T Nation

What temperature does protein denature at

I mix some Grow in to my oatmeal after the oatmeal is done cooking.Should i let it cool for a while? Its still pretty warm when i start eating it. What temperature is ideal?

That’s an amazing question… I always wonder that when I eat my egg whites…I know that protein structure will unfold and denature under extreme temps…It doesnt matter if you let it cool either…I repost another question for us…jenn

Related to your question and Jenn’s post are the questions: Is denatured protein useful? Is a cooked egg more, less, or just as nutritious as a raw one?
Boiling eggs denatures the protein. Apparently, around 150 degrees F, what is called the quaternary and tertiary structure of the globbed-together strands of egg protein (think of a very loose ball of yarn made up of many different strings) unwinds. However, each of these strings (each string being sequences of linked amino acids := protein) remains, for the most part, unbroken. That is, the peptide bonds that make up the amino+acid linkage are strong enough to to remain unbroken. Thus denaturization does not ‘hurt’ the amino acids, but only allows the macro-structure to be rearranged. Anyway, any proteins ingested must first be digested (the peptide links are broken down into separate amino acids) then reassembled into the proper muscle protein. So, when you are denaturing a protein, you are actually saving a little a bit of your body’s energy by unwinding the ‘balls of thread’ for it. Note: There must be some temperature at which there is enough energy to not only break the links, but actually dissociate the independent amino acid into parts, rendering it not useful, but I don’t know what it is. I assume it must be really high. I guess to figure it out you would need the bond dissociation energy of the amino-acid linkage and then find the appropriate temperature. Perhaps some of the chemists reading the forum can shed some insight and offer additional information. My area is computational physics, so please view my information with a critical eye.
Further note: I also found this quote on a website (http://www.dietitian.com/protein.html):
“The nutritional composition of raw and cooked egg is the same. However, the avidin in raw egg whites destroys biotin also found in raw egg whites. Cooking prevents this from happening.”

I don’t know what biotin does but I am pretty sure it is a good thing.
Yr. Obt. Svt.,
-Jason

P.S. …love the ‘Power Drive’ - one hell of an interesting supplement

You really don’t have to worry about protein denaturing. You are not going to use the whole protein anyway, because your digestive system is going to break it down, and then you will use the amino acids. Even if they are not cooked, most of the time the proteins will denature as soon as they hit your stomach because that is what they are supossed to do. The important part are the amino acids that you can use to build muscle, not any poltmer, the monomer is what you are interested in.

The temperature at which a protein denatures varies according to the protein. For example, milk proteins, and eggs, begin to denature somewhere around 78 C, and brief exposure to this temperature does not denature them significantly. On the other hand, this temperature, even for a few seconds, is sufficient to denature and inactivate many key proteins in those bacteria that may be present in milk, so it is possible to sterilize milk (or eggs) by pasteurization (actually by ultrapasteurization: pasteurization per se does not quite sterilize.)

But as Shawn said, for the most part you need not worry. I think it can make a difference though because of disulfide bridges being formed which are not necessarily ever cleaved.

cool, thanks a lot