Characteristic Aromas of Quercus crispula (Japanese Oak)

Abstract

Nature is important in Japanese culture. Many tree species produce diverse fragrances, making Japan's forests a botanical treasure. However, there have been no detailed investigations of the aroma characteristics of trees, a vital factor in forest bathing. Previously, we applied our analytical method to three tree species found mainly in Japan: Chamaecyparis pisifera, Lindera praecox, and Lindera obtusiloba Blume. In this paper, we report investigations of the aroma of Quercus crispula Blume (Japanese oak) using this analysis method. Japanese oak grows mainly in Japan. The odor compounds of Japanese oak were obtained by hexane extraction and monolithic material sorptive extraction and each extracted compound was identified by gas chromatography olfactometry and gas chromatography-mass spectrometry. Comparison of the aromas and compounds in the extracts resulted in the identification of important aroma compounds in Japanese oak: 10 (including eugenol) in the leaves and 15 (including 3-methyl-4-octanolide) in the wood.