Role of mercaptans on acrylamide elimination

The reaction between acrylamide and mercaptans (benzyl mercaptan and N-acetylcysteine) was studied in an attempt to clarify some of the reaction pathways by which amino acids affect the acrylamide content in foods. The obtained results showed that, in the absence of oxygen, mercaptans reacted very rapidly with acrylamide producing the corresponding addition product. The activation energy of this reaction was 28–30 kJ/mol. The produced adduct was stable and only trace amounts of acrylamide were formed by thermal heating of 3-(benzylthio)propanamide. In the presence of oxygen, the addition product was not observed but a higher amount of acrylamide disappeared, more likely as a consequence of radical reactions. These last reactions could be inhibited by antioxidants, which prevented acrylamide losses. All these results constitute a new proof of the complexity of the reactions involved in the formation and elimination of acrylamide in foods, which are also going to depend on the food composition and the presence of oxygen. Potential toxicities of the compounds formed between acrylamide and mercaptans still remain to be analysed.