diglycerides

Diglycerides, or diacylglycerols, are glycerides in which glycerol is esterified with two fatty acid molecules, leaving one hydroxyl group free. They are partial glycerides, sitting between triglycerides and monoacylglycerides in structure. In fats, a mixture of isomers is common, typically including 1,2-di and 1,3-diacyglycerols, with the exact composition influenced by the production method.

Biological relevance: Diglycerides arise during lipid metabolism as intermediates in the breakdown of triglycerides, produced by pancreatic lipase and further processed to monoacylglycerols and fatty acids. In cells, diacylglycerol can function as a second messenger that activates protein kinase C (PKC); this signaling activity is often associated with the 1,2-diacylglycerol isomer, which more effectively stimulates PKC in many contexts. Diacylglycerol can also be generated from phospholipids via phospholipase C.

Industrial and nutritional use: In the food industry, diglycerides are widely used as emulsifiers and processing aids to improve texture and stability. They are often marketed as mono- and diglycerides of fatty acids (commonly labeled as E471). They can be produced industrially by glycerolysis of fats or oils, or by estification of glycerol with fatty acids. Beyond foods, partial glycerides are also used in cosmetics and pharmaceuticals as emulsifying ingredients. Safety assessments generally consider diglycerides to be safe for their approved uses.