Development of Surface Functionality of Casein Particles as the Controlling Parameter of Enzymic Milk Coagulation

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Colloids and Surfaces



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Changes in a colloidal milk system were monitored by measuring changes in turbidity and the modulus of the resultant milk gel. Turbidity was measured in milk of normal concentration and in milk that had been diluted to eliminate the effects of multiple light scattering. The relationship between true gelation time and observed coagulation time, and how gelation time might affect the theoretical modelling of enzymic milk coagulation are discussed. The turbidity of milk at normal concentration cannot be directly related to particle size but it could be correlated with gel modulus measurements.

True gelation time was calculated by fitting gel modulus data to an exponential equation. The result coincided with the inflexion point in the turbidity plots. Surface functionality of casein particles in relation to the collision area and the extent to which k-casein macropeptide must be removed from the particle surface for successful collisions are discussed.