HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF THE GEOMETRICAL-ISOMERS OF BETA-CAROTENE IN SEVERAL FOODSTUFFS

To better evaluate the provitamin A content of foodstuffs, an HPLC separation of the geometric isomers of beta-carotene was developed. Of the several. different stationary phases studied, the best separations of all-trans-, beta-cis- and 13-cis-beta-carotene were obtained with calcium hydroxide columns using isocratic elution with n-hexane, isooctane or mixtures of these solvents. When xanthophyll pigments are also present, a gradient elution with acetone in isooctane is required. These techniques were used to determine the provitamin A content of squash, peaches, dende oil (palm tree oil) and orange juice.