High performance liquid chromatographic separation of interesterified palm oil with tributyrin

Short-chain triacylglycerol, tributyrin (glyceryl-sn-1,2,3-tri-butyric acids), was interesterified with palm oil to produce mixtures of structured triacylglycerol (SL-TAG) species as a low-calorie lipid. Lipozyme RM IM from Rhizomucor miehei, known as a 1,3-regioselective immobilized lipase, was used as a catalyst. During 24 h reaction, the reaction mixture was analyzed with Hypersil®BDSCPS high performance liquid chromatography (HPLC) column to determine neutral lipids composition. Also, the compositional changes of TAG, as well as monoacylglycerol (MAG)/diacylglycerol (DAG) as by-products, were determined. After 24 h, 5.8 g/100 g DAG was found in the reaction mixture, while 89.5 g/100 g TAG was observed. The reaction mixture was also analyzed with Nova-Pak® C18 and Chrompack Si60 columns for separation of SL-TAG species. It was found that the normal-phase (NP)-HPLC with Chrompack Si60 column readily separated SL-TAG species composed of short- and long-chain acyl residues. Further, mass spectrometer was employed for identifying the separated SL-TAG molecules. SL-TAG containing two butyryl and one long-chain acyl residue (e.g., PBB and OBB) were most abundant in the interesterified product.