The 3-monochloropropane-1, 2-diol esters (3-MCPDEs) and glycidyl esters (GEs), which are recognized as contaminants often produced during the deodorization process of refined edible oils, have garnered widespread attention and research interest in recent years due to their potential health risks to humans. Although there have been studies on the formation mechanisms of 3-MCPDEs and GEs, further clarification is still needed in the intrinsic synergistic effects of precursors. Herein, the synergistic effects of acylglycerols, including monoacylglycerols (MAGs), diacylglycerols (DAGs), and triacylglycerols (TAGs) on the formation of 3-MCPDEs and GEs were innovatively investigated through simulated deodorization experiments in model soybean oil systems. Additionally, the effects of simulated deodorization conditions, including temperatures, heating duration, chloride contents, and acylglycerol compositions on the production of 3-MCPDEs and GEs, were also investigated. The results indicated that under the simulated deodorization process and in the presence of chloride ions, the formation of 3-MCPDEs and GEs was facilitated by the synergistic interaction among MAGs, DAGs and TAGs. It is noteworthy that MAGs were more susceptible to forming 3-MCPDEs in the presence of chloride ions, whereas GEs predominantly resulted from the cyclization reaction of DAGs. Concurrently, when the MAGs content was less than 1%, or the presence of DAGs was less than 4% in the model system, the formation of both 3-MCPDEs and GEs was found to be below the EU regulatory limits, thus offering a solid theoretical basis for the control of 3-MCPDEs and GEs in refined oils.
This study investigated whether and how triacylglycerol (TAG) may serve as a precursor for 3-monochloro-1,2-propanediol (3-MCPD) fatty acid ester formation using tristearoylglycerol (TSG). TSG was reacted with inorganic chloride compounds including NaCl, KCl, FeCl2, CuCl2, ZnCl2, FeCl3 and dry HCl, or organic chlorine compound lindane at different temperatures. Only FeCl2 and FeCl3 were able to form 3-MCPD esters from TSG. Further electron spin resonance (ESR) determination of TSG, Fe2(SO4)3 and 5,5-dimethylpyrroline-N-oxide (DMPO) reactions revealed potential of Fe ion in promoting free radical generations under the experimental conditions. To further confirm the effect of Fe ion, chelating agent (EDTA-2Na) was added to the model reactions. The results showed for the first time that EDTA-2Na was able to reduce the generation of 3-MCPD esters. In addition, FT-IR examination indicated a possible involvement of a carbonyl group during the reaction. Taking all the observations together, the possible mechanisms, involving the formation of either a cyclic acyloxonium or a glycidol ester radical intermediate, were proposed for generating 3-MCPD fatty acid di- and mono- esters from TAG under a high temperature and low moisture condition, as well as the coformation of glycidol esters. The results from this study may be useful for reducing the level of 3-MCPD esters and related toxicants in the refined edible oils and food products.
This study investigated the formation and mitigation of 3-monochloro-1,2-propanediol (3-MCPD) ester in vegetable oils under storage, thermal processing, and chloride supplementation. Prolonged storage (>6 months) markedly accelerated formation (80.8–190 μg/kg·month -1 ), a rate substantially higher than in the initial 6 months (15.2–71.9 μg/kg·month -1 ), underscoring a previously underestimated risk in long-term stored oils even if levels remain below EU limits. Thermal treatment revealed a matrix-dependent dynamic equilibrium, with soybean oil peaking at 220°C (1250 μg/kg) and rapeseed oil at 180°C (997 μg/kg). Among chloride salts, CaCl 2 induced the highest 3-MCPD ester level (2189 μg/kg), revealing the critical, previously detailed role of metal cation properties (coordination capacity, charge density) beyond the mere presence of Cl - . Antioxidants provided dose-dependent mitigation (up to 49% suppression), though their efficacy was limited by thermal stability. Most significantly, mesoporous silica nanoparticles (MSNs) demonstrated exceptional efficacy, achieving a 98% adsorption removal rate of 3-MCPD esters from oil, with a high fitted maximum capacity (Q max = 412.5 μg/g). The combined strategy of antioxidant application followed by MSN treatment offers a novel, practical, and industrially viable solution for significantly reducing 3-MCPD ester exposure in oils and lipid-rich foods.
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