The Foaming Properties of Skim Milk Protein Concentrate

Aerated products are popular all over the world, especially those with a foam structure. They are widely represented in the range of the global food market, including that of the Russian Federation. Traditionally, milk proteins are added to stabilize various foods. The present research explains how the concentration of skimmed milk proteins affects the foaming properties of concentrates. The experiment featured the influence of various protein concentrations (from 3.4 to 16.0%) on the foaming properties of reduced skim milk (9.2%) and of milk protein concentrates obtained by ultrafiltration. The research established their practical application for aerated products. The quality of protein foam was evaluated by foaming characteristics and foam stability. The distribution of protein foam bubbles by size was modelled using Erlang distribution. According to the simulation, the foams of protein solutions with a concentration of 12% were more stable. Concentrates with the highest protein content (16%) had not only a greater foaming, but also a greater stabilizing property. The protein samples density increased together with protein concentration. Similarly, the foaming characteristics of protein solutions (multiplicity and density of the foam) increased together with protein concentration. The stability of the foam structure was estimated by the half-life of the foam volume and the average diameter of the foam bubbles in the protein solutions. The most stable foams were those with the highest protein content in the concentrate. The protein concentrates from reduced skim milk were inferior in foaming characteristics to concentrates from milk that was not subjected to drying. However, the results suggest that the reduced skim milk and its protein concentrates are ideal for the production of aerated dairy products because they provide both good foaming and stability.