Source pectin from sugar beet pulp.

To boost profits for sugar beet growers and processors, USDA-ARS scientists are developing new processes to efficiently isolate beet pectin and associated polysaccharides.

Pectin, which can be found in the cell walls of fruits and vegetables, 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.

Sugar beet pectin has different chemical features than citrus pectin, so it could find new uses. Beet pulp is also rich in other highly functional cell wall polysaccharides that could be isolated and put to use. There are several potential applications for pectin. Plant physiologists demonstrated that pectin fragments from orange peel could promote health by increasing the growth of beneficial probiotic bacteria in the large intestine. The orange peel prebiotic work is in the public domain. However, scientists will look to file a patent on specific applications of these prebiotics.

Investigators have also found ways to improve the extraction process. Extracting pectin from plant material takes an hour or more using conventional heating methods. Chemists have 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. The techniques also yield higher quality pectin than conventional heat extraction does. Scientists are adapting these flash extraction techniques to remove pectin from sugar beet pulp--which is even more heat-sensitive--at lower temperatures than those used to extract pectin from citrus.

ARS plant physiologists also have evaluated enzymes from citrus fruits and sugar beet roots for use in modifying the properties of pectin and other cell wall polysaccharides. They have discovered a distinctive citrus enzyme that may be useful for the commercial processing of pectin. They are filing a patent on the discovery and partnering with a U.S. manufacturer to produce the enzyme and determine its usefulness for manufacturing pectin with improved properties in food applications.

The investigators also believe that pectin as a component of food fiber has a role in satiety and obesity food applications. They have developed water-soluble edible films from pectin that can be used in convenience food applications.

Further information. Arland Hotchkiss, USDA-ARS Crop Conversion Science and Engineering, Eastern Regional Research Center, Room 3129, 600 E Mermaid Lane, Wyndmoor, PA 19038; phone: [phone]; fax: [phone]; email: [e-mail].