SDS-PAGE (under reducing conditions) profiles of proteins in buttermilk made from raw or pasteurized cream. STD = molecular weight (MW) standard; 1 = buttermilk from raw cream; 2 = buttermilk from pasteurized cream; 3 = MF permeate (raw); 4 = MF permeate (pasteurized); 5 = MF retentate (raw); 6 = MF retentate (pasteurized). Protein bands are: MUC1 = mucin 1; XO = xanthine oxidase; CD36 = cluster of differentiation; BTN = butyrophilin; PAS 6/7 = periodic acid Schiff 6/7; α-CN = α-casein; β-CN = β-casein; κ-CN = κ-casein; β-LG = β-lactoglobulin; α-LA = α-lactalbumin.