2.5. Sensory evaluation
Sensory experiments were performed at room temperature in a sensory room with single cubicles.
The sensory evaluation of phenethyl esters was done by a panel of five well-trained flavourists
(four females and one male) experienced in aroma evaluation from Firmenich Asia (Singapore).
The compound concentrations were diluted to 20,000 ppm with deionised water. Blank samples containing de-ionised water were also provided for each tested compound.Each 20-mL screw-capped test tube was filled with 8 mL sample and was allowed to equilibrate for 24 h before testing.
Each test tube was coded and presented to the panels with the blank in a randomised order and done in triplicate. The panels individually evaluated the odour by sniffing the sample at room temperature.For the description of the perceived odour, the use of multiple odour attributes was allowed. The odour qualities assigned were collected, and the number of the same answers was listed.
However,there was no overall agreement on one odour quality for all compounds, but multiple attributes were given for some odorants instead. Following this protocol, the odour qualities of the remaining 2-phenethyl esters were determined in triplicate.