“When we see food that doesn’t look good, we wonder, has it gone bad? Has it spoiled already? Take meat as one example. We make sure that the beef is bright red, chicken is light pink, and pork is reddish-pink. But what if the meat has already turned brown? Is brown meat bad, like most people believe in?
Sure, color is a huge factor that affects buyers’ behavior. It is one of the first deciding factor that help us. Is this brown meat worth the purchase? Most consumers would definitely choose that bright red meat. But the truth is that meat that has turned brown does not automatically mean it has gone bad. And perhaps, opting for such meat is maybe an even better idea.
Myoglobin is responsible for the color of meat
Meat is basically just muscle tissue composed of around 70-75% water, 10-20% proteins, and around 5% fat, depending on the animal. The types of meat are generally categorized into two: white meat and red meat.
Myoglobin is a protein that carries oxygen in the muscle of the animal. This oxygen is required, particularly in the working muscles, in order for the animal to move around or exercise.
Another factor that affects the amount of myoglobin in the meat is age. The older the animal, the higher the amount of myoglobin in the meat.
There is this misconception about blood in the meat. Actually, blood is removed during slaughtering of the animal. So that liquid that you see that leaks out of the meat package you bought from the meat market is myoglobin (and water).
Because meat is exposed to a controlled oxygen environment
It is kind of like enzymatic browning in fruits and vegetables. You will see that such meat can be purple or purplish red. This happens because the meat is not exposed to oxygen. These retail displays can provide oxygen that reacts with myoglobin to produce oxymyoglobin. This oxymyoglobin is a pigment that turns the meat bright red
To achieve and maintain this color, oxygen level must be well-maintained at around 70% to 80%. Over time, as the meat is continuously exposed to oxygen, myoglobin turns red to brown or brownish-red. This happens a week later as the iron in the myoglobin is oxidized (metmyoglobin).
But brown meat does not automatically mean spoiled
Typical signs of spoilage include:
- Slimy
- Sticky
- Pungent smell
- Sour smell
Dry-aging meat turn meat brown
Dry-aging is used to improve the quality of the meat. The process is simple. The meat is dry-aged in an air-controlled environment. But the thing is the meat is hanged, exposing all sides of it to air, or in racks. What happens here is that over time, the moisture is removed, the meat darkens, becomes tender, and the flavor intensifies.
Carbon monoxide (low oxygen packaging) as color enhancer
Carbon monoxide (CO) in low concentrations (4% or lower) can be added to vacuum-packed meat. CO works by reacting with myoglobin to create the bright red pigment, carboxymyoglobin.
Aside from color stability for up to 20 days or more, CO also improves meat tenderness, prevent flavor oxidation, bone darkening, and prevent bacteria growth.
The use of CO in fresh meat packaging has been allowed since 2002. However, the use of CO has been met with controversies since its acceptance as a meat color enhancer. In fact, even FDA, once asked to prohibit the use of CO because it hides spoilage (consumer deception) and aging. Furthermore, due to its known potential side effects (environmental hazards), many countries ban the use of CO, not only for meat, but for seafood as well.
Key takeaways
- Myoglobin is a protein that carries oxygen in the muscle of the animal
- The more myoglobin that there is, the darker or redder the meat
- The older the animal, the higher the amount of myoglobin in the meat
- Myoglobin produces oxymyoglobin, a bright red pigment, when it comes into contact with oxygen
- Prolonged exposure of myoglobin to oxygen produces the brown pigment, metmyoglobin
- Brown meat does not always mean spoiled.
- Carbon monoxide is used for better color stability in meat
