Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: Pia on 08/06/2008 16:11:27
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Pia asked the Naked Scientists:
Hi there - love your show (http://www.thenakedscientists.com/HTML/podcasts/) - I try and listed to it any time the kids will let me! My question is why is chicken meat white, salmon pink and beef red?
What makes these meats different colours?
Thanks, Pia.
What do you think?
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What makes a meat red as opposed to white is its myoglobin content. Myoglobin is a protein in muscle tissue that stores oxygen, and is found in higher concentrations in muscles that are often under long periods of exertion, for example a cow which is always supporting its body weight and walking around. These types of muscles are mostly made up of fibers called "slow fibers".
White meat is from muscle tissue that is not usually under constant exertion but can be used for quick bursts of activity, such as fish, they do not need to support any body weight with their muscles since they're weightless underwater and generally only use lots of energy occasionly when fleeing bigger fish. These types of muscles are mostly made of "fast fibres".
So depending on the use of the muscle, it will have different ratios of fast and slow fibres in it, the more slow fibres it has the more myoglobin it will have, and the more red it will be. Salmon meat is fairly red because they swim upstream for long periods of time, and so their muscles are under constant exertion. In a similar way chicken meat which is white varies from a ducks which is more pink; chickens can't really fly around that much and don't do alot other than a bit of pecking, however ducks are always flying and swimming all over the place.
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I thought salmon was pink due to their diet, not the act of swimming.
Chickens and fowl meat is either white or brown depending on muscle useage, look where the chicken meat is brown, is it an area or muscle that has to work?
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Yeah that deep red colour you get in salmon isn't normal. The 'red' muscle is actually white muscle but in farmed salmon and trout, they tend to feed them with large amounts of beta carotenes to boost the red colour, because that's what appeals to the consumer as a "good looking fish". The actually 'red muscle' in the fish is just under the skin and appears a sort of brownish colour. The way I understood it, most pelagic fish will spend the vast majority of time on 'cruise' speed using only the red muscle until they need to give chase or become the chased.
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more than you want to know about the red stuff in salmon can be found here.
http://en.wikipedia.org/wiki/Astaxanthin
Anyone got anything to say about liver, kidneys etc?