glycerolysis

Glycerolysis is a chemical reaction in which glycerol reacts with esters, most often triglycerides from fats and oils, to form glycerol esters such as monoglycerides and diglycerides. It effectively exchanges acyl groups between a fatty acyl chain and glycerol, producing mono- and diacylglycerols and, depending on conditions, residual triglycerides or free fatty acids. The reaction can be driven by different types of catalysts, including acids, bases, or enzymes (lipases). Enzymatic glycerolysis is common in the food and cosmetic industries because it operates under milder conditions and can provide specific product distributions.

Industrial and product implications: mono- and diacylglycerols are valuable emulsifiers and texturizers used in baked goods, confectionery, dairy products, and cosmetics. They can serve as fat replacers, stabilizers, or components of structured lipids with tailored nutritional or rheological properties. The exact mix of MG and DG produced depends on the catalyst, temperature, glycerol-to-oil ratio, and reaction time.

Process considerations: chemical glycerolysis typically requires elevated temperatures (approximately 180–250°C) and may use basic or acidic catalysts; excess glycerol or continual removal of byproducts helps shift the equilibrium toward glyceride formation. Enzymatic glycerolysis uses lipases at lower temperatures (often 30–60°C) with careful control of water activity and glycerol supply to achieve desired selectivity. Glycerolysis is distinct from transesterification used in biodiesel production, which converts triglycerides with short-chain alcohols (such as methanol or ethanol) to fatty acid esters and glycerol as a byproduct.