MadSci Network: General Biology

Re: Cattle, pigs, chickens all have red blood, why is pork /poultry meat white?

Date: Sun Jul 5 18:15:20 1998
Posted By: Fred Moore, Staff, Dept. of Pathology (lab), Jewish Hospital
Area of science: General Biology
ID: 898987101.Gb

Dear Mr. Stein,

Your question is an interesting one.  However, let's clear up a few details.
Red Blood Cells(RBCs) have nothing to do with why meat is dark or white.
RBCs are part of a wonderful mixture of other proteins, nutrients, and waste
particles that flow through your vasculature, otherwise know as "Blood". 
They deliver oxygen to tissues and take away carbon dioxide, in short.  They
do not cause the meat in the animal to be a particular color.

Now to answer your question, let's consider the color of the meat.  This is 
where it's interesting.  There are different "TYPES" of meat, or "Fiber Types."
Fibers are the elemental structures that make up which kind of meat your con-
sidering.  For example, white meat is mostly composed of Fast Twitch Fiber 
(FTF).  Not to get bogged down in cellular details, but this kind is mainly
used for heavy lifting, or to develop a bulky appearance.  It's primary source
of energy is glycogen (glucose).
On the other hand, there's a different type of fiber (muscle) that's usually
associated with dark meat, called "Slow Twitch Fiber" (STF).  It's a group 
of postural muscles that can be found near areas where an animal bears a lot
of body weight, ie., lower back, inner thighs, some parts of the lower leg,
etc.  Their main source of energy is from oxygen.  This meat can be very 
tough and greasy due to it's metabolism.  

The dissimiliar structure and vascular supply in FTFs and STFs makes them 
different in appearance and texture. 

Hopefully this will give you some new information as you devour your dinner.
Just remember, all animals have white meat and dark meat.  The difference is 
in the composition and proportions found in a particular animal's muscle group.

Fred Moore
Louisville, Ky.

Current Queue | Current Queue for General Biology | General Biology archives

Try the links in the MadSci Library for more information on General Biology.

MadSci Network,
© 1995-1998. All rights reserved.