Carotenoid composition in buah merah (Pandanus conoideus Lam.), an indigenous red fruit of the Papua Islands

Abstract

The composition of carotenoid pigments from the fruit of the Pandanus plant, Pandanus conoideus Lam. monocot or locally named as red fruit, indigenous to the Papua Islands, was investigated. By chromatographic and spectrometric analyses using RP-HPLC with C18 and C30 columns and gradient elution, NMR, MS/MS and FT-IR, eight κ-end group carotenoids, 5,6-diepicapsokarpoxanthin, capsorubin, capsanthin, cryptocapsin, 13-cis capsorubin, and three capsanthin epoxides were identified. Additionally, β-cryptoxanthin 5,6-epoxide, α- and β-cryptoxanthin, α- and β-carotene, and other carotenoid-type compounds were found. The κ-end group carotenoids in red fruit comprised 92 % in relative contents and was much higher than that in red chili pepper, Capsicum annuum L., at 64 %. These findings indicate that red fruit has similar carotenoids to those of red chili pepper, not only in composition but also in the content. Xanthophyll cycle carotenoids antheraxanthin and violaxanthin are the precursors of capsanthin and capsorubin, respectively. However, these precursors, as well as the precursors of zeaxanthin, were not detected in the chromatographic separation and identification in the extracts of red fruit, although they were detected in red chili pepper under the same analytical conditions used. Therefore, in red fruit, those precursors are likely not responsible for the biosynthesis of κ-end group carotenoids.