A method for isolating beta-casein.
A new method was developed for obtaining pure beta-CN. Calcium caseinate (3%) was reconstituted, renneted to form a gel, cooled (4 degrees C) to allow beta-CN dissociation from the caseinate gel, and centrifuged. The supernatant was warmed to 30 degrees C, precipitating pure beta-CN from solution. Large quantities of beta-CN were recovered by scaling-up this procedure, but these beta-CN preparations were less pure than the beta-CN that was prepared on a smaller scale. Chromatography (FPLC) and urea-PAGE showed beta-CN to be the main component in the precipitate. Chymosin, used to form the caseinate gel, did not extensively hydrolyze beta-CN under the conditions of these experiments. Calcium concentration, cooling time, and caseinate concentration influenced the recovery of beta-CN. Maximum recovery of beta-CN, under the experimental conditions used, occurred at 10 mM calcium, 48 h of cooling, and 3% caseinate concentration.
Ward
L S
LS
Department of Nutrition and Food Science, University of Minnesota, St. Paul 55108, USA.
Bastian
E D
ED
D002118:Calcium; D002364:Caseins / Q000302:isolation & purification*; D011232:Chemical Precipitation; D002851:Chromatography, High Pressure Liquid; D012085:Chymosin / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005782:Gels; D006868:Hydrolysis; D010446:Peptide Fragments / Q000302:isolation & purification; D014508:Urea
D002364:Caseins; D005782:Gels; D010446:Peptide Fragments; D014508:Urea; C025350:rennet; D012085:Chymosin; D002118:Calcium