Peanut's Oil Extends Shelf Life of Other Varieties

RALEIGH, N.C., Oct. 17--Peanuts may keep their flavor longer after being roasted in oil from peanut lines bred to be high in oleic acid, a U.S. Department of Agriculture researcher said.

"By roasting regular peanuts in oil from high-oleic peanut lines we saw shelf life improvements of 20 to 30 percent," said plant physiologist Tim Sanders with USDA's Agricultural Research Service. "We think this is happening because the high-oleic oil is more stable than regular peanut oil. Its fatty acids don't break down as quickly. It's that breakdown that produces off-flavors."

High-oleic peanuts, such as the University of Florida's Sunoleic 95R, caught Sanders' attention last year. He speculated that roasting regular peanuts in the oil from high-oleic peanuts could extend the shelf life of regular varieties.

At the ARS Market Quality and Handling Research Laboratory in Raleigh, N.C., Sanders tested his idea with peanut varieties commonly grown in Virginia, North Carolina and South Carolina. The high-oleic oil roasting benefitted all the peanuts tested, but the effect was pronounced in the smallest peanut size group.

The finding is valuable to industry since the smallest peanut size contains the highest percentage of immature peanuts. Peanuts in this size class tend to have a shorter shelf life, Sanders said. He also noted that shelf life improvements he saw in peanuts are likely to occur in other food products roasted this way.

"While high-oleic sunflower oil is available commercially, high-oleic peanut oil is not out in the market yet," said Sanders. "But we expect these findings to enhance its potential."

Scientific contact: Tim Sanders, Market Quality and Handling Research, Agricultural Research Service, USDA, Raleigh, North Carolina 27695. Telephone: (919) 515-6312.