DIFFERENTIATION OF VARIOUS GRAPEFRUIT AND POMELO JUICE VARIETIES USING LIQUID-CHROMATOGRAPHY OF FLAVANONE GLYCOSIDES AND PATTERN-RECOGNITION TECHNIQUES

A reversed high liquid chromotographic method was developed to determi ne flavonone glycosides in grapefruits and Pummelos. The flavanonic co mpounds were separated using acetonitrile and water-tetrahydrofuran-ac etic acid gradient and detected at 280 nm. Fifty-seven samples of Citr us paradisi (Mac Fayden) and C grandis (L) Osbeck were analyzed. The p resence of neoeriocitrin in C grandis species (2.9-9.2. mg l(-1)) and of didymin in C paradisi species (1.2-10.9 mg l(-1)) permitted easily the differentiation of these two species. In order to bring out the sp ecific characteristics which may simplify the differentiation of the t wo juice varieties, analytical data of eight flavanonic compounds were treated by using principal component analysis and factorial discrimin ant analysis. The use of a gradient proved very useful for flavanone p rofile studies, which generate multivariate data for juice differentia tions. The reliability of the HPLC procedure was determined by a serie s of recovery experiments in which a base sample was fortified with kn own amounts of flavanone glycosides. The repeatability of the methods was also determined.