• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.250-256
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• 1998

D-Tagatose production from D-galactose was investigated using 35 type strains of American Culture Type Collection (ATCC) and Korean Collection for Type Cultures (KCTC) which have potential to produce D-tagatose. Enterobacter agglomerans ATCC 27987 was selected as a D-tagatose producing strain due to its short fermentation time and high production of D-tagatose. Optimization of the culture conditions for D-tagatose production by E. agglomerans ATCC 27987 was performed. Among various carbon sources, D-galactose was the most effective carbon source for D-tagatose production. As the D-galactose concentration was increased, cell growth and D-tagatose production increased. Effect of nitrogen sources on D-tagatose production was studied. Of inorganic nitrogen sources, ammonium sulfate was effective one for D-tagatose production and yeast extract was the most suitable organic nitrogen nutrient. The concentrations of inorganic compounds such as KH$_2$PO$_4$, K$_2$HPO$_4$, and MgSO$_4$$.$7H$_2$O were also optimized for D-tagatose production. The optimal medium was determined to contain D-galactose of 20 g/l, yeast extract of 5.0 g/l, (NH$_4$)$_2$SO$_4$ of 2.0 g/l, KH$_2$PO$_4$ of 5.0 g/l, K$_2$HPO of 5.0 g/l, and MgSO$_4$$.$7H$_2$O of 5 mg/l. The optimal environmental conditions in a 250-$m\ell$ flask were found to be pH of 6.0, temperature of 30$^{\circ}C$, and agitation speed of 150 rpm. D-tagatose of 0.41 g/l could be obtained in 24 h from 20 g/l D-galactose at the optimal culture condition without induction and cell concentration.

• Food Science and Preservation
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• v.20 no.2
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• pp.191-198
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• 2013

In this study, wheat doenjang was manufactured using Korean wheat meju and soybean meju, and its quality were investigated according to mixing ratio of meju. The general characteristics such as moisture contents, pH and salinity of wheat doenjang, which is fermented and aged at $25^{\circ}C$ for 70 days, were slightly decreased time dependently as similar pattern. The pH of wheat doenjang ranged from 4.95 to 5.11% and generally decreased with aging. The moisture contents was 54.5~57.5%, and there was no significant differences in the aging period. Also, there was no significant changes in the salt contents. The amino-type nitrogen contents were 376.27~600.91 mg% at day 70 of the aging period, and showed 3 fold change compared to the initial contents. The reducing sugar contents showed significant difference between the samples, and repeated fluctuation in the aging period. Wheat meju sample A, which contains 50% of soybean meju, showed the highest antioxidation ability. In addition, wheat meju sample A showed the highest score in the sensory evaluation of the colour, taste, flavor, and overall acceptability. Therefore, wheat doenjang manufacturing at a 1:1 of mixing ratio will lead to desirable quality of wheat doenjang.

• Journal of Life Science
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• v.22 no.10
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• pp.1295-1306
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• 2012

A microorganism producing carboxymethylcellulase (CMCase) was isolated from seawater and identified as Bacillus atrophaeus. This species was designated as B. atrophaeus LBH-18 based on its evolutionary distance and the phylogenetic tree resulting from 16S rDNA sequencing and the neighbor-joining method. The optimal conditions for rice bran (68.1 g/l), peptone (9.1 g/l), and initial pH (7.0) of the medium for cell growth was determined by Design Expert Software based on the response surface method; conditions for production of CMCase were 55.2 g/l, 6.6 g/l, and 7.1, respectively. The optimal temperature for cell growth and the production of CMCase by B. atrophaeus LBH-18 was $30^{\circ}C$. The optimal conditions of agitation speed and aeration rate for cell growth in a 7-l bioreactor were 324 rpm and 0.9 vvm, respectively, whereas those for production of CMCase were 343 rpm and 0.6 vvm, respectively. The optimal inner pressure for cell growth and production of CMCase in a 100-l bioreactor was 0.06 MPa. Maximal production of CMCase under optimal conditions in a 100-l bioreactor was 127.5 U/ml, which was 1.32 times higher than that without an inner pressure. In this study, rice bran was developed as a carbon source for industrial scale production of CMCase by B. atrophaeus LBH-18. Reduced time for the production of CMCase from 7 to 10 days to 3 days by using a bacterial strain with submerged fermentation also resulted in increased productivity of CMCase and a decrease in its production cost.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.214-222
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• 2012

Several acidogenesis batch tests, and BMP (Biochemical Methane Potential) with food waste leachate was tested at various organic loading rates (OLRs) on the mesophilic ($35^{\circ}C$) and thermophilic ($55^{\circ}C$) conditions. In acidogenesis batch test, VS removal efficiencies were 27.3% and 30.6% at $35^{\circ}C$ and $55^{\circ}C$, respectively. Removal efficiency of VS at $55^{\circ}C$ was higher than that at $35^{\circ}C$. With decrease in VS, SCOD increased as reaction time increased. Solubilization efficiency of VS were 27.4% and 33.4% at each reaction temperature within 4 days acid fermentation. Methane yield were 461 and 413 $mLCH_4/gVS$ at mesophilic and thermophilic BMP test, respectively. SCOD solubilizations in the themophilic acid fermenter showed 8~17% higher than those in the mesophilic fermenter. COD removal efficiency showed higher in the mesophilic acid fermenter at low organic loading rate. While at high organic loading rate, it was higher in the thermophilic acid fermenter. VS removal efficiency was higher at the mesophilic temperature, however, it decreased at OLR higher than 6 kg $COD/m^3{\cdot}day$. On the contrary, VS removal efficiency did not decrease but maintain at thermophilic temperature. The amount of methane gas generated from mesophilic methanogenesis digester was 12.6, 21.6, 27.4 L/day at OLR of 4, 5, 6 $COD/m^3{\cdot}day$, respectively. The amount of methane gas generated from themophilic methanogenesis digester was 14.3, 20.6, 25.2 L/day at each OLR, respectively, which is about 15~20 L/day lower than those generated at mesophilic digester.

• Journal of Food Hygiene and Safety
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• v.3 no.4
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• pp.225-232
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• 1988

To improve the storage method for Kimchi, optimal ripening Kimchi was irradiated with doses of 1,3,5 kGy Co-GO gamma radiation, followed by the microbiological, physicochemical and sensory evaluations during storage at $5^{\circ}C$. 1. Total aerobic count increased in the beginning of storage and then decreased slowly as the number of total lactobacilli (anaerobe) increased. The above total aerobic and lactobacilli were reduced by 1 to 3 log cycles with irradiation and at the 90th day after storage the number of total lactobacilli remained $1.30{\times}10^{8}\;per\;ml$ in3 kGy irradiated group. Irradiation treatment at 3 kGy sterilized coli forms and molds contaminating the sample as the level of $2.0{\times}10^{4}\;per\;ml\;and\;5.4{\times}10^{2}\;per\;ml$, respectively and no apparent growth was observed in both control and 1 kGy irradiated groups after 20 days of storage. The population.of yeast, $3.5{\times}10^{3}\;per\;ml$ initially, in, creased steadily during Kimchi storage and at 90 days of storage the number was shown to be $5.6{\times}10^{4}\;per\;ml\;and\;6.5{\times}10^{2}\;per\;ml$ in control and 3 kGy irradiated groups, respectively. 2. In the physicochemical changes during Kimchi storage, pH, acidity and volatile acid of non-irradiated control at the 45th day after storage were 4.0,0.7% and 0.066%, while those of 3 kGy irradiated group were 4.2, 0.59 and 0.06% at the 90th day of storage, respectively. The reducing sugar content of all stored samples changed inversely total acidity content, indicating irradiation delayed the changes of them. The amount of aseorbic acid decreased gradually with the storage time and irradiation dose increase. Textural parameters of 3 kGy irradiated group were superior to those of other groups at the latter stage of storage. 3. Sensory evaluations showed that 3 kGy irradiation was the optimum dose level to extend tite shelf-life of Kimchi more than two months as compared to control.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.127-136
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• 1996

Mak-kimchi (shredded kimchi) which was prepared in a commercial factory was packed in bottle (200 g) under vacuum (560 mmHg) or atmosphere, and chemical characteristics and microbiological parameters were monitored during storage at 5, 15 and $25^{\circ}C$, respectively. Optimum ripening time of the kimchi at different temperature were 2 days at $25^{\circ}C$, 5 days at $15^{\circ}C$ and more than 60 days at $5^{\circ}C$. By vacuum treatment pH and acidity changes in kimchi were considerably retarded. The vacuum of each bottle released within 1 or 2 days at 25 or $15^{\circ}C$, respectively but the pack at $5^{\circ}C$ maintained more than 380 mmHg vacuum for 36 days and then the vacuum slowly released. The colour of kimchi (lightness, redness, yellowness) in bottle increased sharply at $25^{\circ}C$ and $15^{\circ}C$ but sustained a stable level with vacuum treatment at $5^{\circ}C$. The range of total viable count of kimchi in bottle was $10^7{\sim}10^{10}/ml$. The number decreased by storage temperature drop to $5^{\circ}C$ and even more vacuum treatment than atmosphere treatment at $5^{\circ}C$. Lactobacillus brevis, L. plantarum, L. acidophilus, Aerococcus viridans and Streptococcus faecium subsp. casseliflavus were identified in bottled kimchi and L. brevis and L. plantarum contributed to the main function during kimchi fermentation. Those main lactic acid bacteria decreased in numbers at $5^{\circ}C$ than 25 or $15^{\circ}C$ and even more declined in case of vacuum treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.926-934
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• 2006

The base for preparing oyster hydrolysate-added yogurt was consisted of whole milk (1,000 mL), skim milk (44.05 to 42.05 g), enzymatic oyster hydrolysates powder (OHP, 0 to 2.0 g) and pectin. The yogurt base was fermented with 7 kinds of starter cultures (3% based on yogurt volume), such as Lactobacillus acidophilus, lactobacillus bulgaricus, lactobacillus casei, Lactobacillus fermentum, Lactobacillus pentosus, Streptcoccus thermophilus and the mixed starters (L. bulgaricus and S. thermophilus) at optimal temperature. Processing condition and quality characteristics of the yogurt were evaluated by analyzing pH, titratable acidity, viscosity, viable cell count, functional properties and sensory evaluation. The results suggested that the optimal conditions for preparing the good quality yogurt revealed the mixed starters (L. bulgaricus and S. thermophilus) for starter culture, 1.0 g of 3 kDa hydrolysate for amount, and 5.5 hrs for fermentation time. The good quality yogurt showed 4.31 for pH, 1.07% for titratable acidity, 469 cps for viscosity and $4.9{\times}10^8\;CFU/mL$ for viable cell count. The hydrolysate-added yogurt was 2 times higher in ACE inhibitory and antioxidant activities than commercial yogurt, and kept good quality during storage of 15 days at $5^{\circ}C$.

• Korean Journal of Breeding Science
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• v.41 no.1
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• pp.44-50
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• 2009

"Sukang", a winter wheat (Triticum aestivum L.) cultivar was developed by the National Institute of Crop Science, RDA. It was derived from the cross "Suwon266" / "Asakaze" during 1994. "Sukang" was evaluated as "Iksan312" in Advanced Yield Trial Test in 2005. It was tested in the regional yield trial test between 2006 and 2008. "Sukang" is an awned, semi-dwarf and hard winter wheat, similar to "Keumkang" (check cultivar). The heading and maturing date of "Sukang" were similar to "Keumkang". Culm and spike length of "Sukang" were 90 cm and 8.1 cm, longer culm length and similar spike length compared to "Keumkang" (80 cm and 7.9 cm, respectively). "Sukang" had similar test weight (819 g/L) and lower 1,000-grain weight (40.2 g) than "Keumkang" (813 g/L and 44.9 g, respectively). "Sukang" showed resistance to winter hardiness and pre-harvest sprouting, which lower withering rate on the high ridge (4.5%) and rate of pre-harvest sprouting (0.2%) than "Keumkang" (21.9% and 30.4%, respectively). "Sukang" had lower flour yield (71.1%) and higher ash content (0.45%) than "Keumkang" (74.1% and 0.42%, respectively). "Sukang" showed lower lightness (89.13) and higher yellowness (10.93) in flour color than "Keumkang" (90.02 and 9.28, respectively). It showed higher protein content (12.8%) and gluten content (11.1%) and lower SDS-sedimentation volume (56.8 ml) and mixing time of mixograph (2.6 min) than "Keumkang" (11.9%, 10.2%, 62.3 ml and 4.7 min, respectively). Fermentation properties, amylose content and pasting properties of "Sukang" were similar to "Keumkang". "Sukang" showed different compositions in high molecular weight glutenin subunits (HMW-GS, $2^{\ast}$, 13+16, 2+12) and puroindolines (pina-1b/pinb-1a) compared to "Keumkang" ($2^{\ast}$, 7+8, 5+10 in HMW-GS and Pina-1a/Pinb-1b in puroindolines, respectively). "Sukang" showed lower hardness (4.53 N) and similar springiness and cohesiveness of cooked noodles (0.94 and 0.63) compared to "Keumkang" (4.65 N, 0.93 and 0.64, respectively). Average yield of "Sukang" in the regional adaptation yield trial was 5.34 MT/ha in upland and 4.72 MT/ha in paddy field, which was 4% and 1% lower than those of "Keumkang" (5.55 MT/ha and 4.77 MT/ha, respectively). "Sukang" would be suitable for the area above $-10^{\circ}C$ of daily minimum temperature in January in Korean peninsula.

• Food Science and Preservation
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• v.19 no.6
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• pp.858-865
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• 2012

In this research, the soaking and steaming conditions of Korean wheat meju according to the degree of milling were investigated, and the quality characteristic was analyzed, for the manufacture of the standardized Korean wheat meju. As a result of the changes in weight, volume, moisture content, and moisture absorption amount, which indicate the physical properties of Korean wheat meju using 20% polished wheat, 50% polished wheat, whole wheat, and whole wheat flour, most of the wheat materials reached the equilibrium state after 4 hours of soaking. Also, the appropriate steaming time to complete the cooking of the wheat materials was found to be 10 min at $100^{\circ}C$, except for whole wheat. The 20 and 50% polished wheat materials were selected for Korean wheat meju based on the soaking and steaming results. The selected wheat materials were fermented using Aspergillus oryzae and Bacillus subtilis M1, respectively, and the quality properties and enzyme activities showed that A. oryzae would be effective for the manufacture of Korean wheat meju. Also, the 50% polished wheat showed higher total sugar content, reducing sugar content, and ${\alpha}$-amylase activity than the 20% polished wheat. Therefore, it is supposed that the fermentation of 50% polished wheat by A. oryzae would be appropriate for manufacturing superior Korean wheat meju.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.392-406
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• 1985

The soil management practices before transplanting the ginseng plant were studied with two organic matter sources such as a traditional organic matter (wild grass) and commercial organic fertilizer (byproducts of amino acid fermantation) during the late spring to late autumn. During the soil management practices, the soil received 40kg N/10a from five different combination treatments with above two organic matter sources, a wild grass and a commercial organic fertilizer. After the application of the treatments, the soil were ploughed regularly at the interval of 20 days and the changes of physicochemical properties during the soil management practices were investigated. The next year after soil management practices, ginseng plants were transplanted to each treatment, growth and the content of some organic components of ginseng plant were measured for comparision of the different treatments. 1. The decrease in bulk density observed during the first 40 days of management was considered to be the effect of the improved physical conditions caused by ploughing, The decrease in bulk density observed after 40 days of management was considered to be the effect of organic matter. Similar results were observed in particle density, however porosity increased with time. 2. Soil pH tended to decrease during the first 40 days of management, after which period the pH increased and was stabilized. However, CEC increased with organic matter treatment and the exchangeable $NH^+_4-N$ and $NO^-_3-N$ increased in 20 and 40 days after the management practices, respectively, and after that period it became steady. 3. The decomposition rate of treated organic matter was measured by the incubation test in laboratory conditions. The rate of decomposition was rapid during the first 20 days of management, after which period it showed slight changes. 4. The weight of ginseng root significantly increased in the treatment of 10kg N/10a organic fertilizer and 30kg N/10a wild grass. 5. The saponin content of ginseng root was highest in the 40kg N/10a wild grass treatment. The addition of organic fertilizer at the rate of more than 20kg N/10a caused the decrease in the saponin content.