Flavored milks are milks mixed with cocoa powder, coffee, fruit juice or flavoring. Additional ingredients include thickeners (polysaccharides) to stabilize the casein, and sometimes pH-stabilizing agents, such as citrate or phosphate. Flavored milks with a high percentage of fruit juice are stabilized with 0.3% (w/w) high-methoxy pectin to avoid the flocculation of milk proteins. For the stabilization of flavored milk drinks of normal pH (6.7), 0.01 – 0.05% kappa-carrageenan is most commonly used as a thickening agent; it forms a weak three-dimensional gel, within which, e.g., cocoa particles of size 10 to 30 micro-m may be entrapped and prevented from settling. The addition of cocoa powder, fruit juice, coffee or flavoring to milk increases the diversity of products and tastes. Some consumers like them, although added sugar is a nutritional challenge and can contribute to overweight and obesity, especially of children. Prevention of curdling of the milk by the addition of stabilizing polysaccharides, and acidity regulators for higher heat-treatments, may be necessary. Highly esterified pectin for acidic flavored milks with a high percentage (≥ 15%) of added fruit juice is most suitable; the pectin directly interacts with the casein micelles and enhances steric repulsion between the casein micelles. Using κ-carrageenan in neutral flavored milks such as chocolate milk stabilizes the acid- and heat- sensitive milk proteins, prevents sedimentation of added food particles such as cocoa powder, and improves mouthfeel, through absorbing to the surface of the casein micelle via electrostatic interaction. The necessary stabilizing weak gel, in terms of a three-dimensional network, occurs at relatively low kappa-carrageenan concentrations, of 0.01 - 0.05%, within which cocoa particles of 10 to 30 micro-m may be entrapped and prevented from settling. The scientific understanding of the mechanisms involved in the stabilization of the milk proteins, especially of the interactions of the polysaccharides pectin and carrageenan with casein, helps to achieve good quality and stable products. Some other polysaccharides have been tested for the stabilization of neutral flavored milks, but carrageenan remains the most suitable one. An important challenge for flavored milks at present is the reduction of the amount of added sugar for health reasons, while still retaining the liking of the products without compensating with often undesired artificial sweeteners.
