• 한국식품영양학회지
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• 제27권5호
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• pp.971-978
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• 2014

Investigation of the quality characteristics of Takju brewing mashes prepared with several different yeasts was carried out during the 42-day brewing process, including examination of titratable acidity, amino acid content, sugar contents, alcohol contents, pH, reducing sugar, yeast population, lactic acid bacteria, and sensory evaluation. Fermivin yielded the highest titratable acidity, while la parisienne had the lowest. Fermivin also had the highest value of amino acid content (14.33%), while other yeasts shows period tended to increase over exclude Instaferm and Song chun. The amount of sugars in instaferm ($11.33^{\circ}Bx$) and instaferm red ($10.53^{\circ}Bx$) were higher than those in La parisienne red and Song chun ($9.57^{\circ}Bx$). The alcohol contents of instaferm was the highest value (15.20%) while the alchol content of the other yeasts tended to increase the fementation period. Fermivin had the highest pH at $12^{th}$ day among the yeasts(4.02), Instaferm red had the lowest pH among the yeasts (3.87) while safbrew wb-06 had the highest reducing sugar content(117.60 mg/mL). Instaferm obtained the highest preference in the sensory evaluation for all items.

• 미생물학회지
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• 제8권2호
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• pp.77-84
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• 1970

The author attempted the taxonomical studies on yeasts in Takju mash. The samples used for the isolation of yeasts were collected from Takju breweries in Seoul. The yeasts obtained from Takju were identified as follows using the methods of Lodder et al. ; Saccaromyces cerevisiae group II, Saccharmyces cerevisiae group III, other group of Saccharomyces cerevisiae, Hansenula anomala and Pichia polymorpha. Saccharomyces cerevisiae II & III and other group Saccharomyces cerevisiae which were considered as wild yeasts have shown their major role in the fermentation process of Takju brewing. It seems that Hansenula anomala has much connection with the flavour of Takju. Other strains which are poor in their acoholic fermentation and lower in activity of acid production are not considered to be important in Takju brewing.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.767-774
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• 2010

In this study, the problems of high caloric content, increased maturation time, and off-flavors in commercial beer manufacture arising from residual sugar, diacetyl, and acetaldehyde levels were addressed. A recombinant industrial brewing yeast strain (TQ1) was generated from T1 [Lipomyces starkeyi dextranase gene (LSD1) introduced, ${\alpha}$-acetohydroxyacid synthase gene (ILV2) disrupted] by introducing Saccharomyces cerevisiae glucoamylase (SGA1) and a strong promoter (PGK1), while disrupting the gene coding alcohol dehydrogenase (ADH2). The highest glucoamylase activity for TQ1 was 93.26 U/ml compared with host strain T1 (12.36 U/ml) and wild-type industrial yeast strain YSF5 (10.39 U/ml), respectively. European Brewery Convention (EBC) tube fermentation tests comparing the fermentation broths of TQ1 with T1 and YSF5 showed that the real extracts were reduced by 15.79% and 22.47%; the main residual maltotriose concentrations were reduced by 13.75% and 18.82%; the caloric contents were reduced by 27.18 and 35.39 calories per 12 oz. Owing to the disruption of the ADH2 gene in TQ1, the off-flavor acetaldehyde concentrations in the fermentation broth were 9.43% and 13.28%, respectively, lower than that of T1 and YSF5. No heterologous DNA sequences or drug resistance genes were introduced into TQ1. Hence, the gene manipulations in this work properly solved the addressed problems in commercial beer manufacture.

• Journal of Microbiology and Biotechnology
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• 제32권3호
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• pp.307-316
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• 2022

Yeasts play an important role in spontaneous fermentation of traditional alcoholic beverages. Our previous study revealed that a mixed-consortia of both Saccharomyces and non-Saccharomyces yeasts were responsible for fermentation of khadi, a popular, non-standardized traditional beverage with an immense potential for commercialization in Botswana. Functional characterization of isolated fermenting yeasts from mixed consortia is an indispensable step towards the selection of potential starter cultures for commercialization of khadi. In this study, we report the characterization of 13 khadi isolates for the presence of brewing-relevant phenotypes such as their fermentative capacity, ability to utilize a range of carbon sources and their ability to withstand brewing-associated stresses, as a principal step towards selection of starter cultures. Khadi isolates such as Saccharomyces cerevisiae, Saccharomycodes ludwigii and Candida ethanolica showed good brewing credentials but Lachancea fermentati emerged as the isolate with the best brewing attributes with a potential as a starter culture. However, we were then prompted to investigate the potential of L. fermentati to influence the fruity aromatic flavor, characteristic of khadi. The aroma components of 18 khadi samples were extracted using headspace solid phase micro-extraction (HS-SPME) and identified using a GC-MS. We detected esters as the majority of volatile compounds in khadi, typical of the aromatic signature of both khadi and L. fermentati associated fermentations. This work shows that L. fermentati has potential for commercial production of khadi.

• Applied Biological Chemistry
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• 제16권2호
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• pp.85-93
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• 1973

탁주료의 발효(醱酵)에 미치는 효모(酵母)의 종류(種類)와 담금조건(條件)의 영향을 검토(檢討)하여 다음의 결과(結果)를 얻었다. 1. 효모(酵母)의 종류(種類)와 료중의 효모수(酵母數) (1) 일단료를 $20^{\circ}C$에서 $1.5{\sim}2.5$일간(日間) 발효(醱酵)시키거나 $25^{\circ}C$와 $30^{\circ}C$에서 $1{\sim}2$일간(日間) 발효(醱酵)시킨 경우 효모분포(酵母分布)에 있어서 탁주효모(濁酒酵母)인 strain $D_m-1$과 청주효모(淸酒酵母)인 strain No.7사이에 별(別)로 차(差)가 없었다. (2) 이단료를 고온(高溫)($30^{\circ}C$ 또는 $35^{\circ}C$)에서 발효(醱酵)시킨 경우에는 저온발효(低溫醱酵)의 경우에 비(比)하여 료중의 효모수(酵母數)가 감소(減少)되었으나 탁주효모(濁酒酵母)인 strain $D_m-1$의 료중의 생존효모수(生存酵母數)는 청주효모(淸酒酵母)인 strain. No.7의 것보다 훨씬 많았다. 2. 효모(酵母)의 종류(種類)와 숙성료의 성분(成分) (1) 이단료를 고온(高溫) ($30^{\circ}C$ 또는 $35^{\circ}C$)에서 발효(醱酵)시킨 경우 선정(選定)한 탁주효모(濁酒酵母)(strain $D_m-1$, strain Y-1)을 使用한 숙성료의 주도(酒度)는 타효모(他酵母)(strain No.7, strain No.6, strain No.396, 및 strain No.1)를 사용(使用)한 것보다 상당(相當)히 높았다. (2) 료의 산도(酸度)는 strain $D_m-1$과 strain No.7사이에 약간 차이(差異)가 있었다. (3) 이단료를 고온(高溫) ($30^{\circ}C$ 또는 $35^{\circ}C$)에서 발효(醱酵)시킨 경우 strain $D_m-1$을 사용(使用)한 료의 Formol-N는 strain No.7을 사용(使用)한것보다 상당(相當)히 적었다. 3. 담금조건(條件)과 료의 주도(酒度) (1) 밀기울국(麴)의 첨가량(添加量)은 원료(原料)에 대하여 3%가 적당(適當)하였으며 밀가루국(麴)과 혼용(混用)할때에는 밀가루국(麴) 20%, 밀기울국(麴)은 $1{\sim}2%$를 사용(使用)하는 것이 적당(適當)하였다. (2) 일단료의 담금농도(濃度)를 보통(普通)것의 2배(倍)로 희석(稀釋)하여도 효모(酵母)의 증식(增殖)에 이상(異常)이 없었다. (3) 담금용수(用水) 180ml에 대하여 밀가루 $80{\sim}140g$를 사용(使用)한 경우 원료(原料)밀가루량(量)의 증가(增加)에 따라 료의 주도(酒度)가 대략(大略) 비례적(比例的)으로 올랐다. (4) 현행(現行)의 이단식(二段式)담금법(法)보다 삼단식(三段式)담금법(法)이 유리(有利)하다고 인정(認定)되었다.

• 미생물학회지
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• 제8권4호
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• pp.151-162
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• 1970

This experiment was carried out to investigate the yeasts for the brewing of red pepper paste during the fermentation periods. The yeasts in the red pepper paste were isolated and identified, and they were classified by coloring with the treatment of TTC(2, 3, 5, triphenyltetrazolium chloride) agar and counted in process of time.

• 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.

• 미생물학회지
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• 제8권2호
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• pp.69-76
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• 1970

1. The yeasts in the two samples of Nuruk (mold wheat) which one prepared at the College of Agriculture, Choong-Nam University (S) and the other purchased at a market(T), were examined and counted. The yeasts were differe entiated by the market (T), were examined and counted. The yeasts were differe entiated by the TTC(2,3,5-triphenyltetrazolium chloride)agar overlay technique that yields a varied shade of color. The results were : the population of yeasts in 1g of Nuruk S was about $6{\times}10^4$, 56.5% of which were TTC-pink yeasts, 16% TTC-red pink yeasts, 8% were TTC-red yeasts, and 16.5% TTC-white yeasts. In Nuruk T(1g), the number of yeasts accounted for $14{\times}10^4$ and constituted of 42% TTC0pink, 21% TTC-red pink, 23% TTC-red and 9% TTC-white. 2. During the fermentation of Takju (Korean Sake) employing the Nuruk S and T the yeast flora throughout the brewing were observed in 12 hour intervals. TTC pink and red yeasts considered to be the major yeasts were isolated all cultured. The strains ($1{\times}10^5$/ml) were added to the mashes S and T in which pH was adjusted to 4.2 and the change of yeast flora was examined during fermentation.

• 미생물학회지
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• 제8권2호
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• pp.53-64
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• 1970

In order to study ecology of microorganisms during Takju brewing, microflora changes were examined fromm the start to the sixth day of Takju fermentation in 24 hours intervals. Takju made from rice, flour and dried sweet potato in a liter volume open container at the laboratory and a sanple of Takju brewing factory were studied for their microflora and their changes during fermentationl together with a sample of Kokja. Results obtained were as follows ; 1. The followings were the identified microorganisms in Kokja. The molds ; Absidia spinosa, Aspergillus parasiticus. The yeasts ; Candida melinii, Candida Solani, Hansenula anomala. The bacteria ; Luctobacillus casei, Leuconostoc mesenteroides, Bacillus subtilis, Bacillus pumilus. 2. Torulopsis inconspicua, Lactobacillus casei, Leuconotoc mesenteroides, Bacillus subtilis, Bacillus pumilus were isolated from main mash of laboratory-made Takju samples. The yeast, Torupsis inconspicua which was not present in Kokja and, probably of a contaminant yeast, dominated the yeast flora of Takju mash of rice, flour and sweet potato of labotatory brewing. The laboratory brewing lost also always showed large population of lactic acid bacteria flora. 3. None of the wild yeasts which were present in Kokja appeared in Takju mashes. The Kokja appears to be of no use as the yeast source for Takju fermentation. Also the Kokja appears to be of not so effective amylolytic and proteolytic enzyme sources considering the microflora characteristics. Probably the major role of Kokja in Takju fermentation may be to contribute in taste formation. 4. Inoculation of Sacharomyces cerevisiae into the mash to the level of $10^7$ ml at the start of fermentation greatly changed the ecological aspects eliminating conditions of rather slow rising of natural contaminant yeast populaiton and fermentation which might give rise to prosperity of lactic acid and Bacillus bacteria that would be avoidable. 5. Examination of microflora of the large factory scale Takju fermentation showed the quite similar pattern of microflora and their changes to that of the cultured yeast-inoculated laboratory batch Takju fermentation. The cultured yeast dominated as the only predominant microflora, and the lactic acid bacteria flora were completely suppressed and aerobic bacteria, greatly. Probably this may be the regular microflora pattern of normal Takju fermentation. The role of lactic acid bacteria and aerobic bacteria in Takju fermentation may not be clear yet from this experiment alone.

• Applied Biological Chemistry
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• 제13권1호
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• pp.97-103
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• 1970

간장국제조과정중에 생육하는 효모들을 계수 및 분리 동정하고 TTC 정색에 의하여 유발한 결과는 다음과 같다. 1. 간장국 1g 중의 효모수는 3일국에 $97{\times}10^3$, 4일국에 $135{\times}10^3$, 5일국에 $179{\times}10^3$개로서 제국일수의 경과에 따라 효모수가 증가하였다. 2. 이들 효모의 TTC 정색에 었어서 White가 53.6${\sim}$71.9%, Red가 5.6${\sim}$11.1%, Red pink가 6.8${\sim}$1905 pink가 11.1${\sim}$22.6%로서 white 효모가 가장 많았고 Red 효모가 가장 적었다. 3. 30주를 임의 분리하여 동정한 결과 Saccharomyces rouxii 5주, Saccharomyces fermentati 2주, Saccharomyces rosei 1주, Hansenula suaveolens 1주, Hansenula anomala 6주, Pichia polymorpha 6주, Debaryomyces nicotianae 2주, Debaryomyces hansenii 2주, Torulopsis candida 2주, Torulopsis sake 2주, Candida pelliculosa 1주등 6속 11종으로 동정되었다. 4. 등정한 이들 효모를 TTC 정색에 따라 유별한 결과 Hansenula suaveolens, Hansenula anomala, Candida pelliculosa, Debaryomyces nicotianae, Pichia polymorpha 등은 국중에 생육하는 전체 효모의 약 60%를 차지하는 TTC white 효모구에 속하였으며 Saccharomyces rouxii와Saccharomyces rosei는 Red 로 Saccharomyces fermentati와 Debaryomyces hansenii는 Red pink로 Torulopsis candida와 Torulopsis sake는 pink로 나타났다. 5. 분리된 효모의 대부분이 무염 또는 식염10% 합유배지에서 잘 생육하나 15-18% 식염 합유배지에서는 생육이 거이 억제되었다.