Change of fatty acid esters of MCPD and glycidol during restaurant deep frying of fish nuggets and their correlations with total polar compounds
Lirong Xu, Yuanbo Zhang, Mengyue Gong, Jianhua Huang, Qingzhe Jin, Xiaosan Wang, Xiaosan Wang, Xingguo Wang, Xingguo Wang
Abstract
Summary This study examined the fatty acid esters of 2‐monochloropropane‐1,2‐diol (2‐MCPD), 3‐monochloropropane‐1,2‐diol (3‐MCPD) and glycidyl esters (GEs) in frying oils during fish nuggets deep frying. The 3‐MCPD esters significantly increased in the first 12 h and then decreased, whereas 2‐MCPD esters increased to a maximum at 24 h (0.69–0.81 mg kg −1 ) and then decreased. The GEs decreased with frying time and degraded to approximately 0.05 mg kg −1 after 36 h in all frying oils. The correlation results showed that the 3‐MCPD esters had a positive correlation with 2‐MCPD esters ( R = 0.910), so 3‐MCPD esters could be an indicator of the presence of MCPD esters in frying oils. Strong correlations were found between MCPD esters and the peroxide values and p ‐anisidine values, indicating that changes in MCPD esters may be related to oil oxidation. These results may improve our understanding of MCPD esters and GEs in frying oils and find ways to control them during frying.