CHANGES IN THE LIMONOID CONTENT DURING DEVELOPMENT OF CITRON FRUIT (CITRUS-MEDICA L)

Limonoid compounds are bitter principals in the citrus fruit. The chan ges of limonoid in the component parts, seed, flesh, segment membrane, albedo and flavedo, of the citron fruit (Citrus medica L.) , obtained from Azuma town, Kagoshima Prefecture, during the development from No vember to February were investigated. Limonoids were extracted with et hylacetate and analyzed with high performance liquid chromatography. 1 . Different from many other citrus fruits, such as 'Wase satsuma manda rin', 'Natsudaidai' etc., nomilin was a major limonoid in all the part s of citron fruit except seed, in which the content of nomilin was nex t to that of limonin. 2. The total limonoid concentration in the seed was highest, ranging from 3,270 to 1,600 ppm, followed by segment memb rane (350 --> 310 ppm), albedo (250 --> 150 ppm) , flavedo (225 --> 15 0 ppm) and flesh (45 --> 30 ppm) from November to February. 3. In matu re citron fruits, total limonoid content reached the maximal levels in November, and then decreased rapidly in December and then increased s lightly in February. 4. During the maturation of the citron fruit from December to February, the total limonoid concentration in all parts e xcept the albedo increased rapidly, followed by a rapid decrease in th e over ripe stage. Limonoid concentrations continuously increased duri ng maturation in the albedo and in the flesh from 4 to 15 ppm and from 55 to 170 ppm, respectively.