Inhibition of heterocyclic amine formation by water-soluble vitamins in Maillard reaction model systems and beef patties

The inhibitory activities of 11 water-soluble vitamins against heterocyclic amine formation were examined in a PhIP and a MeIQx producing chemical model. Six investigated vitamins (pyridoxiamine, pyridoxine, nicotinic acid, biotin, thiamine and l-ascorbic acid) out of the 11, exhibited significant inhibition (>40%) in both models. Pyridoxamine was the most potent inhibitor, and its inhibitory effect increased with increasing concentration in the model, although not in a linear manner. The activity of pyridoxamine, niacin and ascorbic acid was investigated using fried beef. Moderate inhibition (∼20%) of the formation of PhIP, 4,8-DiMeIQx and MeIQx was found for niacin and ascorbic acid; whereas pyridoxamine reduced the levels of all three HAs by ∼40%. GC–MS analysis showed that pyridoxamine significantly reduced the level of PhIP intermediate, phenylacetaldehyde. LC–ESI–MS/MS analysis revealed that pyridoxamine directly reacts with phenylacetaldehyde to form an adduct, whose structure was characterised by MS and NMR spectroscopy.