• 한국식품과학회지
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• 제32권6호
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• pp.1326-1330
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• 2000

김치발효중 기체조성변화가 숙성정도를 감지할 수 있는지 알아보기 위하여 배추김치를 플라스틱 용기에 일정량 충진하여 밀봉한 후 저장하면서 포장내 기체조성 변화를 조사한 결과, 김치발효중 포장내 기체조성은 $CO_2$ 발생으로 인하여 계속적으로 변화하였다. 김치 발효온도와는 무관하게 $O_2$ 농도는 지수적으로 감소하고 $CO_2$ 농도는 매우 특징적인 2단계 증가양상을 나타내었다. $CO_2$ 농도는 2차 단계에서 다시 증가함에 따라 김치의 pH는 비례적으로 감소하였다. 저장 온도와 계절별 원료 배추에 따라 김치 포장내 $CO_2$ 농도변화 속도가 다르며 최종 농도에 있어서도 상당한 차이를 나타내었다. 고온에서 발효된 김치일수록 포장내 $CO_2$ 농도가 더 높은 경향을 보였고 여름배추 보다 겨울이나 봄 배추로 제조한 김치에서 포장내 $CO_2$ 농도 및 발생속도가 더 높게 나타났다. 이러한 연구결과를 바탕으로 포장내 기체조성 변화를 이용한 김치의 숙성도 감지 가능성을 확인할 수 있었다.

• KSBB Journal
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• 제30권3호
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• pp.125-131
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• 2015

Kluyveromyces marxianus is a well-known thermotolerant yeast. Although Saccharomyces cerevisiae is the most commonly used yeast species for ethanol production, the thermotolerant K. marxianus is more suitable for simultaneous saccharification and fermentation (SSF) processes. This is because enzymatic saccharification usually requires a higher temperature than that needed for the optimum growth of S. cerevisiae. In this study, we compared the fermentation patterns of S. cerevisiae and K. marxianus under various temperatures of fermentation. The results show that at a fermentation temperature of $45^{\circ}C$, K. marxianus exhibited more than two fold higher growth rate and ethanol production rate in comparison to S. cerevisiae. For SSF using starch or corn stover as the sole carbon source by K. marxianus, the high temperature ($45^{\circ}C$) fermentations showed higher enzymatic activities and ethanol production compared to SSF at $30^{\circ}C$. These results demonstrate the potential of the thermotolerant yeast K. marxianus for SSF in the industrial production of biofuels.

• 대한수의학회지
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• 제31권4호
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• pp.509-513
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• 1991

Preliminary survey on the prevalence of swine internal parasites was carried out at 91 pens of 4 piggeries being operated by the sawdust fermentation floor system in Kyunggi province. To investigate the effects of viability of eggs., larva and cysts, temperatures at the underlayer of the sawdust floor and rooms of pens were taken three times a day for 8 days. In a pig farm which has been operated by the sawdust fermentation floor system for G years, eggs and larva of Ascaris suum, Trichuris suis, Oesophagostomum sp., Hyostrongylus sp. and Strongyloides ransomi were detected from 42(70.0%) among 60 pens. Cysts and oocysts of coccidia, Balantidium coli, Entamoeba sp. were also detected from 50(83.3%) among 60 pens. In three pig farms which have been operated by the sawdust fermentation floor system for one year, eggs and larva of nematoda were not detected at all, and the contamination rates of protozoan cysts and oocysts was relatively low situation. The change of the temperature in the pig room was variable according to outside condition, whereas that in underfloor was consistently stable between $28^{\circ}C$ to $30^{\circ}C$ which was strictly suitable for the development of eggs, larva and cysts.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.41-45
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• 1996

This study was conducted to develop the fermentation kinetic model for the prediction of acidity and pH changes in Kimchi as a function of fermentation temperatures. The fitness of the model was evaluated using traditional two-step method and an alternative non-linear regression method. The changes in acidity and pH during fermentation followed the pattern of the first order reaction of a two-step method. As the fermentation temperature increased from 4$^{\circ}C$ to 28, the reaction rates of acidity and pH were increased 8.4 and 7.6 times, respectively. The activation energies of acidity and pH were 16.125 and 16.003kcal/mole. The average activation energies of acidity and pH using a non-linear method were 16.006 by the first order and 15.813 kcal/mole by the zero order, respectively. The non-linear procedure had better fitting 개 experimental data of the acidity and pH than two-step method. The shelf-lives based on the time to reach the 1.0% of acidity were 33.1day at 4$^{\circ}C$ and 2.8 day 28$^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.916-920
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• 2002

This report describes a high-level expression of human alpha-2a interferon ($IFN{\alpha}-2a$) in Escherichia coli and its pilot scale purification by using a monoclonal antibody-independent chromatographic procedure that is based on anion-exchange, cation-exchange, hydrophobic interaction, and gel filtration. The recombinant E. coli produced much more $IFN{\alpha}-2a$ in a soluble form, when cultivated at low temperatures than at high-temperature fermentation. However, if the bacterial growth was taken into consideration, fermentation at $30^{\circ}C$ seemed optimal for the interferon production. By using our new protocol, we recovered approximately 160 mg of $IFN{\alpha}-2a$ with a specific activity of $3.59{\times}10^8$ IU/mg from 201 of the broth. The gel permeation chromatographic and SDS-PAGE indicated that the interferon preparation was purified to homogeneity and was of the correctly folded fast-migrating monomer.

• 한국수산과학회지
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• 제27권3호
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• pp.223-231
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• 1994

오징어 식해 개발을 위하여 식해 숙성시 숙성온도 및 기간에 따른 TBA, fatty acids, free amino acids 및 미생물의 변화와 단백질 분해효소의 정제 실험을 요약하면 다음과 같다. TBA 값은 각 온도에서 숙성 5일만에 최고치를 나타내었다가 감소하였으며 숙성온도 $10^{\circ}C$에서 지질의 산화가 가장 많았다. 오징어 식해의 지방산 조성은 linoleic acid(18:2), oleic acid(18:1)가 $60\%$ 이상 점유하였으며 EPA(20:5) 및 linilenic acid(18:3)은 약 $13\%$ 정도였다. 숙성기간이 길어질수록 linolenic acid 및 EPA는 현저하게 분해되었으며 $10^{\circ}C$ 및 $15^{\circ}C$에서 지방산화가 촉진되었다. 식해의 유리 아미노산 조성 은 Pro, His, Arg, Leu, Glu 등이 높은 점유율을 나타내고 있으며 숙성기간이 증가할수록 Ser, His, Arg 등은 점유율이 낮아지며, 반면에 Glu, Ala, Val, Tyr 등은 높아졌다. 그리고 숙성온도가 증가할 수록 Glu, Val 및 Met은 점유율이 증가하였으며 Ala, Cys, Thr 및 Gly은 감소하였다. 미생물의 변화는 총균수는 온도가 높을수록 증가하였으며 숙성 10일만에 최대로 되었다가 그 후 감소하였다. Lactic acid bacteria 수는 각 숙성온도에서 숙성 15일째에 최대였다가 그후 감소하였으며 숙성온도가 높을 수록 증가속도 및 감소속도도 빨랐다. Proteolytic bacteria 수는 숙성온도가 높을수록 증가량 및 속도가 빨랐으며 숙성기간이 증가함에 따라 감소량도 많았다. Psychrotrophs수는 $10^{\circ}C$ 숙성에서 제일 높았으며 숙성기간 15일째가 최대였다. 단백질분해능이 강한 균주들을 동정하였을 때 모두 Bacillus 속으로 밝혀졌다. 단백질 분해효소는 ammonium sulfate $60{\sim}80\%$ 농도 사이에서 최대로 추출되었으며 이온교환수지로 정제하였을 때 3개의 peak중 마지막 peak에서 활성을 나타내었으며 전기영동 결과 분자량이 대략 $20,000{\sim}40,000$사이에 15개 정도의 bands가 나타났다.

• 한국조리학회지
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• 제14권3호
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• pp.136-142
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• 2008

This study was conducted to investigate the correlation of the physicochemical quality index(pH, acidity, reducing sugar content and lactic acid bacterial count) and sensory index(sourness) of Kakdugi during the fermentation at 5$^{\circ}C$, 10$^{\circ}C$ and 20$^{\circ}C$ respectively. Also, the relations between physicochemical quality index and overall acceptability were carried out. The pH range, based on the middle sour intensity point of 4.5, was 5.75 at 5$^{\circ}C$ fermentation, whereas that was 4.2 at 10$^{\circ}C$ and 20$^{\circ}C$ fermentation. The pH showing the highest overall acceptability decreased along with increased fermentation temperature. The reduced sugar content decreased rapidly up to 0.9% acidity, but after that, decreased slowly from more than 0.9% acidity at all fermentation temperatures. With increased fermentation temperature, the reduced sugar content showing the highest overall acceptability also showed the decreasing tendency. Change patterns of lactic acid bacterial count and sourness didn't coincided at 5$^{\circ}C$ fermentation, whereas those did at 10$^{\circ}C$ and 20$^{\circ}C$ fermentation. The indexes showing high significant correlations with sourness of Kakdugi fermented at 5$^{\circ}C$ were not pH and lactic acid bacterial count but acidity and reducing sugar content(p<0.05). The sourness of Kakdugi fermented at 10$^{\circ}C$ and 20$^{\circ}C$ showed high significant correlations with all of the physicochemical index(p<0.05).

• Preventive Nutrition and Food Science
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• 제9권3호
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• pp.213-217
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• 2004

We evaluated the possibility of rapid fermentation of anchovy sauce using a commercial protease. The fermentation characteristics were monitored by response surface analysis. The content of total nitrogen was high (around 1 %) with fermentation at 51.7～57.5$^{\circ}C$ after 10.2～16.4 hours, but rapidly decreased at higher temperatures (6$0^{\circ}C$ or over), while the $R^2$ of polynomial equation was 0.9185 (p<0.05). The amino acid content rapidly decreased to approximately 600 mg% and less at high temperature (6$0^{\circ}C$ and over), and the $R^2$ was 0.9578 (p<0.01). The free amino acids were affected more by fermentation time when fermentation temperature was lower, and the $R^2$ for total free amino acids was 0.8496 (p<0.10). The $R^2$ for sweet free amino acids was 0.9144 (p<0.05). According to the results of this study, the optimal conditions for anchovy sauce fermentation were predicted to be 52.5～56.9$^{\circ}C$ and 13.3～16.4 hours, and the predicted values and actual values of each response variable were similar to each other when the fermentation was performed at a random point within the optimal range. Also, the comparison of the quality between the quick anchovy sauce and sauces currently on the market showed that the content of sweet amino acids was higher in the former than in the latter.

• 급식외식위생학회지
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• 제5권1호
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• pp.30-39
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• 2024

Rice, nuruk, and water are the main ingredients to prepare takju, a traditional Korean liquor. Takju quality varies depending on the type of ingredients and fermentation temperature. In the current study, different combinations of nuruk (SH, JJ) and rice (glutinous rice, non-glutinous rice) were fermented at different temperatures (20, 25℃) and analyzed for quality characteristics over the fermentation period of 10 days. Regardless of the temperature, higher soluble solids (27.1~29%) were measured in the takju prepared with glutinous rice compared to non-glutinous rice. And acidity increased from 0.03% to 1.1% to all takju fermented at both 20 and 25℃, and, higher acidity was measured in the takju prepared with JJ nuruk. The color value of lightness (L) decreased from 57.9 to 23.9. Alcohol content was less than 15.5% in glutinous rice takju and less than 12.3% in non-glutinous rice takju. Total bacteria count (7~8 Log CFU/mL) and lactic acid bacteria count (4~7 Log CFU/mL) increased in different takju. However, the very high yeast count was recorded in takju prepared from SH nuruk compared to takju prepared from JJ nuruk at 0 day of fermentation. A sharp decline (84.92~98.57%) of yeast was observed just after the 1st day of fermentation which gradually reduced to lowest at 4th day of fermentation. No yeast was observed at 6th day fermentation and onwards. These results indicate that the raw materials, especially rice and nuruk, affect the physiochemical properties of takju.

• Asian-Australasian Journal of Animal Sciences
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• 제12권4호
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• pp.525-530
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• 1999

Prior to ensiling Rhodesgrass (RG) and Italian ryegrass (lRG) were treated with lactic acid bacteria (LAB) or with LAB+cellulases to compare their fermentation characteristics and chemical compositions. LAB (Lactobacillus casei) was added to all ensiling materials (except the untreated control) of RG and IRG at a concentration of $1.0{\times}10^5\;cfu.g^{-1}$ fresh forage. The enzymes used were Acremoniumcellulase (A), Meicelase (M) or a mixture of both (AM). Each enzyme was applied at levels of 0.005, 0.01 and 0.02 % of fresh forage. The silages with each treatment were incubated at 20, 30 and $40^{\circ}C$ and stored for about 2 months. While no marked differences were found between the RG and IRG silages with various treatments on dry matter (DM), volatile basic nitrogen (VBN) and water soluble carbohydrate (WSC) contents, there were significant differences in pH value, and lactic acid and butyric acid contents. LAB inoculation did not affect the fermentation characteristics of either the RG or IRG silages. The combined treatments of LAB+cellulases improved the fermentation quality of both the RG and IRG silages as evidenced by the decrease in pH value and increase in lactic acid content. Increasing the amount of added cellulase resulted in a decrease in pH value and an increase in lactic acid content in both the RG and IRG silages. Cellulases A and AM had a greater effect than cellulase M on the fermentation quality of the RG and IRG silages. Incubation temperatures of 30 and $40^{\circ}C$ appeared to be more appropriate environments for stimulating good fermentation than $20^{\circ}C$.