Re: What is the process that changes an egg left in vinegar or salt to a rubber

Message ID Number: 914951025.Bc
What is the process that changes an egg left in vinegar or salt to a rubber Where can I find out more about this?

I'll answer the second question first because that's what I did first. I wanted to see how frequent this experiment was being carried out and the answer is "a lot".

I used my favorite search engine for science stuff, AltaVista at: http://www.altavista.com/ I used the following terms: +egg +vinegar +rubber +experiment The"+" requires that term to be in the web page +egg +vinegar would find beau coupe (French for "a lot of") mayonnaise recipes. So, I added +rubber +experiment terms to narrow the search to only 152 pages. I've cited some of them below:

http://www.newton.dep.anl.gov/newton/askasci/1993/general/GEN32.HTM
Author: adstaudt
Subject: Rubber Egg
Text: When you soak an egg in vinegar overnight why does it turn to rubber?

Response #: 1 of 1
Author: Joe Schultz
Text: The egg shell is make mostly of calcium carbonate. When soaked in vinegar, which is an acid (acetic acid), the carbonate neutralizes the acid and in the process gets used up. The clear, rubbery 'shell' is the membrane that lines the inside of the egg.

Also: http://www.kusd.edu/schools/mckinleyel/110/holly.html
http://www.edu.ipa.go.jp/mirrors/rika/NARU/004/naru004e.html

The second question:
What is the process that changes an egg left in vinegar or salt to a rubber

Two things are happening:

1. the shell dissolves and
2. the egg white turns to a rubbery substance:

Carbon dioxide (CO2, a gas which bubbles off), a calcium salt (which may dissolve or precipitate) and water.

So when you immerse an egg in vinegar, the first thing you should see are bubbles of carbon dioxide forming on the egg's surface. For faster results, plop a piece of chalk in a little vinegar.

How does 2) happen? (the egg white turns to a rubbery substance) The answer is more complicated so I'll start with a few facts:

• a) The egg white is mostly a protein called an albumin (and the scientific name for the egg white is the "albumen". A coincidence? I think not.) See Canada Egg for more information.
• b) A protein is a chain of "amino acids" (because the acid group of one amino acid is hooked to the amine group of the next, proteins don't taste sour. )
• c) Proteins can be tough (your skin, fingernails, and hair are a kind of protein called "scleroprotein") or fragile such as albumin or globulin.
• d) Proteins such as albumins are easily "denatured"
• e) You can denature proteins in several ways: heat (such as cooking), acidifying, salting or drying.
• f) Denatured proteins become opaque: For instance: the translucent appearance of meat, chicken breast, fish, or egg white turns opaque when it is cooked.

• 1 egg white
• 1 thin slice of fresh white fish or chicken breast
• vinegar or lemon juice
• heat source such as a stove or hot plate and a cold skillet. (Take care not to burn yourself).
• 2 or 3 dark plates.

• divide egg white into 3 or 4 parts and spoon on to separate dark plates & skillet.
• divide fish or chicken into 3 or 4 parts and place on to separate dark plates.
• Plate 1: drip vinegar or lemon juice onto the proteins
• Plate 2: (cold skillet) start heating the skillet until you see change.
• Plate 3: do nothing (control)
• Plate 4?: use another acid for comparison.

Not enough information? You can contact me through the Mad Scientist. Too much? Wait until next year ;^)