P-07 - Exploration of Fruity Aroma Compounds in Japanese Hops "MURAKAMI SEVEN"

Wednesday, August 13, 2025

4:30pm - 5:15pm PDT

Location: Sinatra Ballroom Foyer

Presenting Author(s)

ET

Emiko Tanaka (she/her/hers)

Institute for Future Beverages, Research & Development Division, KIRIN Holdings Company, Limited
Fujisawa, Kanagawa, JAPAN

Co-Author(s)

TT

Taeko Tsukahara

Researcher
Institute for Future Beverages, Research & Development Division, KIRIN Holdings Company, Limited, United States
TS

Tetsu Sugimura

Research Manager
Institute for Future Beverages, Research & Development Division, KIRIN Holdings Company, Limited, United States
KS

Kanako Sasaki

Research Manager
Institute for Future Beverages, Research & Development Division, KIRIN Holdings Company, Limited, United States

Abstract: Background and

Objective: Hops are a crucial raw material that gives beer its bitterness and aroma, and the aroma characteristics vary significantly depending on the hop variety. Beers brewed using Murakami Seven, a Japanese hop variety developed by Kirin, have a unique aroma that has been described as resembling Unshu mikan (mandarin orange) or fig, but the contributing components have not been identified. This study aimed to identify the components that contribute to this characteristic aroma.

Methods: Murakami Seven and three other hop varieties (Hersbrucker, Cascade, and Kirin No. 2) were added to cold wort at the start of fermentation to a final concentration of 4 g/L, and beer samples of each variety were brewed using bottom fermentation (200 L scale). Using gas chromatography-olfactometry for sniffing and gas chromatography–mass spectrometry (GC-MS) for differential analysis, candidate components contributing to the characteristic fruity aroma described as mandarin orange-like and fig-like were selected. A quantitative analysis method for these candidate components was established using GC-MS, and their concentrations in the beer samples were evaluated. Sensory evaluation was also conducted using the GC-MS Aroma Designer developed by Shimadzu Corporation. This system prepared bags that collected all volatile compounds from beer samples using Murakami Seven and bags that excluded the candidate components of the characteristic aroma, followed by sensory evaluation. Furthermore, we harvested the Murakami Seven cones at six different time points during their maturation period and conducted small-scale fermentation tests to investigate changes in the content of the aroma components.

Results: By comparing Murakami Seven with other hop varieties, we identified four key components (2-decanone, 2-nonanol, 2-undecanone, and methyl geranate) that contribute to Murakami Seven's characteristic aroma. The beer sample using Murakami Seven contained 11.0 μg/L of 2-decanone, 24.6 μg/L of 2-nonanol, 21.4 μg/L of 2-undecanone, and 40.7 μg/L of methyl geranate. The sensory evaluation using the GC-MS Aroma Designer indicated that the score for fruity tended to decrease in the bags that collected the aroma components excluding the four key components compared to those that collected all aroma components. Investigation of the harvest timing showed that the content of all four key components tended to increase as the hop cones matured. The present study identified key components for fruity aroma of hops, which will be valuable for breeding diverse hop varieties and using such new varieties in brewing.