In organic chemistry glycerolysis refers to any process in which chemical bonds are broken via a reaction with glycerol. The term refers almost exclusively to the transesterification reaction of glycerol with triglycerides (fats/oils) to form mixtures of monoglycerides and diglycerides. These find a variety of uses; as food emulsifiers (e.g. E471), 'low fat' cooking oils (e.g. diacylglycerol oil) and surfactants (such as monolaurin).

The transesterification process gives a complex mixture of products, however not all of these are of equivalent use.^[1] This has led to the development of optimized processes able to produce better defined products; in particular by using enzymes,^[2] reactions in supercritical carbon dioxide and flow chemistry.^[3] The production of diglycerides (often called diacylglycerols or DAGs) has been investigated extensively due to their use in foods, with total annual sales of approximately US$200 million in Japan since its introduction in the late 1990s until 2009.^[2][4]

Partial acylglycerols, mono- and diacylglycerols (MAGs and DAGs), are industrially produced on the basis of a batch alkaline-catalyzed chemical glycerolysis of edible natural fats and oils at high temperatures (220-250℃) and elevated pressure under nitrogen atmosphere. The process consumes high energy, and the row products have poor quality, i.e. low yield (<50%), dark-colored and burned-tasting due to high reaction temperature, which requires extensive and costly purification steps. The chemical glycerolysis of fat and oil was reviewed in 1982(Refer to the Reference [1]).
Contrary to the chemical process, enzyme (usually lipase)-catalyzed glycerolysis of fat and oil is carried out at much lower temperature (5-65℃) under atmospheric air pressure resulting in no dark-color and no burned taste, but requires much longer reaction time (2-3 days).
The first scientific article concerning lipase-catalyzed glycerolysis of fats and oils was published in 1986,^[5] followed by several articles by the same group.^{[6][7][8][9][10][11]} Later up to recently a number of papers have been published concerning lipase (free or immobilized)-catalyzed glycerolysis of fat and oils^{[12][13][14][15][16][17][18][19][20][21]}.
Most researchers have been tried to produce MAGs or DAGs from vegetable oils through biochemical approach (i.e. lipase catalyzed glycerolysis), however, it was suggested that the products themselves after just separation of the immobilized enzyme particles by centrifuge without subsequent purification (mixture of MAGs, DAGs and remaining unreacted TAGs without the addition of saturated or hydrogenated fat, thus not altering fatty acid compositions), which do not contain any trans fatty acid nor cholesterol, could be utilized as a kind of margarine (named glycerolysis structured oils).^[22][23][24]

• Hydrolysis
• Saponification
• Transesterification