Why does my apple turn brown?

We all know the problem: certain fruits, like apples, pears or bananas turn brown (very) quickly after they bumped into something or after you cut them. Why is that exactly and how does that happen?

When you cut your fruit or bumped into something or bite in it, you actually destroy the cells of the fruit. The cells break down and a so-called oxidation reaction begins as oxygen is free to ‘enter’ your fruit. As a result the spots where the cells have been destroyed turn brown. This reaction is in fact a defence reaction of the fruit’s plant, to repel insects or microbes, but in this case they react with air which eventually makes them brown.

The browning process hardly has an effect on the nutritional value of the fruit. An apple or pear is just as healthy as it was before, only the looks are less attractive. The brown discolouration is mainly a reaction on the surface and therefor only occurs in the cells that have been destroyed by cutting or bumping.

How do we prevent our fruit from turning brown? Well, there are a few ways to slow down or even stop the process. Heating your fruit is an example, as this breaks down the enzymes that are responsible for discolouration (but of course, a heated apple is not as nice as a cold one!). You can also limit the amount of oxygen or add acid. Acid works as an antioxidant, so your fruit will keep its colour longer. You can also try this with lemon juice. Just pour some lemon juice over your apple and you’ll see that your apple keeps looking fresh. And last but not least, use Tomorrow’s Kitchen’s fruit boxes to protect your fruit from bumping.