Browning (chemical process)

Browning is the process of becoming brown, especially referring to food. Browning foods may be desirable, as in caramelization, or undesirable, as in an apple turning brown after being cut. Foods turn brown through an enzymatic or a non-enzymatic process.

Enzymic browning

Enzymic browning is a chemical process involving polyphenol oxidase or other enzymes that create melanins, resulting in a brown color. Enzymic browning is an important color reaction in fruit, vegetables, and seafood. Enzymatic browning of fruits and vegetables creates heavy economic losses for growers.

Enzymic browning is beneficial for:
*Developing flavor in tea (here the reaction is incorrectly called fermentation)
*Developing color and flavor in dried fruit such as figs and raisins.

Enzymatic browning is detrimental to:
*Fresh fruit and vegetables, in particular apples and potatoes
*Seafood such as shrimp

Enzymatic browning is usually controlled with chemicals (such as sodium bisulfite), 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 fruit, particularly apples, by lowering the pH and removing the copper cofactor necessary for the enzyme to function.

Non-enzymatic browning

Non-enzymatic, 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 caramelization and the Maillard reaction. Both vary in reaction rate as a function of water activity.

Caramelization is the oxidation of sugar. It is used extensively in cooking for the resulting nutty flavor and brown color. As the process occurs, volatile chemicals are released producing the characteristic caramel flavor.

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 odors and flavors. The Maillard reaction is the basis of the flavoring industry, since the type of amino acid involved determines the resulting flavor.

ee also

*Browning (partial cooking)
*Decomposition
*Catechol oxidase
*Water activity

External links

* [http://www.fao.org/ag/ags/agsi/ENZYMEFINAL/Enzymatic%20Browning.html FAO page on enzymatic browning]
* [http://www.decagon.com/food_science/info/safety.php Stability Diagram of Foods]


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Browning (food process) — An example of enzymatic browning in the skin of a banana Caramelization in …   Wikipedia

  • Browning — may refer to: * Browning (chemical process), the chemical process of browning food * Browning (slang), a light skinned woman or man of African or East Indian descent. A term that is used in Jamaica. * Browning (partial cooking), the cooking… …   Wikipedia

  • oxidation–reduction reaction — ▪ chemical reaction Introduction also called  redox reaction        any chemical reaction in which the oxidation number of a participating chemical species changes. The term covers a large and diverse body of processes. Many oxidation– reduction… …   Universalium

  • Grilling — Charbroil redirects here. For the G.I. Joe character, see Charbroil (G.I. Joe). Grilled redirects here. For the 2006 film, see Grilled (film). For Breaking Bad episode, see Grilled (Breaking Bad). Grilling mangals and kebabs …   Wikipedia

  • Food chemistry — is the study of chemical processes and interactions of all biological and non biological components of foods. The biological substances include such items as meat, poultry, lettuce, beer, and milk as examples. It is similar to biochemistry in its …   Wikipedia

  • Patina — For the village in Estonia, see Pattina. For the United States Navy ship, see USS Pattina (SP 675). A bronze coin of the Han Dynasty circa 1st century BC with green patina. Patina ( …   Wikipedia

  • Holocaust denial — Antisemitism Part of Jewish history …   Wikipedia

  • baking — Process of cooking by dry heat, especially in an oven. Baked products include bread, cookies, pies, and pastries. Ingredients used in baking include flour, water, leavening agents (baker s yeast, baking soda, baking powder), shortening (fats,… …   Universalium

  • food preservation — Any method by which food is protected against spoilage by oxidation, bacteria, molds, and microorganisms. Traditional methods include dehydration, smoking, salting, controlled fermentation (including pickling), and candying; certain spices have… …   Universalium

  • fruit processing — Introduction       preparation of fruit for human consumption.  Fruit is sometimes defined as the product of growth from an angiosperm, or flowering plant. From a purely botanical point of view, the fruit may be only the fleshy growth that arises …   Universalium


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.