Colloidal properties of milk and plant-based milk alternatives: A structural perspective

Plant-based milk alternatives (PMAs) are less nutritious and more difficult to standardise than dairy milk. Their low colloidal stability is one of the major challenges hindering efforts to enhance their nutritional value by increasing components such as protein and lipids. This property often leads to undesirable phenomena such as phase separation, sedimentation, and creaming, all of which affect product acceptability, manufacturing processes, and even digestibility. This article outlines the colloidal properties and structural characteristics of protein particles and fat globules/oil droplets in both cow milk and PMAs, highlighting the differences in their behaviours during processing and digestion. It also presents strategies to formulate PMAs with colloidal properties that more closely resemble those of cow milk, particularly in terms of stability under processing conditions. Finally, it proposes the use of hybrid protein particles containing a combination of plant and milk proteins, which exhibit unique structural features, improved functional properties, and distinct digestion behaviours, to improve PMA characteristics.