Effect of Succinylation on Oxidation–Aggregation of Low-Density Lipoprotein and Formation of Off-Flavors in Heated Egg Yolks

Abstract

This study examined the effect of succinylation on protein oxidation–aggregation and the formation of off-flavors in heated egg yolks (EYs). The sensory evaluation, content of volatile compounds, stability of low-density lipoprotein (LDL) particles, and oxidation of lipid and protein at six levels of succinylated EY (0.25%, 0.5%, 1%, 2%, 5%, and 10%, w/w) were determined. The results showed that the succinylated thermal EY’s concentration of volatiles and off-flavors was reduced. Oil exudation and lipid and protein oxidation decreased with the improved succinylation degree. Succinylation also reduced the LDL particle size and changed the secondary structure (decreased the β-sheets and increased the α-helices) of protein in LDL particles. Meanwhile, succinylation could effectively change the thermal oxidation–aggregation of LDL protein by introducing succinyl groups with negative charges, thus increasing the stability of LDL particles in succinylated EY during heating. These results further revealed the relationship between the oxidation–aggregation of LDL and the formation of off-flavors in heated EY. These results also help improve the flavor quality of heat-treated EY and expands the application scope of egg products.

Keywords

• egg yolk
• heat treatment
• succinylation
• off-flavor
• lipoprotein oxidation