Effect of Smelling Green Tea Rich in Aroma Components on EEG Activity and Memory Task Performance

In this study, we investigated the memory task performance and the central nervous activity after smelling two kinds of pan-fired Japanese green tea to examine the differences of their physical and psychological effects. Twenty eight subjects (14 male and 14 female) participated in this study. We used Koushun and Kouju for test samples, which were made by different manufacturing processes. After smelling each odor sample, a memory task and an arithmetic task were used to test mental stress. Electroencephalogram (EEG) was recorded before and after smelling the test samples, and EEG activity was estimated for 4 frequency bands (alpha 1, alpha 2, beta 1 and beta 2). The profiles of mood states (POMS) and the visual analog scale (VAS) after mental stress task were completed for subjective assessments. The results showed that the odor of Kouju may induce a positive emotion such as a more familiar and a less hate feeling. It may also affect the EEG band power of beta 1 at right frontal region and improve memory task performance as well.