Diglyceride

Diglyceride‏‎, also known as diacylglycerol (DAG), is a type of lipid that is composed of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Diglycerides are commonly found in natural fats and oils, and they play a crucial role in the body as a component of phospholipids, which are the main structural components of cell membranes.

Structure and Properties

The structure of a diglyceride molecule consists of a glycerol backbone with two fatty acid chains attached to it. The fatty acid chains can be either saturated or unsaturated, and their length and degree of saturation determine the physical properties of the diglyceride, such as its melting point and solubility in water.

Diglycerides are amphipathic molecules, meaning they have both hydrophilic (water-loving) and hydrophobic (water-fearing) properties. The glycerol backbone and the ester linkages are hydrophilic, while the fatty acid chains are hydrophobic. This amphipathic nature allows diglycerides to form micelles and liposomes in water, which are structures that can encapsulate and transport hydrophobic substances in the body.

Biological Functions

In the human body, diglycerides serve several important functions. They are intermediates in the biosynthesis and breakdown of triglycerides, which are the main form of energy storage in the body. Diglycerides are also precursors for the synthesis of phospholipids, which are essential for the formation and maintenance of cell membranes.

In addition, diglycerides act as second messengers in cellular signaling pathways, particularly in the regulation of protein kinase C (PKC). Activation of PKC by diglycerides leads to a cascade of events that can result in changes in gene expression, cell growth, and cell differentiation.

Dietary Sources and Uses

Diglycerides are naturally present in many foods, including vegetable oils, animal fats, and dairy products. They are also added to processed foods as emulsifiers to improve texture and prevent separation of ingredients. In the food industry, diglycerides are often used in combination with monoglycerides in the formulation of food products such as margarine, shortening, and baked goods.

Despite their widespread use in the food industry, the consumption of diglycerides is generally considered safe. However, like all fats, they should be consumed in moderation as part of a balanced diet.

See Also

• Triglyceride
• Monoglyceride
• Lipid metabolism
• Protein kinase C