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.