The chemical assay of limonin, the bitter principle of oranges

Abstract

A method is presented for the determination of limonin, the bitter principle of oranges, based upon selective extraction and conversion to the dinitrophenylhydrazone, which is separated by thin‐layer chromatography for estimation by spectrophotometry. The method can be used as a routine procedure for the study of variations in the limonin content of oranges and processed juices. Some examples are given of its application to the study of the problem of bitterness in orange juice.

Limonoids and Flavonoids in Juices of Oroblanco and Melogold Grapefruit Hybrids

“…The limonoid bitterness is an important economic problem in commercial citrus juice production. Of the 36 limonoid aglycones isolated from citrus and its hybrids, limonin is the major cause of limonoid bitterness (Chandler and Kefford, 1966), though nomilin is also involved (Rouseff, 1982). Natural debittering of limonoids through glucosidation of the limonoid aglycones occurs in the fruit tissues and seeds at late stages of fruit growth and maturation .…”

Bitterness in Citrus Juices

“…Several elution solvents have been used, including: chloroform and acetic acid in a 98: 1 ratio (Chandler and Kefford 1966); a top layer of toluene, ethanol, distilled water, and glacial acetic acid in a 200: 40: 15: 1 ratio after overnight standing (Hasegawa, Patel, and Snyder 1982), ethylacetate and cyclohexane in a 3: 2 ratio (Hasegawa 1980); and acetone elution followed by elution with benzene, hexane, acetone, and acetic acid in a 65: 25: 10: 3 ratio (Tatum and Berry 1973). However, instead of using a packed column to separate the components of a sample, the separation takes place on a flat silica-coated plate.…”

Method for Estimating Limonin Content of Citrus Juices

“…Sixteen solvent systems were developed for the separation of limonin from citrus juices (Table 1). Two spray reagents were used: (I) 10% sulfuric acid in ethanol (Chandler, 1966) and (2) 2% sulfuric acid, 1% p-dimethylaminobenzaldehyde in ethanol (Wasicky, 1962).…”