Browning is the process of food turning brown due to the chemical reactions that take place do grapes have to be refrigerated. Browning has many important implications on the food industry relating to nutrition, technology, and economic cost. The production of quinones undergoes more reactions which eventually form brown pigments on the surface of the food.
Enzymatic browning is one of the most important reactions that takes place in most fruits and vegetables as well as in seafood. These processes affect the taste, color, and value of such foods. Developing color and flavor in coffee, cocoa beans, and tea. Developing color and flavor in dried fruit such as figs and raisins.
Fresh fruit and vegetables, including apples, potatoes, bananas and avocados. Polyphenols oxidases is the major reaction in the formation of melanosis in crustaceans such as shrimp. A desirable enzymatic browning reaction is involved in the process of grapes becoming raisins. A non-desirable enzymatic browning reaction is involved in the formation of brown spots on the peel of bananas. The control of enzymatic browning has always been a challenge for the food industry. A variety of approaches are used to prevent or slow down enzymatic browning of foods, each method aimed at targeting specific steps of the chemical reaction. The different types of enzymatic browning control can be classified into two large groups: physical and chemical.
Treating food with heat, such as blanching or roasting, denaturates enzymes and destroys the reactants responsible for browning. Refrigeration and freezing are the most common ways of storing food, preventing decay. The activity of browning enzymes, i. Presence of oxygen is crucial for enzymatic browning, therefore eliminating oxygen from the environment helps to slow down the browning reaction. Browning enzymes, as other enzymes, are active at a specific range of pH. For example, PPO shows optimal activity at pH 5-7 and is inhibited below pH 3.