Production of glycerol monolaurate-enriched monoacylglycerols by llpase-catalyzed glycerolysis from coconut oil

摘要

In order to study the potential of producing glycerol monolaurate (GML) under a mild condition, enzymatic catalyzed glycerolysis in microemulsion system and molecular distillation were used to produce glycerol monolaurate-enriched MAGs from coconut oil. For the process of glycerolysis, the catalytic abilities of three lipases were compared, and the reaction conditions were studied. Moreover, evaporator temperatures of two-step molecular distillations were optimized. The results showed that the suitable lipase was Novozym 435, and the optimum glycerolysis parameters were molar ratio of coconut oil to glycerol 1:4; the concentrations of Novozym 435 and sodium (bis-2-ethyl-hexyl) sulfosuccinate 8 and 16%, respectively; and the reaction temperature 50°C. Under these conditions, with a 240min reaction time, glycerides which contained 62.5% MAGs, 30.4% DAGs, and 5.8% TAGs were obtained. The content of GML was 29.3% and the acid value (AV) was 8.0 mg KOH/g. Then, by two-step molecular distillations conducted at 90 and 120°C (0.5-1.0 Pa), the content of GML and MAGs were efficiently increased to 60.0 and 97.6%, respectively. Meanwhile, the content of DAGs and the AV were decreased to 2.0% and 0.02 mg KOH/g.