About Monoglycerides
Monoglyceride (MG) or monoacylglycerol is an amphiphilic compound that is typically derived from fatty acid and glycerol. It contains two hydroxyl groups (polar) and one long chain alkyl group (non-polar). The alkyl moiety is a type of fatty acid. Monoglycerides are given a GRAS (Generally Accepted As Safe) status by the US FDA.
Monoglycerides are unique in that they have functional groups that enable (1) excellent emulsifying properties and (2) further synthesis into useful compounds. Thus, they are also being investigated as starting materials for pharmaceuticals, polymers and other chemicals. Because MGs are safe, researchers have also tried incorporating them as drug delivery vehicles to be used in vivo.
Monoglycerides are important emulsifiers, preservatives, and additives in food, cosmetics and pharmaceuticals. The alkyl group can vary in the presence or absence and type of functional group it has (e.g., MG from ricinoleic acid can contain an additional hydroxyl group in the alkyl long chain). Additional functionalities have prompted researchers to study some types of MGs for application as biobased polymer starting materials (e.g., for polyurethane). They are also attractive intermediates for the synthesis of more complex lipids like selectively functionalized triglycerides, glycolipids or phospholipids.
Currently, MG production remains costly and inefficient. It often suffers from low yield or a mixture with diglycerides and triglycerides. To obtain high grade MG, conventional production requires molecular distillation, which is a relatively expensive process. Furthermore, the reaction is carried out at high temperatures (e.g., 210-240°C), something that would immediately exclude the production of unsaturated MGs. These unsaturated MGs have a tendency to polymerize or be unstable under high temperature conditions.