Effects of non-covalently bound polyphenols/vitamins on the structure and functional characteristics of egg yolk powder

The egg yolk powder (EYP) was modified in this study by incorporating the tea polyphenols (TP), rosemary extract (RE), curcumin (CC), ascorbic acid (AA), and vitamin E (VE) to create the complex of polyphenols/ vitamins-EYP. The structure, flavor, and emulsification properties of the complex were investigated. The results demonstrated that the addition of these five substances enhanced the flavor of EYP. Among them, VEP (EYP modified by VE) exhibited the flavor profile closest to EYP, while TPP (EYP modified by TP) had the most different flavor compared to EYP. This was because VE could induce secondary and tertiary structural changes in EYP and exposed more functional groups for binding with volatile flavor compounds such as hexanal, 1-octen-3ol, and benzaldehyde, thereby improving the overall flavor of EYP. However, due to its larger molecular weight (1099.62 Da), VE exhibited the limited degree of interaction with EYP, thereby enabling it to preserve the overall flavor profile of EYP. On the other hand, TP possessed most active hydroxyl groups, which easily interacted with EYP, forming new complexes that significantly altered its flavor characteristics. Among the five modified powders, VEP had the highest emulsification, but it was still lower than that of EYP. This was because the particle size of VEP (1592.75 nm) was higher than that of EYP (821.88 nm), which was not conducive to the rapid movement to the oil-water interface, resulting in the reduced emulsification.