Putting the Heat on Pectin

Microwaves are good for heating other things besides yesterday’s leftovers. Agricultural Research Service scientists have developed a method for extracting pectin from citrus fruits using microwave technology.

Pectin is a natural ingredient that is mostly present in the pulp, peel and albedo--the white material between the outer peel and fruit sections--of citrus fruits. Pectin is also found in apples and sugar beets. It is used as a gelling agent in jelly foods and as a texturizer in premixed yogurt to give it a smooth texture and pleasant mouth feel.

Industry uses conventional heating to extract pectin from fruit peels. It can take more than an hour to process a batch of fruit peels. Overheating can reduce pectin quality by breaking it down.

Researchers with the Plant Science and Technology Research Unit, part of the ARS Eastern Regional Research Center in Wyndmoor, Pa., developed technology that uses microwaves to heat fruit peels and acidified water in pressure-resistant containers. Using this method, pectin can be extracted in 10 minutes. Also, less energy is used and the pectin is a higher quality than when extracted using conventional heating.

Pectin is an imported high-value product that costs about $6 to $8 a pound. Cutting the extraction time could reduce this cost significantly and open the door for domestic pectin production for the first time in decades.

This technology can be used on a variety of agricultural commodities. The researchers are currently testing the method for extracting pectin from sugar beets to improve its quality for incorporation into nonfood products.

ARS has filed for a patent on this technology. ARS is the U.S. Department of Agriculture’s chief research agency.

Scientific contact: Marshall L. Fishman, ARS Plant Science and Technology Research Unit, Eastern Regional Research Center, Wyndmoor, Pa.; phone (215) 233-6450, fax (215) 233-6406, mfishman@arserrc.gov.