Abstract: Egg yolk is a complex supramolecular system composed of diverse proteins with high nutritional value and outstanding functional characteristics. Cryopreservation is commonly used in the food industry as an effective way to prolong egg yolk shelf life and improve transportation convenience. However, low temperature induces the aggregation of protein in egg yolk, resulting in egg yolk gelation and consequently reduced fluidity and solubility, affecting the functional properties of egg yolk, which are not conducive to the application of egg yolk in food processing. This article introduces the composition, structure and functional characteristics of egg yolk as well as the causes of egg yolk freezing and the mechanism of egg yolk gelation, and discusses the effect of egg yolk gelation induced by freezing on egg yolk quality. This review focuses on the physical, chemical and biological pretreatments for inhibiting protein aggregation during egg yolk, which is of guiding significance for inhibiting egg yolk gelation induced by freezing and for improving the quality of frozen egg yolk.

Key words: egg yolk; freezing-induced gelation; quality deterioration; protein aggregation; inhibition methods