Final answer:
Lecithins and other phospholipids in the body mainly function as emulsifiers, vital for the formation of cell membranes and the emulsification of fats within the body as well as in various food products.
Step-by-step explanation:
Lecithins and other phospholipids primarily function as emulsifiers in the body. These substances are crucial for the formation of membranes and for the emulsification of fats. An emulsifier is a substance that helps to blend liquids that typically do not mix well, such as oil and water. Phospholipids form a bilayer in cell membranes, creating a barrier that protects the interior of the cell while still allowing necessary substances to enter and exit.
In food science, lecithins are widely used to help mix ingredients that contain fats with those that contain water. Additionally, phospholipids are involved in other biological functions, such as being a component in the myelin sheaths of nerve cells, contributing to brain tissue structure, and aiding in blood clotting through cephalins. Phosphatidylcholines, or lecithins found in high concentrations in egg yolks and isolated from soybeans, are utilized in foods as emulsifiers for this reason.
Although not their primary role, phospholipids also aid in maintaining membrane fluidity alongside cholesterol, which acts as a temperature regulator. Cholesterol helps to buffer the effects of temperature changes on the membrane, ensuring that the membrane stays functional across different temperatures.