Hops Session
Kiyoshi Takoi, SAPPORO BREWERIES LTD, 10 Okatohme, Yaizu, Shizuoka, 425-0013 Japan
Co-author(s): Yutaka Itoga, Sapporo Breweries Ltd., Sorachi-Gun,
Japan; Junji Takayanagi, Takayuki Kosugi, Toru Shioi, and Junji Watari,
Sapporo Breweries Ltd., Yaizu, Japan
ABSTRACT: In a previous study, we focused on
biotransformation of hop-derived monoterpene alcohols (linalool,
geraniol, beta-citronellol, nerol, and alpha-terpineol) and their
contribution to the flavor of hopped beer. As a result, beta-citronellol
was almost absent in hop and wort and gently increased during
fermentation, because of the biotransformation from geraniol to
beta-citronellol by brewing yeast. The concentrations of geraniol and
beta-citronellol in finished beer could be enriched depending on the
initial geraniol content in the wort by using a geraniol-rich hop. As a
result of sensory evaluation, we found that there was an additive effect
among linalool, geraniol, and beta-citronellol and that the flavor
impression became lime-like by coexistence of these three monoterpene
alcohols. Therefore, we proposed that geraniol metabolism by brewing
yeasts contributes part of the hop-derived citrus flavor in beer. In
this study, we compared the compositions of monoterpene alcohols in
various hops and found several geraniol-rich hops in U.S. hop varieties.
Such compositions were almost not observed in European traditional
aroma hops. We suggest that a geraniol-rich profile is one of the
important characters in U.S. hops. In addition, we discuss the behavior
of geraniol and beta-citronellol under various hopping conditions and
other factors influencing the citrus flavor of hopped beer.
Kiyoshi
Takoi graduated from Tohoku University with an M.S. degree in
agricultural chemistry in 1989 and joined the Brewing Research
Laboratories of Sapporo Breweries, Ltd. as a biochemist. From 1989 to
2002, he worked on brewing chemistry and mainly investigated beer foam
stability. During 2002–2005, he evaluated the brewing properties of
malts and hops using the pilot malting and brewing plants in the
Production & Technology Development Center. In 2006, he managed
product development in the New Product Development Center. During
2007–2008, he worked in the Frontier Laboratories of Value Creation as a
lead research brewer and mainly investigated hop-derived flavor
compounds. At present, he belongs to the Value Creation Department of
Sapporo and develops new products. He received a Ph.D. degree in
agricultural chemistry from Tohoku University in 2011.
VIEW PRESENTATION 143