Influence of minerals on the foaming properties of milk

A comprehensive study on the effect of mineral content on milk foaming properties was conducted. Samples with increased mineral concentration were prepared by adding four different types of minerals (KH₂PO₄, K₃Cit, CaCl₂ and MgCl₂) at three different concentration levels (5, 10 and 20 mM) in both reconstituted skim milk powder and milk protein concentrate. Samples with reduced minerals were prepared by reconstituting milk protein concentrate in modified simulated milk ultrafiltrates. Different mineral types showed different effects on the physicochemical properties of milk samples. The addition of K₃Cit increased the viscosity and decreased the surface tension while there were no significant differences between the samples added with KH₂PO₄, MgCl_2, or CaCl₂. In terms of foaming properties, the addition of CaCl₂ or MgCl₂ significantly increased the foam strength and stability while decreasing foamability. In contrast, the addition of K₃Cit significantly decreased foam stability and foam strength while increasing foamability. It was also found that reduction in minerals in the range studied did not affect the foaming properties of milk. These results indicate that the effect of minerals on milk foaming properties depends on the type of mineral and the concentration. This provides an insight that while designing dairy-based food products, the mineral content can be manipulated to achieve the desired foaming properties.