Red Juice Sac of Citrus and Its Main Pigments
Xu Juan and Deng Xiuxin (National Key Lab of Crop Genetic Improvement, HuaihongAfficultural University, Wuhan,Hubei 430070 China)
There are many citrus cultivars with red juice sacs around the world, such as red fleshed grapefruit (Citrus paradisii Macf.) and Blood Orange (C. sinensis Osbeck). The light red color of the juice sac of the red fleshed grapefruit is caused by the existence of lycopene, and the blood red color of the juice sac of Blood Orange is caused by the pigment of anthocyanin. There are still many citrus cultivars with red juice sacs, but their pigments remain unknown, such as red -fleshed Hongjiangcheng (C. sinensis L.), orange-red Yuanhong (C. reticulata Blanco) and amaranth colored Wubu Red Fleshed Pomelo (C. grandis L.) and so on; their unique color also enhance consumer acceptance. Furthermore, pigments in these citrus cultivars provide special nutrients, which could soften the blood vessels, eliminate free radicals inside body and has the function of resisting cancer.In this article, the local and foreign cultivars with red juice sacs of mandarin,sweet orange, pomelo .grapefruit and citrus hybrid are mentioned and the biosynthesis of pigments-anthocyanins and carotenoids- which caused the trait of red juice sac are elucidated.