• The Korean Journal of Mycology
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• v.40 no.4
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• pp.244-253
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• 2012

The effect of fermented Rhus verniciflua stem bark (FRVSB) extract on the microbial count, enzyme activity, concentrations of free amino acids and organic acids, and physiochemical properties of doenjang (soybean paste) was evaluated during brine fermentation. The FRVSB extract increased the total free amino acid concentration by 1.3-3.1-fold on the $42^{nd}$ day of brine fermentation. After the filtration of brine, the following microbial counts were obtained in the doenjang: bacteria, $0.3{\times}10^8-12.0{\times}10^8$ cfu/g; mold, $3.0{\times}10^4-21.0{\times}10^4$ cfu/g; yeast, $1.0{\times}10^4-2.0{\times}10^4$ cfu/g; Escherichia coli, not detected; and Bacillus cereus, $3.0{\times}10^2-25.0{\times}10^2$ cfu/g. The FRVSB extract addition enhanced the protein and starch degrading activity by 13.8-26.0% and 16.1-35.1%, respectively. The extract increased the total free amino acid content by 1.4-3.0-fold. Lactic acid, acetic acid, and pyroglutamic acid were the predominant organic acids in doenjang. Moreover, the proximate composition, pH, moisture, ash, salt, and amino nitrogen content were increased.

• Journal of Animal Science and Technology
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• v.45 no.1
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• pp.131-142
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• 2003

We evaluated the effects of adding fibrolytic enzyme into ruminant diets on ruminal fermentation (in vitro) and lactational performances of dairy cows (in vivo). Through the in vitro experiment that was carried out with different contents of NDF (34, 38, 43%) in diets, digestibilities of NDF in the rumen appeared not significantly different by the addition of enzyme but were different by NDF content in diets showing higher digestibility in NDF 43% diet. It could be attributed by the relatively higher amount of hemicellulose in the current experimental diets than in conventional diets that might have been digested easily by the addition of fibrolytic enzyme in the rumen. The addition of fibrolytic enzyme tended to increase NDF digestibilities to a little extent both in 0.05 and 0.1% enzyme levels. Ruminal pH, NH3-N concentrations and VFA production in the rumen were not affected by the addition of fibrolytic enzyme. Activities of CMCase and xylanase were higher in enzyme treated diets of both NDF 34 and 38%. In particular, the activities of xylanase that slowly decreased from 0 to 12 hr but rapidly after 24 hr indicates that the major action of the enzyme in the rumen occurs in early period of incubation. Through an in vivo experiment, fibrolytic enzyme addition into the diets of dairy cows indeed affected lactational performance of milk yield. The cows fed enzyme treated diets produced 8% (1.9kg/d) more amounts of milk than with no enzyme addition. Milk composition of milk fat and protein was not affected by enzyme addition. Overall, the results of this in vivo study indicates that fibrolytic enzyme can be used to improve milk production in lactating cows. In respect that animals in different treatments of this study had the same amounts of intake, the increased milk yield with enzyme addition may be attributed to the improved utilization of nutrients in the digestive tract.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.702-708
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• 2015

The aim of this study was to investigate the physicochemical characteristics of commercial Mukeunji product along with its sensory properties. Six different types of commercial Mukeunji products were purchased through an on-line market, and each product had a different fermentation period. General commercial Baechu Kimchi was compared with commercial Mukeunji products in order to standardize quality properties of Mukeunji. As a result, commercial Mukeunji showed a lower pH value (pH 3.96, mean value) than commercial Baechu Kimchi (pH 5.92), whereas commercial Mukeunji samples showed higher acidity and salinity. Color values (L, a, and b) of commercial Mukeunji decreased as the storage period increased. Hardness and thickness of commercial Mukeunji showed a lower range compared to Baechu Kimchi. The reducing sugar content decreased as the storage period of commercial Mukeunji increased. Acetic, lactic, and succinic acids were detected in commercial Mukeunji samples, whereas citric acid and malic acid were additionally detected in Baechu Kimchi. Commercial Mukeunji samples showed lower contents of acetic and succinic acid and higher content of lactic acid than Baechu Kimchi. Commercial Mukeunji samples showed a significant difference in all descriptive sensory attributes except for bitterness. Overall intensity, sourness, moldy odor, redness, sour smell, saltiness, and carbonated taste increased as the storage period increased, whereas cabbage flavor, crispiness, sweetness, firmness, and savory taste decreased as the storage period increased.

• Food Science and Preservation
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• v.31 no.1
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• pp.149-160
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• 2024

Dextran is a glucose homo-polysaccharide with a predominantly α-1,6 glycosidic linkage of microbial source and is known to be produced primarily by lactic acid bacteria. However, it can also be obtained through the dextran dextrinase of acetic acid bacteria (Gluconobacter oxydans). The dextrin-based dextran was obtained from rice starch using G. oxydans fermentation of rice hydrolysate, and its properties were studied. Both dextrin- and rice hydrolysate-added media maintained the OD value of 6 after 20 h of incubation with acetic acid bacteria, and the gel permeation chromatography (GPC) analysis of the supernatant after 72 h of incubation confirmed that a polymeric material with DP of 480 and 405, which was different from the composition of the substrate in the medium, was produced. The glucose linkage pattern of the polysaccharide was confirmed using the proton nuclear magnetic resonance (¹H-NMR) and the increased α-1,4:α-1,6 bond ratio from 0.23 and 0.13 to 1:2.37 and 1:4.4, respectively, indicating that the main bonds were converted to α-1,6 bonds. The treatment of dextrin with a rat-derived alpha-glucosidase digestive enzyme resulted in a slow release of glucose, suggesting that rice hydrolysate can be converted to dextran using acetic acid bacteria with glycosyltransferase activity to produce high-value bio-materials with slowly digestible properties.

• Journal of Mushroom
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• v.10 no.3
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• pp.136-142
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• 2012

This study was carried out to determine the supplemental level of spent mushroom (Flammulina velutipes) substrates as an energy source in manufacturing of high moisture sorghum whole crop silage. Whole crop sorghum was harvested at heading stage and ensiled with spent mushroom substrates of 20% (S-20), 40% (S-40) and 60% (S-60) as fresh matter basis. Each silage was manufactured in plastic buckets included vinyl bag by three replications and stored for 0, 3, 6 and 9 weeks, respectively. Fermentation characteristics and quality of sorghum silages manufactured by supplemental level of spent mushroom substrates were as follows. Moisture contents of whole crop sorghum and spent mushroom substrates were 83.85% and 54.3%, respectively, and that of silages was 78% for S-20, 71% for S-40 and 68% for S-60. Ether extracts content of silages was significantly (P<0.05) increased during the fermentation periods. The pH in silages fermented for 3 weeks and above ranged from 4.24 to 4.42, and the decrease of pH by fermentation was relatively greater in S-40 compare to the other treatments. The lactic acid content of silage inclined that the S-40 was higher compared to the other treatments and decreased with elongation of fermentation period of silage. The contents of acetic acid and propionic acid of silages were not influenced by treatments and fermentation period. Flieg's score for estimation of silage quality ranged from 60 to 83, and was relatively high quality in the S-40 fermented for 9 week, and was relatively low quality in the S-60 fermented for 9 week. From above results, we suggest that 40% supplementation of spent Flammulina velutipes mushroom substrates as an energy source is resonable level in manufacturing of high moisture sorghum whole crop silage.

• Journal of Mushroom
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• v.12 no.2
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• pp.138-143
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• 2014

This study was conducted to know the optimal supplementary level of spent mushroom substrates (Flammulina velutipes) as an energy source and fermentation period in manufacturing of rye silage. Whole crop rye was harvested at full bloom stage and ensiled with spent mushroom substrates of 20%(S-20), 40%(S-40) and 60%(S-60) as fresh matter basis. Each silage was prepared in plastic buckets included with vinyl bag by three replications and fermented for 3, 6 and 9 weeks, respectively. Moisture contents of whole crop rye at full bloom stage and spent mushroom substrates were 62.3% and 54.3%, respectively, and those of silages was ranged from 58% to 64%. Ether extracts content of silages was significantly (P<0.05) increased in 6 weeks of fermentation period. The pH of silages ranged from 4.46 to 5.05, and fluctuated in the changes by fermentation period beside of decreased with elapsing the period in the S-60. The organic acid content of silages was higher in the order of lactic acid, butyric acid, acetic acid and propionic acid. Lactic acid content was higher when fermented for 6 weeks compared to the other fermentation period. Flieg's score for estimation of silage quality ranged from 63 to 80, and was relatively high level in the S-20 and the S-40 fermented for 6 weeks, and was high level in S-20, and was relatively low level in the silages fermented for 3 week. Hence, we suggest that supplementation of 20% spent mushroom substrates in fresh matter basis and fermentation for 6 weeks are resonable for a good quality of rye silage.

• Food Science and Preservation
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• v.15 no.4
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• pp.512-517
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• 2008

Fermentation characteristics of chestnut-added yakju prepared using various proportions of raw materials such as rice koji, rice flour, cornflour koji and cornflour were investigated. The pH of chestnut-added yakju prepared with cornflour koji and saccharified cornflour showed a higher value than that of chestnut-yakju prepared with rice koji and saccharified rice flour. The total acid content of chestnut-added yakju prepared with rice koji and saccharified rice flour was higher than that of chestnut-added yakju prepared using cornflour koji and sacharified cornflour. The reducing of sugar in chestnut-added yakju prepared with saccharified rice flour or saccharified cornflour was rapid at the first brewing stage, decreased dramatically after 2 days, and then decreased slowly after 5 days of fermentation. The value of L and a, the Hunter values, were high in chestnut-added yakju prepared with cornflour koji, and value b was high in chestnut-added yakju with rice koji. The content of iso-amyl alcohol was the highest of seven kinds of fusel oil found in chestnut-added yakju. Ethanol content increased to $17.6{\sim}18.2%$(v/v) after 8 days of fermentation. The content of lactic acid was the highest of all organic acids in the chestnut-added yakju. Sensory test results on chestnut-added yakju prepared with saccharifed corn flour showed that if rice flour is used as a sugar supplement for chestnut, the yakju prepared using koji had better flavor and taste. If cornflour was used in the preparation of chestnut-added yakju, the used of saccharified cornflour offered superior flavor and taste.

• Journal of Life Science
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• v.29 no.6
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• pp.688-696
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• 2019

This study investigated changes in triglyceride and cholesterol synthesis and tyrosinase activity induced by ice plant (Mesembryanthemum crystallinum L.) extract, which cannot be stored for long periods of time due to its high moisture content when it was fermented to improve its storage stability. The accumulation of triglyceride and cholesterol in HepG2 cells inhibited the accumulation with a relatively large magnitude in n-butanol and aqueous fractions that generally have high polarity, however, changes in inhibition potency due to the fermentation were not significant. As for the effect to inhibit tyrosinase activity, when L-tyrosine was used as a substrate, the inhibitory activity was the highest for the aqueous fraction at $60.58{\pm}4.03%$ and $63.35{\pm}4.35%$, before and after fermentation, respectively, which amounted to 72% of that of the positive control group (arbutin, $100{\mu}g/ml$). In addition, when L-3,4-dihydroxyphenylalanine (L-DOPA) was used as a substrate, the inhibitory activity was also found the highest for the aqueous fraction at $56.85{\pm}1.57%$ and $59.38{\pm}1.74%$, before and after fermentation, respectively, which amounted to at least 88% of that in the positive control (kojic acid, $100{\mu}g/ml$). Overall, the activity of the fermented ice plant extract was similar or a little higher compared to that of the one without fermentation, indicating that fermentation can be a good approach to improve the storage stability of the ice plant.

• Journal of the Korean Society of Food Culture
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• v.6 no.3
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• pp.237-244
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• 1991

This study was undertaken to examine the effects of ginseng on the acceptability of kimchi for 9 days at $20^{\circ}C$. Kimchi was analyzed for the measurement of acidity, pH, saltiness, reducing sugar, hardness by Instron and organic acids by HPLC. Ten highly trained panelists were involved in the sensory evaluation. The data analysis revealed followings; 1. While saltiness was maintained at around 2.3% level during the entire fermentation periods, kimchi containing 2% and 4% ginseng showed higher pH, reducing sugar, hardness by Instron, and lower acidity than without ginseng. 2. Results from analysis of organic acids contained by HPLC revealed that all three groups contained relatively high concentration of oxalic acid, lactic acid and malic acid. It was also found that, as fermented progressed, the amounts of lactic acid and acetic acid increased, and those of tartaric acid and malic acid decreased while the concentration of oxalic acid did not change significantly. 3. A result of sensory evaluation revealed that kimchi containing 2% and 4% ginseng was higher in hardness, savory taste and carbonated taste, and lower in sour taste, moldy off flavor than kimchi without ginseng, thus scoring high in overall eating quality. Considering all results obtained throughout this experiments, it can be concluded that the addition of small amount of ginseng to kimchi improve overall acceptability and retard rancidity, thus increasing the period during which is eatable.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5179-5186
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• 2012

Miglitol, a well-known therapeutic intervention agents for diabetes, exhibits competitive inhibitory activity against ${\alpha}$-glucosidase and it is usually produced through three sequential steps including chemical and bioconversion processes. Gluconobactor oxydans (G. oxydans) belonging to acetic acid bacteria biologically, converts 1-deoxy-1-(2-hydroxyethylamino)-D-glucitol (P1) into a key intermidiate, 6-(2-hydroxyetyl) amino-6-deoxy-${\alpha}$-L-sorbofuranose (P2) by incomplete oxidation. In this study, we identified and optimized fermentation conditions of CK-2165, that was selected in soil samples by comparing the bioconversion yield. CK-2165 strain was found to be closely related to G. oxydans based on the result of phylogenetic analysis using 16S rDNA sequence. Utilization of API 20 kits revealed that this strain could use glucose, mannose, inositol, sorbitol, rhamnose, sucrose, melibiose, amygdalin and arabinose as carbon sources. The culture conditions were optimized for industrial production and several important factors affecting bioconversion rate were also tested using mycelial cake. Cell harvested at the late-stationary phase showed the highest bioconversion yield and $MgSO_4$ was critically required for the catalytic activity.