| Summary: | 碩士 === 大同大學 === 生物工程學系(所) === 94 === Sake is a traditional alcohol beverage of Japan produced from steamed rice by use of Aspergillus oryzae and Saccharomyces cerevisiae. Sake brewing process is a combination of saccharification and fermentation proceeded simultaneous. The polished rice, rice koji, yeast starter (called moto) and water were mixed to become mash (called moromi) at low temperature. The moromi is then pressed, filtered, and the sake was further pasteurized and aging. The alcohol content of sake can be as high as 20 % (v/v). Rice was the most important raw materials of sake. Rice was also the most popular crop in Taiwan. Sake brewing can increase the value of rice. This is one of the strategies to consume local rice production.
In this report, we present the processes of making high quality sake that include rice species selection, strain choosing and fermentation exploration. The flavors of sake included ethyl acetate, butyl acetate, ethyl lactate, isobutyric acetate, isoamyl acetate, ethyl alcohol, propyl alcohol, isobutyl alcohol, isoamyl alcohol, phenyl ethyl alcohol, etc. We found very similar flavor pattern in this study as comparing with those from several commercial Japanese sake. The alcohol concentration of sake of this study was 15 %. The flavor of ginjo-shu (isoamyl acetate) of sake for this study was 1.73 ppm. The sake from yeast (Kyokai No 6) was intensively fruity flavor (phenylethyl alcohol). The sake from yeast (Kyokai No 9) has apparent ginjo-shu flavor. The acidity of sake from polished rice was less than that of unpolished rice. The sake from unpolished rice has a ethyl octanoate flavor that was not found from commercial Japanese sake. The conclusion was to brew high quality sake must use polished rice and Kyokai No 9 yeast.
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