LAUSR

Abstract Caffeoyl structured lipids (CSLs), including hydrophilic glyceryl caffeates (GCs) and lipophilic caffeoylated acylglycerols (CAGs), are novel derivatives of caffeic acid. In the work, CSLs were successfully synthesized by enzymatic transesterification using different monoacylglycerols as caffeoyl acceptors. The effect of monoacylglycerols on reaction selectivities (for hydrophilic GCs and lipophilic CAGs) was compared. The thermodynamics, kinetic analyses, and reaction mechanism of the transesterification were also evaluated. The apparent activation energies for the transesterification, GCs and CAGs formation were 23.10, 12.03, 28.32 kJ/mol for monooleate, and 25.85, 19.19, 32.02 kJ/mol for monostearate, respectively. The values of Vmax, K m ' and KIA for the reaction using monooleate as caffeoyl acceptors were 1.19 × 10−3 mol/(L min), 0.82 mol/L, and 2.31 mol/L, respectively. High ethyl caffeate conversion and CSLs yields (98.2 ± 1.8%, 94.7 ± 2.8% for monooleate; and 96.8 ± 2.3%, 93.9 ± 2.7% for monostearate) were achieved under the optimized conditions.