Foods for (shelf) life: for advances in longevity, researchers increasingly are changing foods themselves.

Enhancing shelf life used to mean finding better preservatives. But food scientists more and more are changing the food itself as they search for cleaner-reading labels, better taste and stronger nutritional profiles to go along with improved shelf life.

Much of the attention in shelf-life

gains has been going to advances in modified atmosphere packaging and controlled-atmosphere storage to lengthen the useful lives of the growing entries into home meal replacement and fresh-cut produce. But researchers also are modifying such basic foods as oils, beef and fruit on the molecular or genetic level for the sake of preserving flavor or preventing spoilage.

New day for snack oils

One of the bigger changes in the next few years could be in offs for frying snacks and other foods. Research into high-oleic versions of such oils as sunflower, soybean and corn oil is bringing to market offs that offer extended shelf life for fried and other foods without requiring hydrogenation. Higher-oleic oils may offer relatively modest or no gains in shelf life compared with hydrogenated oils, but they offer substantial gains over unmodified oils and provide an alternative to the costs and health risks of hydrogenation.

The biggest change may be coming in sunflower off, with the entire U.S. crop of sunflowers expected to be converted to higher-oleic NuSun oil hybrids by 2001, according to Jeff Miller, agronomist with the USDA at the Red River Valley Agricultural Research Center in Fargo, N.D.

"The National Sunflower Association has supported this as an industry effort, and our plans are to have the entire crop converted by 2001, so it's not going to be a specialty oil," Miller says. "NuSun may not be a word we use in 2002. We may go back and use the term sunflower oil and it will mean NuSun. That's our overall objective."

NuSun commands a slight premium because of the cost paid to farmers for "identity preservation" for the NuSun seeds. But by converting the entire crop, that premium could be eliminated.

NuSun is low in saturated fat, and has several times as much oleic acid and less than half as much linoleic acid as traditional sunflower oil. Some medical research indicates that a moderately low-fat diet with a high oleic acid content lowers serum cholesterol and the risk of coronary heart disease. Beyond that, however, NuSun also is designed to extend the shelf life of sunflower oils and foods that are fried in it without forcing processors to resort to hydrogenation.