Figure 4: SDS-PAGE for protein fractions of the new separation process. Lane 1: β-amylase (OPTIMALT® BBA ,Genencor); Lane 2, gel filtration purified β-amylase (Sephadex G-75); Lane 3, the 30 kDa MWCO UF retentate (i.e. Sample 3#, denoted in Table 1); Lane 4, the 3 kDa MWCO UF retentate (i.e. Sample 2#, denoted in Table 1); Lane 5: crude soybean whey (i.e. Sample 1#, denoted in Table 1).