Monostearates

Monostearates are esters derived from stearic acid and a polyol, such as glycerol or sorbitol, and are used as emulsifiers, stabilizers, and texturizing agents in foods, cosmetics, and pharmaceuticals. The term encompasses several specific compounds, including glycerol monostearate (GMS) and sorbitan monostearate (often referred to as Span 60), as well as other monoesters of stearic acid with different polyols.

Chemically, monostearates are amphiphilic molecules with a hydrophobic stearate chain and a hydrophilic polyol head. This structure enables them to reduce interfacial tension between oil and water and to modify the rheology of mixtures. They generally exhibit low to moderate hydrophilic-lipophilic balance (HLB) values, and their emulsifying properties depend on the particular polyol used and the degree of esterification.

Production typically involves esterification of stearic acid with a polyol under heat and catalysis, followed by purification to yield solid or paste products. Glycerol monostearate is common in foods, while sorbitan monostearate is widely used as an emulsifier in both food and cosmetic formulations. Additional monostearate variants can be prepared from other polyols such as propylene glycol.

Applications vary by sector. In foods, monostearates act as emulsifiers, stabilizers, and fat replacers, helping to create smooth textures in products like baked goods, confectionery, ice cream, and chocolates. In cosmetics and personal care, they function as emollients, thickening agents, and surfactants, improving spreadability and texture. In pharmaceuticals, they can serve as excipients that aid in the dispersion of active ingredients. Regulatory status is region-dependent, but monostearates are widely used and generally regarded as safe within established usage guidelines.