A question re "blood" in cooked meat...

Can someone explain this to me, please?

When you buy meat - let's say a nice, aged piece of beef - what's the red stuff that comes out of it when you cook it? Pete heard or read somewhere that it isn't actually blood - which makes sense, as all animals are bled when slaughtered to prevent them going off. The topic came up tonight at dinner when we had a rare top cap roast, which oozed lots of "blood" after it was sliced.

Many thanks!

Celia

It is water, mixed with a protein called myoglobin, which is what makes the meat red, and stores the oxygen. I'm sure someone will chim in with a more detailed explanation. I just remember this from a cooking class I took.

It is hemoglobin in the blood that makes it red. Myoglobin is a protein that is in muscle tissue. When it oxidizes it turns brown. Karen is right the "red" is myoglobin with a water ligand. I think.

The blood is not completely removed from the capillaries when the animal is processed. There is still blood in them that veins. If you squeeze the raw meat, you will force blood from the capillaries that service all the tissue.

my impression is that if the meat were well enough aged, there would be little or any of this. it is, as you no doubt noticed, fairly watery and can be somewhat eliminated by letting the meat 'rest' on paper towels. it is especially undesirable if you are serving a sauce with the meat, since it will water down the sauces influence.

It's probably myoglobin and water. I would think that the blood left in capillaries in the meat would all coagulate during the aging process.

Exposure to oxygen oxidizes the iron atom in myoglobin from the Fe++ (ferrous) state to the Fe+++ (ferric) state. Ferric myoglobin is called metmyoglobin and is brown in color. This is why red meat turns brown when exposed to air.

-Paul W.

The red color in red meat is indeed primarily from the ferrous form of myoglobin. There is some hemoglobin left from residual blood, but that is equally true of "white meat" muscle tissue, so the primary colorant in red meat is the myoglobin. Paul is also right that the oxidation of Fe(II) -> Fe(III) in myoglobin results in the browning of meat. That's why many supermarkets have started putting carbon monoxide into their meat packaging, because carbon monoxide (like cyanide and hydrogen sulfide) reacts with the Fe(II) form of myoglobin and keeps it from picking up an oxygen ligand, thereby keeping it red. (That's also why CO, CN and H2S are so toxic -- they bind the Fe(II) form of other iron heme proteins and shut down respiration). Hemoglobin's Fe(II) form is blue, however, which is why your veins look blue under the skin and why cyanide poisoning turns you blue.

Mark Lipton

The red color in red meat is indeed primarily from the ferrous form of myoglobin. There is some hemoglobin left from residual blood, but that is equally true of "white meat" muscle tissue, so the primary colorant in red meat is the myoglobin. Paul is also right that the oxidation of Fe(II) -> Fe(III) in myoglobin results in the browning of meat. That's why many supermarkets have started putting carbon monoxide into their meat packaging, because carbon monoxide (like cyanide and hydrogen sulfide) reacts with the Fe(II) form of myoglobin and keeps it from picking up an oxygen ligand, thereby keeping it red. (That's also why CO, CN and H2S are so toxic -- they bind the Fe(II) form of other iron heme proteins and shut down respiration). Hemoglobin's Fe(II) form is blue, however, which is why your veins look blue under the skin and why cyanide poisoning turns you blue.

Mark Lipton

*swoon* You macho pedant wino/scientific types know how to talk.

Do you, like Bernie, squeeze the meat, Mark?

Do you, like Bernie, squeeze the meat, Mark?

Thank you all! Mark, Paul, I'm swooning as well...

I will make sure to squeeze my meat next time and see what comes out..

Thank you all! Mark, Paul, I'm swooning as well...

I will make sure to squeeze my meat next time and see what comes out..

Harrumph.

Russell, don't be like that. I'm still picking myself up off the floor over your photo at 20...

Hemoglobin's Fe(II) form is blue, however, which is why your veins look blue under the skin and why cyanide poisoning turns you blue.

Hemoglobin's natural state (just as with myoglobin) is the ferrous Fe++ state. Fe+++ hemoglobin is called methemoglobin and is brown in color. Ferrous (Fe++) hemoglobin is vivid red when it's oxidized, and a darker red when it's reduced. This is why arterial blood (oxygen-rich) is crimson red, while venous blood (oxygen-poor) is less red. Cyanohemoglobin, I think, is still in the ferrous state, but it's blue in color (as are a lot of cyanide compounds). And the reaction of cyanide with hemoglobin isn't readily reversible, as is the case with oxygen. Carbon monoxide also adheres to hemoglobin more tenaciously than oxygen, which is why both CN and CO are toxic. Cyanide also irreversibly combines with the Fe++ in the cytochrome enzymes that are essential in respiratory transport of electrons and the conversion of oxygen to H20. This is why cyanide is so horribly toxic. But it's the conversion of hemoglobin to Fe++ cyanohemoglobin (which is blue) that results in the blue color from cyanide poisoning.

There are several genetic conditions that result in methemoglobin circulating in the bloodstream. They result in both cyanosis (blue skin color) and a chocolate brown color to the tongue.

-Paul W.

Hemoglobin's Fe(II) form is blue, however, which is why your veins look blue under the skin and why cyanide poisoning turns you blue.

Hemoglobin's natural state (just as with myoglobin) is the ferrous Fe++ state. Fe+++ hemoglobin is called methemoglobin and is brown in color. Ferrous (Fe++) hemoglobin is vivid red when it's oxidized, and a darker red when it's reduced. This is why arterial blood (oxygen-rich) is crimson red, while venous blood (oxygen-poor) is less red. Cyanohemoglobin, I think, is still in the ferrous state, but it's blue in color (as are a lot of cyanide compounds). And the reaction of cyanide with hemoglobin isn't readily reversible, as is the case with oxygen. Carbon monoxide also adheres to hemoglobin more tenaciously than oxygen, which is why both CN and CO are toxic. Cyanide also irreversibly combines with the Fe++ in the cytochrome enzymes that are essential in respiratory transport of electrons and the conversion of oxygen to H20. This is why cyanide is so horribly toxic. But it's the conversion of hemoglobin to Fe++ cyanohemoglobin (which is blue) that results in the blue color from cyanide poisoning.

There are several genetic conditions that result in methemoglobin circulating in the bloodstream. They result in both cyanosis (blue skin color) and a chocolate brown color to the tongue.

Paul,
Yes, I should have been more clear: Fe(II)-O2 is red; Fe(II)-CN and Fe(II)-CO are blue. (It has to do with the strength of the respective bonds to Fe and ligand field theory, not my strong suit). Fe(III), as you know, isn't found normally in biological systems in any quantity and appears brown (as in dried blood) -- in fact, it's been implicated in atherosclerosis. I'm not sure if the Fe(II) center of myoglobin also looks blue in the CN or CO bound states, but that's probably known somewhere.

Mark Lipton