• 한국식품과학회지
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• 제16권4호
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• pp.443-450
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• 1984

온도와 식염농도를 달리하여 김치를 발효시키면서 생화학적 및 미생물의 변화를 검토하였다. 김치의 적숙시기는 발효온도와 식염농도에 따라 달랐다. 김치발효는 저온, 고식염농도에서 보다, 고온 저식염 농도에서 더 빨리 진행되었고 김치의 비휘발성 유기산에 대한 휘발성 유기산의 비는 김치 적숙시기에 최대로 되었다가 김치가 시어지면서 감소되었다. 식염농도와 발효온도를 달리 하여 숙성시킨 김치에서 Leu. mesenteroids, Lac. brevis, Lac. plantarum, Ped. cerevisiae, St. faecalis 및 산생성이 낮은 Lactobacilli가 분리되었다. 그러나 김치발효에 관여하는 주 미생물은 Leu. mesenteroides이며, Lac. plantarum은 김치의 숙성보다는 산패와 더 관련이 있는 것으로 추정되었다. 총 생균수는 발효초기에 급증하여 적숙기간에 최대로 되었다가, 그 이후 서서히 감소되었고, 호기성 세균과 사상균수는 발효가 진행되면서 계속 감소하였고, 효모는 $10^{\circ}C$ 전후의 온도와 고 식염농도에서 그 수가 증가하였다가 다시 감소되었다.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.335-342
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• 2013

In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

• 한국미생물·생명공학회지
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• 제23권5호
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• pp.624-631
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• 1995

The fermentation characteristics of Saccharomyces cerevisiae F38-1, a newly isolated thermotolerant yeast strain from a high temperature environment have been studied using a fermentation medium containing 20% glucose, 0.2% yeast extract, 0.2% polypeptone, 0.3% (NH$_{4}$)$_{2}$SO$_{4}$, 0.1% KH$_{2}$PO$_{4}$, and 0.2% MgSO$_{4}$ without shaking at 30$\circ$C to 43$\circ$C for 5 days. The fermentability was over 90% at 30$\circ$C, 88% at 37$\circ$C, 77% at 40$\circ$C and 30% at 43$\circ$C. A similar fermentation result was obtained at pH between 4 and 6 at 30$\circ$C and 40$\circ$C. Aeration stimulated the growth of the strain at the beginning of the fermentation, but it reduced alcohol production at the end of alcohol fermentation. Optimal glucose concentration was determined to be between 18 and 22% at 40$\circ$C as well as 30$\circ$C, but the growth was inhibited at the glucose concentration of over 30%. A fermentability of over 90% was observed at 40$\circ$C in 2 days when the medium was supplemented by 2% yeast extract. A higher inoculum size increased the initial fermentation rate, but not the fermentation. A fermentability of over 90% was achieved in 2 days at 40$\circ$C in a fermentor experiment using an optimized medium containing 20% glucose and 1% yeast extract.

• 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.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1021-1027
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• 1997

$CO_2$production in fermentation of dongchimi was measured and interrelated with changes in pH and titratable acidity. The effects of salt content and temperature on $CO_2$production rate were analysed. Fermentation of dongchimi showed drastic pH decrease in early stage and subsequent levelling off around 3.9, with linearly increased acidity up to 0.3~0.4% optimum quality. $CO_2$production of dongchimi could be analysed to consist of two consecutive stages of constant rate. The first stage $CO_2$production of higher rate moved to the second stage of lower rate when acidity rose beyond 0.3%. When compared to those of 1 and 2% salt content, dongchimi of 3% salt showed lower $CO_2$production rate in the 1st stage and slower acidity change through the whole fermentation period. However, it resulted in the product of highest $CO_2$accumulation at optimal ripeness because of consistent $CO_2$production of longer 1st stage period and relatively high $CO_2$production rate in 2nd stage. $CO_2$production depended on temperature less compared to acidity change(activation energy: 57.3 and 44.3kJ/mol for $CO_2$production of 1st and 2nd stages, respectively; 79.3kJ/mol for acidity change), which means higher ratio of $CO_2$production rate relative to acidity increase at lower temperature. Slower increase in acidity at low temperature also was shown to extend the period of 1st stage $CO_2$production. Therefore, low temperature fermentation was effective in producing the high $CO_2$content dongchimi at adequate acidity, which is desirable organoleptically.

• Asian-Australasian Journal of Animal Sciences
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• 제32권10호
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• pp.1528-1539
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• 2019

Objective: To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from $5^{\circ}C$ to $25^{\circ}C$ on corn silage which was previously fermented at ambient or low temperature. Methods: Whole-plant corn silage was fermented in vacuum bag mini-silos at either $10^{\circ}C$ or $20^{\circ}C$ for two months and stored at $5^{\circ}C$ for two months. The mini-silos were then subjected to additional incubation from $5^{\circ}C$ to $25^{\circ}C$ in $5^{\circ}C$ increments. Bacterial and fungal diversity was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiling and biochemical analysis from mini-silos collected at each temperature. Results: A temperature of $10^{\circ}C$ during fermentation restricted silage fermentation compared to fermentation temperature of $20^{\circ}C$. As storage temperature increased from $5^{\circ}C$ to $25^{\circ}C$, little changes occurred in silages fermented at $20^{\circ}C$, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a high number of enterobacteria and yeasts (4 to $5\;log_{10}$ colony forming unit/g fresh materials) were detected at $15^{\circ}C$ and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at $10^{\circ}C$, no significant changes were observed in most silage characteristics when temperature was increased from $5^{\circ}C$ to $20^{\circ}C$. However, above $20^{\circ}C$, silage fermentation resumed as observed from the significantly increased number of lactic acid bacteria colonies, acetic acid content, and the rapid decline in pH and water-soluble carbohydrates concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from $20^{\circ}C$ to $25^{\circ}C$. Conclusion: Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at $20^{\circ}C$ indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.

• 한국식품영양학회지
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• 제21권4호
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• pp.391-396
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• 2008

In this study, we attempted to optimize the fermentation processes in the production of lactic acid juice with 20% Maesil(Prunus mume) extract using Lactobacillus plantarum isolated from Kimchi, assessing a variety of pH, temperature, sugar compositions, and sugar concentrations. In the preparation of fermented Maesil(Prunus mume) extract, the optimal pH and fermentation temperature were 4.0 and $35^{\circ}C$, respectively. When the effects of various sugar sources and concentrations on lactic acid fermentation were assessed, 15% fructose was shown to yield more acid productivity than was observed with other sugar sources. The optimum composition, on the basis of our sensory evaluations, was determined to be a fructose concentration of 15% and a fermentation time of $72{\sim}96$ hours.

• 한국미생물·생명공학회지
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• 제15권5호
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• pp.356-360
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• 1987

Sisomicin 발효에 대한 온도의 영향을 살펴보았다. 각각의 온도에 대하여 균체의 비생육속도로부터 8.2 kcal/g-mol의 activation energy를 얻었다. 이 값은 발효중 균체가 균사체를 이루어 배지성분이나 산소에 대한 Internal diffusion layer를 형성하는 것을 시사해주고 있다. 한편 최종 항생물질농도는 온도가 증가함에 따라 감소하였으며, 온도의 변화를 주는 실험으로부터 대수증식기에 유지되는 배양온도가 최종 항생물질의 농도에 심한 영향을 주는 것으로 나타났다. 배양온도를 변화시켜 항생물질의 생산성을 증가시키는 방법에 대해 생각하여 보았다.

• Food Science and Biotechnology
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• 제15권5호
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• pp.814-816
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• 2006

Monacolin K (MK) was produced on soybean using Monascus ruber GM011 by a two-stage-fermentation process. The optimal temperature was identified as $28^{\circ}C$. Higher yield was obtained by multiple-level-temperature cultivation than by single-level-temperature cultivation. The highest yield of total MK, 4.810 mg/g dry soybean product, was attained after 30 days of solid-state fermentation. No citrinin could be detected in the fermented soybean.

• 한국수산과학회지
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• 제45권6호
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• pp.627-634
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• 2012

Squid Sikhae is traditional salt-fermented food in Korea. We evaluated the standardization of optimal processing conditions for desirable quality-controlled squid Sikhae using analyses of physiochemical properties, microbiological species, and organoleptic tests. Among several squid Sikhae preparation processes, the optimal fermentation temperature sun-dried sea salt concentration, and fermentation period for squid Sikhae of acceptable quality were $10^{\circ}C$, 4%, and 6 days, respectively. Amino-N and volatile basic nitrogen (VBN) contents of the acceptable quality squid Sikhae were 162.51 mg/100 g and 15.25 mg/100 g, respectively.