HPLC analysis of carotenoids : analysis of red bell pepper (Capsicum annuum) and marigold flowers (Tagetes erecta)

Includes bibliographical references (pages 105-112)A methodology for the analysis of carotenoids and\ud carotenoid esters using High Performance Liquid\ud Chromatography was standardized. A reversed phase bonded\ud octadecyl silica stationary phase and a new mobile phase based on methanol-ethyl acetate gave excellent separation of carotenoid hydrocarbons and free and acylated\ud xanthophylls. Analysis of red bell pepper by HPLC has shown that\ud there are three predominant carotenoids, capsanthin\ud (80%), capsorubin (4%) and beta-carotene (16%). The\ud total carotenoid content ranged from 88 pgjg to 166\ud Ag/g. Capsanthin was found to be present as free\ud xanthophyll, mono- and diesters. Three diesters and six\ud monoesters were observed. Capsorubin was present as the\ud diester only. The mean beta-carotene content was 20 Ag/g\ud which is equivalent to approximately 3 RE/g. Red bell peppers were also analyzed by a\ud conventional method involving the quantitation of total\ud carotenoids by absorbance of total extractive. Total\ud carotenoids were determined as capsanthin. The mean\ud total carotenoid content was 150 Ag/g. No significant\ud difference was found between determination of total\ud carotenoid content by HPLC versus a conventional method. A study of the composition of carotenoids in marigold flowers has shown that only lutein esters are\ud present. Four diesters of lutein were observed. Total\ud lutein content ranged from 4 Ag/g to 800 Ag/g. A\ud significant negative correlation was found between color\ud determination (as L values) and concentration of lutein\ud esters in the flowers