Seasonal Changes of Carotenoid and Chlorophyll in Citrus hassaku Peel and Leaves

Abstract

The relationships between color and pigment composition in the peel and leaves of Citrus hassaku during maturation were studied. (1) Seasonal changes of the peel color were classified into the three stages. In the first stage the peel color is green due to the high chlorophyll content regardless of the carotenoid content. In the second stage the peel color changes from green to yellow, because of the drastic decrease of the chrolophyll content, even when the carotenoid content is at the minimum level. In the third stage, the peel color becomes yellow-orange due to the disappearance of chlorophyll and the increase of carotenoids. (2) During the first stage, among the catotenoids separated by TLC the content of Hydrocarbon (H) in the peel was the highest, and Diol (D) and Dioldiepoxide (DD) followed. The carotenoid pattern was named as H-D-DD type. Then it changed to D-H-DD soon, followed by D-DD-H and subsequently by DD-D-H in the second stage. In the final stage the pattern became DD-M (Monol)-D by way of DD-D-M. (3) The greenness of the leaves from autumn to winter was attributed to the high chlorophyll content (40-180mg/100g). The leaf's carotenoid pattern was constantly D-H-DD type except for being H-D-DD type in fresh verdure. It resembled the carotenoid pattern of the green peel.