The effects of chloride and the antioxidant capacity of fried foods on 3-Chloro-1,2-propanediol esters and glycidyl esters during long-term deep-frying

Abstract The effects of sodium chloride (NaCl) and tert-butylhydroquinone (TBHQ) on 3-monochloropropane-1,2-diol (3-MCPD) ester and glycidyl esters (GEs) contents were investigated during long-term deep-frying (177 °C, 4 days). The properties of fried food probably affect the formation of 3-MCPD esters and GEs in frying oil. Less NaCl promoted lower 3-MCPD ester and GEs contents, contents of 3-MCPD ester and GEs in the extracted oils from Youtiao (0 mg/kg TBHQ) reduced from 1.272 to 0.360 mg/kg and 0.559 to 0.346 mg/kg, respectively, while the amount of NaCl in Youtiao reduced from 1.5 to 0.0 g/100g. TBHQ possibly decreased the 3-MCPD ester and GEs contents by suppressing the formation of radical intermediates. The 3-MCPD ester and GEs contents in the extracted oils from Youtiao (1.5 g/100g NaCl) decreased from 1.221 to 0.893 mg/kg and 0.534 to 0.312 mg/kg, respectively, while the amount of TBHQ in Youtiao increased from 0 to 300 mg/kg. The formation of 3-MCPD esters might be accompanied by decomposition, GEs were rarely generated but decomposed during long-term frying. 3-MCPD esters and GEs entered fried food through frying oil, and the 3-MCPD ester and GEs contents in the extracted oil from Youtiao were closely related to those in the frying oils.