Chemical characterisation of two Australian-grown strawberry varieties by using comprehensive two-dimensional gas chromatography–mass spectrometry

The volatile compositions of two strawberry varieties (‘Albion’ and ‘Juliette’) grown in Australia were analysed with comprehensive two-dimensional gas chromatography (GC × GC) combined with time-of-flight mass spectrometry (ToFMS). A suitable data processing method was created that should be sufficiently robust to compare sample chromatograms within a harvest season as well as between seasons with relative ease. Ninety-four compounds were tentatively or positively identified between the two varieties of which 20 have apparently not been previously reported to be components of strawberry volatiles. It was determined that Albion and Juliette have comparable total soluble solids content close to 11 °Brix. However, since Juliette exhibited a lower titratable acidity content than Albion, it consequently has a slightly larger sugar/acid ratio. The presence of 2,5-dimethyl-4-hydroxy-(2H)-furan-3-one (furaneol) was detected only in Juliette and this variety also had a higher area percentage of 2,5-dimethyl-4-methoxy-(2H)-furan-3-one (mesifuran), according to the sampling protocol. These experimental results offer possible explanations as to why Juliette is perceived to have a sweeter flavour than Albion.