Researchers Solve Pickles Pickle

When it comes to preserving crisp cucumbers, industrial food processors used to find themselves in a bit of a pickle -- at least until they consulted Buescher.

For centuries, people have used salt water to preserve cucumbers as pickles, and today the food industry processes pickles by the millions. Because the saltwater mixture used to store the pickles can harm the environment, most pickle producers recycle the storage brine from their large vats, using it repeatedly for storing large numbers of pickles. Unfortunately, the brines sometimes become contaminated with an enzyme that destroys the cucumber's crisp surface, leaving behind a soggy substitute.

Buescher began to look at low-cost substances already used by the food industry that could be used to eliminate the pickle preying enzymes. He tested different substances that absorb enzymes and finally dug up something that worked -- a specific kind of clay traditionally used to bleach soybean oil.

Buescher and graduate students Cathy Hamilton and Svetlana Zivanovic will present these findings at the American Chemical Society's 220th national meeting in Washington, D.C., on Monday, Aug. 21.

This particular clay comes from a former river bed along the Florida-Georgia border, and it works better than any other clays the researchers tried. Some of the clays didn't absorb the enzymes efficiently while others expanded, taking up too much volume in the tanks.

"Clays have different characteristics depending upon where you are in the world," Buescher said.

The research has been applied by the pickle industry to large vats. Once the pickles are removed from the vats for processing, the clay is mixed into the vats and allowed to settle, attracting the enzymes through opposite electrical charges. Then the brine, minus the enzymes, can be decanted.

The researchers also found that when the clay becomes saturated with enzymes, it can be washed using water or an alkaline solution. The enzymes will fall away, leaving the clay ready to be used again.

This simple and inexpensive treatment benefits the pickle manufacturers, consumers and the environment by improving pickle texture, conserving resources and reducing the need for wastewater disposal. The scientists continue to explore new methods to improve the treatment.