Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: thedoc on 23/10/2012 16:45:57

Title: Why does meat change colour when cooked?
Post by: thedoc on 23/10/2012 16:45:57
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.
Asked by Elias Haddad

                                        Visit the webpage for the podcast in which this question is answered. (


Title: Why does meat change colour when cooked?
Post by: thedoc on 23/10/2012 16:45:57
We answered this question on the show...

 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.  
[img float=right]/forum/copies/RTEmagicC_grilled_meat_01.jpg.jpg[/img]If 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.