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Chemists Marshall L. Fishman (left) and Hoa K. Chau prepare orange peels for flash extraction of pectin using microwave heating under pressure. Click the image for more information about it.

An orange peel a day keeps the doctor away   Prebiotics boost gut bacteria   Pectin heats up—in the microwave

Great Expectations for Pectin

By Laura McGinnis
February 13, 2007

To boost profits for sugar beet growers and processors, Agricultural Research Service (ARS) scientists are developing new processes to efficiently isolate beet pectin and associated polysaccharides and find profitable uses for them.

Pectin, which can be found in the cell walls of fruits and vegetables, is a polysaccharide, a large molecule made up of many simple carbohydrates (sugars) linked together. It is often used as a gelling agent and fat substitute.

Most commercial pectin is extracted from citrus peels, but sugar beet pulp is an untapped source with great profit potential. Every year, U.S. processors generate about 1.5 million tons of dry beet pulp, most of which is sold for little profit as animal feed. ARS researchers are investigating how the chemical features of sugar beet pectin could expand the pulp market.

They have also found ways to improve the extraction process. Extracting pectin from plant material takes an hour or more using conventional heating methods. To save time and reduce cost, chemist Marshall L. Fishman, who retired from ARS and is now a collaborator at the ARS Eastern Regional Research Center, Wyndmoor, Pa., developed microwave and steam-injection techniques to heat fruit peels with acidified water in pressure-resistant containers. These methods can extract high-quality pectin within 10 minutes, using less energy.

How will this pectin be used?

In one study, ARS chemist LinShu Liu developed material from pectin and other natural polymers that can be used in biomedical supplies, such as prosthetic devices and scaffolding for tissue repair. In another study, plant physiologist Arland T. Hotchkiss, Jr. and cooperators demonstrated that pectin fragments from orange peel could promote health by increasing the growth of beneficial probiotic bacteria in the large intestine.

Read more about the research in the February 2007 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.