The influence of temperature and electrolytes upon the apparent size and shape of α- and β-casein

Investigation of the caseinate-phosphate-calcium complexes as they exist naturally in milk

“…quantity of a^-caseln agrees with the data presented In the section concerning moving boundary electro phoresis and likewise with the moving boundary electrophoretlc results ofBohren and Wenner (1961) for the caselnate fraction not sedlmented at low temperature Sullivan et al (1955). had previously reported that p-caseln Is depolymerlzed (more soluble) at low (4.4 C) than at high (25-30 C) temperatures a fact supported by Waugh (1962) who found that the minimum conditions for stable micelle formation are a^-, %-caseln, and divalent cations and that p-caseln Is Incorporated Into the micelle as the temperature is increased.…”

“…Temperature has been indicated to be a critical factor in the results obtained (Sullivan _et ^, 1955) and undoubtedly the method of preparing samples for electrophoresis plays a part.…”

“…likewise obtained an OP:ON ratio of 0.048 for the whey-soluble casein fraction obtained at 20 0. Since pcasein has a lower organic phosphorus content than a-caseln, 0.6^ and 1.0$, respectively, and p-caseln is reportedly more soluble at temperatures below 30 C(Sullivan et al, 1955), the low OP:ON ratio for the whey-soluble casein fraction is undoubtedly a reflection of the Increased p-casein content in this fraction. This fact is substantiated by moving boundary and gel electrophoresis to be discussed in later sections.No explanation can be given for the discrepancy in the data ofFord and Martinez-Mateo (1958) and the data obtained in this study.…”

Investigation of the caseinate-phosphate-calcium complexes as they exist naturally in milk

“…The addition of g-casein complicates this picture and its role has yet to be elucidated. The increased solubility of 3"casein at low temperature (Sullivan 1955) has been suggested by moving boundary electrophoresis In this study (I.E. whey soluble fraction) and by Bohren and Wenner (1961) and confirmed by USG and USG-MCE in this study.…”

“…From the phosphorus content of a-casein, Perlmann (1954) suggested a minimum mole cular weight of 31^000. Sullivan _et (1955), using centri fugal methods, investigated the Influence of temperature and electrolytes upon the apparent size and shape of a-and p-casein. They concluded that p-caseln has a molecular weight of 24,100 below 15 C and has a marked tendency to form aggre gates at room temperature.…”