Burgers, like many other types of meat, can turn brown in the fridge due to a process called oxidation. This natural chemical reaction occurs when the meat is exposed to air. Here's how it happens:
Myoglobin: Meat contains a protein called myoglobin, which is responsible for its red color when freshly cut. Myoglobin contains iron, and in its oxygenated form, it has a bright red color.
Oxygen Exposure: When you cook the burger and then store it in the fridge or leave it exposed to the air, the myoglobin comes into contact with oxygen from the air.
Oxidation: The oxygen reacts with the iron in the myoglobin, causing it to change its chemical structure. The new structure formed, called metmyoglobin, is brownish in color.
Color Change: As more myoglobin molecules undergo this oxidation process, the overall color of the burger changes from red to brown.
The browning of the burger doesn't necessarily mean it's spoiled or unsafe to eat. It's a natural process and generally harmless. However, it can be an indicator that the meat has been exposed to air for an extended period, and its quality might have degraded. If the burger smells off, has a slimy texture, or shows other signs of spoilage, it's best to discard it.
To slow down the oxidation process and keep burgers fresher for longer, you can take the following steps:
Refrigeration: Store the cooked burgers in an airtight container or wrap them tightly in plastic wrap before refrigerating. Minimizing their exposure to air can help reduce the oxidation.
Freezing: If you don't plan to consume the burgers within a couple of days, consider freezing them. Freezing significantly slows down the oxidation process and helps preserve the color and quality of the meat for a longer time.
Vacuum Sealing: Using a vacuum sealer to remove excess air from the packaging can also help in preventing oxidation.
Remember to always practice proper food safety measures, and when in doubt about the quality or safety of any food item, it's best to err on the side of caution and discard it.