HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH PHOTODIODE-ARRAY DETECTION OF CAROTENOIDS AND CAROTINOID ESTERS IN FRUITS AND VEGETABLES

A procedure for the simultaneous, one-step analysis of polar xanthophy lls, xanthophyll mono- and diesters and geometric isomers of carotenes in selected fruits and vegetables using high-performance liquid chrom atography (HPLC) and photodiode-array detector is described. The separ ation of carotenoid extracts was first performed on a column of 6 mu m particles using different mobile phases and variable wavelength detec tors to monitor column effluents. This procedure had limitations regar ding separation efficiency and ease of spectrum analysis during the ch romatographic run. The method was further developed by using a column of 6 mu m particles and a mobile phase consisting of acetonitrile-isop ropanol-methanol-water (39:52:5:4 v/v/v). This development permitted t he isocratic separation of about 45 components in less than 50 minutes . Rapid and precise identification of the individual carotenoids was a chieved by using photodiode-array detector under the control of chroma tographic software which also allowed for rapid test of peak purity an d complete mapping of the whole separation profile including major lip id classes and fat-soluble materials. A wide variety of carotenoids an d carotenoid fatty acid esters were separated and quantified in select ed fruits and vegetables such as spice red pepper, tomato, carrot, ora nge and apricot. cis isomers of beta-carotene, the most effective prov itamin A, were also separated and differentiated from their correspond ing trans forms.