How much heme is in cooked pork and beef; why is cooked pork ("the other white meat") not red?

Question

The new video See how Impossible Pork will make you forget about pig meat includes a very short discussion of

1. the addition of heme to the product to make it taste like beef
2. the deep red color of a heme solution
3. that pork is not nearly as red as beef, (after cooking it's essentially off-white)

Does pork (pig/swine muscle tissue) have substantially less heme content than beef (steer/bovine muscle tissue)? If heme is contributing to the flavor of cooked meats (rather than raw) such as pork and beef, why do they no longer have a red color after cooking?

Answer 1

Yes.

Pork has substantially less heme than beef (Cross et al. 2013).

As to why the red colour is lost, it is due to the Maillard reaction, by which the iron in the myglobin is oxidized from Fe(II) to Fe(III). This results in a colour change in the meat (Tamanna & Mahmood 2015).

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Sources:

• Cross AJ, Harnly JM, Ferrucci LM, Risch A, Mayne ST, Sinha R. 2013. Developing a heme iron database for meats according to meat type, cooking method and doneness level. Food Nutr Sci 3(7): 905–913.

• Tamanna N, Mahmood N. 2015. Food Processing and Maillard Reaction Products: Effect on Human Health and Nutrition. International journal of food science 2015: 526762. doi:10.1155/2015/526762