Effect of transition metal ion on aroma compounds generation from model reaction of L- ascorbic acid and L-cysteine

The identification of aroma compounds, generated from model reaction of L-ascorbic acid and L-cysteine was performed using a solid-phase microextraction-gas chromatography-mass spectrometry technology. The effects of the small amount of Fe²⁺-ions, Zn²⁺-ions or Cu²⁺-ions on aroma compounds generation from model system of L-ascorbic acid and L-cysteine were investigated. The classification of aroma compounds was not affected much by Fe²⁺-ions, Zn²⁺-ions or Cu²⁺-ions, but the yield of each type of aroma compounds was decreased observably. The yield of each type of aroma compounds appeared to be affected much more by Cu²⁺-ions than by Zn²⁺-ions or Fe²⁺-ions depended on the different ions concentration. A plausible explanation for this phenomenon was that Fe²⁺-ions, Zn²⁺-ions or Cu²⁺-ions depressed the thermal degradation of L-cysteine, on the other hand, but stimulated the active intermediates to convert high molecular weight compounds.