What is thick white substance on egg yolks?

The thick white substance on egg yolks is called the vitelline membrane.

It's a thin, transparent membrane that surrounds the yolk and helps hold it together. It's sometimes called the "chalaza" because it's attached to the yolk by two twisted cords called chalazae.

The vitelline membrane is made up of proteins and lipids, and it helps protect the yolk from damage and keeps it from spreading out.

Here's a quick summary:

* What it is: A thin, transparent membrane surrounding the yolk.

* Purpose: Protects the yolk and holds it together.

* Other name: Chalaza (due to the attached twisted cords).

* Composition: Proteins and lipids.

Let me know if you have any other questions! 😊