Carotenoids and volatile profiles of yellow- and red-fleshed papaya fruit in relation to the expression of carotenoid cleavage dioxygenase genes

• The carotenoid profiles in flesh of two papaya cultivars were characterized.
• 6-Methyl-5-hepten-2-one and β-ionone were only detected in ‘Sui hong’ fruit.
• Low expressions of CpCCD1 and CpCCD7 existed in ‘Sui huang’ fruit.
• High expression of CpCCD1 might result in the formation of two typical volatiles.

Fruit of two different papaya cultivars (‘Sui huang’, yellow flesh, and ‘Sui hong’, red flesh) were characterized in terms of carotenoid and volatile profiles throughout storage at 25 °C. The results showed that ‘Sui huang’ cultivar exhibited significantly lower carotenoid contents than ‘Sui hong’, which accounted for the different color characteristic. The analyses of HPLC coupled to mass spectrometry showed that zeaxanthin, β-cryptoxanthin and and β-carotene were identified as the most abundant carotenoids in ‘Sui huang’ fruit while the most abundant carotenoids were lycopene, followed by β-carotene, zeaxanthin and β-cryptoxant hin in ‘Sui hong’ fruit. The high expression of carotenoid cleavage dioxygenase gene (CpCCD1) in ‘Sui hong’ papaya fruit might stimulate the degradation of β-carotene and lycopene and then form the specific volatiles of 6-methyl-5-hepten-2-one and β-ionone.