Mechanistic evidence for the effect of sulphur-based additive: methionine, on acrylamide reduction

The unavoidable presence of acrylamide in foods has fuelled the search for a suitable food additive, one that can successfully mitigate dietary acrylamide levels without changing food quality or compromising the health of consumers. The purpose of this study was to investigate the effect of a sulphur-based additive and amino acid, methionine, on acrylamide reduction. Differential scanning calorimetry, supported by chromatographic measurements, has shown that methionine interacts with acrylamide at a possible optimum temperature of 160°C, thereby disfavouring acrylamide polymerisation. Analysis of the methionine-acrylamide interaction via density functional theoretical modelling (DFT/6-31 + G(d)/RCAM-B3LYP) revealed that methionine's reducing effect may be driven by a Michael-type conjugation of the vinyl group of acrylamide at both the sulphur atom (∆G_f = -53 kJ mol^-1) and the amino group (∆G_f = -11.84 kJ mol^-1) of methionine. The former conjugation pathway results in a product that is more thermodynamically feasible.