2013 Volume 12 Issue 2 Pages 37-43
The purpose of this study was to investigate the electroencephalographic activity after smelling two kinds of green tea and to examine any anti-stress effects of smelling green tea. Ten subjects (6 male and 4 female) participated in this study. We used two kinds of green tea, Sagara and Shaded White Tea, which were made from the same kind of tea leaf but by different manufacturing processes. We used an arithmetic task and an auditory discrimination task to test mental stress. An electroencephalogram (EEG) was recorded before and after smelling the tea samples and before and after performing the mental tasks. Subjective ratings about mental status were obtained with the profiles of mood states (POMS) and the visual analog scale (VAS) at the end of each task. EEG was recorded from 4 scalp positions of the international 10/20 system (F3, F4, O1 and O2), and EEG activity was estimated for 4 frequency bands (alpha1, alpha2, beta1 and beta2). The results showed that the subjective rating about relaxed feeling increased and electroencephalographic activities changed after smelling green tea, especially Shaded White Tea, suggesting that smelling green tea may have anti-stress effects.