Relationship between rheological properties and degree of κ-casein proteolysis during renneting of milk

Abstract

Simultaneous measurement of viscosity and degree of proteolysis of κ-casein, α, in skim milk at three different concentrations of rennet and three different concentrations of casein showed that viscosity was a function of α until the former reached its minimum value. Then the relation between viscosity and α depended on the enzyme concentration. This is considered to be caused by casein micelles starting to aggregate at this point. The minimum in viscosity was found when α was between 0·6 and 0·7, indicating that casein micelles started aggregating at a lower degree of proteolysis than was believed earlier. The rate of gel firming was found to depend on the concentration of added rennet even after κ-casein was completely proteolysed. The results demonstrated that both proteolysis of κ-casein and aggregation of casein micelles must be taken into account when modelling the renneting reaction.

Rennet-Induced Milk Coagulation by Continuous Steady Shear Stress

“…However, both results indicate that the viscosity of the lag phase is not less than the milk viscosity, which supports the findings of Green et al (19). Furthermore, contrary to Lomholt and Qvist (22), steady shear stress of 0.5 Pa applied during coagulation (corresponds to a shear rate of 100 1/s and more) inhibited the formation of milk coagulum.…”

Inhibition of the proteolytic activity of indigenous plasmin or exogenous chymosin and pepsin in bovine milk by blood serum

“…2) but not the hydrolysis of a heptapeptide. A reduced rate of casein hydrolysis, particularly of k-casein, can lead to an increase in the CT of milk by chymosin (Tables 1 and 2); furthermore, a reduced rate of hydrolysis of k-casein leads to the formation of a weaker gel (Lomholt & Qvist, 1997), as observed in the presence of porcine serum (Fig. 1).…”

The influence of brine concentration on chemical composition and texture of Iranian White cheese

“…After a gel has been formed, collisions between casein micelle aggregates and network strands lead to a further aggregation (Lomholt & Qvist, 1997) and densing of the network. Probably this process progressively strengthens the links between micelles (Green, Hobbs, Morant, & Hill, 1978).…”