Lutein as an antioxidant inhibits the Maillard reaction in heated egg yolk

Abstract

Lutein is the key carotenoid in egg yolks with excellent antioxidant activity, and lutein-free yolks can mimic chicken aroma after heating. The aim of this study was to verify the effect of lutein on the Maillard reaction. The egg yolk samples were heated at 100 °C for 10 min, and then the precursors, intermediates and end products of Maillard reaction were analyzed by ¹H NMR coupled with ATR-FTIR spectroscopy. The results demonstrated that the precursors of Maillard reaction in the sample without lutein were significantly lower than those in the samples containing lutein after heating, while the content of the products or related groups of Maillard reaction were just the opposite. The egg yolk sample containing tert-butyl hydroquinone (TBHQ, an antioxidant) and the modeling reaction also verified the inhibitory effect of lutein on the Maillard reaction. This study demonstrated that the removal of lutein from egg yolks could promote the Maillard reaction after heating because the inhibitory effect of lutein on the reaction was disabled, thus generating large quantities of Maillard reaction products which would be essential for food aroma. This work offers a practical approach for the transformation of food aroma by the removal of antioxidants from food.