Changes of Aroma Components During Fruit Maturation of Two Early Apple Cultivars

The aroma components during fruit maturation of two early apple cultivars (‘Taishan Zaoxia’ and ‘Liaofu’) were analyzed by static headspace and gas chromatography-mass spectrometry. Results showed that eight character impact components (CICs) were identified in Taishan Zaoxia, including butyl acetate, 2-methyl-1-butyl acetate, hexyl acetate, ethyl butanoate, ethyl 2-methylbutanoate, propyl butanoate, butyl 2-methylbutanoate and ethyl hexanoate. Meanwhile, six CICs were found in Liaofu and they were hexanal, (E)-2-hexenal, hexyl acetate, ethyl butanoate, ethyl 2-methylbutanoate and ethyl hexanoate. The quantitatively significant components were esters in Taishan Zaoxia and alcohols in Liaofu during fruit maturation, respectively. It showed difference in ester types between two cultivars that the major ester components were acetate esters in Taishan Zaoxia and butanoate esters in Liaofu. It was also observed that the contents of esters and alcohols in two cultivars increased significantly during fruit maturation. The total content of esters in Taishan Zaoxia at 45 days after full bloom (DAFB) was obviously higher than the contents of other components and the esters in Liaofu, which implied the starting of ester synthesis in Taishan Zaoxia was earlier. However, the stage of alcohol synthesis largely in Liaofu was from 45 to 60 DAFB, earlier than the stage from 60 to 75 DAFB in Taishan Zaoxia, which indicated the difference between apple cultivars.