To find new ways for reducing the potential of palm oil to form 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl esters during refining it is helpful to know more about the influence of different precursors like diacylglycerols (DAGs) and monoacylglycerols (MAGs), lecithin, and chlorine containing compounds. After adding increasing amounts of the different precursors to a model oil obtained by removal of polar compounds from crude palm oil and heating the mixture under standardized conditions to 240°C for 2 h the contents of 3-MCPD and glycidyl esters were analyzed according to the standard procedure of DGF C-VI 18 (10). DAGs and MAGs were found to increase the potential of palm oil to form 3-MCPD and glycidyl esters, but refined lecithin showed no influence. Sodium chloride as well as tetra-n-butylammoniumchloride (TBAC) led to higher contents of the esters. Whereas the addition of TBAC raised the amount of glycidyl esters as well as 3-MCPD esters, sodium chloride largely raised the amount of 3-MCPD esters. An addition of 5 mmol of sodium carbonate/kg model oil spiked with sodium chloride reduced the amount of glycidyl esters almost completely; the 3-MCPD esters were reduced by 50%. About 1 mmol sodium hydrogen carbonate/kg oil reduced both 3-MCPD and glycidyl esters almost completely.
Practical applications: For the mitigation of the formation of 3-MCPD esters and related compounds in refined edible oils, it is helpful to know more about the effect of different possible precursors. Using a broader data basis, it is possible to adopt the oil processing but especially the choice of the raw material to the demands of the market for lower contents of the esters in the refined products.