Optimization of Strawberry Volatile Sampling by Direct Gas Chromatography Olfactometry
Résumé
The aim of this work was to determine the most suitable sampling headspace technique for the study of strawberry (Fragaria ×ananassa Duch.) fruit aroma. The aromatic qualities of different headspace extracts of strawberry (‘Festival’) puree were evaluated using direct gas chromatography-olfactometry (D-GC-O), a technique that allows assessing global odor from solvent-free extracts without chromatographic separation. Two solid phase microextraction (SPME) extracts, with different types of fibers, polydimethylsiloxane/divinylbenzene (PDMS/DVB) and divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), and two static headspace extracts, with different phase ratios (ratio of gas to sample phase volumes), were evaluated using D-GC-O. A similarity test with three panelists allowed comparison of the odor of these extracts to that of strawberry puree. The results indicated that SPME using a DVB/CAR/PDMS fiber generated the most representative odor, a “green” impression and a strong “fruity” note. A fruity note was also obtained with the 10-mL static headspace extracts, which exhibited a volatile concentration that was higher than that in the 20-mL headspace. When comparing the aroma profile of each extract, the DVB/CAR/PDMS extract showed the highest concentration of methyl butanoate and ethyl butanoate, two key compounds in strawberry aroma