Browning (food Process) - Enzymatic Browning

Enzymatic Browning

Enzymatic browning is a chemical process, involving polyphenol oxidase, catechol oxidase and other enzymes that create melanins and benzoquinone from natural phenols, resulting in a brown color. Enzymatic browning generally requires exposure to oxygen, thus the browning that occurs when an apple, for example, is cut.

Enzymatic browning can be beneficial for:

• Developing flavor in tea
• Developing color and flavor in dried fruit such as figs and raisins.

Enzymatic browning is often detrimental to:

• Fresh fruit and vegetables, including apples, potatoes and bananas
• Seafood such as shrimp

A variety of techniques exist for preventing enzymatic browning, each exploiting a different aspect of the biochemical process.

• Lemon juice and other acids lower the pH and remove the copper cofactor necessary for the responsible enzymes to function
• Blanching to denature enzymes and destroy responsible reactants
• Low temperatures can also prevent enzymatic browning by reducing rate of reaction.
• Inert gas, like nitrogen, prevent necessary oxygen from reacting
• Chemicals such as sodium bisulfite and citrates