Science Questions

Why does red meat turn white with cooking?

Sun, 21st Oct 2012

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Elias Haddad asked:

Hi Chris


We bought 2 kilos of minced beef last weekend from a new butcher. My wife added her usual mix of chopped onion, salt, pepper, cumin, paprika and cinnamon.


When fried as beef burgers, the meat turns white in colour. It also does not taste of "meat" and not the super burgers my wife usually makes.


Do you have any thoughts on this???


Thank you.






Ginny -   When you think about meat, itís made of protein and when protein is heated, the shape of it changes.  Normally, itís quite a long molecule.  But as itís heated, it actually shrinks.  So, if you imagine cooking a chicken breast, you see that as it cooks, it gets smaller and it also changes colour and this is because of the change in the proteins.  We say they denature and that's when they go white and they scrunch up and shrink.  Red meat contains an iron rich chemical called myoglobin which also changes its shape when it cooks and changes colour from red when itís raw to sort of brownish grey when itís fully cooked.  

Grilled meatIf you're cooking red meat, sometimes you get a lovely brown colour on the outside and that really tasty meat smell that always makes you hungry.  This happens because there's something called the maillard reaction.  This is a chemical reaction between the amino acids found in the protein and some sugars, and it requires heat to occur.  So, the temperature has to get up to about 154 degrees for the maillard reaction to occur and obviously, this is higher than the boiling point of water.  So that means that if there's too much water in your meat or if your pan isnít hot enough, this browning wonít occur.  Your meat instead will cook in the water and it will just turn to light brownish grey colour, without you getting any of that lovely, crispy brown outside.


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