Indonesia
Why Do Cut Apples Turn to Brown?
Sarah has a fresh green apple. She also has Raka to accompany her at the cafetaria. Then, she wants to share the apple with him. She slices the fresh apple in half, then talks with him. After ten minutes talking, she notices the apple turn brown. How can it happen?
Sarah has a fresh green apple. She also has Raka to accompany her at the cafetaria. Then, she wants to share the apple with him. She slices the fresh apple in half, then talks with him. After ten minutes talking, she notices the apple turn brown. How can it happen?
Superkids, eating fresh apples everyday is good for health. But, we have to consume the apples right away after we cut them into pieces or slices. The delicious green or red apples do not taste and look the same if we cut and store them. They turn brown when exposed to air for some time.
Apples and other fruits such as pears, peaches, and potatoes, contain an enzyme called polyphenol oxidase (PPO) or tyrosinase. The enzyme reacts with oxygen. The oxidation reaction forms a sort of rust on the surface of the fruit. When the fruit is cut or bruised, these actions damage the cells in the fruit and allowing oxygen in the air to react with the enzyme.
Then, why some apples brown faster than others? It depends on the variety, age and growing conditions. All apples contain PPO, but the levels are various. A red apple generally turns brown faster than a firmer and more acidic green apple. It also depends on the plant’s genetic composition, growing conditions and soil type.
Can we prevent the oxydation? Yes, but not 100%. Brush the cut apple pieces with lemon juice or pineapple juice. These juices are acidic in nature to cause the PPO activity to slow down; thus preventing the apples from turning brown. Sprinkle powered sugar or salt the the exposed part of an apple. This act reduces the oxygen diffusion and slows down the browning process. Or, wrap in plastic or heat in boiling water (blanching) to prevents apples from turning brown.
Now tell Sarah why do apples turn brown when cut open.
TEGUH WAHYU UTOMO
PHOTOS: PHOTOS
