O-24
Identification of astringent substances in beer
Presenter: Norihiko Kageyama, Suntory Ltd, Osaka, Japan
Co-Authors: Takako Inui, Suntory Ltd, Osaka, Japan; Hajime Komura, Suntory Institute for Bioorganic Research, Osaka, Japan; and Koichi Nakahara and Nobuyuki Fukui, Suntory Ltd, Osaka, Japan

The acrospire is a tissue of the seedling of germinating barley. At the 116th convention of MBAA in 2003, we presented that the malt acrospire contained an astringent ingredient that aggravated aftertaste and that this astringent substance was extracted from the malt acrospire, isolated, and identified by using two-dimensional HPLC. In this presentation, astringent fractions were extracted and isolated from malt acrospires and finally fractionated into three fractions responsible for astringent taste in beer. After purifications of each fractions by HPLC, the structures of astringent substances were determined mainly based on NMR and mass spectral data. It was shown that all astringent substances were the glycosides of a series of Hordatines generally known anti-fungal substance. As the result of our studies, the contents of these astringent substances had correlation with astringency of beer, and the quality of beer could be improved by reducing these astringent substances.

Norihiko Kageyama received his M.S. degree in chemistry from Osaka University in 1998. He joined the Institute for Fundamental Research, Suntory, Ltd., in April 1998 as a chemist for researching natural products. He has been belonging to Process Development Department, and developing beer and material processing technologies, since October 2002. He was a winner of JB Award, for his excellent article published in the Journal of Biochemistry by The Japanese Biochemical Society, in October 2000. He received The SCEJ Technology Award from The Society of Chemical Engineers, Japan, in March 2005.