CARBOHYDRATE-COMPOSITION OF SOYBEAN FLOURS, PROTEIN-CONCENTRATES, AND ISOLATES

Total carbohydrate content and the amounts of each sugar present in commercial samples of soybean protein products were determined by hydrolysis and gas-liquid chromatography of the alditol acetate derivatives of the sugars. Dehulled, defatted soybean flours contained the following mean sugar content: rhamnose, 0.6%; fucose, 0.1%; ribose, 0.1%; arabinose, 2.4%; xylose, 1.0%; pinitol, 0.9%; mannose, 0.9%; galactose, 7.6%; and glucose, 8.1%. The same sugars were found in soybean protein concentrates; however, the amount of each was less. Soybean protein isolates contained mannose, 0.8%; galactose, 0.5%; and glucose, 0.5%, with traces of the other five sugars. © 1979, American Chemical Society. All rights reserved.