Abstract
Carotenoid development of red fleshed papaya fruit (Carica papaya L.) was investigated in the course of a complete pre- and postharvest period using HPLC-DAD coupled to mass spectrometry. Esterified xanthophylls such as β-cryptoxanthin laurate and caprate were the most abundant pigments during incipient carotenoid biosynthesis. Subsequent fruit maturation led to a gradual accumulation of carotenoids, whereas particularly β-cryptoxanthin laurate and total lycopene contents disproportionately increased, reaching maximum contents of up to 775 and 3168 μg/100 g of fresh weight (FW), respectively. Total carotenoid contents of fully ripe papaya ranged from 5414 to 6214 μg/100 g of FW, while corresponding biosynthetic precursors like phytoene, phytofluene, and ζ-carotene were only detected in trace amounts. Due to high contents of vitamin A precursors like β-carotene and β-cryptoxanthins, edible parts of the ripe fruit contained 132-166 μg retinol equivalents per 100 g of FW.
Furthermore, the development of morphological and physico-chemical fruit traits was characterized revealing significant correlations to carotenoid accumulation. A ripening index derived from several parameters was developed to easily allow exact assignment of ripening stages in studies of carotenoid development during fruit ontogenesis. Additionally, on-tree ripened versus postharvest ripened fruits were compared revealing striking similarity of their physico-chemical parameters and contents of individual carotenoids.
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