Although citrus growers are trying to popularize mandarins with a green tinge, they claim that shoppers are expecting a perfect orange color. The popular imperial mandarin variety is meant to have touches of green on the skin, but growers use ethylene gas to speed up the ripening process, removing this green coloring. This practice, called ‘degreening’, is intended to make the fruit more desirable to consumers.
Gayndah citrus grower and member of Citrus Australia, Dennis Smith, said he used ethylene gas on his mandarins, but it didn't improve the taste. He said mandarin trees produced ethylene gas naturally, which slowly ripened the fruit over six to eight weeks.
The use of a degreening room condensed the ripening time to a few days by feeding the fruit a low but consistent amount of ethylene gas. Smith said mandarins lost their acid content and contained too much sugar to sustain the gassing when the season hit the four-week mark.
Source: abc.net.au