Color protection includes sulfur treatment, sulfur treatment, sulfur-free color protection, sulfur fumigation and sulfur impregnation. When the fruit comes into contact with air during processing, it will brown rapidly, which will affect the appearance and quality. Browning includes enzymatic browning and non-enzymatic browning.

Color protection is an important problem in preserved fruit processing industry. If it is not handled well, it will seriously affect the production and sales of products. With the emphasis on "green food" today, the research and development of natural and harmless color fixative or its compound will surely become a hot spot.