Effect of Insoluble Calcium Concentration on Rennet Coagulation Properties of Milk

a) Storage modulus (G′) and b) loss tangent (LT) as a function of time for rennet-induced milk gels made from milk acidified to pH 6.7 (■), 6.4 (□), 6.0 (▾), 5.8 (▿), 5.6 (●), and pH 5.4 (○). Results are means of triplicates with error bars for standard deviation.

a) Storage modulus (G′) and b) loss tangent (LT) as a function of time for rennet-induced milk gels made with different EDTA levels and subsequently adjusted to pH 6.0; normal milk at pH 6.7 (■), and milk at pH 6.0 with 0 (▾), 2 (▿), 4 (●), and 6mM (○) added EDTA. Results are means of triplicates with error bars for standard deviation.

Shear stress as a function of applied deformation (strain) at a constant shear rate (∼ 0.01s⁻¹) for a) rennet-induced milk gels made from milk acidified to pH 6.7 (■), 6.4 (□), 6.0 (▾), 5.8 (▿), 5.6 (●), and pH 5.4 (○); b) rennet gels made with different EDTA levels and subsequently adjusted to pH 6.0; normal milk at pH 6.7 (■), and milk at pH 6.0 with 0 (▾), 2 (▿), 4 (●), and 6mM (○) added EDTA. Results are means of triplicates with error bars for standard deviation.

Microstructure of rennet-induced gels made from milk at different acidification pH values examined at the time of the maximum value for storage modulus (G′), milk at pH 6.7 (a), 6.4 (b), 6.0 (c), 5.8 (g), 5.6 (h), and 5.4 (i), and gels examined between 2 and 6h after this maximum in G′, milk at pH 6.7 (d), 6.4 (e), 6.0 (f), 5.8 (j), 5.6 (k), and 5.4 (l). The protein matrix is white and pores are dark. Scale bar = 50μm.

Microstructure of rennet-induced gels made with different EDTA concentrations examined at the time of maximum value for the storage modulus (G′), milk at pH 6.7 (a), and milk at pH 6.0 with 0 (b), 2 (c), 4 (g), and 6mM (h) added EDTA, and gels examined between 3 and 10h after this maximum in G′, milk at pH 6.7 (d), and milk at pH 6.0 with 0 (e), 2 (f), 4 (i), and 6mM (j) added EDTA. The protein matrix is white and pores are dark. Scale bar = 50μm.