A METHOD FOR ISOLATING BETA-CASEIN

A new method was developed for obtaining pure beta-CN. Calcium caseina te (3%) was reconstituted, renneted to form a gel, cooled (4 degrees C ) to allow beta-CN dissociation from the caseinate gel, and centrifuge d. The supernatant was warmed to 30 degrees C, precipitating pure beta -CN from solution. Large quantities of beta-CN were recovered by scali ng-up this procedure, but these beta-CN preparations were less pure th an the beta-CN that was prepared on a smaller scale. Chromatography (F PLC(R)) and urea-PAGE showed beta-CN to be the main component in the p recipitate. Chymosin, used to form the caseinate gel, did not extensiv ely hydrolyze beta-CN under the conditions of these experiments. Calci um concentration, cooling time, and caseinate concentration influenced the recovery of beta-CN. Maximum recovery of beta-CN, under the exper imental conditions used, occurred at 10 mM calcium, 48 h of cooling, a nd 3% caseinate concentration.