Mitigation Strategies for the Reduction of 2- and 3-MCPD Esters and Glycidyl Esters in the Vegetable Oil Processing Industry.

The refining of vegetable oils leads to the formation of 2- and 3-monochloropropane-1,2-diol esters (2- and 3-MCPD-E), and glycidyl esters (Gly-E). A literature review was performed aiming to provide up-to-date knowledge on mitigation strategies during oil refining that can reduce the formation of these three processing contaminants. The review used the database Scopus and covered the period from 2009 to 2017. Most of the 18 papers dealt with palm oil and two papers with vegetable oil. Most studies focused on 3-MCPD-E, some on Gly-E, and none on 2-MCPD-E. Water degumming was able to reduce the concentrations of 3-MCPD-E by 84% and Gly-E by 26%. Neutralization of the oil reduced concentrations of 3-MCPD-E by 81% and Gly-E by 84%. Bleaching with synthetic magnesium silicate reduced the 3-MCPD-E concentration by 67%. For the deodorization step, several mitigation strategies, such as double-deodorization, the addition of various antioxidants, or a longer deodorization time, can reduce the formations of 3-MCPD-E by 82% and Gly-E by 78%. Postrefining mitigation, including the use of absorbents, enzymes, or rebleaching of the oil, has also been reported to produce desirable contaminant reduction. Postrefining treatment with calcinated zeolite was able to reduce the 3-MCPD-E concentration by 19% and the Gly-E concentration by 77%. Applying combined mitigation strategies to multiple steps of oil refining is likely crucial in order to adequately reduce levels of 3-MCPD-E and Gly-E.

Chemical refining methods effectively mitigate 2-MCPD esters, 3-MCPD esters, and glycidyl esters formation in refined vegetable oils.

Esters of 3-monochloro-1,2-propanediol (3-MCPDE), 2-monochloro-1,3-propanediol (2-MCPDE), and glycidyl esters (GE) are processing contaminants that can be found in refined edible fats and oils. Recently, the European Commission has implemented maximum limits for the presence of free and bound 3-MCPDE in vegetable fats and oils and in marine and fish oils. This boosted the necessity of oil producers to develop refining methods to limit the concentration of both 3-MCPDE and GE in their final products. Physical refining may lack the potential to mitigate the formation of 2- and 3-MCPDE. Therefore, in this study, the chemical refining method were explored to provide a viable mitigation strategy aimed at industrial application. Several pilot plant treatments with organic palm oil were performed. The investigated refining methods included a neutralization, a water washing process, reduced deodorization temperature, and a combination of them. The best performing chemical refining treatment achieved a final concentration of 0.42 (-49%), 0.78 (-52%), and 0.99 (-73%) mg/kg for 2-MCPDE, 3-MCPDE, and GE in organic palm oil, respectively. Results thus showed chemical refining has great potential for the simultaneous mitigation of 2-, 3-MCPDE, and GE.

Effective physical refining for the mitigation of processing contaminants in palm oil at pilot scale.

This study aimed to develop a mitigation strategy for the formation of 2-monochloropropane-1,3-diol esters (2-MCPDE), 3-monochloropropane-1,2-diol esters (3-MCPDE), and glycidol fatty acid esters (GE) during palm oil refining. Single physical refining was the starting point (the control) for this study. Experimental treatments including a double refining repeating the entire single refining process (T1), double refining with a high-low deodorization temperature (T2), and double deodorization (T3) with similar temperature settings as T2 were performed. Compared with the control experiment, T2 successfully reduced the formation of GE by 87%; in particular, the second degumming and bleaching were crucial for eliminating GE. Both 2- and 3-MCPDE were formed prior to the deodorization process in all treatments. MCPDE concentrations remained stable throughout the refining process and, hence, they require a different mitigation approach as compared to GE. These results provide useful insights which can directly be implemented by the oil industry.

Discrimination of processing grades of olive oil and other vegetable oils by monochloropropanediol esters and glycidyl esters.

In this study, the processing derived contaminants 2- and 3-monochloropropanediol (2- and 3-MCPD) esters and glycidyl esters (GEs) were analysed in 84 oil samples by GC-MS/MS for the discrimination of processing grades of olive oils as a potential authentication tool. Concentrations of 2- and 3-MCPD esters and GEs varied in the ranges 0-6 mg/kg, 0-1.5 mg/kg, and 0-1 mg/kg oil, respectively. The concentrations of the three compounds in lower grade olive oils were significantly higher (P < .001) than that in EVOO. A similar difference was observed for other refined and cold-pressed vegetable oils. The limit of fraud detection of lower grade oils in EVOO was 2% when using 3-MCPD esters, 5% for 2-MCPD esters, and 13-14% for GEs based on calculations of virtual mixtures of the current sample set. Especially the MCPD esters appear very specific and promising for the detection of lower processing grade oils in EVOO.