Fruit Juice Carotenol Fatty Acid Esters and Carotenoids As Identified by Matrix-Assisted Laser Desorption Ionization (MALDI) Mass Spectrometry

Abstract

Gradient and isocratic HPLC separated as many as 38 carotenoid components in extracts from fruit juices. Several oxygenated carotenoids (xanthophylls), hydrocarbon carotenoids, and carotenol mono- and bis-fatty acid esters were identified. Structural elucidation was based on UV/vis spectroscopy, matrix-assisted laser desorption ionization (MALDI) post-source-decay (PSD) mass spectrometry, and comparison with synthetic reference compounds. Straight-chain fatty acid esters (caprate, laurate, myristate, palmitoleate, palmitate, oleate) of β-cryptoxanthin were identified as major carotenoid constituents in tangerine juice concentrate. Fatty acid components were identified by MALDI PSD fragment ion analysis. The xanthophylls violaxanthin, luteoxanthin, neoxanthin, taraxanthin, antheraxanthin, mutatoxanthin, β-cryptoxanthin-5,6:5‘,6‘-diepoxide, lutein, zeaxanthin, α-cryptoxanthin, and β-cryptoxanthin were present in the extracts of saponified tangerine concentrate. The chromatographic profiles of orange juice concentrate showed marked differences from those of tangerine concentrate. In the saponified extract, the oxygenated carotenoid zeaxanthin predominated over β-cryptoxanthin. Keywords: Carotenoids; carotenol esters; carotenoid analysis; mass spectrometry; matrix-assisted laser desorption ionization