How to Keep Apples from Turning Brown

Loaded with essential nutrients for health, apples lead the list of top ten superfood. According to fruit nutrition facts, they serve as a rich source for antioxidants (vitamin C and more), fiber (especially pectin) and carbohydrate. More importantly, apples have a low glycemic index, contain less cholesterol and are low in calories. For consumption part, apples are delicious, less messy to eat, and you can carry whole apples easily for anytime snacking. But, when cut into slices, they turn brown very soon. Here, we shall focus on the causes for apple flesh turning brown after peeling, and tips to keep apples from turning brown after cutting them.

What Causes Apples to Turn Brown after Slicing?

In addition to sugar, water, dietary fiber, vitamin C and many other nutrients, apple contains several enzymes. It is the tyrosinase and alike phenolic oxidase enzymes present in chloroplast cells, which are responsible for brown coloration of apples after cutting. After peeling and exposing apple flesh to air, these enzymes react with atmospheric air, and catalyze the conversion of phenolic compounds into o-quinones. These substances cause apple slices to turn brown. Likewise, bruises in the apple skin are browned due to the action of phenolic oxidase enzymes.

The key tips for keeping apples from turning brown are concentrated on reducing conversion of phenolic compounds. In addition to oxidation reaction triggered by enzymes, there are several factors that affect browning of apples. Say for example, some types of apples are browned more quickly than others. As per a study report, the red delicious apple variety is more susceptible to browning than the golden delicious type. In comparison to these, granny smith has a tendency to withstand browning for a longer period. Besides variety, the provided growth conditions and maturity of apple fruit are equally responsible for apple flesh to turn brown. The more ripe they are, the quicker apples turn brown, and vice-versa.

How to Keep Apples from Turning Brown after Slicing?

Due to browning effect of apple slices after cutting, usually they are not preferred for addition in mixed fruit salads. While consuming in the formal style, apples are peeled first and cut into slices. During the preparation processes, they already turn brown. If not, then also you are expected to eat them as soon possible. To avoid such cases, there are some tips for reducing browning effect of cut apples. The logic is to slow down or prevent the oxidation of phenolic compounds. Here's how to keep cut up apples from turning brown with simple instructions.

The first thing that you need to do is select different types of apples that are less prone to browning. You can conduct a brief research on apple types and their uses, before purchasing them from the supermarket. For making apple pies, apple juice, applesauce or other apple recipes, selecting apple of specific variety is not a concern. What you should look for is apple variety ideal for making cut slices for snacking.

As far as the query 'how to prevent apples from turning brown' goes, using lemon juice is the best alternative. This mild acid counteracts oxidation reaction, and reduces the browning effect easily. And the plus point for using lemon juice is, it is purely natural and you don't have to rely on chemical preservatives for keeping cut apples. Similarly, you can use pineapple juice and ginger ale for the same purpose.

Tossing the cut pieces in sugary water or saline water also helps. This option is not healthy, as excess sugar or salt consumption is not recommended for health. Also, people with high blood sugar and those who are predisposed to diabetics are restricted from having too much sugar. Consider these aspects first, and decide whether you want to toss cut apple pieces in sugar or not.

Speaking more on keeping cut apples from browning, you can place cut halves in water, ensuring that the cut side is immersed in water. By doing so, you are preventing the contact of apple flesh and air. As a consequence, there will be no oxidation of phenolic compounds, and the apple halves do not turn brown. However, some water-soluble nutrients may be leached out in water.

Last but not the least, you have a choice of heating up the apple slices to slow down chemical reaction. But, the unfortunate part is, changing texture of apple. Also, wrapping the cut apples with plastic or blanching them in boiling water reduce browning of cut apple slices.