• Journal of Microbiology and Biotechnology
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• 제21권5호
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• pp.519-524
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• 2011

The correlation between alcoholic fermentation rate, measured as carbon dioxide ($CO_2$) evolution, and the rate of hydrogen sulfide ($H_2S$) formation during wine production was investigated. Both rates and the resulting concentration peaks in fermentor headspace $H_2S$ were directly impacted by yeast assimilable nitrogenous compounds in the grape juice. A series of model fermentations was conducted in temperature-controlled and stirred fermentors using a complex model juice with defined concentrations of ammonium ions and/or amino acids. The fermentation rate was measured indirectly by noting the weight loss of the fermentor; $H_2S$ was quantitatively trapped in realtime using a pre-calibrated $H_2S$ detection tube which was inserted into a fermentor gas relief port. Evolution rates for $CO_2$ and $H_2S$ as well as the relative ratios between them were calculated. These fermentations confirmed that total sulfide formation was strongly yeast strain-dependent, and high concentrations of yeast assimilable nitrogen did not necessarily protect against elevated $H_2S$ formation. High initial concentrations of ammonium ions via addition of diammonium phosphate (DAP) caused a higher evolution of $H_2S$ when compared with a non-supplemented but nondeficient juice. It was observed that the excess availability of a certain yeast assimilable amino acid, arginine, could result in a more sustained $CO_2$ production rate throughout the wine fermentation. The contribution of yeast assimilable amino acids from conventional commercial yeast foods to lowering of the $H_2S$ formation was marginal.

• 한국식품영양과학회지
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• 제32권6호
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• pp.812-817
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• 2003

딸기식초 제조를 위해 1차 단계로 Saccharomyce kluyeri DJ97을 이용하여 딸기과즙을 14$^{\circ}$Brix로 보당한 후 28$^{\circ}C$에서 50시간동안 발효시켜 딸기 알콜발효액을 얻은 후 사용하였다. 2차 단계에서, 초산발효를 시킨 결과 산도는 초기산도가 1.48%, 교반속도가 195.76 rpm, 발효시간이 7.34 day일 때 가장 높은 4.60%를 나타내었다. 색차계 a값은 초기산도가 1.78%, 교반속도가 117.63 rpm. 발효시간이 7.35 day일 때 가장 높은 11.82를 나타내었다. 딸기식초 제조를 위해서는 Acetobacter sp. PA97를 이용하여 초기산도 1.5% 및 교반속도 196 rpm에서 176시간 발효함으로서 산도 4% 이상의 식초를 얻었다.

• 상하수도학회지
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• 제18권1호
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• pp.15-21
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• 2004

The purpose of this research was to investigate loading rate of influent for acidogenic fermentation. Laboratory batch experiments were conducted, at $35^{\circ}C$, HRT 18hr, pH 6 and used 3.5L reactor. Loading rate of influent was varied 2.0 to 4.0g VSS/L, TOA concentration is decreased according to increasing loading rate Over 2.5g VSS/L. When loading rate is 2.0g VSS/L, hydrolysis percentage show the maximum value of 87%. Most of SCFA is consist of HAc, HPr, I-HBu and MBu. HAc concentration is 5,233mg/L in the 2.0g VSS/L condition. So, for this study, we think that limiting loading rate is 2.5g VSS/L. SCFA species was investigated to HAc, HPr, I-HBu and n-HBu during our studying. HAc/SCFA ratio is about 89.3%, SCFA production rate is highest to $1,104mg\;COD/L/d{\cdot}gPCOD$ for 2.0g VSS/L loading rate.

• 한국미생물·생명공학회지
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• 제20권5호
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• pp.588-596
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• 1992

Zymomonas mobilis KCTC 1534 균체를 alginate에 고정화시킨 후 기질농도의 상관성으로 회분발효와 반연속발효에서 에탄올 생산을 시도하였다. 회분발효에서 17 glucose 농도를 발효시간 25시간에서 최대 에탄올 생산성 2.91g/l.h 얻었고 이경우 비에탄올 생산속도 $29.14g/{\ell}{\cdot}h$, 비기질 소모속도 $60.24g/{\ell}{\cdot}h$, 에탄올 수율 계수 0.48g/g, 기질전환율 98.4이었다. 생산배지의 전량 교환에 변수를 준 반복발효는 교환시간 20-24 시간에서 약 30일 동안 에탄올생산성이 2.24-$2.94g/{\ell}{\cdot}h$, 에탄올 수율계수 0.42-0.51g/g, 기질전환율 95.9-99.6%로 실행할 수 있었다. 반연속 발효의 경우 생산 배지의 교환 간격을 희석속도로 이용한 유효 희석속도 $0.36h^{-1}$에서 17% glucose 농도로 최대 에탄올생산성 $15.7g/{\ell}{\cdot}h$를 얻었고 이 경우 비 에탄올 생산속도 $156.9g/{\ell}{\cdot}h$ 비기질 소모속도 $396.0g/{\ell}{\cdot}h$, 에탄올 수율계수 0.39, 기질전환율 64.7% 이었다.

• Applied Biological Chemistry
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• 제34권3호
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• pp.235-241
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• 1991

김치에 사용되는 여러가지 향신료가 발효 숙성에 미치는 영향을 알기 위하여 주재료인 배추에 향신료의 종류와 배합량을 달리하여 담근 김치의 숙성중 발효속도, pH, 적정산도, 환원당 함량 및 ascorbic acid 함량의 변화를 측정한 결과는 다음과 같다. 절인 배추의 염농도를 3%로 조절한 다음 고추가루, 마늘 및 청파는 1, 2, 3%를, 생강은 0.5, 1.0, 1.5%를 각각 첨가한 시험에서 숙성 30시간 경부터 고추가루 2% 첨가구의 발효속도는 높아져 최고치를 보이다가 낮아졌으나 3% 첨가구는 최대값을 보이지 않고 계속 증가하였다. 고추가루 첨가구의 환원당함량과 적정 산도는 높았으며, pH는 약간 낮게 나타났다. 마늘 첨가구의 발효속도는 숙성 12시간부터 높게 나타났고, pH 및 환원당은 같은 시간에 감소하기 시작하였으나 적정산도는 높아졌다. Ascorbic acid는 숙성 6시간 후 증가하여 최고치를 나타내는 18시간경에는 담금 시보다 높았다. 청파 및 생강은 첨가 효과가 크게 나타나지 않았다.

• 한국식품과학회지
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• 제35권4호
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• pp.642-647
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• 2003

곶감가공 부산물인 감껍질을 효율적으로 이용하기 위하여 2단계로 알콜 및 초산 발효에 의해 감식초를 제조하였다. 감껍질을 이용한 알콜발효에서 알콜함량은 가수량이 12.43 mL/g 일 때, 초기 당함량 $12.41^{\circ}Brix$ 및 발효시간이 48.05 hr의 발효조건에서 최대치(8.22%)를 나타내었다. 산함량은 가수량이 12.18 mL/g 초기 당함량 $13.72^{\circ}Brix$ 및 발효시간이 46.22의 발효시간에서 최소치(0.30%)를 나타내었다. 초산발효에서 총산의 함량은 초기산도가 2.02%, 교반속도가 67.98 rpm 및 발효시간이 6.94 day일 때 최대치(6.40%)를 나타내었고, 갈색도는 초기산도가 1.50%, 교반속도가 150.00 rpm및 발효시간이 6.00 day일 때 가장 낮은 흡광도를 나타내었다. 감껍질을 이용하여 감식초를 제조하기 위해서 1차 알콜 발효조건은 가수량 12 mL/g, 초기 당함량 $12^{\circ}Brix$ 및 발효시간 48 hr로 할 때 감 알콜발효액을 제조할 수 있으며, 2차 초산발효조건은 초기산도 1.8%, 교반속도 70 rpm 및 발효시간 6 day인 것으로 나타났다.

• 한국식품영양과학회지
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• 제26권5호
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• pp.807-813
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• 1997

Various additives(glucono-$\delta$-lactone, glycine, chitosan, Chinese pepper extract+msutard oil, cinnamon oil+ginger oil+mustard oil, Chinese pepper extract), used in the Korean patents singularly or in combination, were tested for extension of shelf-life of kimchi. Addition of glucono-$\delta$-lactone or chitosan was somewhat effective in delaying the fermentation rate, however no such effect was seen by other additives. Chitosan at the concentrations of 0.5, 1.0, and 1.5% was similarily effective in delaying the fermen-tation rate. Mustard oil or cinnamon oil tend to delay the fermentation rate by singular addition at the concern tration of 0.5% or 1%. Soaking of the salted and washed Chinese cabbage in 0.5% chitosan solution resulted in delay of the fermentation rate of kimchi.

• 한국축산시설환경학회지
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• 제18권3호
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• pp.137-144
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• 2012

본 연구는 유산균과 효모로 구성된 혼합 생균제를 양돈 사료에 첨가하여 양돈용 발효사료를 제조하기 위한 최적 발효조건 구명 및 발효사료 급여에 의한 돼지 장내 환경변화를 평가하고, 원료사료별 발효능을 측정하기 위해 수행되었다. 1. 양돈 발효사료의 유산균과 효모 수를 측정하였을 때 사료 내 혼합 생균제 첨가수준은 0.25%, 수분 함량은 40~50% 정도가 적정하였다. 2. 비육돈에 발효사료를 급여하였을 때가 발효되지 않은 사료를 급여하였을 때보다 소화율은 유의적인 차이가 없었지만 분 중 휘발성지방산의 농도가 높게 나타났다. 3. 양돈용 단미사료의 발효특성을 확인하기 위하여 휘발성지방산의 농도를 측정한 결과, 비트펄프와 타피오카가 우수한 발효기질로 확인되었다.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.479-484
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• 1995

The effect of initial cell concentration on the characteristics of ethanol fermentation was investigated in the batch fermentation of Saccharomyces cerevisiae ATCC 24858. The characteristics were investigated in the range of 60 to 230 g/l of the initial sugar concentrations and 0.5 to 85 g/l of the initial cell concentrations. When the initial cell concentrations were 27 g/l for 60 g/l of the initial sugar and 85 g/l for 230 g/l, the fermentation time required for the complete consumption of the initial sugar was one hour, respectively. The ethanol productivity increased with the initial cell concentration so that, in the case of 100 g/l of initial sugar, the productivity rose up to 55 g/l/hr at 55 g/l of the initial cell concentration. The specific growth rate decreased according to the increase in the initial biomass concentration and finally became zero at around 25 g/l of the cell concentration regardless of the initial sugar concentration. The specific ethanol production rate was constant as 1.02 g/l/hr up to 150 g/l of the initial sugar. However, the rates decreased sharply with the augmentation of concentration of the initial sugar above 160 g/l. The overall ethanol yield represented a constant value, 0.475 g/g irrespective of the initial cell and sugar concentrations. The overall biomass yietd showed a trend to diminish in values with the biomass and ultimately to reach zero more than 25 g/l of the initial cell concentration.

• 한국지역사회생활과학회지
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• 제26권1호
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• pp.127-133
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• 2015

This study identifies the factors improving bread quality by using fermented liquid dough. Fermented liquid dough, the main part of bread dough, contains yeasts that are prepared in order to enhance the fermentation rate. This study investigates the fermentation rate after mixing dough, the pH of dough, loaf volume, water activity, hardness, and sensory properties of loaf bread samples with different amounts of fermented liquid dough. The fermentation rate was slightly higher in the bread samples, the control dough and 10% fermented liquid dough, than in samples with more than 20% dough. The pH values of dough decreased with an increase in the content of fermented liquid dough. The loaf volume of bread with 10% fermented liquid dough was the highest. The water activity of loaf bread increased with an increase in amount of fermented liquid dough. For the sensory evaluation of loaf bread, adding 10% fermented liquid dough improved the loaf volume and evenness of baking. These results suggest that 10% fermented liquid dough increased the fermentation rate and bread quality. Further research is required to enhance internal quality characteristics of loaf bread, including taste and flavor.