Inhibition mechanism against hemoglobin oxidation of volatile pyrroles from Maillard reaction

This study aimed to investigate the antioxidant mechanisms of Maillard reaction-derived volatile pyrroles – 2-acetylpyrrole (2AP), N-methylpyrrole (NMP) and pyrrole-2-carboxaldehyde (2PC) on hemoglobin (Hb) oxidation. The findings revealed that during 4-days storage, the 2AP group showed lower carbonyl and dimerised tyrosine contents of Hb than the untreated Hb group, and 2AP preserved the conformation of heme porphyrin in Hb through microenvironmental polarity modulation. In stark contrast, NMP exhibited pro-oxidative properties with accelerated protein aggregation, while 2PC exhibited a biphasic effect – suppressing Hb oxidation initially but accelerating it subsequently – this late-stage oxidation was attributed to its enhanced Hb surface hydrophilicity. Generally, the inhibition activity of the three pyrroles is closely related to the position of the substituents in the pyrrole ring and the availability of electrons. This study provided a basis for investigating the antioxidant properties and applications of Maillard reaction-derived volatile small molecules in fresh meat preservation.