Blueberries are originated from Canada and Northern United States. The predominant cultivated species are Vaccinium corymbosum (Northern and Southern Highbush), Vaccinium ashei (Southern Rabbiteye ), and Vaccinium angustifolium (Lowbush or also called "Wild blueberries"). Northern Highbush blueberry is the most planted worldwide. Plant breeders have developed and enhanced the consumer’s favorable features of various cultivars of highbush blueberries through natural selection and breeding programs. Although sugars and acids are important flavor attributes and can be modified through breeding, forecasting volatile aroma is more challenging and rewarding. The impact of aroma on fruit quality stimulates the need better to understand the complexity of blueberry volatile organic compounds. Aroma-active compounds in blueberry were identified using gas chromatography-olfactometry and mass spectrometry (GC/O-MS). It was found ethyl 2/3-methylbutanoate, (Z)-3-hexenal, 1-octen-3-one, (E)-3-hexenol, linalool, (E,Z)-2,6-nonadienal, 2-methylbutanoic acid, (E,E)-2,4-nonadienal, β-damascenone, geraniol, and vanillin. The volatile composition of 11 blueberry cultivars and developing varieties were further studied, including the chiral enantiomer distribution. Heatmap with hierarchical clustering dendrogram elucidated the three varieties ORUS 235-4, ORUS 235-3, and ORUS-10-1 were close together with a high level of branch-chain esters and, in turn, close to ‘Draper’ and ‘Duke’. However, they differed from the other cultivars, including ’Aurora’, ‘Bluecrop’, ‘Elliott’, ‘Legacy’, ‘Liberty,’ and ORUS-202-2. One-way ANOVA analysis demonstrated terpenoids varied most among cultivars. Also, the Pearson correlation showed terpenoids, except eucalyptol, exhibited a strong positive correlation, especially between linalool and α-terpineol. Enantiomer analysis revealed S-(+)-linalool was dominant in blueberry, whereas the S-(−)-α-terpineol was slightly elevated than R-(+)-α-terpineol. This study provided a detailed volatile composition database for unraveling the complex genetics of the various blueberry flavor aspects to assist the breeding purposes of new blueberry crops.

Qin Zhou

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