Formation of 3-chloropropane-1,2-diol esters in model systems simulating thermal processing of edible oil

• Fe3+ could significantly promote the formation of 3-MCPD esters.
• 3-MCPD esters decreased dramatically with the increase of pH value.
• 3-MCPD esters decomposed by heating long time at high temperature.
• The continuous heating model generated more 3-MCPD esters than the intermittent one.

3-chloropropane-1, 2-diol (3-MCPD) esters are a kind of food processing contaminants that especially occur in edible oil. This study investigated the impact of various factors on the formation of 3-MCPD esters in edible oil models with sodium chloride as chlorine donator during heat processing. The amount of 3-MCPD esters generated in the models were positively correlated with the concentration of sodium chloride. Fe3+ could significantly promote the formation of 3-MCPD esters. The formation of 3-MCPD esters also depended on pH value of oil, heating temperature and time. The highest level of 3-MCPD esters were obtained at pH 4.0 (2925.3 μg/kg), at 220 °C (9509.8 μg/kg) and for 8 h (4852.4 μg/kg), respectively. 3-MCPD esters were generated much more in the continuous heating model than in the intermittent one. The results are valuable to better understand the formation of 3-MCPD esters and also can provide references for reduction of 3-MCPD esters during edible oil processing and household cooking.