Why Do Some Apples Turn Brown Faster Than Others?


One issue with slicing up apples in advance is that the slices quickly start turning an unappetizing brown color. You aren’t alone in wanting to find the varieties that brown less than others. Why do some brown faster than others?

Some apples turn brown faster than others because of the variety of apple, how ripe it is, and how you store it after cutting. Apple varieties with lower levels of the enzyme that causes browning will mean they brown more slowly.

Apples brown when the flesh of the fruit is exposed to oxygen in the air. This interaction causes a chemical reaction that leads to the formation of brown pigments on the surface of the fruit.

But you’ve probably seen prepacked sliced apples you can buy at the store or at a fast food restaurant that don’t seem to turn brown.

I decided to find out if there are certain varieties of apples that don’t turn brown and how you can stop apples in general from browning. Read on to see what I found out.

Why Do Cut Apples Turn Brown?

The browning reaction stems from the polyphenol oxidase enzyme (PPO) which is found in most fruit cells, and a process called enzymatic browning.

This enzymatic browning happens when PPO comes into contact with oxygen and other compounds found in apple cells. This causes a series of reactions that result in the formation of brown pigments.

Normally the different compounds are kept apart in separate plant cells, but when the flesh is damaged by cutting or biting they are able to combine. The oxygen in the air they are now exposed to helps trigger oxidization and this results in enzymatic browning.

Do All Apples Turn Brown When Cut?

Apples can be genetically modified to stop browning. All non-GM apples will turn brown eventually when cut but some varieties discolor more slowly than others due to lower levels of polyphenol oxidase enzymes and other compounds.

An example of apples that are genetically modified to resist browning are the Arctic apples. This company uses gene silencing to prevent the enzymes from turning them brown.

For standard apples, the speed at which an apple turns brown is affected by the type of apple, how ripe it is, and how you store it after cutting.

So, if you’re looking for an apple that stays fresh-looking longer after slicing, it’s worth considering one of the varieties that brown more slowly.

Remember to wash your apples as they usually contain a wax coating – I wrote a post about what this actually is.

What Type Of Apple Browns The Slowest?

There are varieties of apples that are naturally slow in the browning process and which don’t brown at all. Here’s a list of the main types:

  • Ambrosia
  • Arctic (these are genetically modified to resist browning)
  • Cameo
  • Cortland
  • Empire
  • Gala
  • Ginger Gold
  • Goldrush
  • Opal
  • Shizuka
  • Snowsweet

Many of these apples will brown more slowly due to naturally lower levels of the enzymes that cause oxidation and browning. This might come from producers cross-breeding apples naturally to get the desired result.

Arctic apples are a special type of apple that has been genetically modified so that it resists browning by silencing the genes associated with the browning enzyme. These were approved for sale by the US Food and Drug Administration in 2015 and are seen as safe to eat.

It appears that Red Delicious apples are some of the fastest to go brown. But there are ways to slow the process down as mentioned later in this article.

See if you can find some of these apples in your local store.

Why Don’t Pre Cut Apples Turn Brown?

When you buy a pre-packed bag of apple slices from the store or at your favorite fast food restaurant, you may wonder how they manage to keep them looking fresh for several days.

The apple slices are dipped in a natural preservative such as calcium ascorbate (which is a blend of vitamin C and calcium) or citric acid (from citrus fruits such as lemons or oranges).

It’s this preparation and storage which prevents the browning. Both the calcium ascorbate and citric acid methods are completely food safe. The apple slices are then packaged up and refrigerated until sold.

This is done at a factory and on an industrial scale, so how can you stop the apple browning process at home?

How To Keep Sliced Apples From Turning Brown In Your Lunch Box

One of the best ways to stop apple slices from browning is to soak them in salt water for 10 minutes then rinse them in fresh water. This keeps your apple from browning for hours and without any salty taste.

There are various ways you can keep your sliced apples looking fresh for longer. Some work better than others and some use ingredients you may not have to hand.

The most effective way I’ve seen from a study is to use a mild salt solution. The salt helps to inhibit the enzymatic reaction which causes browning. Soak your apple slices in a salt solution after cutting and they will stay white for hours.

Here’s the method:

  • Mix up enough salt solution to soak your apple slices at the ratio of half a teaspoon of salt to one cup of water.
  • Make sure the salt is completely dissolved before immersing the apple slices.
  • Soak the fruit pieces for 10 minutes and then remove and rinse in fresh water.
  • Let them drain and pat dry.
  • Pack in an airtight container and eat within a few hours.

Even if you don’t rinse them after soaking, you will barely notice any salty taste as it is so weak.

Try it out for yourself and see how fresh the apples look and taste when you come to eat them at lunchtime if you’ve prepared them like this in the morning.

Other ways without salt

If you don’t like the thought of using a salt solution, here are some of the other most popular methods that work to some degree but often affect the taste:

  • Pineapple juice – Dip in pineapple juice then drain and pat dry (this is one of the most effective methods)
  • Honey and water – Dip in a mixture of one tablespoon honey and two cups of water, then drain and pat dry (this is also quite effective)
  • White grape juice – Soak in white grape juice then drain and pat dry with a paper towel
  • Apple cider vinegar – Brush with apple cider vinegar then rinse with water (you can also just soak the slices in straight vinegar for 5 minutes)

You can also put the apple slices in cold water if you’re going to eat them within 15 to 30 minutes after slicing. Any longer and they will start to brown and become mushy.

Lemon water solution is another popular method, but I’ve seen this to have mixed results with some actually seeing worse results than just submerging in plain water.

Do Organic Apples Turn Brown Faster?

Organic apples do not turn brown any faster than non-organic apples.

However, there are some varieties of organic apples that are more resistant to browning such as the Opal apple. This is due to the higher levels of antioxidants in the skin. These apples are the first variety in the U.S. to be verified by the Non-GMO Project.

So, if you’re looking for an organic option that will naturally stay white for longer, choose the Opal.

Conclusion

So there you have it, the reason some apples turn brown faster than others is mainly to do with the amount of polyphenol oxidase they contain. The more they have, the quicker the enzymatic browning process occurs.

Luckily there are several apple varieties that are naturally low in enzymes and so slices don’t go brown quite so quickly. One to avoid if you want to slice it beforehand is Red Delicious though as that seems to be the worst.

There are many ways to prevent sliced apples from turning brown, but one of the most effective will be soaking them in a salt solution. The salt helps to inhibit the enzymatic reaction which causes browning and it really works.

Although organic apples don’t necessarily turn brown faster than non-organic ones, some organic varieties do have a higher resistance to browning.

Tom

Hey, I'm Tom. I set up Boss The Kitchen to start answering the thousands of questions people have while cooking. For me, the kitchen is my happy place and I hope to help other people with the knowledge I've gained along the way.

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