The effect of the aroma from soybeans after heating on EEG

Soybeans are often heated during food processing with a large number of products generated during this process. These individual components are believed to have various physiological activities. In this study, we investigated the effect of the aroma of soybeans heated to various temperatures on electroencephalography (EEG). We prepared slight, medium and deep heated soybeans, and in order to investigate the relationship of the amino-carbonyl reaction products upon EEG, we also prepared heated soybeans after immersion in distilled water or 0.2 M Fructose–Glycine solution. Fourteen healthy females (right-handed, 21–26 years old) participated in the study. We recorded EEGs from 19 electrode sites and calculated the power spectrum of the alpha activity using FFT analysis at each site. Results showed that the amount of alpha waves in the higher frequency range was greatest in the cases that had smelt medium heated soybeans. In addition, when soybeans were heated after immersion in Fructose–Glycine solution, the alpha waves increased, as compared with those that were immersed in distilled water. These results suggest the possibility that amino-carbonyl reaction aroma products increase brain alpha waves.