The effect of various compounds with purported 'antioxidant properties' (epigallocatechin-3-gallate, catechin hydrate, 4-methylcatechol, cysteine, bisulfite) on the generation and fate of pyrazinium radicals in the Maillard reaction was investigated. In this study, glyoxal and glycolaldehyde, two important intermediates formed during Maillard sugar fragmentation, as well as glucose, were used to generate pyrazinium radicals. Electron paramagnetic resonance (EPR) was used to study the resulting radicals' structural information and to quantify radical yield. It was observed in most of the cases that in glyoxal and glycolaldehyde models, low concentrations (<50 mM) of these antioxidants increased pyrazinium radical generation, while high concentrations of these tested compounds suppressed it. In glucose models, these antioxidants were only found to have inhibitory effects on the radical generation as concentrations increased. This finding demonstrating inhibition of radical formation supports previous published studies in which polyphenols and bisulfite decrease the formation of several products during the Maillard reaction by binding to, or reacting with, product precursors. However, the observation that low concentrations of these compounds catalyze pyrazinium radical formation in glyoxal and glycolaldehyde models is novel, and may help to elucidate other important mechanistic details of the Maillard reaction.

Investigating the effect of common antioxidants on the generation and fate of pyrazinium radicals in the Maillard reaction

240th National Meeting (2010)

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