ENZYMATIC BROWNING Meaning and
Definition
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Enzymatic browning is a natural chemical process that occurs when certain enzymes present in fruits, vegetables, and other foods interact with oxygen in the air, resulting in the browning or darkening of the exposed surface. This process is caused by the presence of polyphenol oxidase enzymes, commonly found in the cells of plant tissues, which catalyze the oxidation of certain phenolic compounds when they come into contact with atmospheric oxygen.
Enzymatic browning is a complex chain reaction involving the conversion of various phenolic compounds, such as catecholamines and o-diphenols, to highly reactive quinones. These quinones further react with amino acids and proteins present in the food, forming brown-colored pigments known as melanins. This reaction is responsible for the browning of cut apples, bananas, potatoes, and other fruits and vegetables when left exposed to air for an extended period.
The enzymatic browning process can be influenced by several factors, including temperature, pH, and the availability of oxygen. It is generally accelerated by warmer temperatures, higher pH levels, and the presence of oxygen, while cold temperatures, low pH levels, and the absence of oxygen can slow down or inhibit the browning reaction.
Various methods can be employed to prevent or delay enzymatic browning, including the use of acids (such as lemon juice) to lower pH levels, blanching or boiling to denature enzymes, and the application of antioxidants to inhibit the oxidation process. These techniques are commonly employed in food preparation and preservation to maintain the desired appearance and quality of fruits, vegetables, and other food products.
Etymology of ENZYMATIC BROWNING
The term "enzymatic browning" is composed of two parts: "enzymatic" and "browning".
The word "enzyme" is derived from the Greek words "en" meaning "in" or "within", and "zymē" meaning "leaven" or "yeast". It was coined in 1878 by the German physiologist Wilhelm Kühne to describe the biocatalysts that facilitate chemical reactions in living organisms.
The word "browning" refers to the process of food turning brown due to various chemical reactions, such as the Maillard reaction or caramelization. It comes from the Middle English word "broun" meaning the color brown.
When combined, "enzymatic browning" describes the specific type of browning that occurs as a result of enzymatic reactions in food.
