• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.49-57
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• 2004

The effect of gas sparging on continuous fermentative $H_2$ production was investigated using external gases ($N_2$, $CO_2$) with various flow rates (100, 200, 300, 400 ml/min). Gas sparging showed a higher $H_2$ yield than no sparging, indicating that the decrease of $H_2$ partial pressure by gas sparging had a good effect on $H_2$ fermentation. Especially, $CO_2$ sparging was more effective in the reactor performance than $N_2$ sparging. The composition of butyrate, the main metabolic product of $H_2$ fermentation by Clostridium sp., was much higher in $CO_2$ sparging. $H_2$ production increased with increasing flow rate only in $CO_2$ sparging. The best performance was obtained by $CO_2$ sparging at 300 ml/min, resulting in the highest $H_2$ yield of 1.65 mol $H_2/mol$ hexoseconsumed and the maximum $H_2$ production of 6.77 L $H_2/g$ VSS/day. Compared to $N_2$ sparging, there could be another beneficial effect in $CO_2$ sparging apart from lowering down the $H_2$ partial pressure. High partial pressure of $CO_2$ had little effect on $H_2$ producing bacteria but inhibitory effect on other microorganisms like lactic acid bacteria and acetogens which were competitive with $H_2$ producing bacteria.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1785-1791
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• 2012

This study aimed to characterize and compare makgeolli (a Korean rice wine) made using different raw materials. Five cultivars of rice and wheat flour were used as starch materials for makgeolli and assessed for their moisture, crude lipid, crude protein, and crude dietary fiber content. Overall, wheat flour was higher in crude lipid and crude protein and lower in moisture than rice. Makgeolli characteristics were assessed for pH, total acids, organic acids, free sugars, color and appearance. We found no significant differences in pH and total acids between makgeolli made from rice and wheat flour. In addition, the major free sugar in the makgeolli made from rice and wheat flour was glucose, although the content of total free sugars was lower in the wheat flour makgeolli (67.75 mg/mL) than the rice makgeolli (76.41~84.53 mg/mL). In terms of organic acids content, the total organic acid content was highest in the wheat flour makgeolli, while the major organic acids of the makgeolli made from rice and wheat flour were lactic acid and succinic acid, respectively. There were no significant differences in color values among rice makgeolli, but the rice makgeolli was higher in sensory scores (indicating preference) than the wheat flour makgeolli. As the degree of milling increased, moisture, crude lipid, and crude protein in the rice decreased. Acetic acid in the makgeolli also decreased, while there were no significant differences in pH, total acids, free sugars, color values, and sensory scores (except fruitiness). Traditional nuruk (TN) and cultured nuruk (CN) were compared as fermentation starters. Nuruk is a Korean traditional starter for fermentation of makgeolli and a raw material for makgeolli making. The pH in the makgoelli made with TN and CN were 4.29~4.65 and 4.02~4.23, respectively. Total organic acid content was higher in the TN makgeolli (3.5~6.3 mg/mL) compared to the CN makgeolli (2.3~4.3 mg/mL). The content of free sugars in the makgeolli made with CN was higher (59.44~73.34 mg/mL) than that with TN (56.45~59.75 mg/mL). The Hunter color test showed that makgeolli made with TN was lighter and higher in red and yellow color compared to CN. Overall sensory acceptability was higher in the CN makgeolli compared to the TN makgeolli.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.1
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• pp.6-11
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• 2015

This study was undertaken to characterize feed value and silage quality according to storage period and film layers for whole-crop barley silage. The crude protein (CP) content increased in all silage during the storage periods compared to those before silage, this content slightly increased over the prolonged storage period but it was not significant (p>0.05). Depending on the film layers of silage, 6 layers were higher than 4 layers. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents also increased in all silage during storage periods compared to those before silage (P<0.05), but they were maintained at similar levels during the storage period. Depending on the film layers of silage, 6 layers were higher than 4 layers. The total digestible nutrients (TDN) content decreased in all silage during the storage periods. However, it was maintained at a similar level for the duration of each storage period. Depending on the film layers of silage, 6 layers were lower than 4 layers. The pH value was decreased during the prolonged storage period and depending on the film layers, 6 layers were lower than 4 layers. In the organic acid contents during the prolonged storage period, lactic acid increased, acetic acid was lower, and butyric acid was significantly higher (p<0.05). Depending on the film layers, 6 layers showed higher levels of lactic acid and lower levels of butyric acid (p<0.05). Therefore, these results showed that 6 layer wrapping was advantageous for long term storage of whole crop barley silage, while also indicating that it is desirable to use 4 layer wrapping within a six month period.

• Food Science and Preservation
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• v.22 no.3
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• pp.369-376
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• 2015

This study was performed to develop the maufacturing processes of Makgeolli using red ginseng starch (RGS). After the fermentation of RGS with koji, nuruk, and yeast, the different temperature effects on the number of the yeast cells, the content of organic acid, free sugars, and total acid, and pH were investigated. There were no changes in the composition of the yeast cell number and content of organic acid amd during 20 days at $4^{\circ}C$. The content of free sugars (sucrose, glucose and mannose) and the pH value of red ginseng Makgeolli decreased during storage at $4^{\circ}C$. This meant that the total acid content and pH value increased after organic acid was produced from fermentation. Therefore, red ginseng Makgeolli is highly acidic and sour. Since high acidity helps improve storage conditions, so this developed red ginseng Makgeolli is considered safe for consumption. Furthermore, the total content of ginsenoside was 2.47 mg/mL, which was differentiate Makgeolli using red ginseng starch, with others. Therefore, new red ginseng Makgeolli is rich in organic acid, free sugars, and ginsenoside. As a result, its storage, taste, and flavor improved.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.2
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• pp.80-86
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• 2020

This study was conducted to research on the efficacy of chemical treatment as an effective method for reducing mycotoxin in rice straw silage. As a chemical treatment method, ammonia and sodium hydroxid were treated at 4% level of rice straws contaminated with mycotoxin, and the effects of silage storage on fungal toxin reduction, fermentation quality, and fiber digestion were evaluated. Aflatoxin B₁, B₂, G₁, G₂ and fumonisin B₁, B₂ as well as deoxynivalenol were not detected in all experimental groups, and ochratoxin A and zearalenone were detected. Ochratoxin A was detected lower in the chemical treatment than control (41.23 g / kg) (p<0.05). Zearalenone showed lower results in sodium hydroxide treatment (297.44 ㎍ / kg) than control (600.33 ㎍ / kg) and ammonia treatment (376.00 ㎍ / kg) (p<0.05). The pH of rice straw silage was the lowest in ammonia treatment and the highest in sodium hydroxide treatment (p<0.05). The lactic acid contents of control and ammonia treatments were similar, but sodium hydroxide treatment was the lowest (p<0.05). Propionic acid was higher in the control than in the chemical treatments (p<0.05), and showed similar contents in the ammonia and sodium hydroxide treatment. Both the rumen microbial degradation rate of NDF and ADF showed the highest in sodium hydroxide treatment, followed by ammonia treatment, and the control showed the lowest level (p<0.05). Therefore, the results of this study are demonstrated to have a good effect on the treatment of ammonia and sodium hydroxide to reduce the mycotoxins and increase the rumen microbial degradation rate in the rice straw silage. Sodium hydroxide treatment was more effective in reducing mycotoxins and improving fiber degradation rate than ammonia treatment, but it is thought to have an inefficient effect on silage fermentation in rice straw silage.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.54-59
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• 1996

Three strains of inhibitory lactic acid bacteria (No. 49, No. 61, No. 75) against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escheirchia coli(ATCC33694) and Bacillus subtilis(ATCC6633) were isolated from kimchi, and then, identified to be Lactobacillus plantarum after examinations of their biological and physiological characteristics. To investigate a possible application of these three lactobacilli in milk fermentation industry, we made yogurts and then evaluated their ${\beta}-galactosidase$ activities at various; incubation time(from 24 hrs to 72 hrs). The result of experiment was that ${\beta}-galactosidase$ activities were reached maximum at 48 hrs and that reduced gradually with the lapse of time. And the ${\beta}-galactosidase$ activity of lactobacilli, and their viable cell counts at $37^{\circ}C$ for 2 hrs under various pH conditions were investigated. ${\beta}-galactosidase$ activities of 3 strains were reduced 50% at pH 3.5, but there were no remaining activities at pH 2.5, and pH 1.5, respectively. The frequency of the survival cell of lactobacilli in yogurt were $0.12{\sim}0.75%$ at pH 2.5, $$6.3{\times}10^{-5}{\sim}2.7{\times}10^{-3}% at pH 1.5, respectively, but there was no significant difference at pH 3.5. The values of original pH, titratable acidity as lactic acid, viscosity, and viable cells of yogurts were $4.08{\sim}4.30,\;1.05{\sim}1.25%,\;1,818{\sim}2,124\;cps\;and\;7.3{\times}10^8{\sim}3.0{\times}10^9\;cfu/m{\ell}$, respectively. To estimate buffer capacity of yogurt, the volume of 1.0 N HCl to 2 unit below original pH of yogurt($100\;m{\ell}$) was $11.98{\sim}13.02\;m{\ell}$ and the volume of 1.0N NaOH to 4 unit above original pH of yogurt($100\;m{\ell}$) was $10.82{\sim}12.86\;m{\ell}.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1030-1036
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• 2008

In Korea, many types of traditional grape wine have existed starting from seven hundred years ago and horse-blossom-like-grape (mayu-podo) was mainly cultivated. Korean traditional wine (KTW) was manufactured by a unique method in which grape juice-added porridge made from glutinous rice was fermented by nuruk as a starter for brewing. Unfortunately, KTW making was discontinued in 20th century; thus, restoration of Korean wine culture is needed. KTWs were prepared by four traditional methods, and their qualities were compared to commercial wine made by sugaring grape juice. Ethyl alcohol contents, total acidity, pH and amino acid of the four KTWs were $9.2{\sim}11.2%$, $0.93{\sim}1.20\;mg$/100 mL, $3.02{\sim}3.48$ and $0.80{\sim}0.88\;mg$/100 mL respectively. The KTWs showed higher values in total acidity and amino acid than those of commercial grape wine. KTWs were rich in maltose, acetic acid and lactic acid. L, a and b value in Hunter's color value ranged $3.59{\sim}3.69$, $20.63{\sim}38.06$, and $1.20{\sim}1.56$, respectively. Sensory quality properties in color, flavor, taste and overall of KTWs were not different from commercial dry wine. Contents of total phenolic compounds and free radical scavenging activity using DPPH of KTWs were $599.6{\sim}652.2\;mg$/100 mL and $50.59{\sim}56.75%$, respectively.

• The Korean Journal of Food And Nutrition
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• v.18 no.3
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• pp.207-218
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• 2005

In room temperature, Kimchi becomes acidified and a little decayed, scenting a bad smell, and It couldn't be well kept. But if it should be made into a pill, it could be preserved for a long time for marketing, with nutrition highly concentrated as well as with no scent. Therefore, making Kimchi into a pill needs drying. When dried Kimchi, lactic acid and fragrant ingredient will vanish along with volatilization. The cyclodextrin(CD) as a stabilizer shows that the protecting rate of volatility of lactic acid in Kimchi is higher before than that of after fermentation, and it is higher at the addition $2\%\;than\;of\;1\%$ in case of Kimchi with CD. But it doesn't give much effect on total sugar, reducing sugar, protein and amino acid. Evaporation rate of lactic acid is the least in freeze dry, and natural dry, heat dry come next, respectively. In heat dry, if dried at more than $60^{\circ}C$ for a long time, Kimchi exudes boiling and scorched scent, causing bitter taste. The result of HPLC with superose 12 column at 280nm and 210nm shows that place and amount of main peak is almost the same, but the distribution of other peaks are different, with the revelation of various peaks like peptide and amino acid. The Kimchi pill made by the addition of $1\%$ CD shows that concentration is eight times higher than general Kimchi, total sugar is $14.4\%$, reducing sugar is $8.8\%$, protein is $4.8\%$, amino acid is $2.4\%$, and other contents are $74.4\%$, acidity is 32.8, and pH is 3.5 each. The result of letting 20 people with obesity, 20 patients with constipation have 30 pills(total weight 30g) three times a day for 60 days reveals they lost $2.29\%$ in weight on the average, and 7 among 20 were all relieved in constipation, and 8 responded that they experienced its efficacy.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.249-254
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• 2002

To determine the abilities as both lactic starter and probiotics for fermented foods, we investigated the potency of acid production, proteolytic activity and lactose metabolism of Lactobacillus amylovorus IMC-1. And the strain was cultured with lactococci in 10% skim milk medium. It was also examined the bactericidal action of antibacterial substance, produced by the strain IMC-1, against pathogenic bacteria. L. amylovorus IMC-1 showed excellent production of acid in 10% skim milk supplemented with yeast extract, and produced 0.8 and 2.7% of acid at 12 and 72 h incubation, respectively. It was found that the activity of ${\beta}-galactosidase$, about $39\;{\mu}M/minute/dry$ cell weight (mg), was stronger than that of $phospho-{\beta}-galactosidase$ in the strain IMC-1. The strain showed weak proteolytic activity in 10% skim milk, thus it produced 6 and $69\;{\mu}g/mL$ of free tyrosine at 12 and 72 h cultivation, respectively. It was known that the strain utilized mainly ${\alpha}-casein$ than ${\beta}-casein$ from patterns of SDS-PAGE. Mixed culture produced more acid than single cultures of L. amylovorus IMC-1 and Streptococcus thermophilus NIAI 510. Single culture of Str. thermophilus and mixed culture showed increasing cheese flavor with incubation times. Optimal fermentation time of mixed culture for the acid production and flora of lactic starter was 16 and 12 h by adding 0.1 and 0.5% of yeast extract to 10% skim milk, respectively. Antibacterial substance produced by the strain IMC-1 reduced about 2 log of the viable cell counts of both Escherichia coli O157 and Shigella flexneri after 24 and 4 h incubation, and they were not detected after 48 and 6 h incubation, respectively.

• Journal of Life Science
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• v.24 no.10
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• pp.1102-1109
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• 2014

Chungkookjang has several functional properties, such as fibrinolytic activity, anticancer effects, and antioxidant effects. However, children do not like Chungkookjang because of its foul odor. A mixed culture of Bacillus subtilis MC31 and Lactobacillus sakei 383 was used to improve the production of GABA in Chungkookjang and its flavor. Most of the foul odor of Chungkookjang was removed. The slime content and viscosity of Chungkookjang fermented in the mixed culture were similar to those of commercial Chungkookjang when B. subtilis MC31 and Lactobacillus sakei 383 were inoculated in a 1:1 ratio. The maximum GABA content was obtained when Chungkookjang was fermented with B. subtilis MC31 and L. sakei 383, which was fermented at $37^{\circ}C$ for 72 hr. During the period of fermentation, the viable cell number of B. subtilis MC31 reached a peak (log 9.13 CFU/g) at six days, and L. sakei 383 reached a peak (log 6.78 CFU/g) at two days. The moisture, crude ash, crude protein, crude fat, and crude fiber contents were 61.71%, 2.05%, 17.54%, 8.36%, and 1.95%, respectively. The amino-type nitrogen content of Chungkookjang fermented by B. subtilis MC31 and L. sakei 383 was less than Chungkookjang fermented by B. subtilis MC31 alone. The ammonia-type nitrogen and reducing sugar content of the Chungkookjang fermented by B. subtilis MC31 and L. sakei 383 were higher than that of steamed soybean. The glutamic acid and GABA content detected with an amino acid analyzer were 1.40 mg/g and 0.47 mg/g, respectively. These results suggest that fermentation with B. subtilis MC31 and L. sakei 383 in a 1:1 ratio removes more of the foul odor and increases the GABA content compared with single fermentation.