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Tuesday, June 8, 2010

To brown or not to brown. That is the question.

Enzymic or (Enzymatic) browning is a chemical process involving, poliphenol oxidase or other enzymes that create melanins, resulting in a brown color. Enzymic Browning is an important color reaction in food, vegetables and seafood.

Enzymic browning is beneficial for:

Developing flavor in tea (Here the reaction is incorrectly called "fermentation")
Developing color and flavor in fruits such as figs and raisins

Enzymic browning is detrimental to:

Fresh fruits and vegetables, in particular apples and potatoes
Seafood such as shrimp

Enzymic browning is usually controlled with chemicals, or by destroying the responsible chemicals with heat. Blanching to destroy the enzymes is commonly used to preserve color in vegetables. Lemon juice and other acids are used to preserve color in fruits, particularly apples, by lowering the ph and removing the coper cofactor necessary for the enzyme to function

Non-enzymic browning

Non-enzymatic browning, or oxidative, browning is a chemical process that produces a brown color in foods without the activity of enzymes. Melanins and other chemicals are responsible for the brown color. The two main forms of non-enzymatic browning are caramelizing and the Maillard reaction. Both vary in reaction rate as a function of water activity.

Caramelizing is the oxidation of sugar. it is used extensively in cooking for the result of nutty flavor and brown color. as the process occurs, volatile chemicals are released producing the characteristic brown color

The Maillard reaction is a chemical reaction between an amino acid and a reducing sugar, usually requiring the addition of heat. The sugar interacts with the amino acid, producing a variety of odours and flavors. The Maillard reaction is the basis of the flavouring industry, since the type of amino acid involved determines the resulting flavor. It also produces toast

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