Effect of pH, calcium concentration and temperature on the evolution of the refractometric signal produced during rennet coagulation of milk

Summary An industrial refractometer connected to a microcomputer was used to study the rennet coagulation of milk. The amplitude of the refractometer's signal changes during coagulation was about 104 times more important than the resolution of the computerized refractometer. The signal v. time derivatives were calculated and the inflection point time (ti) was correlated with pH, Ca concentration and temperature. The inflection point time was inversely proportional to the rennet and Ca concentrations and the logarithm of the proportionality factor (k) was linearly correlated with pH. The relation between ti and temperature was curvilinear. It is concluded that the refractometer tested could be used for research on the coagulation process.

[1]  J. Maubois,et al.  COMPUTER DATA ACQUISITION OF SINUSOID ALLY VARYING STRESS AND STRAIN , 1985 .

[2]  D. Dalgleish,et al.  Coagulation of homogenized milk particles by rennet , 1984, Journal of Dairy Research.

[3]  D. McMahon,et al.  Enzymic Milk Coagulation: Role of Equations Involving Coagulation Time and Curd Firmness in Describing Coagulation , 1984 .

[4]  C. A. Ernstrom,et al.  Effects of Calcium, Phosphate and Bulk Culture Media on Milk Coagulation , 1984 .

[5]  C. A. Ernstrom,et al.  Enzymic Coagulation of Milk Casein Micelles , 1984 .

[6]  D. E. Johnston.  Application of polymer cross-linking theory to rennet-induced milk gels , 1984, Journal of Dairy Research.

[7]  D. Dalgleish.  Coagulation of renneted bovine casein micelles: dependence on temperature, calcium ion concentration and ionic strength , 1983, Journal of Dairy Research.

[8]  J. Fanni,et al.  Application of Reflection Photometry to the Measurement of Milk Coagulation , 1981 .

[9]  D. Dalgleish.  Proteolysis and aggregation of casein micelles treated with immobilized or soluble chymosin , 1979, Journal of Dairy Research.

[10]  N. Olson,et al.  Effects of pH and Temperature on the Secondary Phase of Milk Clotting by Rennet , 1977 .

[11]  K. Guthy,et al.  Observations on the primary phase of milk coagulation by rennet under standardized conditions , 1977, Journal of Dairy Research.

[12]  D. Dalgleish,et al.  The potential application of the theory of branching processes to the association of milk protein , 1977, Journal of Dairy Research.

[13]  P. Fox.  Milk-clotting and proteolytic activities of rennet, and of bovine pepsin and porcine pepsin , 1969, Journal of Dairy Research.

[14]  G. W. Blair,et al.  An equation to describe the rate of setting of blood and milk , 1963 .

[15]  G. W. Scott Blair,et al.  A viscometric study of the breakdown of casein in milk by rennin and rennet , 1961, Journal of Dairy Research.

[16]  G. W. Blair,et al.  Physical changes in Milk caused by the action of rennet: V. Effects of varying concentrations of milk powder and of low-temperature pretreatment , 1959, Journal of Dairy Research.

[17]  G. W. Blair,et al.  Physical changes in milk caused by the action of rennet: IV. Effects of varying rennet concentration and temperature. , 1959, Journal of Dairy Research.

[18]  G. W. Blair,et al.  736. Physical changes in milk caused by the action of rennet: III. Effects of separation, homogenization and pasteurization and of varying calcium content on the rigidity moduli and viscosities of curd , 1958, Journal of Dairy Research.

[19]  G. W. Blair,et al.  716. Physical changes in milk caused by the action of rennet: I. Description of apparatus for measuring rigidity moduli and internal viscosities, tests of reliability and some observations on syneresis , 1958, Journal of Dairy Research.

[20]  K. Mikawa,et al.  Action of Rennin on Casein. III. Effect of αs- and β-Casein on the Secondary Phase , 1980 .

[21]  B. T. D. L. Fuente,et al.  Étude thrombélastographique de la coagulation du lait par la présure: action de la température et de la concentration en calcium , 1966 .

[22]  R. Frentz,et al.  Application de la thrombélastographie de Hartert a l'étude de la coagulation du lait , 1965 .

[23]  Mlle H. Marçais.  Emploi de la thrombélastographie pour l'étude de la coagulation du lait , 1965 .

[24]  L. M. Libbey,et al.  Spectrbphotometric observations on the reaction of rennin with sodium caseinate. , 1960 .