Abstract:

The skin color and its uniformity are two main indicators of the appearance quality of citrus fruits. However,
the peels and pulps of some early-season or earlier harvested citrus fruits are often mature with acceptable eating quality
while the rind is still green. In order to improve the external skin color and the export market acceptance, citrus fruit are
usually treated with ethylene (a degreening agent) in the citrus industry in both China and abroad. This paper reviews the
recent advances in citrus degreening by ethylene treatment with respect to parameter conditions, degreening mechanism,
influencing factors, its impact on the quality of citrus and the existing problems as well as possible solutions. Therefore, this
review will provide a theoretical reference for further optimization of ethylene degreening treatment of citrus fruits.

Key words: citrus, ethylene, degreening treatment, color formation, quality