Carotenoids Accumulation and Changes of Carotenoid Pattern of Japanese Persimmon by Cathode Ray Irradiation

Abstract

Effect of cathode ray irradiation on the carotenoids of Japanese persimmon Hiratanenashi and Yotsumizo have been investigated._
Nearly ripe Hiratanenashi was irradiated at 0.1 and 0.5 Mrad and stored at 5°C for 15 days. Total carotenoids of non-irradiated, 0.1 and 0.5 Mrad were 8.71, 9.31 and 8.17mg% respectively. Constitution of carotenoids in fully ripe Hiratanenashi were hydrocarbon: 23.7%, monol: 41.5%, diol: 6.3%, diol monoepoxide: 12.7%, diol diepoxide: 14.9% and polyol: 2.7%.
Carotenoid patterns of Yotsumizo varied in different stages of maturity and the constitution of caroenoid group in fully ripe Yotsumizo were hydrocarbon: 15.6%. monol: 19.3%, -Diol: 20.9%, diol monoepoxide: 15.4%, diol diepoxide: 24.4% and polyol: 5.4%. Nearly ripe Yotsumizo were irradiated at 0.1 and 0.3 Mrad and analysed by total carotenoids and carotenoid pattern at 5, 8, and 12 days after irradiation. Total carotenoid content in 0.1 Mrad samples was higher than that in non-irradiated throughout the experiment and 8 days after irradiation it reached the maximum value of 1.4 times as much as non-irradiated. Total carotenoid content in 0.3 Mrad sample was 1.3 times as much as non-irradiated at 5 days after irradiation, but it decreased rapidyl and was less than that of non-irradiated subsequently.
Carotenoid pattern of 0.1 Mrad was similar to that of ripe sample throughout the experiment but the pattern of 0.3 Mrad changed in each analysis. These differences between 0.1 and 0.3 Mrad suggested that the irradiation activated the normal carotenoid biosynthesis path way in the case of 0.1 Mrad, on the other hand there was a disturbance of carotenoid biosynthesis in 0.3 Mrad and the irradiation at the does of 0.3 Mrad made a temporary carotenoids accumulation at 5 days after irradiation.