Saccharides alleviate the thermal instability behavior of liquid egg yolk: Influence on rheology property, emulsifying property and protein conformation

Liquid egg yolk (LEY) is a kind of thermally sensitive food ingredient, and the heat treatment involved in pasteurization and processing causes its denaturation, viscosity increase and emulsification instability, which limit its wider applications. Hence, new methods of preparing LEY with enhanced heat stability were explored. Results showed that saccharides exhibit great promise in alleviating aggregation behavior and undesirable loss in properties caused by heat treatment. Enhanced thermal denaturation temperature and weaker aggregation behavior contributed to the phenomenon, which was proven by rheology, particle size distribution, scanning electron microscope, confocal laser scanning microscopy, and low field-nuclear magnetic resonance. Raman spectra results indicated that heat treatment affected the microenvironment of tryptophan residues, and that additives could enhance protein stability. Overall, this study provides several greater selections of improved thermal tolerance of LEY in commercial operation compared with conventional additive (sucrose), which could provide a theoretical basis for producing LEY with enhanced heat stability.