Studies on Citrus Carotenoids

Part II. Carotenoid pattern of citrus unshiu peel at different mature stages

Abstract

Changes of carotenoids in several varieties of Citrus Unshiu peel at six different mature stage from Otober to middle of December have been studied.
Carotenoid mixtures were separated into nine groups, such as hydrocarbon, monol, monol monoepoxide, diol, diol monoepoxide 1, diol diepoxide 1, diol monoepoxide 2, diol diepoxide 2 and polyol, by TLC in the case of general Unshiu varieties. On the other hand, unknown carotenoid group appeared in var. Benidobashi between monol and diol on the plate in stead of disappearance of monol monoepoxide and the unknown group characterized the deep red color of var. Benidobashi.
Caroteaoid pattern in general Citrus Unshiu peel have changed with orange color development and orange coloring was owing to rapid increase of monol and diol diepoxide groups.
Unknown carotenoid in var. Benidobashi increased remarkably with deep red color development and showed highest ratio for total carotenoids as fully mature stage.
Carotenoid pattern of several ripe Citrus Unshiu peel indicated that the deeper orange color developed, the more monol and diol diepoxide and the smaller diol diepoxide 1/diol diepoxide 2 ratio existed.