Abstract
The comparative studies were carried out on the effects of heat on the sodium αs-, K- and β-caseinate solutions, when they were heated at temperatures ranging from 100° to 140°C for periods up to sixty minutes. The results obtained are as follows:
1. By heating, non-protein nitrogen was liberated most from K-casein and least from β-casein. The phosphorus in each casein fraction was liberated almost completely by heating at 140°C for sixty minutes.
2. Trypsin, as well as pepsin, digested the unheated αs- and K-caseins better than β-casein. By heating, the digestibility of K-casein by trypsin and of αs- and, β-caseins by pepsin were increased a little.
3. By heating at 120°C for thirty minutes, K-casein lost its ability to stabilize as-casein against calcium ion.
4. The esdimentation constant and relative electrophoretic mobility of αs- and K-caseins decreased by heating, while those of β-casein increased. No newly formed component was observed in heated casein both by sedimentation and electrophoretic analyses. Acknowledgement. This study was supported by the research grant of The Morinaga Hoshikai, to whom the authors wish to express their sincere thanks.
