Why is Deli Roast Beef Red? The Science Behind Its Vibrant Color

Stroll down the deli counter at your local supermarket and you’ll spot roast beef’s signature ruby red color shining through. The vivid crimson hue stands out against paler sliced meats, but why is freshly-sliced roast beef such a bright red compared to other deli meats?

The red color comes down to meat science and chemistry. Understanding the factors involved can help you determine when your deli roast beef is at peak freshness versus past its prime.

Myoglobin Causes Redness in Beef

Raw beef contains a protein called myoglobin that lends its red color. Myoglobin stores and transports oxygen in muscle cells. The more myoglobin a muscle contains, the darker the red color. Since muscles that get exercised frequently like legs and shoulder require more oxygen, they appear darker. Less active muscles like the tenderloin have less myoglobin and look lighter pink.

In addition to myoglobin concentration, the oxidation state affects beef’s color. Oxygenated myoglobin that gives beef its bright cherry red color is called oxymyoglobin. This is what makes freshly-sliced deli roast beef look so vibrantly red.

Why Does Cooked Beef Turn Brown?

Heat from cooking causes the myoglobin in beef to change form just like heat changes the clear albumin in egg whites opaque white. Once beef is cooked the myoglobin denatures into a new protein called denatured globin that reflects light differently, making the meat appear tan or brown.

Well-done beef tends to look more grey-brown because more myoglobin gets converted to denatured globin. While cooked beef is no longer red, some pinkness suggests it is still nice and juicy

Why Does Beef Turn Brown in the Fridge?

Exposure to air causes the myoglobin in raw beef to oxidize into a form called metmyoglobin. This chemical reaction turns beef from bright red to brown or grey.

Refrigeration temperature moisture level, and air exposure impact metmyoglobin formation. The colder and dryer the environment, the more rapidly myoglobin oxidizes.

This is why properly vacuum-sealed or packaged deli roast beef stays red longer than loosely wrapped meat. Limiting air exposure preserves that appetizing red color.

Is Brown Deli Meat Safe?

Beef turning brown in the fridge or after cooking is perfectly normal. It does not indicate spoiled or unsafe meat by itself. Only if sliminess, off-odor, or mold accompany discoloration is beef unsound.

For sliced deli meats, follow use-by dates. Roast beef staying refrigerated at 40°F or below should retain good quality 3-5 days past the sell-by date on the packaging. But rely on smell and texture rather than just color to assess freshness.

Other Factors Affecting Deli Meat Color

Beyond myoglobin, other aspects influence deli roast beef’s color:

• Ingredients – Nitrates/nitrites in processed meats preserve redness. Ascorbic acid retards browning.

• Display lighting – Bright fluorescent lighting fractures myoglobin, causing redness loss. Dim lighting makes meat look dark.

• Freezer burn – Dehydration and oxidation from freezer burn causes browning.

• Packaging – Vacuum sealing with no air exposure maintains red color.

• Slicing – Thinner slices appear brighter red. Thick cuts look darker from more myoglobin.

For peak freshness, choose roast beef with vibrant red lean, avoiding any brown spots. The richness of that red color indicates prime freshness. But even if your leftovers turn brown after a few days, they are likely still perfectly safe to enjoy. So rely on your senses, not just the color, to determine deli meat’s ultimate edibility.

Storing Deli Roast Beef to Maintain Red Color

Preserving that appetizing red color means limiting myoglobin’s exposure to air and light. Here are some storage tips:

• Store sealed roast beef on the bottom shelf of the fridge furthest from light.

• Avoid opening the packaging multiple times, which exposes more air.

• Portion deli meat out into airtight containers to minimize air introduction from repeatedly opening the original packaging.

• Place deli containers inside larger bags or bins to further block light exposure.

• Use deli beef within 3-5 days for maximum freshness, even if still red. The sell-by date indicates peak quality.

With proper refrigeration and packaging, you can keep deli roast beef looking freshly-sliced red longer. But don’t rely on color alone – trust your nose and fingers too when determining safety and quality.

How to Prevent Brown Deli Meats

Brown and gray deli meats may not seem very appealing, but rest assured they are likely still perfectly fine to eat. You can minimize oxidation that leads to color changes by:

• Opting for nitrate/nitrite-free deli meat to limit certain preservatives.

• Checking sell-by dates and only buying what you’ll use within 5 days.

• Always refrigerating immediately and maintaining a temperature of 40°F or below.

• Separating meat into smaller portions to minimize air exposure.

• Avoiding opening the packaging repeatedly. Reseal tightly.

• Storing meat on lower refrigerator shelves away from light sources.

• Freezing extra deli meat if not eating within 5 days.

With proper handling, you can maximize your roast beef’s bright red bloom. But don’t avoid those last few darker slices at the bottom of the pack – enjoy them knowing the color alone doesn’t mean spoilage.

So relish that ruby red roast beef in all its glory knowing the science behind its stunning color. With proper storage, you can keep that freshly-sliced color lasting longer.