Effects of Sugar and Nitrogen Content in Peel on Color Development in Satsuma Mandarin Fruits

Abstract

Changes in constituents in peel during color development were investigated for different fruit parts, locations of production and cultivars of satsuma mandarin. Total sugar in peel accumulated rapidly as degreening was initiated, whereas nitrogen content decreased simultaneously. There was a significant positive correlation between sugar content in peel and color development, but a negative correlation existed between nitrogen content and color development. Color development was more closely related to sugar status in peel than to that in juice.
Color development of peel was studied using peel segments which were kept on an agar medium containing various concentrations of sugar and nitrogen. Color development of peel was controlled by sugar and nitrogen supplies in the agar medium. A high concentration of sucrose in the medium promoted degreening, whereas nitrogenous compounds acted in opposition to sucrose by inhibiting degreening.
It was suggested that color development of satsuma mandarin was caused by the elevated sugar content and reduced nitrogen content in the peel.