Bipolar membrane electroacidification to produce bovine milk casein isolate

Bipolar membrane electroacidification (BM:EA) has been developed previously (Bazinet et al., Report for the Canadian Electricity Association 9326 U 98 7, 1996; Bazinet et al., J. Agric. Food Chem. 1997, 45, 2419-2425, 3788-379 4) and has been used for isoelectric precipitation of soybean proteins. The purpose of this study was to validate the feasibility of BMEA for the prec ipitation of milk casein and to investigate the effect of flow rate. High-p urity isolates containing 1.23 and 2.00% ash and 85.4 and 91.6% total prote in were obtained with flow rates of 0.2 and 1.2 gal/min. The molecular comp osition profiles of the isolates obtained by HPLC showed that only caseins were precipitated. However, except for protein precipitation curves, the fl ow rate did not influence the final composition and purity of the isolates. These results showed that BMEA is a new alternative process for the produc tion of high-purity bovine milk casein isolate.