Conversion of 3-aminopropionamide and 3-alkylaminopropionamides into acrylamide in model systems

Carbonyl compounds have been shown to play a major role in the conversion of asparagine into acrylamide. However, it is unclear at this point if its role is only restricted to the decarboxylation of the amino acid or if carbonyl compounds also play a role in the deamination reaction of the decarboxylated intermediates 3-aminopropionamide and 3-(alkylamino)propionamides. This study describes the deamination reaction of 3-aminopropionamide and 3-(alkylamino)propionamides (benzyl, phenylethyl, butyl, and octyl) in model systems and in the presence, or not, of different carbonyl compounds (alkadienals, alkenals, and alkanals). All these reactions were mainly produced at almost neutral or basic pH values. In addition, the reaction yields and the activation energies not only depended on the type of aminopropionamide involved but also on the water activity (a(w)) and in the presence, or not, of carbonyl compounds. However, there was not a clear correlation among the activation energies calculated for the different deamination reactions and the yields of acrylamide obtained; therefore, suggesting the existence of diverse pathways by which 3-aminopropionamide and 3-(alkylamino)propionamides are converted into acrylamide. In addition, these reactions are also competing with other carbonyl-amine reactions when carbonyl compounds are present. All these results suggest that the type of the intermediate aminopropionamide involved is going to play a major role in both the amount of acrylamide produced and the conditions required for its formation. On the other hand, the role of carbonyl compounds in the acrylamide produced, but not in the activation energy of the reactions implicated, seems to be more limited than either the type of amine or the a(w). A detailed analysis of the type of the intermediate aminopropionamide formed in foods may help to define strategies for mitigating the formation of this food toxicant.