Effects of pH and Ionic Strength in Calcium on the Stability and Aeration Characteristics of Dairy Emulsion

The effects of different pH levels and ionic strength in calcium on the stability and aeration characteristics of dairy emulsions were investigated in this study. The results revealed that the stability and aeration characteristics of the emulsion were enhanced as the pH value increased from 6.5 to 7.0 and were optimal within the pH of 6.8~7.0, while the concentration of free calcium ions (Ca(2+)) was 2.94~3.22 mM. With the pH subsequently fixed at 6.8 and 7.0, when the addition of CaCl(2) was increased to 2.00 mM (free Ca(2+) strength > 4.11 mM), stability and aeration characteristics reduced significantly, including the flocculation of fat globules, an increase in particle size, and a decrease in the zeta potential and viscosity of the O/W emulsion, all leading to an increase in interfacial protein mass and decreased overrun and foam firmness. Overall, the results indicated that pH changes and CaCl(2) addition significantly influenced the stability and aeration characteristics of dairy emulsions, by influencing free Ca(2+) strength, which is an important factor in determining the quality of dairy emulsions.