Modification to the renneting functionality of casein micelles caused by nonionic surfactants

Stability of skim milk with 0.5% Tween 20 (●; Sigma Chemical Co., St. Louis, MO), 1% Tween 20 (■), and 2% Tween 20 (▴) monitored with diffusing wave spectroscopy: A) turbidity parameter (1/l*) and (B) radius over time. Also shown are the initial values for skim milk (♦).

Size exclusion chromatograms of the sera of skim milk (solid line), skim milk with 0.5% Tween 20 (dashed line; Sigma Chemical Co., St. Louis, MO), and skim milk with 2% Tween 20 (dotted line).

Percentage casein macro peptide (CMP) release versus time after addition of rennet in skim milk (●), skim milk with 0.5% Tween 20 (■; Sigma Chemical Co., St. Louis, MO), and skim milk with 2% Tween 20 (▴). See Table 1 for statistical significance.

Casein macro peptide (CMP) release of a 4% caseinate solution versus time after addition of rennet for sodium–calcium caseinate (●) and sodium–calcium caseinate with 2% Tween 20 (○; Sigma Chemical Co., St. Louis, MO).

Rennet coagulation process monitored by diffusing wave spectroscopy and rheometer of skim milk (●), skim milk with 0.5% Tween 20 (■; Sigma Chemical Co., St. Louis, MO), and skim milk with 2% Tween 20 (▴): A) the transport mean free path (1/l*), B) radius, C) mean square displacement (MSD) slope, and D) storage modulus versus time after addition of rennet. See Table 1 for statistical significance.

Development of storage modulus (G′; open symbols) and the transport mean free path (1/l*; filled symbols) versus casein macro peptide (CMP) release of skim milk (●,○), skim milk with 0.5% Tween 20 (■,□; Sigma Chemical Co., St. Louis, MO), and skim milk with 2% Tween 20 (▴,▵).

Increase in storage modulus (G′) values as rennet coagulation occurs in skim milk (●), skim milk with 2% Tween 20 (□; Sigma Chemical Co., St. Louis, MO), and skim milk with 2% Tween 80 (▵).