• 농업과학연구
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• 제35권1호
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• pp.1-9
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• 2008

메주를 만들 때 저온숙성의 경우 상온숙성보다 발효 특성과 관련이 있는 pH, 아미노산성 질소 등의 양이 낮았으며 동일한 아미노태 질소 함량에 도달하기까지 숙성기간이 약 2~3배정도 필요한 것으로 나타났고, 된장의 색상이 약 2배정도 밝은 것으로 나타났다. 그리고 숙성초기 낮은 온도로 인해 산성생균의 활동성이 낮아지고 이로 인한 유기산 생성량이 낮아져 상온숙성 된장에 비해 pH가 높고, acidity I이 낮으며, 저온숙성된장은 가수분해 효소에 의한 분해속도의 저하로 낮은 아미노산성 질소 함량을 보였다.

• 한국식품영양과학회지
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• 제27권1호
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• pp.16-23
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• 1998

Effect of Fermentation temperature on the changes of chemical components in Kakudgi during fermentation was investigated by measuring free sugar, organic acid and volatile compounds up to 57 days at several temperatures. The mannitol was increased in palatable period in contrast with those of other free sugars. The higher the initial fermentation temperature was and the longer the initial fermentation time at 2$0^{\circ}C$ was, the faster the second increasing period was and the less the initial contents was. Lactic acid was increased 6~31 times from a little amount at the initial period. The higher the initial fermentation temperature was and the more the increasing content was. But malic acid which was abundant(55.1% of total nonvolatile organic acid) in the initial fermentation period was remarkably decreased in the palatable period. The change of the sulfides among the volatile compounds was remarkable. Methyl allyl sulfide which was a little in the initial fermentation period was remarkably increased in the final fermentation period, and the correlation coefficients between the content of methyl allyl sulfide and aroma in sensory evaluation were high. It could be suggested that the fermentation temperature should be set to 4$^{\circ}C$ after fermentating at 2$0^{\circ}C$ for 36 hours in the view point of keeping the Kakdugi taste and quality well because of high content of free sugar and nonvolatile organic acids.

• 수산해양교육연구
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• 제24권6호
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• pp.755-762
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• 2012

Qualities properties of fish sauce made jack mackerel (Trachurns japonicus) at different salt concentrations (25~35%) for 240 days at fermentation temperature ($25{\sim}55^{\circ}C$) were investigated. Total nitrogen content of the fish sauce made jack mackerel at 25% salt concentration after 240 day of fermentation was higher than those of 30%, 35% salt concentration. Total nitrogen content was increased under the same condition as fermentation temperature increased except at $55^{\circ}C$. Amino nitrogen contents at 25% salt concentration after 240 day of fermentation at 35, 45, $55^{\circ}C$ were 949.3, 812.8 and 834.4 mg/100 g, respectively. Those at 25, $55^{\circ}C$ fermentation temperature were 811.2 and 614.8 mg/100 g, respectively. The amino acid nitrogen content at 30 and 35% salt concentration ware lower than 20% salt concentration and that after 240 day of fermentation at $55^{\circ}C$ was lowest. The volatile basic nitrogen content increased during fermentation as fermentation temperature increased. However, increasing salt concentration controlled the formation of volatile basic nitrogen. Histamine content of samples fermented at $25{\sim}55^{\circ}C$ after 240 days were 9~20 mg/kg showing that it was not significantly different among salt concentration. The results indicated that the controlled salt concentration and fermentation temperature could be used as a successful process for fish sauce of jack mackerel as an unused resource.

• 한국가정과학회지
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• 제5권1호
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• pp.48-61
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• 2002

This study was carried out to investigate the effects of four kinds of leavening agents on Jeung-Pyun fermantation. Milk-wine(M), fresh yeast(F), dry yeast(D), instant yeast(I) were used in Jeung-Pyun ingredients. The physicochemical properties, sensory evaluation were examined. The results of this study are summarized as follows: 1. Basic recipes for Jeung-Pyun by preliminary test were developed. 2. Specific volumes and expansion ratio of Jeung-Pyun was higher in the fresh yeast-added sample. 3. The pH of Jeung-Pyun was decreased significantly as the fermentation progressed 4. In the result comparing Jeung-Pyun extracting after 1st fermentation with Jeung-Pyun extracting 2nd fermentation by SEM, the former was widely distributed in stability of bubble and pore than the latter. 5. Standard recipe by Q.D.A. test added four kinds of leavening agents were as follows: (1)Jeung-Pyun added milk wine was 240min for 1st fermentation time, 60min for 2nd fermentation time, 35$^{\circ}C$ for fermentation temperature, 80% for fermentation humidity respectively. (2) Jeung-Pyun added fresh yeast was 90min for 1st fermentation time, 40min for 2nd fermentation time, 35$^{\circ}C$ for fermentation temperature, 80% for fermentation humidity respectively. (3)Jeung-Pyun added dry yeast was 90min for 1st fermentation time, 60min for 2nd fermentation time, 35$^{\circ}C$ for fermentation temperature, 60% for fermentation humidity respectively. (4)Jeung-Pyun added instant yeast was 90min for 1st fermentation time, 40min for 2nd fermentation time, 30$^{\circ}C$ for fermentation temperature, 60% for fermentation humidity respectively. 6.Based on sensory evaluation, Jeung-Pyun added fresh yeast was significantry higher than others in color, sweetness, moistness, softness, and overall quality. There was negative significance between milk wine flavor and astrigentness, and yeast flavor.

• 상하수도학회지
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• 제21권4호
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• pp.467-475
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• 2007

This study was conducted to examine temperature effects on hydrogen production in anaerobic fermentation. 18 batch reactors were operated at mesophilic ($35^{\circ}C$) and thermophilic conditions ($55^{\circ}C$) to achieve maximum hydrogen production in anaerobic fermentation. Optimum hydrogen production conditions were also investigated at each temperature. Different trends were observed regarding pH effects on hydrogen production. This effect was not significant for mesophilic fermentation ($35^{\circ}C$). In this case, pH may not drop to interfere hydrogen production during the test. However, hydrogen production decreased without pH control for thermophilic condition ($55^{\circ}C$). Effects of heat treatment were observed for both fermentation process. Hydrogen production with heat treatment was higher than hydrogen production without heat treatment for both fermentation processes. The amount of produced hydrogen for each substrate concentration with temperature changes showed that more hydrogen was produced at $35^{\circ}C$ than at $55^{\circ}C$.

• 미생물학회지
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• 제20권2호
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• pp.67-72
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• 1982

The effect of fermentation temperature on the production of high content alcohol has been investigated with high substrate concentration. The maximum specific growth rate, ${\mu}max\;was\;0.461hr^{-1}\;at\;35^{\circ}C$ which was the highest, whereas the maximum biomass concentration waas 8.7g/l at $25^{\circ}C$, at the growth rate lower than at $35^{\circ}C$. Approximately 140g/l of ethanol was produced in the temperature range of 20 to $25^{\circ}C$ with nearly complete comsumption of the substrate. Extended fermentation time has been required at lower temperatures, however, for the maximum values of biomass concentration and alcohol content, hence higher ethanol productivity, as the temperature was elevated to $40^{\circ}C$. The viability of yeasts was greatly improved by lowering the fermentation temperature down to $25^{\circ}C$ and also extended survival of the cells has been observed at lower fermentation temperatures, although the ethanol concentration of both waas higher.

• 한국미생물·생명공학회지
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• 제17권6호
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• pp.619-623
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• 1989

효모의 성장 및 에탄을 생산에 미치는 온도의 영향에 대해서 회분식 배양을 실시한 결과 최대의 비효모 성장속도를 나타내는 온도는 36$^{\circ}C$였고 최대의 비에탄을 생산속도를 나타내는 온도는 33$^{\circ}C$임을 알 수 있었다. 온도의 영향에 대한 실험을 토대로 수학적 모델식을 선정했으며 매개변수를 추정하여 모사를 해 본 결과 배양 초기에는 36$^{\circ}C$ 정도의 온도에서 배양하다가 점차로 온도를 낮추어 3$0^{\circ}C$ 정도로 배양하는 것이 최적의 발효공정임을 알 수 있었다.

• 한국식품영양과학회지
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• 제28권4호
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• pp.773-779
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• 1999

This study was conducted to determine the changes in the contents of vitamin C and fermentation characteristics of kimchi on different Chinese cabbage variety(Koreangji Yureum: KY, Kalak Shin Il Ho: KS) and fermentation temperature(5oC, 15oC). Kimchi were fermented at 5oC and 15oC for 140 days and 25 days respectively. In all samples, total acidity increased, and the pH, total sugar and reducing sugar content decreased as the fermentation proceeded. Also, the number of lactic acid bacteria reached the maximum at the optimum fermenting stage. On the other hand, total ascorbic acid, dehydroascorbic acid and ascorbic acid from individual kimchi solid tissue significantly decreased with fermentation periods, however, increased kimchi liquid at the 7day in KS 15(kimchi prepared with Kalak Shin Il Ho at 15oC), KY 15(kimchi prepared with Korangji Yureum at 15oC) and at the 65day in KY 5(kimchi prepared with Korangji Yureum at 5oC) respectively. Therefore, different fermentation temperature as well as variety affected ascorbic acid contents and chemical characteristics of kimchi.

• Journal of Microbiology and Biotechnology
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• 제4권4호
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• pp.316-321
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• 1994

We investigated the possibility of industrial application and economit process of high temperature fermentation by thermotolerant alcohol producing yeasts as previously reported. From the 20% glucose media, the RA-74-2 produced 11.8% (v/v) ethanol at $32^{\circ}C$ (0.5% inoculum) and 10.6% (v/v) ethanol at $40^{\circ}C$ (3% inoculum), respectively. Also, 11.3% (v/v) ethanol was produced for 96 hours in the temperature-gradient fermentation. These results suggest that the RA-74-2 could isuccessfully be applied to save the cooling water and energy in industrial scale without re-investment or modification of established fermentation systems. When potato starch was used as the substrate for the RA-74-2, high temperature fermentation above $40^{\circ}C$ was more appropriate for industrial utilization because organic nitrogen was not necessary to economical fermentation. As the naked barley media just prior to industrial inoculation, taken from the Poongkuk alcohol industry Co., were used, 9.6% (v/v) ethanol was produced at $40^{\circ}C$ for 48 hours in jar-fermentor scale (actually, 9.5-9.8% (v/v) ethanol was produced at 30~$32^{\circ}C$ for 100 hours in industrial scale). The ethanol productivity was increased by the high glucoamylase activity as well as the high metabolic ratio at $40^{\circ}C$ Therefore, if the thermotolerant yeast RA-74-2 would be used in industrial scale, we could obtain a high productivity and saving of the cooling water and energy. Meanwhile, the RA-912 produced 6%(v/v) ethanol in 10% glucose media at $45^{\circ}C$ and showed the less ethanol-tolerance compared with industrial strains. As the produced alcohol was recovered by the vacuum evaporator at $45^{\circ}C$ in 15% glucose media, the final fermentation ratio was enhanced (76% of theoretical yields). This suggest that a hyperproductive process could be achieved by a continuous input of the substrate and continuous recovery of the product under vacuum in high cell-density culture.

• 한국식생활문화학회지
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• 제16권5호
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• pp.431-441
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• 2001

To develop the low-temperature and long-term fermented kimchi, kimchi was prepared according to the recipe of a specific ratio of major and minor ingredients and adjusted its salinity to 3.7%. Prepared kimchi fermented at $15{\pm}1^{\circ}C$ for 24 hours and transferred and fermented in a refrigerator only used to make low-temperature and long-term fermented kimchi at $-1{\pm}1^{\circ}C$ for 30 weeks. During 30 weeks of fermentation the changes in physicochemical and microbiological properties of low-temperature and long-term fermented kimchi were studied. The initial pH of 6.47 decrease gradually and dropped to pH 4.0 after 14 weeks of fermentation, and then it maintained at same level. Acidity increased to 0.49% on 2 weeks of fermentation and kept at 0.47 $\sim$0.50% during 2 to 30 weeks fermentation. Salinity was slightly increased at early stage and started to decrease on 4 weeks of fermentation, and then it did not change. The change of reducing sugar content was closely related to the trend of pH change with a very high correlation coefficient(r =0.912). Lactic acid, citric acid, malic acid, succinic acid and acetic acid were major organic acids contained in low-temperature and long-term fermented kimchi. Vitamin C content decreased at initial stage of fermentation and then slightly increased up to the maximum of 22.3 mg% on 8weeks of fermentation. In color measurement, L value continued to increase during the fermentation and reached at the highest of 55.45 on 22 weeks of fermentation, and a and b values of 3.62 and 4.54 also increased to 31.26 and 37.32 on 30 weeks of fermentation, respectively. Total microbial count increased slowly from beginning and was the highest on 4 weeks of fermentation, and then began to decrease slowly. Count of Lactobacillus spp. was highest after 6weeks, but count of Lactobacillus spp. was highest on 2 weeks of fermentation, and then both showed a slow decrease. Yeast count wasn't increased until 4 weeks of fermentation and then increased rapidly to get the highest on 10 weeks of fermentation.