Carotenogenesis and physico-chemical characteristics during maturation of red fleshed papaya fruit (Carica papaya L.)

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 3168μg/100gof fresh weight (FW), respectively. Total carotenoid contents of fully ripe papaya ranged from 5414 to 6214μg/100gofFW, 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 132-166μg retinol equivalents per 100g 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.