AbstractmOver a period of 3 years, the essential volatile compounds of several strawberry varieties were analysed by gas chromatography, gas chromatography-olfactometry and mass spectrometry. In general, a strong variability in the dependence of the amount of these compounds on the ripening stage, climate and location was found, nevertheless, the key compounds of the aroma showed typical, genetically determined basic patterns. The quantification of the key aroma compounds in cultivated and wild strawberries resulted in a definition of aroma types which corresponded with the sensory evaluation. These aroma types can be used to establish a criterion for the selection of quality in strawberry breeding.

Plant breeders are interested in strawberry species as donors of volatile compounds in breeding programmes because of the diversity and intensity of wild strawberry aroma. Therefore, the topic of this paper is the prospective analysis of four accessions of four wild strawberry accessions in comparison to a standard cultivar of Fragaria · ananassa Duch. by using human sensory, gas chromatography mass spectrometry (GCMS) and gas chromatographyolfactometry (GCO). The wild species have higher aroma intensities compared with the cultivated one. The flavour quality differs significantly. Semiquantitative GC analysis revealed that F. · ananassa cv. 'Elsanta' has the lowest content of volatile compounds whereas Fragaria moschata L. 'Cotta' has the highest. The aroma impressions, measured by GCO, support the findings of GCMS analyses. The nasal impact frequency (NIF)-profiles of the wild types are more manifold and of higher intensities than those of the cultivated F. · ananassa cv. 'Elsanta' which corresponds with the overall flavour impression when tasting the fresh fruits.

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The suitability of the headspace solid phase microextraction (HSSPME) for gas chromatography-olfactometry (GC-O) with aroma extract dilution analysis in comparison to the dynamic head space sampling on a Tenax trap was tested exemplarily by the aroma volatiles of fresh broccoli. A high number of odour sensations in qualitative olfactometry was registered with both sample preparation techniques. The key aroma compounds of the fresh broccoli material are represented by high flavour dilution factors with dynamic head space sampling and headspace SPME. The SPME method has found to be a convenient and fast technique suitable especially for qualitative GC-O. The adsorption selectivity of the fiber and the substance discrimination have to be taken into account for quantitative use like aroma extract dilution analysis.

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