Abstract
The limonoid content in the component parts of Hassaku (Citrus hassaku hort. ex Tanaka) and pummelo(Citrus grandis Osbeck) fruits was investigated at monthly intervals.
1. The major limonoid in Hassaku fruit was limonin, showing a maximal concentration of 50ppm in the flesh in September. The nomilin concentrations in the flesh and segment membrane reached maxima of 20 and 500ppm, respectively, in August and then decreased rapidly. In the seeds, nomilin and limonin showed maximal concentrations in October and November, respectively.
2. All the parts of pummelo fruit except flavedo contained a large amount of nomilin, and it was particulary true in albedo and segment membrane. The deoxylimonin content in the segment membrane was similar to the limonin content in the segment membrane during fruit maturation. The limonin concentration in the seeds showed a maximum in December and it was far higher in the kernel than in the seed coat.
3. In pummelo fruit, the total limonoid content reached a maximum of 200mg per fruit. The total limonoid content in the seeds was less than that in albedo or segment membrane in spite of a high concentration of limonoids in the seeds. It became clear that in both Hassaku and pummelo fruits the limonin concentration reached a maximum one month later than the nomilin concentration in all the component parts.
