The essential oil of Ulva pertusa was prepared by a steam distillation under the reduced pressure. The characteristic aroma compounds were determined by a GC-sniff test and odor unit values. Seventeen compounds were picked up as the constituents of the characteristic aroma. Thirteen compounds selected as the model solution from the characteristic compounds (17 compounds) were mixed together on the basis of GC peak area. The odor was smelled like a seaweed aroma but not real aroma of Ulva pertusa. Frequency analysis of electroencephalogram (EEG) with the model solution was conducted and then expressed as the potential difference which occurred with the relating some events, P300 values (one of the event-related potential). From the retention time and amplitude of the P300 pulse, it was found that aroma of the model solution affected decreasing of the amplitude of the pulse. This means the aroma affects the decrease of mind concentration for some events. This physiological activity observed in the model solution was positively correlated with that of fraction 3 fractionated from the volatiles in Ulva pertusa.

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The filter-paper-disk method was employed for measuring the spacial taste thresholds. Sixty-nine healthy individuals (32 females, 37 males) aged 18-38 were studied. Taste substance same as those of the Taste Disk ^【○!R】 were sequentially diluted (13 stages from 80% for sucrose, 12 stages from 20% for NaCl, 12 stages from 8% for tartaric acid and 14 stages from 4% for HCl quinine). The sites measurd were a center of tongue-tip, a left-side foliate papillae, and a center of soft palate. Recognition thresholds were determined by ascending method of limits. The filter disk was 8mm in diameter. PC-SAS (Ver.6.04) was used for statistical analysis. The summarized results are : (1) No difference by sex was detected in sweet taste, but women were more sensitive to sour taste in the tongue-tip, and salty and bitter tastes in the soft palate. (2) No difference by site was noted for sweet, salty or bitter, but both sexes were less sensitive to sour taste in soft palate than tongue-tip, with men's soft palate even less sensitive than tongue-root. (3) Smoking had negative influence to threshold at soft palate either for women or men.

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