Fruits turn brown when cut due to a process called enzymatic browning, which occurs when damaged cells release enzymes that react with natural compounds in the presence of oxygen.
How the reaction occurs
When you cut a fruit, you break its cells and expose its interior to the air. This activates enzymes such as polyphenol oxidase, which catalyze the oxidation of natural phenolic compounds (such as quercetin in apples). This process transforms colorful molecules into melanins, brown pigments.
Factors that influence it
The speed of browning depends on:
- Type of fruit: Apples, bananas and papayas show this effect more intensely.
- Temperature: The higher the heat, the faster it develops.
- Humidity: Refrigerated fruits tend to brown more slowly.
How to prevent it?
There are several effective strategies:
- Applying lemon juice or vinegar: Their acids inhibit the enzymes responsible for browning.
- Wrapping the fruit in plastic: Reduces exposure to oxygen.
- Freezing: Stops the chemical reactions until it thaws.
- Using commercial agents: Products like ascorbic acid (vitamin C) are potent antagonists of the enzymes.
Is it harmful?
Enzymatic browning does not involve nutrient loss or health risks. It is simply a natural chemical reaction. However, it can affect the visual appearance and flavor, especially in recipes where preserving the fresh look of the fruit is desired.
¡Qué interesante! Nunca sabía que las manzanas reaccionaban así con el oxígeno, gracias por explicarlo tan claro.
¿Sabéis si esto también pasa con los aguacates? Me encanta aprender estos trucos de ciencia para la cocina.