title: Preparation of casein using carbon dioxide.
abstract: The effects of pressure, temperature, residence time, and mass of skim milk on some characteristics of casein, prepared by precipitation with high pressure CO2, were examined in a batch reactor. For a 500-g milk sample, precipitation occurred at pressures > 2760 kPa and temperatures > 32 degrees C. Residence time was not significant and was held at 5 min. Yields were maximum at 2750 to 5520 kPa and at 38 to 49 degrees C for a 500-g milk sample. The resulting whey had a pH of 6.0. The casein product had an acceptable appearance and had greater solids, ash, and Ca contents than commercial acid caseins. Particle size distribution studies showed that the mean particle size was sensitive to precipitation pressure and temperature and was similar to that of acid caseins produced under laboratory conditions. The HPLC studies of the casein and whey fractions showed that precipitation by CO2 did not result in fractionation of casein or whey proteins to their component proteins.
authors.affiliation: Agricultural Research Service, USDA Eastern Regional Research Center, Philadelphia, PA 19118, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Tomasula
authors.forename: J C
authors.initials: JC
authors.lastname: Craig
authors.forename: R T
authors.initials: RT
authors.lastname: Boswell
authors.forename: R D
authors.initials: RD
authors.lastname: Cook
authors.forename: M J
authors.initials: MJ
authors.lastname: Kurantz
authors.forename: M
authors.initials: M
authors.lastname: Maxwell
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D002245:Carbon Dioxide; D002364:Caseins / Q000302:isolation & purification*; D011232:Chemical Precipitation; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000302:isolation & purification; D010316:Particle Size; D011312:Pressure; D013696:Temperature; D000067816:Whey Proteins
chemical_list: D002364:Caseins; D008894:Milk Proteins; D000067816:Whey Proteins; D002245:Carbon Dioxide; D002118:Calcium