Assessors were selected and trained following international
standards (ISO, 2002). The panel had prior experience in descriptive
analysis of orange juices and had undergone specific training
in juice off-flavours (Ruiz Perez-Cacho, Mahattanatawee, Smoot,
& Rouseff, 2007). Firstly, guaiacol odour recognition tests were
carried out in water. Panelists were specifically asked to describe
the odour perceived and to memorise the perception. Next, orange
juice was spiked with 100 lg/l guaiacol. Assessors were asked to
smell the samples to get familiarised with the odour in the orange
matrix. Olfactory training sessions were repeated several times
until the guaiacol odour was memorised. Finally, three triangle
tests were performed as a training exercise.