The effect of 0.1-0.7% (w/w) of polyglycerol esters (PGEmix-8) on palm oil crystallization was studied using focused beam reflectance measurement (FBRM) to analyze the in-line changes of crystal size distribution during the crystallization. FBRM results show that 0.1-0.5% (w/w) of PGEmix-8 did not significantly affect nucleation but slightly retarded crystal growth. The use of 0.7% (w/w) additive showed greater heterogeneous nucleation compared to those with lower dosages of additive. Crystal growth was also greatly reduced when using 0.7% (w/w) dosage. The morphological study indicated that the palm oil crystals were smaller and more even in size than when more additive was added. Isothermal crystallization studies using differential scanning calorimetry (DSC) showed increased inhibitory effects on palm oil crystal growth with increasing concentration of PGEmix-8. These results imply that PGEmix-8 is a nucleation enhancing and crystal growth retarding additive in palm oil crystallization at 0.7% (w/w) dosage.

This paper examines the interactions of degumming and bleaching processes as well as their influences on the formation of 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters in refined, bleached and deodorized palm oil by using D-optimal design. Water degumming effectively reduced the 3-MCPDE content up to 50%. Acid activated bleaching earth had a greater effect on 3-MCPDE reduction compared to natural bleaching earth and acid activated bleaching earth with neutral pH, indicating that performance and adsorption capacities of bleaching earth are the predominant factors in the removal of esters, rather than its acidity profile. The combination of high dosage phosphoric acid during degumming with the use of acid activated bleaching earth eliminated almost all glycidyl esters during refining. Besides, the effects of crude palm oil quality was assessed and it was found that the quality of crude palm oil determines the level of formation of 3-MCPDE and glycidyl esters in palm oil during the high temperature deodorization step of physical refining process. Poor quality crude palm oil has strong impact towards 3-MCPDE and glycidyl esters formation due to the intrinsic components present within. The findings are useful to palm oil refining industry in choosing raw materials as an input during the refining process.

A method for the determination of acephate, methamidophos and monocrotophos in oil matrices is described. Pesticide residues in crude palm oil were extracted with acetonitrile, and a clean-up process was performed by cooling the entire extract below 10 7C, followed by a discolouring process using a Carbograph SPE cartridge. The extract was analysed using gas chromatography coupled with a pulsed flame photometry detector. The limit of detection for the method was calculated from regression data, and the recovery test results were in the range of 85-109%.

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Thiosultap-disodium (thiosultap) has been identified to be the potential alternative to monocrotophos and methamidophos for controlling bagworms and leaf earting caterpillars infestation in oil palm plantations. This article reports a simple and fast method of determining thiosultap residue in palm oil matrix using liquid chromatography coupled to a triple quadrupole mass spectrometer. The proposed method has been inhouse validated. Method recoveries were found to be satisfactory within the range of 72% to 103%, method precision was good with a relative standard deviation (RSD) of 4% to 6% for repeatability and RSD of less than 12% for intermediate precision. Method limit of detection and determination were estimated from matrix matched calibration curves, the values were 2.9 ng ml-1 and 8.7 ng ml-1 , respectively. The fact that no maximum residue limit has been set for thiosultap in palm oil internationally, suggesting that the default value of 0.01 mg kg-1 maximum allowable limit is to be enforced. An analytical method that will enable the determination of thiosultap residue at this default level therefore is required to facilitate the monitoring of potential thiosultap residue contamination in palm oil traded in Malaysia.