Oxidizing browning is a common phenomenon in food. The so-called browning refers to the phenomenon of food darkening or browning after processing, storage and damage. The common food browning phenomena in our daily life, such as apples, potatoes and eggplant peeling, will change color after a while.

　　1、Browning Types：

　　Browning include Enzymatic browning and Non-enzymatic browning.

　　1)Enzymatic browning, it is the browning phenomenon that occurs under the effect of enzymes

　　2)Non-enzymatic browning, it refers to a type of browning without enzyme participation

　　In general, enzymatic browning is a malignant color change phenomenon, which is the result of the formation of phenolic substances and polymers by phenolic enzymes in food, which can affect the food's perception, taste, and over time will lead to food corruption. Non-enzyme browning is a relatively benign color change phenomenon, product production process, in order to achieve a unique color and taste, often artificial use of this browning means, such as: roasting, barbecue, bacon, coffee, soy sauce, etc. (these belong to the arginine browning, belong to one of the non-enzyme browning).

　　Below we’d like to discuss more about enzymatic browning：

　　For example, red herring is a special fruit of China, accounting for 95% of the world's total production of red dates. In the process of storage, the red dates tend to brown, resulting in poor perception of the product, but also caused the loss of nutritional value. Experiments show that the brownness of red dates is highly related to the total phenol content (TP value) and polyphenol oxidase activity (correlation coefficients R to 2 are 0.9974 and 0.9993, respectively), and it is concluded that the browning of red dates is mainly caused by enzymatic browning.

　　In addition to red dates, there are many products are facing the problem of browning in the storage process. Such as chestnuts, the flesh is rich in polyphenol oxidase and peroxidase;

　　2、Solutions for oxidizing browning：

　　Enzymatic browning must have three conditions: proper phenolic substrates, phenolic oxidase and oxygen, which are indispensable. In practice, the method of controlling enzymatic browning mainly starts with the control of phenolic oxidase and oxygen, because phenolic substrates are basically unable to control.

　　3、Solutions for browning of packaging foods：

　　Packaged food in the storage process, can not control phenolic oxidase, so only by controlling oxygen to solve the problem of browning. Specific solutions for the use of aerobic packaging, vacuum packaging and inflatable packaging is commonly used oxygen packaging, to completely remove the oxygen inside the packaging (especially the trace oxygen adsorbed on food) is difficult, must be sealed in the packaging "Oxygen Absorber" to absorb residual oxygen in the packaging, and can absorb the packaging food in the storage and transportation process through the packaging material trace oxygen, so that the treatment can be long-term to maintain the low oxygen state of the packaging, effectively prevent food oxidation. At present, most foods use soft plastic packaging materials, oxygen-blocking packaging should be selected with high oxygen-repulsive PET, PA, PVDC, aluminum foil and other composite packaging materials as the main barrier layer.