Final answer:
Phospholipids like lecithin primarily function as emulsifiers in foods. They help stabilize mixtures of oil and water by taking advantage of their hydrophobic and hydrophilic properties. These substances also play crucial roles in cell membrane structure and function.
Step-by-step explanation:
A major function of phospholipids, such as lecithin, in foods is to act as an emulsifier. Phospholipids are unique in that they have both hydrophobic (water-fearing) and hydrophilic (water-loving) properties. This dual nature allows them to stabilize emulsions, which are mixtures of two substances that typically don't mix well, like oil and water. In the context of cell biology, phospholipids are also important components of the plasma membrane of cells, creating a barrier that is permeable to select molecules and provides structural integrity to the cell. Additionally, phosphatidylcholine, a type of phospholipid with a choline head group, is necessary for the formation of lipoproteins and has critical roles in nerve and brain tissue.