Use of phastgel sodium dodecyl sulphate polyacrylamide gel electrophoresisfor rapid characterization of soybean proteins in commercial soybean products

Commercial soybean products for human consumption (soybean protein isolate, soybean flour, textured soybean, and soybean powdered milks) are character ized for the first time by Sodium Dodecyl Sulphate Polyacrylamide Gel Elect rophoresis (SDS-PAGE) using the PhastSystem(R), a semi-automatic electropho retic system. It makes SDS-PAGE very fast and gives very sharp bands that s implify the identification. The time from loading the gel to characterizati on is less than 1 hour and the resolution is similar to that of large conve ntional gels. Proteic fractions obtained from these commercial soybean prod ucts by using a fractionation procedure described in literature are also an alyzed. The electrophoretic patterns of these globulin fractions exhibited some differences which were attributed to the different technological proce ss used for the preparation of each product investigated. Furthermore, the electrophoretic patterns obtained for commercial soybean products enabled t he differentiation between products derived from soybean protein isolates a nd those prepared directly from whole soybeans.