Grapevine gum alternative
A sap oozing from the stem of a native U.S. grapevine has chemical and functional similarities to acacia gum.

PEORIA, ILL. — Researchers from the U.S. Department of Agriculture have found that a sap oozing from the stem of a native U.S. grapevine has chemical and functional similarities to gum Arabic, also known as acacia gum. Harvested commercially from acacia trees in the Sahara region of Africa, gum Arabic acts as a thickening agent and emulsifier in such products as cake frosting and candies.

The grapevine, Vitis riparia, is called frost grape and is found throughout North America. Nuclear magnetic resonance spectroscopy methods showed the sap from the grapevine’s stem is a polysaccharide, a long-chain carbohydrate whose ratio of two primary sugars (arabinose and galactose) resembles that of gum Arabic, which typically is sold in powdered form at a current market price of $3,000 per ton.

Neil Price, a chemist with the U.S.D.A.’s National Center for Agricultural Utilization Research in Peoria, has led research on the domestic equivalent of gum Arabic. The polysaccharide from the grapevine’s stem may be made into a white powder, viscous liquid or clear gel. In experiments using a water solution and grapefruit oil, a common beverage flavoring, adding a 1% or less concentration of the polysaccharide produced emulsions that remained stable beyond the trial’s 72-hour evaluation period.