Analysis of the Flavor Code of Newly Cultivated Excellent Apple Varieties in China Using the Sensomics

"Rui Yang", "Rui Xue", and "Rui Xiang Hong" are newly cultivated apple varieties with excellent flavor. However, the key aroma-active compounds responsible for its excellent flavor quality were unclear. This study determined the characteristics of aroma compounds among three new apple varieties and their parental species by Sensomics. A total of 150 aroma compounds were detected by GC × GC-QTOFMS. Gas chromatography-olfactometry and odor activity values indicated that 23 aroma-active compounds were the major aroma contributors in different apple varieties. Principal component analysis and orthogonal partial least-squares-discriminant analysis results showed significant differences in aroma compounds between the new apple varieties and their parents, and hexanol, hexanal, (E)-2-hexenal, 2-methylbutyl acetate, hexyl acetate, and ethyl butyrate were identified as differential aroma compounds. The apple aroma recombination model could well restore the real aroma characteristics, which confirmed the accuracy of the identification and quantification of the aroma-active compounds. Omission experiments verified that ethyl butyrate, isopropyl butyrate, 2-methylbutyl acetate, hexyl acetate, linalool, hexanal, (E)-2-hexenal, (E,E)-2,4-nonadienal, 1-octen-3-one, β-damascenone, and geranylacetone were the key aroma-active compounds in the three apple varieties. This provides valuable information about aroma compounds for the cultivation of excellent apples.