Masaru Kato (1), Yuko Fukushima (2), Takeo Imai (1), Toshihiro Kamada (1), Mayura Mochizuki (1), Toshinori Sasaki (2); (1) Research Laboratories for Alcoholic Beverage Technologies, Kirin Co., Ltd., Yokohama, Japan; (2) Central Laboratories for Key Technologies, Kirin Co., Ltd., Japan

Technical Session 16: Barley & Malt II
Tuesday, August 16  •  2:00–3:15 p.m.
Plaza Building, Concourse Level, Governor’s Square 14

Low and high molecular weight (HMW) maltodextrins contribute to the body and mouthfeel of beer (Gastl et al. 2013, EBC). However, no reports have demonstrated causality between beer taste and HMW proteins or polypeptides. In the present study, we examined the influence of HMW proteins and polypeptides on beer taste. Beer and happoshu samples were fractionated by preparative size-exclusion chromatography, and protein, polypeptide and maltodextrin fractions were purified by solid-phase extraction and ion-exchange resin columns. The purified fractions were added to happoshu, which consisted of 49% malt and 51% barley, increasing each original fraction by 20~50%, and sensory evaluations were then performed. The results of the analysis indicated that the maltodextrin fraction (DP=2~10) increased the palate fullness, whereas the smoothness was improved and the astringency was decreased by the HMW protein fraction (10~20 kDa). In addition, the body and umami taste were increased by the low molecular weight polypeptide fraction (2~3 kDa). By performing two-dimensional gel electrophoresis and protein identification by LC-MS/MS, the HMW protein fraction was found to contain several unique proteins, which were reported as a candidates of foam protein (Iimure et. al., 2015, EBC), including barley dimeric alpha-amylase inhibitor-1 (BDAI-1) and non-specific lipid-transfer protein 1 (LTP1). Taken together, these results demonstrate that HMW proteins and polypeptides contribute to beer taste.

Masaru Kato received an M.A. degree in agricultural chemistry from Tokyo University of Agriculture and Technology in Fuchu, Tokyo. He began employment with Kirin Brewery Company, Ltd. in March 1990 as a researcher in enzymology in the Applied Bioresearch Center. He also received a Ph.D. degree from Tokyo University of Agriculture and Technology in 2002. Since March 2005, he has been the manager of the Microbial Enzyme Group in the Central Laboratories for Key Technology, Kirin Brewery Company, Ltd. He has been working at Research Laboratories for Alcoholic Beverage Technologies, Kirin Company, Ltd. since 2010.