Weakening of hen egg vitelline membrane during egg storage at room temperature is associated with modifications of its mass, thickness and proteomic profile

The hen egg vitelline membrane is a protein layer surrounding the egg yolk. The integrity of this membrane is important for both the shell egg and the egg products industries; however, its physical properties are altered during prolonged storage, depending on storage temperature. This study aimed to identify the structural and molecular changes of the hen egg vitelline membrane during a 28-day storage at +4 °C and +20 °C using a combination of physicochemical, ultrastructural and proteomic approaches. Our results demonstrated that the degradation of the vitelline membrane during storage at +20 °C was associated with a significant loss of dry matter, a decrease in the thickness of the outer vitelline membrane layer, and alterations in its proteome. Indeed, the abundance of two main components of the outer layer, namely ovomucin and VMO1, decreased during storage at room temperature. VMO1 actually dissociates from the vitelline membrane during egg storage and accumulates in the egg white. Taken together, these results contribute to a better understanding of the mechanisms of alterations of the vitelline membrane during the storage of eggs at room temperature, and provide evidence that VMO1 is a major biomarker of the integrity of the vitelline membrane.