Distribution of limonin in the fruit tissues of nine grapefruit cultivars

Abstract

This report presents the results of a study conducted to determine the distribution of limonin within the fruit tissues of nine grapefruit cultivars. It was found that the highest limonin levels within the fruit tissues were found in the cotyledon, followed by inner seed coat, outer seed coat, central pith, segment membrane, albedo and flavedo, and juice vesicles, in decreasing amounts. The concentration of limonin in the tissues of the individual cultivars is also presented, and the variation in limonin content within a single tissue and within single fruit is discussed. The limonin content of the fruit of the nine cultivars was also compared. The overall results showed that Davis Krome was significantly higher in limonin content followed by Triumph, Duncan, White Marsh, and Foster Pink (which were statistically equivalent to each other) and then by Thompson Pink, Wheeney, and Mott. Leonardy contained the lowest ppm of limonin. The ranking of the cultivars according to the limonin content of each tissue is also presented.Limonin is the intensely bitter triterpenoid dilactone derivative which is widely distributed throughout the Rutaceae. This compound is of major importance in certain citrus fruits, grapefruits and navel oranges, as well as their processed products. In the past, limonin localization and distribution in citrus fruit and plant parts has received only minimal attention since an assay procedure that is rapid, is sensitive, is objective, and permits a high sample throughout has not existed. We have reported on the recent development of a radioimmunoassay (RIA) for limonin (Weiler and Mansell, 1980;Mansell and Weiler, 1980) which has made it possible to do studies which heretofore were impractical.Recently we have presented the first in a series of reports on the limonin levels in grapefruit cultivars (Manesell and McIntosh, 1980). In this study samples were taken from truckloads of grapefruit being brought into processing plants. This sampling tended to minimize variation within and between fruits and trees but not between different varieties, groves, and trees of different age, nutritional status, and geographical distribution. Statistically significant differences were observed between the various cultivars sampled and between the test houses of the various processing plants.

Concentration and distribution of main bitter compounds in fruit tissues of ‘Oroblanco’ (Citrus grandis L.×Citrus paradisi Macf.)

“…Compared with the previous report, the deceasing degrees of limonin in different tissues followed the order of segment membranes > albedo > flavedo > juice vesicles (McIntosh et al, 1982). While in our study, the deceasing degrees of limonin followed the order of segment membranes > albedo > juice sacs > flavedo.…”

Flavor and Color of Fruits as Affected by Processing

“…Limonin occurs at the highest concentrations in the cotyledon. It also is present in the seed coat, pith, segment membranes, albedo, flavedo, and juice vesicles in order of decreasing concentration (McIntosh et al 1982). Naringin ( Fig.…”

Three-Dimensional Distribution of Limonin, Limonoate A-Ring Monolactone, and Naringin in the Fruit Tissues of Three Varieties of Citrus paradisi

“…Results from a previous study of the distribution of limonin in grapefruit tissues of nine grapefruit cultivars showed that the concentration range within each tissue varied more than 10-fold (McIntosh et al, 1982). The observed ranges in concentration could be due to random events.…”

“…This compound has been one of the most extensively studied of the limonoids due to its abundance and its importance in processed citrus fruit, especially juices. Previous studies have shown that lemon, C. limon, leaves are able to synthesize limonin from nomilin, and ultimately this compound or its nonbitter precursor, limonoate A-ring monolactone, is subsequently transported to the fruit where it accumulates in the seeds, carpellary membranes, and the central pith (Hasegawa and Hoagland, 1977;Hasegawa et al, 1980Hasegawa et al, , 1986McIntosh et al, 1982;Ronneberg et al, 1995).…”