Impact of phloretin and phloridzin on the formation of Maillard reaction products in model systems

Abstract

Maillard reaction is of great importance in food industry. Some flavonoids from natural plants have been found to possess inhibitory effects on harmful advanced glycation end-products (AGEs). However, few studies paid attention to effects of these natural AGE inhibitors on the Maillard reaction happening under thermal conditions. In the present work, we aimed to investigate effects of the two apple phenols, phloretin and phloridzin, on the Maillard reaction taking place in both thermal and non-thermal models. It was found that either phloretin or phloridzin could inhibit the formation of Maillard-type volatiles in various thermal Maillard model systems (glucose-lysine, glucose-lysine derivatives with α-amino group blocked, and ribose-cysteine, respectively). In addition, both phloretin and phloridzin could obviously affect color development induced by Maillard reaction. For the study of non-thermal Maillard reaction, effects of phloretin and phloridzin were evaluated in methylglyoxal (MGO)-induced glycation systems consisting of amino acids, peptides and protein (creatine kinase), respectively. Arginine residue was found as an active site for glycation, and the addition of phloretin and phloridzin could significantly inhibit the arginine-site glycation. Interestingly, the addition of phloretin could promote the consumption of cysteine residue exposed to MGO, while cysteine residue kept unchanged when incubated solely with MGO. The promoting effect of phloretin on cysteine residue consumption is caused by the condensation reaction among phloretin, MGO and cysteine residue. Based on findings given in the work, phloretin and phloridzin could play multiple roles in the Maillard reaction by trapping reactive carbonyl species, which may give us an alternative way to better understand the potential effects of natural flavonoids on food processing and human health.