Understanding the formation and mitigation of chloropropanol esters during traditional Chinese cooking using a lipase hydrolysis-based method

Chloropropanol esters are major contaminants in food, but their formation during traditional Chinese cooking remains unclear. In this study, a method based on lipase hydrolysis pretreatment was developed and validated to determine 4 chloropropanol esters. The formation of these esters during stir-frying and hotpot cooking under various conditions was investigated. The results showed that the proposed method outperformed the fast alkali-catalyzed transesterification method. Higher NaCl concentrations led to increased formation of chloropropanol esters. Chloropropanol esters decreased with increasing cooking time due to degradation. Refined oils with a higher ratio of unsaturated fatty acids produced more chloropropanol esters. Adding NaCl at the beginning or end of cooking resulted in fewer chloropropanol esters. Free radicals contribute to the chloropropanol esters, resulting in a strong correlation between chloropropanol esters, the peroxide value, and total polar compounds. This study provides valuable insights into the formation of chloropropanol esters and their mitigation during cooking.