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Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: annie123 on 07/06/2012 02:13:38

Title: Why is the flesh of fish white?
Post by: annie123 on 07/06/2012 02:13:38
Can someone tell me why some fish have white flesh although presumably there is blood flowing in it when the fish is alive and should still be there when  the fish is dead.
Title: Re: fish flesh
Post by: CliffordK on 07/06/2012 20:24:07
I believe the color of meat is caused by myoglobin and not hemoglobin.

http://en.wikipedia.org/wiki/Myoglobin#Meat_color

When hunting, there is often a problem of bloodshot meat which caused by bruising around the bullet would, in which too much blood remains in the meat, which is often discarded.

Ahh, here are some more notes on myoglobin and meat color.
http://www.exploratorium.edu/cooking/meat/INT-what-meat-color.html
http://meat.tamu.edu/color.html

So, I would assume that different types of fish, from salmon to cod would vary in their myoglobin content, and thus the ability for the muscle to store oxygen.

I am seeing that some critters also have hemocyanin that contains copper instead of iron which gives blue blood.
http://www.daviddarling.info/encyclopedia/B/blood.html
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.daviddarling.info%2Fimages%2Fblue_blood.jpg&hash=d114d3bec4fb91d928758e97e76bfd53)
Title: Re: fish flesh
Post by: annie123 on 09/06/2012 02:21:02
But "The only time myoglobin is found in the bloodstream is when it is released following muscle injury. It is an abnormal finding, and can be diagnostically relevant when found in blood. [2]"(Wiki) It seems hemoglobin is the normal constituent carrying oxygen.
Title: Re: fish flesh
Post by: CliffordK on 09/06/2012 03:33:19
But "The only time myoglobin is found in the bloodstream is when it is released following muscle injury. It is an abnormal finding, and can be diagnostically relevant when found in blood. [2]"(Wiki) It seems hemoglobin is the normal constituent carrying oxygen.
The myoglobin is the hemoglobin analog in the muscle.  Not in blood, but it is what is in the muscle itself that gives the muscle color.

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