We identified a new interesterification reaction between tripalmitin and dicarboxylic acid using lipase. Tripalmitin and dicarboxylic acid were incubated at 70 degrees C for 72 h with Lipozyme (R) RM IM. The reaction mixture was analyzed by MALDI TOF-MS and liquid chromatography/mass spectrometry. The products found were a dimer [(alpha(gamma),beta-dipalmitoyl)-glyceryl]-gamma(alpha)-(omega-carbooctadecanoyl)-alpha'(gamma'),beta'-dipalmitoyl-glycerol and oligomers of glyceride. This dinner was also found in Japan wax, traditionally used as cosmetics. (c) 2005 Elsevier B.V. All rights reserved.