Evaluation of fruit aroma quality : comparison between gas chromatography-olfactometry (GC-O) and odour activity value (OAV) aroma patterns of strawberries

Gas chromatography-olfactometry (GC-O) is based on the use of human assessors as a sensitive and selective detector to ascertain odour-active volatile compounds in a sample extract, whereas odour intensity value (OAV) determination is widely used to obtain odour patterns starting from quantitative compositions. Whether there is an exact parallelism between odour patterns obtained from GC-O parameters and OAV is not yet well investigated. To this aim, the OAV and GC-O odour patterns of six strawberry genotypes were compared. Esters represented 97.9-99.8% of total volatiles, with methyl butanoate being the main Compound; dimethyl disulfide, dimethyl trisulfide, gamma-heptalactone and delta-decalactone were detected only by GC-O. OAV indicated that 25 volatiles out of 39 could actually contribute to the odour pattern, while the GC-O sensory panel perceived 30 odorous events. The major odour contributors in OAV and the maximum odour intensities of odour events in GC-O were genotype dependent. Comparing OAV with GC-O patterns, the spatial relationships in principal component analysis biplots were comparable: 'VR4' was opposed to 'Alba' and 'CS4', and 'Dora' to 'Darselect' and 'Eva'. GC-O and OAV resulted in comparable strawberry odour patterns, GC-O giving the most detailed qualitative and quantitative description. However, being GC-O, a time-consuming method, it should not be routinely used.