P-13
Characterization of retronasal aroma in beer
Presenter: Akira Wanikawa, Asahi Breweries Ltd., Moriya, Ibaraki, Japan
Co-Authors: Kazutaka Ozaki, Minoru Kobayashi, and Hiroshi Yamashita, Asahi Breweries Ltd., Moriya, Ibaraki, Japan

Beer aroma, as well as other aromas of food origin in general, is detected and recognized by olfactory organs through orthonasal and retronasal routes. It has been reported that retronasal aroma, comprised of volatiles occurring inside the oral cavity, plays a more predominant role in flavor recognition than orthonasal aroma, which is detected by inhalation through the nasal cavity. Recently, a retronasal aroma simulator (RAS) has been developed and utilized to characterize various aroma types perceived by food ingestion. In this study, the application of RAS to beer aroma analysis was evaluated. For this purpose, the optimal sampling parameters, including collecting device, sample temperature, sampling time, and recovery rate of volatiles, were investigated to simulate the actual situation for beer drinking. Under the optimal conditions, the beer aroma analysis based on RAS was validated and found to be highly precise. Subsequently, volatile compounds obtained from 10 samples of beers and low-malt beers categorized as 'Happoshu' were analyzed, using GC/MS and GC/O with the established experimental conditions. As a result, the RAS technique identified fruity note, characteristic of esters, and floral notes as key components among the volatile compounds found in beer. Furthermore, sensory evaluation of the identical beer samples was conducted using the quantitative descriptive method. The comparative study demonstrated that several key components identified by RAS correlated well with flavor scores obtained from sensory analysis.

Akira Wanikawa received a B.S. in agricultural chemistry from Hokkaido University in Japan. He joined The Nikka Whisky Distilling in April 1987 in a cider plant, Hirosaki Plant. He was transferred to R&D Institute in 1992, and then to Brewing R&D Laboratory of Asahi Brewery, a same group company, in April 2001. He earned a Ph.D in agricultural chemistry from Hokkaido University in 2002 with work on sweet and fatty flavor compounds in malt whisky and their pathway. He received the Technical Award from the Brewing Society of Japan in 2004 for work entitled "A study on the influence of lactic acid bacteria affected to the characteristic quality of whisky." His current work is research on several flavor compounds of alcoholic beverages.