Characterization of Typical Reaction Products from Seven Amino Acids with Acrolein

Acrolein is an endogenous food toxin produced during thermal processing of foods. To investigate the significantly reduced reasons of acrolein in fried potato chips, seven amino acids (glycine, asparagine, aspartic acid, glutamic acid, glutamine, valine, and threonine) with high level in potato were chosen to react with acrolein under different reaction temperature and time. The structures of reaction products were identified after purification, and the scavenging effect as well as the mechanism of amino acids on acrolein were correspondingly studied. The selected amino acids were found to effectively eliminate acrolein and eight new main reaction products were identified for the first time. The supposed reaction mechanism is: one molecule of amino acid reacts with two molecules of acrolein via Michael addition, and then forms a more stable ring (similar to the structure of pyridine) through aldol condensation. However, the simplest amino acid, glycine, generates another major product composed of 3 molecules of acrolein and 2 molecules of glycine. The reaction mechanism was speculated as follows: after one molecule of glycine undergoes Michael addition with two molecules of acrolein, one of the two aldehyde groups in the adduct reacts with another molecule of glycine to form a Schiff base, while another acrolein in the adduct undergoes aldol condensation with the third molecule of acrolein, resulting in a conjugated structure. In addition, an HPLC-MS/MS analysis method was developed and it was found that the reaction adducts exist in fried potato crisps, such as asparagine-acrolein, indicating that free amino acids in potato may play an important role in the reduction of acrolein in fried potato chips. © 2022, Editorial Office of Journal of CIFST. All right reserved.