DIFFERENTIATION OF CITRUS JUICES BY FACTORIAL DISCRIMINANT-ANALYSIS USING LIQUID-CHROMATOGRAPHY OF FLAVANONE GLYCOSIDES

Flavanone glycosides (FG) found in citrus juices have been separated a nd quantitatively determined by reversed-phase liquid chromatography ( LC) using a C-18 packed column and water-acetonitrile-tetrahydrofuran- glacial acetic acid eluent system. The influence of juice pH on hesper idin and narirutin determinations, from commercial orange juices, has been studied at different pH values (from 2.0 to 6.2). The response fa ctors, averages, relative standard deviations, and recoveries of six F G were determined using LC with an UV detector at 280 nn. The six FG a nd three unknown compounds found in citrus juices were determined in 1 24 samples of lemons, limes, grapefruits, and sweet oranges. The major FG in each citrus group were as follows: in lemon and lime, eriocitri n (47-94 mg L(-1)) and hesperidin (84-196 mg L(-1)); in sweet orange, narirutin (30-84 mg L(-1)) and hesperidin (235-407 mg L(-1)); in grape fruit, narirutin (33-161 mg L(-1)) and naringin (113-481 mg L(-1)). Fa ctorial discriminant analysis of the data obtained effectively differe ntiated lemon and lime and varieties of grapefruits (white, pink, red, and green) and sweet oranges (Valencia, navel, blood, Thomson, and Ma lta).