Since You Asked: Oxygen hits fruit enzymes where it hurts

When the local peaches are in season, I love picking, canning and eating them at almost every meal. What's the best way to keep them from browning once I've cut them up? I tried Fruit Fresh already, but the peach slices were brown the next day. Should I have used lemon juice, too? Or did I not use enough Fruit Fresh?

— Kelly H., Butte Falls

You're smart to use a produce protector, such as Fruit Fresh, in peak peach season. The product does a good job, but it doesn't last forever.

According to Ball's website,, Fruit Fresh is only good for eight hours. It lasts long enough to eat the fruit or to preserve it by freezing or canning.

The change that makes fruit darken when it's cut is called enzymatic browning. When enzymes in the fruit's flesh are exposed to oxygen, pigments in the flesh cause it to brown.

There are two ways to stop it: Either eliminate the fruit's exposure to air by covering tightly with plastic or immersing it in water, or deactivate its enzymes. Here are some simple ways of doing that.

Dip cut fruit in salted water, toss it with an acid such as lemon juice or pineapple juice or dissolve vitamin-C tablets in water and dip fruit in that. Even a little sugar will protect fruit for a little while.

Products such as ascorbic acid or Fruit Fresh work by giving the oxygen something to react with. But once it's used up, the oxygen will go back to reacting with the enzymes. So you can slow down the browning, but you can't stop it unless you freeze or can your peaches. Or use them in this week's Quick Fix recipe.

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