• Biotechnology and Bioprocess Engineering:BBE
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• 제8권3호
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• pp.179-182
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• 2003

Anaerobic fermentation was attempted to produce methane from the wood chip (Eucalyptus globulus). By the pretreatment of the wood chip using hot water with high temperature, NaOH, and steam explosion, the production of methane gas was enhanced. The pretreatment using Steam explosion resulted in more amount of methane gas produced than the treatment using either hot water or 1% (w/w) NaOH with high temperature, and the steam explosion at a steam pressure of 25 atm and a steaming time of 3 min was the most effective for the methane production. The amount of methane gas produced depended on the ratio of weight of Klason lignin, a high molecular weight lignin, in the treated wood chip.

• 한국식품영양과학회지
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• 제29권5호
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• pp.860-864
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• 2000

The steady and dynamic shear rheological properties of traditional kochujang fermented at three different temperatures (20${^circ}C$, 25${^circ}C$ and 30${^circ}C$) were studied. Flow of kochujang samples showed time dependence, which was quantitatively described by the Weltman model, Kochujang samples were highly shear thinning fluids (n=0.25~0.27) with large magnitudes of Casson yield stresses (1.09~1.21 kPa). Consistency index (K) and apparent viscosity (${\eta}_{a,20}$) increased with increase in fermentation temperature of kochujang. Storage (G') and loss (G") moduli increased with increase in frequency (ω), while complex viscosity (${\eta}^{\ast}$) decreased. Based on dynamic shear data, kochujang samples exhibit structural properties similar to weak gels. The complex and steady shear viscosities at different fermentation temperatures followed the Cox-Merz superposition rule with the application of the shift factor (a=0.011~0.016).

• 한국식품영양학회지
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• 제30권6호
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• pp.1184-1190
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• 2017

Baking characteristics of gluten-free rice bread were investigated, when 20, 30, 40, 50 and $60^{\circ}C$ water was added during mixing. The temperature of the dough before fermentation was affected by the temperature of the water and the mixing time. When $60^{\circ}C$ water was added, the specific gravity of the dough was the highest before fermentation (p<0.01). The specific gravity of the dough after fermentation was 32~39% of the specific gravity of the dough before fermentation. When $50^{\circ}C$ water was added, the volume and the specific volume of rice bread were higher than those in addition of water at other temperatures (p<0.001). In case of adding water of $50^{\circ}C$, the shape of the rice bread showed the largest volume, high appearance and a round shape. After storage for 2 and 24 hours, the addition of water of $50^{\circ}C$ resulted in the lowest hardness and chewiness values of rice bread. The sensory descriptive analysis revealed that when $50^{\circ}C$ water was added, the air cell size, springiness and hardness values of gluten-free rice bread were lower than those in addition of water at other temperatures. There was a difference in the appearance and texture of gluten-free rice bread, when 20, 30, 40, 50 and $60^{\circ}C$ water was added during mixing.

• 한국식품영양학회지
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• 제33권6호
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• pp.631-638
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• 2020

This study was conducted to investigate the temperatures inside and outside the pot as well as the quality characteristics of traditional Doenjang made by seven different farmers, in the Gyeonggi province during fermentation. The outside temperature of each region in the province was 5 to 10℃ higher in one place, in which fermentation took place inside the glass greenhouse, compared to other regions, while six other places showed similar changes in temperature. The moisture contents of the samples decreased according to the progress of the fermentation period from 53.6~62.3% to 51.0~58.5%. The salinity generally increased from 9.7~14.2% to 10.6~16.3% except for samples B and D, which declined from 17.0~17.2% to 16.6~16.9%. The amino-type nitrogen contents increased from 180.3~557.8 mg% to 437.3~840.7 mg%. The ammonia-type nitrogen contents decreased from 116.3~561.9 mg% to 70.7~149.2 mg%. Overall, the color of Doenjang was similar, but sample E had higher a and b values than the other regions, and the total bacterial count in the entire region was similar.

• 한국식품영양학회지
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• 제30권2호
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• pp.305-311
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• 2017

보리와 밀의 혼합막걸리 제조조건을 설정하기 위하여 발효온도(20, 25, $30^{\circ}C$)및 시간(3, 6, 9일)을 달리하여 제조한 혼합막걸리의 발효특성을 조사하였다. pH와 당도는 발효온도 및 시간이 증가함에 따라 전반적으로 증가하는 경향을 나타내었으며, 총산은 발효온도와 시간에 따라 비례적으로 증가하였다. 환원당과 알코올 함량은 발효온도 $20^{\circ}C$와 $25^{\circ}C$에서는 발효시간이 경과됨에 따라 환원당은 감소하고, 알코올은 증가하는 반면, 발효온도 $30^{\circ}C$에서는 발효 6일에 알코올 함량이 감소하였다. 색도는 L값은 대부분 발효온도가 증가함에 따라 감소하는 경향을 보였으며, a값과 b값은 발효 9일차에 발효온도에 따른 유의적 차이를 보이지 않았으나, 발효시간이 경과함에 따라 유의적으로 증가하는 경향을 나타내었다(p<0.05). 보리와 밀 혼합막걸리의 미생물수를 측정한 결과, 효모수는 발효 3일차에 발효온도 $20^{\circ}C$, $25^{\circ}C$ 및 $30^{\circ}C$에서 각각 8.14, 7.93 및 7.67 Log(CFU/mL)로 가장 높은 수준을 나타냈고, 발효시간 경과에 따라 감소하였다. 이것은 발효온도와 상관없이 총균수와 유산균수가 모두 동일하게 나타났다. 유기산 조성은 citric acid와 lactic acid가 대부분을 차지했으며, 그 외 malic acid와 pyruvic acid도 일부 검출되었다. 이상의 결과를 종합했을 때 보리와 밀 혼합막걸리의 최적 발효조건은 발효온도 $20{\sim}25^{\circ}C$에서 6일간 발효했을 때 우수한 막걸리를 제조할 수 있을 것으로 판단하였다.

• Journal of Animal Science and Technology
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• 제62권2호
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• pp.227-238
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• 2020

Use of raw feedstuffs for livestock is limited by low digestibility. Recently, fermentation of feedstuffs has been highlighted as a new way to improve nutrient absorption through the production of organic acids using inoculated microorganisms, which can also play a probiotic role. However, standard procedures for feedstuff fermentation have not been clearly defined because the process is influenced by climatic variation, and an analytical standard for fermented feedstuffs is lacking. This study aimed to evaluate the microbiological and biochemical changes of feedstuffs during fermentation at temperatures corresponding to different seasons (10℃, 20℃, 30℃, and 40℃). We also investigated the effects of yeast, lactic acid bacteria (LAB), and Bacillus spp. on fermentation and determined the results of their interactions during fermentation. The viable cells were observed within 8 days in single-strain fermentation. However, when feedstuffs were inoculated with a culture of mixed strains, LAB were predominant at low temperatures (10℃ and 20℃), while Bacillus spp. was predominant at high temperatures (30℃ and 40℃). A significant drop in pH from 6.5 to 4.3 was observed when LAB was the dominant strain in the culture, which correlated with the concentrations of lactic acid. Slight ethanol production was detected above 20℃ regardless of the incubation temperature, suggesting active metabolism of yeast, despite this organism making up a marginal portion of the microbes in the mixed culture. These results suggested that fermentation temperature significantly affects microbiological profiles and biochemical parameters, such as pH and the lactic acid concentration, of fermented feedstuffs. Our data provide valuable information for the determination of industrial standards for fermented feedstuffs.

• 한국식품저장유통학회지
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• 제17권6호
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• pp.826-834
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• 2010

고문헌에서 발췌한 7가지의 벽향주 제조방법에서 발효 기간별 온도변화와 품질특성을 비교하였다. 술덧발효 온도에 있어서 2차담금 시기가 첫 담금 한 날부터 7일 이상인 처리구들은 실내온도보다 낮은 경향을 보였으며, 2 3차 담금일 사이의 기간이 가장 짧은 처리구가(2일 간격) $28^{\circ}C$이상의 온도를 가장 길게 유지하였다. 발효가 진행됨에 따라 pH는 낮아졌으며, 적정산도는 전반적으로 2차담금 이전까지 증가하다가 2차담금 이후 낮아졌다. 아미노산은 가수량 대비 원료비율이 가장 낮은 5제법을 제외하고는 모두 증가되었다. 알코올 함량은 2차담금 시기가 짧았던 2제법을 제외하고 모두 2차담금 이전에 알코올 함량이 급격히 증가되었다. 관능평가에서 전반적인 기호도가 가장 좋은 것은 3제법으로 제조한 벽향주였다.

• 동아시아식생활학회지
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• 제14권3호
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• pp.257-264
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• 2004

The quality changes of the extracts of salt-fermented Ammodytes personatus during the storage were examined at 1 month interval during 3 months fermentation period. To prepare the extracts of Ammodytes personatus, 17%, 20% and 25% salt were added respectively and then stored for 3 months at room temperature and then extracted with hot water. During the storage, moisture and lipid contents of the samples decreased, but the crude protein contents increased gradually. On the other hand, ash content and pH showed little changes during the fermentation storage. After 6 months fermentation, the extracts of salt-fermented Ammodytes personatus were rich in free amino acids, such as glutamic acid, alanine, lysine, leucine, isoleucine, valine and aspartic acid in the order. As the fermentation progressed, the fish odor, turbidity, salty taste, savory flavor and overall preferences were similar to those of Ammotlytes personatus sauce in the market. The total cell numbers were 450∼570 cfu/mL at 0 day, but there were none revealed during the fermentation.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.108-114
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• 1992

The fermentative characteristics in ethanol production from lactose, with increased ethanol tolerance, of a fusant yeast strain constructed by protoplast fusion of Saccharomyces cerevisiae and Kluyveromyces fragilis were studied. The ethanol tolerance of this strain was increased to 8.0%, compared with the parent K. fragilis. During batch ethanol fermentation the optimal cultivation conditions for this fusant yeast were an initial pH of 4.5, a culture temperature $30^\circ{C}$. stirring at 100 rpm without aeration in 10% lactose medium (supplied with 1.0% yeast extract). Using this fusant strain in whey fermentation to ethanol, maximum ethanol production reached 3.41% (w/v) (theoretical yield; 66.7%) after a 48 hour cultivation period.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.297-302
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• 1999

Simultaneous saccharification and fermentation (SSF) experiments were carried out with a lignocellulosic biomass. The effects of temperature on enzymatic saccharification and the ethanol fermentation were also investigated. The batch SSF process gave a final ethanol concentration of 10.44 g/l and equivalent glucose yield of 0.55 g/g, which was increased by 67％ or higher over the saccharification at 42℃. The optimal operating condition was found to vary in several parameters, such as the transmembrane pressure, permeation rate, and separation coefficient, related to the SSF combined with membrane system (semi-batch system). When the fermentation was operated in a semi-batch mode, the efficiency of the enzymes and yeast lasted three times longer than in a batch mode.