title: Formation of 3-monochloro-1,2-propanediol (3-MCPD) di- and monoesters from tristearoylglycerol (TSG) and the potential catalytic effect of Fe²⁺ and Fe³⁺.
abstract: 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.
authors: Institute of Food and Nutraceutical Science, School of Agriculture and Biology, Shanghai Jiao Tong University , Shanghai 200240, China.
authors: Zhongfei
authors: Z
authors: Zhang
authors: Boyan
authors: B
authors: Gao
authors: Xiaowei
authors: X
authors: Zhang
authors: Yuanrong
authors: Y
authors: Jiang
authors: Xuebing
authors: X
authors: Xu
authors: Liangli Lucy
authors: LL
authors: Yu
mesh_terms: D002712:Chlorides / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004042:Dietary Fats, Unsaturated / Q000032:analysis; D004578:Electron Spin Resonance Spectroscopy; D004952:Esters / Q000138:chemical synthesis; D005290:Ferric Compounds / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D005506:Food Contamination / Q000517:prevention & control; D005609:Free Radicals / Q000032:analysis; D013058:Mass Spectrometry; D014280:Triglycerides / Q000737:chemistry*; D000517:alpha-Chlorohydrin / Q000138:chemical synthesis*
chemical_list: D002712:Chlorides; D004042:Dietary Fats, Unsaturated; D004952:Esters; D005290:Ferric Compounds; D005296:Ferrous Compounds; D005609:Free Radicals; D014280:Triglycerides; D000517:alpha-Chlorohydrin; C022618:tristearin
keywords: 3-MCPD esters; EDTA-2Na; ESR; formation mechanism; iron ion; lipid peroxidation