You may notice that when you cut certain fruits and vegetables, they start to turn brown even before you manage to start cooking them. In this post I will cover
What is enzymic browning? Where do we see enzymic browning?
Why does the colour change? What can I do to stop enzymic browning?
Is there such a thing as non-enzymic browning?
What is enzymic browning? The colour change from pale to rusty brown caused by the action of enzymes within the cells of some fruits and vegetables when they are exposed to air.
Where do we see enzymic browning? You may notice it the most when peeling and slicing cooking apples, eating apples, bananas and aubergines and avocado.
Less noticeable browning occurs with parsnips, potatoes and pears.
Why does the colour change?
Air will activate the enzymes in fruit or vegetable cells once you cut or peel them.
The more you cut open the cells the quicker the air enters and this allows the enzymes to work gradually changing the colour to rusty brown.
Look at the difference between sliced apple and grated apple visible in 20 minutes.
More cells have been cut open when the apple is grated – so more activated enzymes results in darker browning – try this yourself
Is enzymic browning it harmful? Can I eat it?
It does not harm you, you can eat browned apples, bananas or pears but you might notice the texture of the product may be slightly different.
What can I do to stop enzymic browning?
During preparation before cooking you can add lemon juice or plunge the cut pieces into cold water or cook the fruit or vegetable You can try to stop enzymes being active by using water, acid, alkaline, salt, sugar or excluding air. This is a typical experiment to try when trialling investigation for GCSE Food preparation and nutrition (NEA 1).
Is enzymic browning the same as bruising?
Are there other types of browning?
Yes, there is enzymic browning and non-enzymic browning.
Remember enzymic browning is caused by enzymes.
Non-enzymic browning is browning caused by other methods such as heat from the oven or from the grill. They have different names: caramelisation and dextrinization.
I hope this helps you understand why browning occurs whilst you are trying to prepare food. Typically, you might be preparing dishes such as: