Characterization and quantitation of soybean proteins in commercial soybean products by capillary electrophoresis

Capillary electrophoresis was applied for the first time to determine soybean proteins in commercial soybean products. The most suitable conditions for the analysis of these products in less than 7 min were 0.05 M phosphate buffer (pH 8) with 1 M urea; detection wavelength, 254 nm; applied voltage, 20 kV; and temperature, 30o C. Quantitation of soybean proteins was achieved using referenced conditions by means of the method of standard additions, using as standard a soybean protein isolate. This method was validated and applied to the quantitation of soybean proteins in commercial products derived from soybean protein isolate and soybean seeds.The authors thank the University of Alcalµ de Henares (project E002/98) and the Comunidad Autónoma de Madrid (project COR 0035/94 and 06G/047/96) for financial support and C. Marina for linguistic assistance