• 미생물학회지
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• 제54권4호
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• pp.379-383
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• 2018

맥주는 가장 대중적인 알코올 발효주이지만 퓨린(purine) 함량이 높아 고요산혈증 및 통풍 발생과 연관이 있다고 알려져 있다. 본 연구에서는 맥주 발효 온도를 달리함으로써 맥주의 퓨린 함량을 낮출 수 있는지 알아보았다. 맥주 제조의 주된 발효법인 상면 발효와 하면 발효에서 주로 사용되는 $20^{\circ}C$와 $10^{\circ}C$ 온도에서 맥주를 발효한 후, 각각에서 대표적 퓨린 화합물인 adenine, guanine 그리고 xanthine들의 함량을 high performance liquid chromatography 방법으로 측정하였다. 그 결과, $10^{\circ}C$ 발효 맥주가 $20^{\circ}C$ 발효 맥주에 비해 총 퓨린 함량이 낮았으며, 특히 adenine의 함량이 의미있게 낮아져 있음을 확인하였다.

• Korean Chemical Engineering Research
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• 제44권1호
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• pp.52-57
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• 2006

에탄올과 함께 탄소, 질소원을 함유한 맥주 폐 발효액을 저렴한 대체배지로 사용하고 Gluconacetobacter hansenii PJK(KCTC 10505 BP) 균주를 이용하여 미생물셀룰로오스를 생산하였다. 맥주 폐 발효액은 기본배지보다도 탄소원과 질소원이 풍부하였으며 미량의 황과 4％ 이상의 에탄올을 함유하였다. 진탕배양에서 맥주 폐 발효액을 사용하여 생산된 셀룰로오스량은 기본배지를 사용하여 생산된 셀룰로오스량과 필적하였다. 교반배양에서는 셀룰로오스 생산균주($Cel^+$ 균주)가 셀룰로오스를 생산하지 못하는 균주($Cel^-$ 돌연변이주)로 전환되는 률은 낮았지만 셀룰로오스 생산량은 감소하였다.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.297-304
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• 2007

The effect of yeast propagated at different aeration conditions on yeast physiology, fermentation ability, and beer quality was investigated using three strains of Saccharomyces cerevisiae. It was shown that yeast cells grown under continuous aeration conditions during propagation were almost two times higher as compared with discontinuous aeration conditions. The maximum of cell growth of all samples reached between 36 hand 48 h. The concentration of trehalose was increased under continuous aerated yeasts, whereas glycogen was decreased. It was also observed that the concentration of glycogen and trehalose in yeast cells had no direct effect on subsequent fermentation ability. The effect of yeast propagated under different aeration conditions on subsequent fermentation ability was different from yeast strains, in which the influence will be most pronounced at the first fermentation. Later, the yeasts might regain its original characteristics in the following fermentations. Generally, continuously propagated yeast had a positive effect on beer quality in subsequent fermentation. Hence, the concentration of aroma compounds obtained with yeast propagated under 6 1/h for 48 h aeration was lower than those grown under other aeration conditions in the bottom yeasts; in particular, the amounts of phenylethyl alcohol, ester, and fatty acids were decreased.

• 한국미생물·생명공학회지
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• 제3권1호
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• pp.31-34
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• 1975

종내의 맥주발효에 따른 제반조건을 가능한 한 그대로 유지하면서 율이 높은 발효법을 몇가지 설계해 보았다. 발효개시후 3일만에 발효액의 $\frac{1}{2}$또는 $\frac{1}{3}$양을 새로운 맥즙으로 대치한 다음 5일또는 4일로써 발효를 완성시키므로써 재내의 9일 간전분양효에 비하여 약 20 내지 30%의 율상승이 이론적으로 가능하다.

• 대한가정학회지
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• 제46권3호
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• pp.49-55
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• 2008

The purpose of this study was to investigate the effects of green tea extracts (GTE) on the fermentation properties of polyphenol-enriched beers. As such, the formation patterns of tannoid in beer with GTE were investigated at 3 different infusion times, while the ale and the lager beers fortified with GTE were analyze to ascertain effects on gravity, pH, yeast viability, total polyphenol, and tannoid during fermentation period. The results were as follows: 1) The formation of tannoid in beer with GTE in the tannometer; In reaction of GTE with polyvinylpyrrolidon (PVP), control lager beer peaked in the formation of tannoid at $70\;{\sim}\;80\;mg$ of PVP, the 1st extract exceeded the detection limit, the 2nd extract at $170\;{\sim}\;180\;mg$, while the third extract at $150\;{\sim}\;160\;mg$ of PVP. The GTE were slow in reacting with PVP, and their formation patterns were different from those of polyphenols from barley and hop. 2) Ale fermentation; The final alcohol content was 9.25% (ABV). The addition of GTE increased the yeast viability after 2 days and finally reached 52.3% from 30.9%. Total polyphenol in GTE beer increased by 1.5 times (p < .05). However, its tannoid contents increased by 6.4 times. 3) Lager fermentation; The final alcohol content was 5.93% (ABV). The effect of GTE on lager beer was minimal for all variables. However, total polyphenol of GTE beer increased by 1.4 times (p < .05). Its tannoid increased by 3.3 times (p < .05).

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1539-1545
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• 2010

In beer, glutathione works as the main antioxidant compound, which also correlates with the stability of the beer flavor. In addition, high residual sugars in beer contribute to major nonvolatile components, which are reflected in a high caloric content. Therefore, in this study, the Saccharomyces cerevisiae GSH1 gene encoding glutamylcysteine synthetase and the Saccharomycopsis fibuligera ALP1 gene encoding ${\alpha}$-amylase were coexpressed in industrial brewing yeast strain Y31 targeting the ${\alpha}$-acetolactate synthase (AHAS) gene (ILV2) and alcohol dehydrogenase gene (ADH2), resulting in the new recombinant strain TY3. The glutathione content in the fermentation broth of TY3 increased to 43.83 mg/l as compared with 33.34 mg/l in the fermentation broth of Y31. The recombinant strain showed a high ${\alpha}$-amylase activity and utilized more than 46% of the starch as the sole carbon source after 5 days. European Brewery Convention tube fermentation tests comparing the fermentation broths of TY3 and Y31 showed that the flavor stability index for TY3 was 1.3-fold higher, whereas its residual sugar concentration was 76.8% lower. Owing to the interruption of the ILV2 gene and ADH2 gene, the contents of diacetyl and acetaldehyde as off-flavor compounds were reduced by 56.93% and 31.25%, respectively, when compared with the contents in the Y31 fermentation broth. In addition, since no drug-resistant genes were introduced to the new recombinant strain, it should be more suitable for use in the beer industry, owing to its better flavor stability and other beneficial characteristics.

• Food Science and Biotechnology
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• 제17권4호
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• pp.739-744
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• 2008

The method of yeast propagation has an influence on yeast physiology, fermentation ability, flocculation rate, and taste stability of beer. In order to find optimal conditions for propagation, several parameters were investigated in combinations. The bottom brewing yeast grown at $10^{\circ}C$ indicated that a higher flocculation capacity during the $1^{st}$ fermentation. However, the taste stability and the aroma profile were not affected by parameters of propagation investigated. The beer quality was rather affected by storage duration. In addition, a correlation between tasting and chemiluminescence was found at the beer, which was produced using bottom brewing yeast. The propagation at $10-25^{\circ}C$ with addition of zinc ion indicated the best condition to improve fermentation ability, flocculation rate, and filterability for bottom brewing yeast, whereas the propagation at $30^{\circ}C$ with addition of zinc ion showed the best condition to increase fermentation ability for top brewing yeasts.

• 한국미생물·생명공학회지
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• 제3권2호
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• pp.89-93
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• 1975

재내식 발효법에 협사한 조건하에서 맥주를 더욱 방률적으로 생산하기 위하여 발효개시 3일후에 일정양의 새로운 맥즙을 첨가시키고 나머지 발효를 4일내지 6일사이에 완성시켜 보았다. 그 결과 1/3 용량과 $\frac{1}{2}$ 용량의 새로운 맥즙을 체가하고 5일동안 더 발효한 맥주가 미각검사에 합격되므로써 종내외 9일간 발효에 비하여 각각 22%내지 28%의 방율증가가 可能하게 되었다.

• Korean Chemical Engineering Research
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• 제51권6호
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• pp.709-715
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• 2013

맥주 폐 효모액(waste from beer fermentation broth, WBFB)은 바이오 에탄올 생산을 위한 우수하고 저렴한 원료이다. 본 연구에서는 바이오 에탄올 생산을 위해 WBFB의 당화능과 발효능을 확인하는 실험을 진행하였다. 당화능은 온도를 30, 40, 50, 60, $70^{\circ}C$로 다르게 하여 실험했는데 온도가 올라감에 따라 당화능은 증가하였고 4시간 후 $60^{\circ}C$와 $70^{\circ}C$에서 많은 양의 glucose가 생산되었다. WBFB와 chemically defined media (CDM) 혼합물에서는 어떠한 미생물의 첨가 없이도 발효가 되어 에탄올이 생산되었다. 동시당화발효능을 30, 40, 50, $60^{\circ}C$의 다양한 온도에서 실험해본 결과 $30^{\circ}C$에서 에탄올이 가장 많이 생산되었다. 또 이 실험은 WBFB, starch 용액 그리고 CDM을 이용하여 수행하였는데 WBFB에 있는 당화 효소와 효모가 어떠한 추가적 미생물 첨가 없이 당화와 발효를 가능케 하는 요인이었다.

• Journal of Applied Biological Chemistry
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• 제63권3호
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• pp.229-234
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• 2020

Beer production with rice or other malt substitutes suffers from a lack of suitable enzymes for saccharification. For this reason, rice nuruk (fermentation starter) was tested as a starch replacement for malt in the saccharification process of beer production. The results of this study show that the enzyme activities of rice nuruk made with brewing fungi were higher than those of malt. Saccharification and glucoamylase activities were high in Aspergillus awamori KCCM 30790 and α-amylase activity was high in Aspergillus oryzae CF1003. Overall, malt beer had significantly higher alcohol, pH, total acid, volatile acids, amino acids, free amino nitrogen, bitterness unit and ΔE than rice nuruk beer. Where as Aspergillus awamori KCCM 30790 beer had significantly higher soluble solids, reducing sugar than malt beer. According to a sensory evaluation, malt beer was better color, flavor and Aspergillus oryzae CF1003 beer was better taste, texture, overall acceptability than other beer. Therefore Aspergillus awamori KCCM 30790 beer was suitable considering enzyme activities (saccharification, glucoalmylase) and physicochemical characteristics (soluble solids, reducing sugar). And then Aspergillus oryzae CF1003 beer was suitable considering sensory evaluation (taste, texture, overall acceptability). Therefore rice nuruk like Aspergillus awamori KCCM 30790 and Aspergillus oryzae CF1003 were suitable as a substitute material that can replace for malt in beer proceccing.