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Sun, Sand, and ... Soy

Soybean oil is the main ingredient in a new, all-natural skin and hair care product formulated to block the sun's ultraviolet light.

The product, SoyScreen, is the invention of Joe Laszlo and Dave Compton, Agricultural Research Service chemists in Peoria, Ill., who are exploring new, value-added uses for commodities, especially soy oil. By one estimate, the U.S. soy industry generates 800 million pounds of surplus oil each year. With private industry help, the researchers hope to exploit this surplus as a natural alternative to chemical sunscreen ingredients now used in lotions, lip balms and other skin/hair care products.

Soy oil itself doesn't offer sun protection, so the researchers figured out how to chemically connect it to ferulic acid, an antioxidant abundant in oat bran and other natural sources that absorbs ultraviolet (UV) light. Their approach also makes ferulic acid more lipid-like, so it doesn't dissolve in water, such as during a swim.

SoyScreen is also environmentally benign, and the method for making it--biocatalysis--uses recyclable enzymes instead of harsh solvents, notes Laszlo, at ARS' National Center for Agricultural Utilization Research in Peoria.

In studies there, the scientists ran Sun Protection Factor tests comparing SoyScreen to four commercial sunscreens: oxybenzone, dioxybenzone, octyl methoxycinnamate and padimate-O. The latter two scored highest for UVB absorbency at wavelengths of 290-320 nanometers, a range that can cause short-term exposure problems, such as sunburn from a day on the beach. SoyScreen, however, offered the best overall protection against both UVB and UVA, another type of sunlight radiation that can cause long-term exposure problems, such as skin cancer.

ARS, which patented SoyScreen on behalf of the U.S. Department of Agriculture, is negotiating an exclusive license with a company. A longer article about the natural sunscreen appears in the December issue of Agricultural Research magazine.

ARS is USDA's main scientific research agency.