• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.443-449
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• 1999

Bacillus subtilis BK-17 which produces a novel protease with fibrinolytic activity was isolated from soybean paste. Bioreactor production of the enzyme was studied in order to optimize fermentation conditions such as medium concentration, pH, agitation speed, and temperature. Under most cultural conditions, enzyme production initially began when the cell growth stopped. The onset of the enzyme production was indicated by rapid increase in both dissolved oxygen (DO) and pH. Two- to three-times more concentrated medium than the flask optimum medium yielded higher enzyme production in the bioreactor fermentation. When the medium pH was controlled constant, pH 6.5 exhibited the highest activity in the range of 6.0 to 7.5, but the activity was similar to the case when the pH was initially adjusted to 7.5 and subsequently maintained within a relatively wide range of 6.4 to 7.8. Agitation speed did not affect the enzyme production with an exception of DO reaching zero. Fermentation time was reduced when temperature increased within the range of $25^{\circ}C$ to$37^{\circ}C$. However, the highest activity, along with the slow decrease of the enzymatic activity after reaching the maximum value, was observed at $25^{\circ}C$. By shifting the temperature from $37^{\circ}C$ to $25^{\circ}C$immediately after DO reached the minimum level, the high enzyme production of 1,100 U/ml along with the short fermentation period of 13 h could be obtained.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.247-259
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• 2008

Terminal-restriction fragment length polymorphism (T-RFLP) analysis, one of rapid culture-independent microbial community analysis methods, was used to determine the lactic acid bacterial complexity and dynamics during kimchi fermentation at $15^{\circ}C$ and $4^{\circ}C$. At both temperatures, the common presence of Leuconostoc mesenteroides, Lc. inhae, Lc. kimchi, Weissella koreensis, W. cibaria, Lactobacillus sakei, Lb. curvatus, Lb. plantarum, Lb. paraplantarum, Lb. pentosus, and Lb. brevis was predicted. Lc. citreum and Enterococcus faecalis were detected at $15^{\circ}C$ and $4^{\circ}C$, respectively. W. koreensis predominated during the mid stage of kimchi fermentation whereas lactobacilli were dominants during later stage. Lb. sakei and Lb. curvatus became dominants regardless of fermentation temperature but the growth of Lb. plantarum, Lb. paraplantarum, Lb. pentosus, and Lb. brevis was restricted at psychrophilic temperature. Some species of leuconostocs were maintained until the later stage of kimchi fermentation.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.86-91
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• 2004

Changes in erotic acid (OA) contents of raw milk and during cultivation and storage at refrigerated temperature were determined. OA contents of raw and 10% reconstituted milk held at $121^{\circ}C$ for up to 15 min decreased by 17.6 and 22.4%, and those fermented at 40 and $37^{\circ}C$ for 72 hr with Lactobacillus helveticus 166 and Lactobacillus casei 955 decreased 37.8-43.2 and 41.8-76%, whereas when fermented at $40^{\circ}C$ for 72 hr with Streptococcus thermophilus ST-37, did not decrease significantly compared with fermentation by other lactobacilli. OA content did not change during storage at refrigeration temperature. OA reduction by Lactobacillus sp. was dramatically increased at the initiation of stationary phase during fermentation. OA reduction varied among different lactobacilli. These results show decrease in cultivation time, rapid cooling of yogurt, and proper selection of Lactobacillus sp. prevent OA content reduction.

• Korean journal of food and cookery science
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• v.29 no.3
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• pp.267-274
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• 2013

Demand for a rice cake, a popular traditional food in Korea, is rising, but its industrial-scale production is extremely difficult due to its short shelf-life caused by starch retrogradation and microbial spoilage. By means of the sourdough fermentation technique, we attempt to develop rice cakes with a longer shelf-life. Heterofermentative lactic acid bacteria (Weissella koreensis HO20, Weissella kimchii HO22) isolated from kimchi were used to ferment wet-milled rice flour for their abilities to produce exopolysaccharides and to inhibit the microbial spoilage of rice cakes. After 24 hr of fermentation at $25^{\circ}C$, viable cell counts in rice dough increased from $10^6$ CFU/g to $10^8$ CFU/g and total titratable acidity increased from 0.05% to 0.20%, whereas pH decreased from 6.5 to 5.1. Fermented rice flour showed significantly lower peak, trough, and final viscosities as well as breakdown and setback viscosities measured by rapid viscoanalyzer. Both lactic acid bacteria showed in vitro antifungal activity against Penicillium crustosum isolated from rice cakes. The antifungal activity remained constant after the treatments with heat, proteinase K and trypsin, but fell significantly by increase of pH. Rice cakes made of fermented rice flour were found to retard mycelial growth of P. crustosum. The degree of retrogradation as measured by the hardness of the rice cake was significantly reduced by the use of fermented rice flour. The results suggest that use of fermented rice flour has a beneficial role in retarding starch retrogradation and in preventing fungal growth, hence extending the shelf-life of rice cakes.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.483-487
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• 1988

The viscosity of salt solution and Kimchi juice and salt penetration and hardness of Chinese cabbage were investigated during brining and fermentation at $4-35^{\circ}C$. The rate of salt penetration during brining increased as the temperature and salt concentration increased from 5% to 15% while the effect of temperature on the salt penetration rates(%/hr) was rather reduced as salt concentration increased. The hardness of the cabbage measured by puncture test showed a rapid initial decrease during salting and the viscosity of brine changed little. Fermentation of Kimchi resulted a little increase in viscosity of Kimchi juice while the hardness of the cabbage decreased rapidly as pH reduced to pH 4.2-4.3 and then increased a little thereafter.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.54-61
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• 1995

In order to investigate the effects of Ganoderma lucidum on the fermentation of media by Kluyveromyces fragilis KCCM 35458, with 0%, 0.1%, 0.5%, and 1.0% (w/v) of Ganoderma lucidum extract were added to skin milk and fermented in the suspension culture at $30^{\circ}C$ for 72 hours. The pH, acidity, $CO_2$ evolution, alcohol production, number of yeast cells and lactose content were investigated. The results are summarized as follows; 1. As fermentation time advanced by the pH was decreased and the acidity was increased in the media of 1.0% Gnaoderma lucidum extract as fermentation time advanced. 2. $CO_2$ evolution was increased in the all of Genoderma lucidum extract and significantly effect showed in 1.0% extract medium. 3. During 72 hours culturing, alcohol was detected in all Gandoderma lucidum extract media, 1.0% Ganoderma lucidum extract medium showed extremly high in alcohol and shortened fermentation time. 4. The number of yeast was increased more at logarithmic phase and the growth of yeast was more rapid in all Ganoderma lucidum extract especially 0.5%, 1.0% media samples than control. 5. As fermentation time goes by, the lactose content of media were decreased more rapidly in 1.0% Ganoderma lucidum extract medium than control.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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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.

• Animal Bioscience
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• v.37 no.8
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• pp.1398-1407
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• 2024

Objective: The objective of this study was to determine internal structure spectral profile of by-products from coffee processing that were affected by added-microorganism fermentation duration in relation to truly absorbed feed nutrient supply in ruminant system. Methods: The by-products from coffee processing were fermented using commercial fermentation product, consisting of various microorganisms: for 0 (control), 7, 14, 21, and 28 days. In this study, carbohydrate-related spectral profiles of coffee by-products were correlated with their chemical and nutritional properties (chemical composition, total digestible nutrient, bioenergy values, carbohydrate sub-fractions and predicted degradation and digestion parameters as well as milk value of feed). The vibrational spectra of coffee by-products samples after fermentation for 0 (control), 7, 14, 21, and 28 days were determined using a JASCO FT/IR-4200 spectroscopy coupled with accessory of attenuated total reflectance (ATR). The molecular spectral analyses with univariate approach were conducted with the OMNIC 7.3 software. Results: Molecular spectral analysis parameters in fermented and non-fermented by-products from coffee processing included structural carbohydrate, cellulosic compounds, non-structural carbohydrates, lignin compound, CH-bending, structural carbohydrate peak1, structural carbohydrate peak2, structural carbohydrate peak3, hemicellulosic compound, non-structural carbohydrate peak1, non-structural carbohydrate peak2, non-structural carbohydrate peak3. The study results show that added-microorganism fermentation induced chemical and nutritional changes of coffee by-products including carbohydrate chemical composition profiles, bioenergy value, feed milk value, carbohydrate subfractions, estimated degradable and undegradable fractions in the rumen, and intestinal digested nutrient supply in ruminant system. Conclusion: In conclusion, carbohydrate nutrition value changes by added-microorganism fermentation duration were in an agreement with the change of their spectral profile in the coffee by-products. The studies show that the vibrational ATR-FT/IR spectroscopic technique could be applied as a rapid analytical tool to evaluate fermented by-products and connect with truly digestible carbohydrate supply in ruminant system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.521-527
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• 2008

Acanthopanacis cortex extracts added Yakju was manufactured and then fermentation and quality characteristics of Yakju were examined. Acanthopanacis cortex extracts added Yakju showed totally similar characteristics with the non-extract added Yakju of control groups. The pH showed almost no change to pH 4.0 after 6 days of fermentation and it was decreased only once in only fermentation time of 3 days. The acidity of Acanthopanacis cortex extracts added group showed no difference to the control group. The sugar obrix and reducing sugar content showed decrease in all two groups in the initial fermentation stage; however, it showed slow decrease as the late fermentation stage. The Acanthopanacis cortex extracts added Yakju showed less alcohol content than the control group in the initial fermentation stage. However, after 6 days of fermentation, the Acanthopanacis cortex extracts added Yakju showed more alcohol contents and constant increase till the final fermentation day. The pH, acidity, reducing sugar and alcohol content showed rapid changes between fermentation days 0 through 3. Therefore, it means that the Acanthopanacis cortex extracts added Yakju fermentation actively takes place between the days 0 through 3. Organic acids detected in Yakju were acetic, lactic, oxalic, malic and succinic acids. The acetic acid was the highest among the total acid contents. Eleutheroside E and chlorogenic acid, known as the effective components of Acanthopanacis cortex, showed stable status without changes in component content till stage two fermentation. The contents of eleutheroside E and chlorogenic acid were $7.61\pm0.39{\mu}g/mL$ and $3.63\pm0.18{\mu}g/mL$ on the final fermentation day, respectively. The fusel oil was slightly detected in both groups with values of $0.08\pm0.001{\sim}0.86\pm0.03mg%$ in n-propyl alcohol, isobutyl alcohol and isoamyl alcohol content. The Acanthopanacis cortex extracts added group was similar to the control group in the overall sensory test.

• Korean journal of food and cookery science
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• v.17 no.4
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• pp.329-337
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• 2001

This study was carried out to observe the changes of Oiji quality during fermentation by preparing the samples with various functional ingredients (Chinese pepper(Sancho), onion, pine leaves) exerting antimicrobial effect. The pH values of all experiment groups decreased significantly in proportion to the ripening period(P＜0.05). Control and Chinese pepper-added groups showed a rapid decrease in pH after 5 days of ripening, and Onion- and Pine leaves-added groups after 3 days of ripening. All experimental groups showed the lowest pH value at the 20th day of ripening. Rapid permeation of salt solution occured in all groups at the 3rd day of ripening. But the increase rate of salt permeation decreased gradually after 3 days of ripening. Lightness and redness in color decreased gradually in all groups, but the redness of Pine leaves-added group increased at the 30th day of ripening. Yellowness of control group was higher than that of others after 10 days of ripening(P＜0.05), and the yellowness of pine leaves-added Oiji was the lowest among all after 5 days of ripening(P<0.05). The maximum cutting force of raw cucumber was observed at stem end followed by blossom end and middle part, and the Oiji samples also showed the same order at the early stage of ripening. In general, maximum cutting force of minor ingredient-added Oiji was higher than that of control and maximum cutting force was decreased at the 30th day of ripening. Onion-added group showed the highest value among all at the 40th day of ripening. Chinese pepper-added group was ranked low, but onion- and pine leaves-added groups were ranked high in sensory evaluation.