Agronomijas v stis - Latvijas Lauksaimniecības universitāte

carrier gas was helium, the GC temperature program was held isothermically at 40°C for 1 min(splitless injection mode), ramped from 40° to 220 °C at a rate of 4.5 °C min, and finally held at220 °C for 4 min (analysis time: 45 min). The MS source was adjusted to 220 °C and a mass rangeof m/z 40 – 300 was recorded. Compounds were tentatively identified based on mass spectraldatabase search using the NIST05 MS Database, a customized in-house fruit flavour MS database,and retention indices from literature.Statistic Analysis. GC/MS data (TIC) were analysed using AMDIS deconvolution software (v.2.64). The raw data sets of 32 samples were aligned using the on-line service ‘SpectConnect’ atMassachusetts Institute of Technology (MIT, 2009). Chemometric Principal Component Analysis(PCA) was carried out with the statistical software Minitab (v. 15.1.30).Results and DiscussionThe application of HS-SPME coupled with GC/MS revealed 132 volatile aroma compounds in 32different samples of blueberries harvested at different loactions in Norway. A total of 99compounds could be tentatively identified using mass spectral database search. The most abundantcompounds were related to the group of C 6 -structures or so-called ‘green leaf volatiles’ (Figure 1).In addition, impact-aroma compounds belonging to the chemical group of monoterpenes, couldalso be extracted from all samples, e.g. 1,8-cineole, linalool, and linalyl acetate.Figure 1. GC/MS chromatogram of a headspace-SPME profile of blueberry aroma volatiles.Important compounds such as C 6 -structures or ‘green leaf volatiles’ (hexyl- and hexenyl-derivatives),terpenes (1,8-cineole, linalool) and aldehydes (nonanal, decanal) are indicated in the figure.Based on chemometric PCA of all data sets from GC/MS analyses, blueberry samples could begrouped into different clusters depending on from which location the blueberries were harvested(Figure 2). Samples from South Norway clustered in an own group, while the samples from MidandNorth-Norway were overlapping. Regarding differences in the maturation stage, not-fullyripened blueberries were clearly separated from fully-ripened fruits, thus indicating significantdifferences in their aroma profiles.100