Evaluation of odorants contributing to 'Toyonoka' strawberry aroma in extracts using an adsorptive column and aroma dilution analysis

The volatiles of the 'Toyonoka' strawberry were extracted by using an adsorptive column (PQ) and evaluated by gas chromatography - olfactometry (GC - O) and aroma extract dilution analysis (AEDA). Although the overall odor of the extract was perceived as having a natural strawberry like smell, 52 odorants were detected by GC-O. Upon diluting the original extracts in AEDA, we identified 14 odorants with high dilution (FD) factors of 81 or higher. The odorant, 2, 5 -dimethyl-4-hydroxy-2H-furan-3-one, which has a caramel-like odor (sweet), had the highest FD factor, followed by gamma - dodecalactone, gamma - decalactone, and delta decalactone with coconut or peach-like odors (sweet), and hexanoic acid and 2 methylbutanoic acid with sour odors; all had FD factors higher than 81. The odorants with FD factor 81 were cis 3 hexenal, trans - 3 - hexenol, and cis-2-nonenal with a green odor, trans-nerolidol with a sweaty odor, delta - dodecalactone and vanillin with a sweet odor, linalool with a floral odor accompanied by a citrus like odor, and an unknown compound with a cinnamon-like odor. In addition to these 14 odorants, the fruity odorants included mainly ethyl 2-methylbutanoate, ethyl 3 methylbutanoate, and ethyl hexanoate, which show relatively high volatility. The above identifiable compounds are considered to be the main contributors to the aroma of the 'Toyonoka' strawberry.