Natural Organochlorines as Precursors of 3-Monochloropropanediol Esters in Vegetable Oils

Abstract

During high-temperature refining of vegetable oils, 3-monochloropropanediol (3-MCPD) esters, possible carcinogens, are formed from acylglycerol in the presence of a chlorine source. To investigate organochlorine compounds in vegetable oils as possible precursors for 3-MCPD esters, we tested crude palm, soybean, rapeseed, sunflower, corn, coconut, and olive oils for the presence of organochlorine compounds. Having found them in all vegetable oils tested, we focused subsequent study on oil palm products. Analysis of the chlorine isotope mass pattern exhibited in high-resolution mass spectrometry enabled organochlorine compound identification in crude palm oils as constituents of wax esters, fatty acid, diacylglycerols, and sphingolipids, which are produced endogenously in oil palm mesocarp throughout ripening. Analysis of thermal decomposition and changes during refining suggested that these naturally present organochlorine compounds in palm oils and perhaps in other vegetable oils are precursors of 3-MCPD esters. Enrichment and dose-response showed a linear relationship to 3-MCPD ester formation and indicated that the sphingolipid-based organochlorine compounds are the most active precursors of 3-MCPD esters.

Untitled

“…The latter affects the formation of 3-MCPDE in palm oil during the refining stage. Study shows that the total chlorine content in CPO has a direct correlation with 3-MCPDE in refined palm oil with R2 > 0.73, as shown in Figure 1 18 . Nagy et al 26 discovered that there are more than 200 monochlorinated organic compounds along with some chlorinated inorganic compounds such as FeCl2, FeCl3, MgCl2 and CaCl2 in CPO.…”

“…Nagy et al 26 discovered that there are more than 200 monochlorinated organic compounds along with some chlorinated inorganic compounds such as FeCl2, FeCl3, MgCl2 and CaCl2 in CPO. Organochlorine compounds had also been identified as lipid constituents produced naturally and showed potential to liberate chlorine during deodorisation to form 3-MCPDE 18,26 . The fact that organochlorine compounds function as chlorine precursors for 3-MCPDE was further confirmed.…”

“…The fact that organochlorine compounds function as chlorine precursors for 3-MCPDE was further confirmed. A model by Tiong et al 18 showed that an addition of enriched organochlorine compound mixture yielded higher 3-MCPDE formation after thermal treatment. It was reported that organochlorine compounds were biosynthesised in oil palm fruits.…”

“…Therefore, EFSA has proposed to limit the presence of 3-MCPDEs in palm oil to 2.5 ppm and below from 2021 onwards 15 . Various studies showed that CPO with high levels of FFA, DAG and traces of chlorine promote the formation of 3-MCPDE during the refining stage 16,17,18 . In response to these research works; Malaysian authorities have recently proposed the limit of chlorine content in CPO to be below 2 ppm (see Table 1).…”

Changes in 3-, 2-Monochloropropandiol and Glycidyl Esters during a Conventional Baking System with Addition of Antioxidants

“…In addition, chlorine, as one of the important precursors for 3-MCPD ester formation, can be introduced through various sources of ingredients, such as flour [41]. The relationship between chlorine content and the 3-MCPD ester has proven to be a strong positive one based on a previous study [42]. However, the recipe used during the experiments was controlled and therefore no significant change in the total chlorine percentage was observed throughout the experiment (see Table 2).…”