Seasonal Changes of Isoprenoid Related Substances in Citrus Peels

Abstract

Some isoprenoid related substances in the citrus peels were seasonally examined with 9 cultivars, including Satsuma mandarin, and other citrus fruits. (1) The total chlorophyll contents in the flavedo were 8 to 15mg/100g at the early stage of each cultivar. The ratio of chlorophyll a to b was almost constant throughout the growing stages. (2) The carotenoid contents in Satsuma mandarin and Ponkan increased drastically during the ripening stage and finally amounted to 12 and 8mg/100g, respectively. In Buntan and sour orages, in contrast, carotenoids were less than 2mg/100g and decreased during the ripening stage. (3) α-Tocopherol was present more in the flavedo than in the albedo. In many cultivars in september it accumulated to the level of 5 to 9mg/100g. The highest level of α-tocopherol in Satsuma mandarin was about 17mg/100g in November. (4) β-Sitosterol accumulated up to in 10 to 40mg/100g throughout the growing stages in all cultivars. The highest levels of 30 to 40mg/100g were observed in September in Buntan, in July in Ponkan, Natsudaidai, Iyokan and Buntan, and in November in Satsuma mandarin. Campesterol was contained in the range of 3 to 8mg/100g in all cultivars tested. Its content decreased with the maturation in every cultivars except Satsuma mandarin.