INFLUENCE OF THE COMPOSITION OF MILK POWDER ON WATER ACTIVITY APPLYING THE GAB MODEL

Abstract

The use of sorption isotherms at 25°C, for analyze the influence of water activity (aw) of the different compositions of whole milk, skim and low in lactose powder, was study. Precisely the latter incorporating previous work can extend the differential behavior of the various components. The work can establish the relationship between the moisture content of the milk powders studied, with its water activity (aw). The experimental results are evaluated with reference model GAB, noting that the layout of the isotherms and the model parameters were successfully adjusted to the values obtained. The clear influence of the presence of monosaccharides (glucose and galactose) in the reduced-lactose milk, which reduce the water activity aw from greater value of 0.4 due to the higher solubility of these, is observed. The fat content in whole milk, not being adsorbent is manifested in higher values for water activity.

Keywords

• isotherm
• adsorption
• desorption
• milk powder