Enzymatic Browning

• Enzymatic browning is caused by the oxidation, the combining of oxygen with the pigments in fruit. Oxidation activates enzymes in the fruit, which in turn cause the browning process. The pigment melanin is responsible for the discoloration.
  
  

Enzymes and Pigments

• Enzymes are proteins, which work as activators for the browning process. Pigment, the chemical that causes color in animals and plants, also causes the fruit to darken. In fruit, the enzyme phenolase activates the pigment melanin.
  
  

Natural Methods of Prevention

• One way to stop browning is to blanch fruit in water for several minutes. Another way is to coat the fruit in vitamin C, which will oxidize in place of the pigments. Using a sugar-syrup coating prevents air from reaching the exposed fruit. Products found at a supermarket can also be added to fruit to prevent browning.
  
  

Non-enzymatic Browning

• Fruit can also brown from cooking -- specifically during carmelization, which is when fruit or other food is cooked in sugar. The process sweetens the fruit and typically browns it. Carmelization is a common technique for cooking desserts and other sweet dishes.