition and structure to learn how they will behave when they are used in final products such as margarine, shortening and frying oil, says Kathleen Warner, research leader of the Food Quality and Safety Research Group.
With FDA labeling in the future, "There is a big rush to find alternatives to the traditional method of hydrogenation," Warner says, "which is the main way the food industry gets oils for products like margarine and frying oil." The next step for Warner's lab is to do more performance tests on products made from the larger quantities of oils produced at the pilot reactor. Preliminary taste tests at the USDA labs have shown the oils to have improved flavor and odor characteristics as compared to traditional oils, Pintauro says.
Tulane has filed both domestic and international patents on the process. Pintauro says he hopes commercial production of the oil will begin within the next two years.
This article is reprinted with permission from the Summer, 1998 issue of Tulanian magazine.