# What material is synthesized in the rubber egg demo?

One of the popular do-at-home chemistry demonstrations is placing an egg in a container of vinegar for two days. After that period most if not all of the eggshell has dissolved and the outer part of the egg has congealed giving the egg a 'rubber' like appearance and feel.

So chemically the vinegar (acetic acid) reacts with the egg protein (albumen).

Chemically speaking, what is this product?

• So far I've reached the fact that the protein has these aminoacids: Glycine, tryptophan, tyrosine, and cysteine. – M.A.R. Feb 5 '15 at 17:20

The shell dissolution reaction is the calcium carbonate in the egg being dissolved by the acetic acid, resulting in release of $\ce{CO2}$ and formation of calcium acetate.
$$\ce{CaCO3 + 2 CH3COOH -> Ca(CH3COO)2 + CO2 + H2O}$$
So the products are primarily calcium acetate, $\ce{CO2}$, and denatured albumin.