Glycerol monolaurate beyond an emulsifier: Synthesis, in vivo fate, food quality benefits and health efficacies

Glycerol monolaurate (GML) is a fatty acid monoglyceride, which richly exists in coconut oil, palm oil, and human milk. Except for the recognized emulsifying properties, GML's good antibacterial ability and low energy density also make it an ideal functional additive and food quality improver. This review discusses GML synthesis, health benefits, positive effects on food storage and quality, and critically discusses its fate and safety in vivo. The routine emulsification of GML in foods is beyond the scope of this review. GML is synthesized through direct esterification, methyl laurate glycerolysis or laurate glycerolysis. Although the in vivo fate of GML is assumed to be similar to that of glyceryl trilaurate, there is no direct experimental evidence for this inference. Previous studies proved that GML functions beyond an emulsifier. In food quality, GML inhibits the growth of harmful microorganisms and extends shelf life. It also improves the nutritional value and sensory properties of animal-derived food by regulating amino acid and fatty acid metabolism. In health efficacies, GML reduces lipid accumulation, rebuilds the intestinal barrier, modulates immune activity, and may have positive effects on the nervous system. These are associated with the direct intervention of GML on gut microbiota, immune cell activity and energy metabolism. However, developing more efficient GML synthesis schemes, enhancing the application of GML on food quality, and exploring the in vivo fate, health efficacy mechanism or safety of GML in different experimental models remain interesting topics in the future.