18C-14 |
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Y.-R. KIM1, J.-Y. Lee2, S.-K. Lee2, and S.-K. Park2. (1) Research center, Ottogi corporation., Anyang-Si, 431-070, South Korea, (2) Dept. of Food Science and Biotechnology, Kyung Hee Univ., Yongin-Si, 449-701, South Korea Hops are important ingredients in brewing since they contribute both aroma and taste to the beer. Many investigators have attempted to determine hop-derived aroma compounds that may influence the aroma quality of beer. Among many aroma compounds in hops, volatile sulfur compounds (VSC) have received the most attention because VSC are detrimental to the quality of fresh beer. Of the VSC, hydrogen sulfide (H2S) has extremely low sensory threshold with a “rotten-egg” character and it is a predominant VSC produced by yeast during fermentation. In this study, the effects of hops on the production of H2S resulting from beer fermentation were studied. Five hop varieties with two yeast strains were investigated for their H2S production using laboratory scale fermentors. H2S was quantitatively measured by using a sulfide detecting tubes that can easily and conveniently measure H2S produced by yeast during fermentation. Except for one hop variety, the worts fermented in the absence of hops (the control) produced 11.1 µg H2S from a 1.3 L laboratory scale fermenter, whereas the worts fermented in presence of hops produced a large amount of H2S (32.4 µg to 75.3 µg) during fermentation. The levels of H2S production seems to be influenced by the levels of sulfur residue left on the hops and the methods of kilning the hops. These results indicated that the hops are important source of H2S production in brewing and the H2S production can be monitored and measured accurately by using the sulfide detecting tubes.
Session 18C, Food Chemistry: Food composition, analysis and volatiles
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |