Occurrence of 3-MCPD, 2-MCPD and glycidyl esters in extra virgin olive oils, olive oils and oil blends and correlation with identity and quality parameters

Abstract

3-MCPDE (3-monochloropropane-1,2-diol esters), 2-MCPDE (2-monochloropropane-1,3-diol esters) and GE (glycidyl esters) are heat-induced contaminants that are formed during the refining of vegetable oils under high temperatures, mainly during the deodorization step. Samples commercialized as extra virgin olive oils (EVOO), olive oils and oil blends (n = 76) were analysed for 3-MCPDE, 2-MCPDE and GE. A possible correlation with the identity and quality parameters established for olive oils was also evaluated. Concentrations of 3-MCPDE, 2-MCPDE and GE ranged from not detected to 1.16 mg/kg, not detected to 0.58 mg/kg and not detected to 1.98 mg/kg in EVOO, respectively. Samples commercialized as olive oil presented levels ranging from 0.28 to 3.77 mg/kg for 3-MCPDE, 0.17–1.91 mg/kg for 2-MCPDE and not detected to 1.88 mg/kg for GE. For oil blends, 3-MCPDE levels were from 0.18 to 0.61 mg/kg, 2-MCPDE were from not detected to 0.25 mg/kg and GE from 0.31 to 1.84 mg/kg. As the processing of EVOO does not require the use of high temperatures, these esters were not expected at quantifiable levels in these products, indicating that they were probably adulterated with the addition of some type of refined oil. According to this study, analysis of 3-MCPDE, 2-MCPDE and GE may also be used as a complementary indicator of adulteration of EVOO.