• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.394-398
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• 2002

Acetic acid bacteria have been isolated from running high-acid vinegar fermentation. The color of the isolated colony was beige-yellowish. Isolated cell was rod-shaped, small, pale, absolutely aerobic and gram-negative. Microscopically the cells appeared as non-motile and non-flagellated, preferentially occuring in pairs. The optimum temperature and pH for culture were 30$\^{C}$ and 2.7, respectively. The strain was able to grow in the presence of acetic acid, ethanol and glucose. Ethanol was oxidized to acetic acid which was not oxidized any more. The isolated strain utilized glucose, fructose, maltose, sucrose, mannitol and sorbitol as carbon source. Cellulose formation was not detected on bouillon. The DNA (G +C) content of isolated strain was determined to be 56.2 mol%. The strain isolated from industrial vinegar fermentation was identified as Gluconacetobacter europaeus.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.378-384
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• 2015

Nuruk is a fermentation agent, which has been used for the production of traditional Korean alcoholic beverages. The objective of this study was to investigate the effects of temperature on nuruk fermentation. One wheat nuruk sample was fermented at $36^{\circ}C$ for 30 days (TN-A) and another at $45^{\circ}C$ for 10 days followed by $36^{\circ}C$ for 20 days (TN-B). The activities of ${\alpha}$-amylase, glucoamylase, and acidic protease, as well as metabolite contents were measured. Initially, the enzymatic activities increased rapidly regardless of the fermentation temperature. After 3 days of fermentation, the enzymatic activities were maintained in TN-A, but gradually decreased in TN-B until the end of fermentation process. Metabolite analysis using $^1H$-NMR showed that the levels of glucose, glycerol, fructose, mannitol, and lactose initially increased quickly and then decreased in TN-A. However, they initially decreased and then were maintained over the fermentation period in TN-B. The contents of glycine, proline, and serine were higher in TN-A than in TN-B. This study suggests that a constant temperature of approximately $36^{\circ}C$ is appropriate for achieving high amylolytic and proteolytic activities in the production of wheat nuruk.

• Preventive Nutrition and Food Science
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• v.4 no.4
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• pp.236-240
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• 1999

The characteristics of natural lactic acid fermentation of radish juice were investigated at different salt concentrations (0~2%) and temperatures (10~3$0^{\circ}C$). Major lactic acid bacteria isolated from the radish juice fermented at 2% slat concentration were Leuconostoc mesenteroides, Lactobacillus plantarum, and Lactobacillus brevis. The percentage of lactic acid bacteria against total microbe in the fermented radish juice was over 80% at 0~1% salt concentrations, suggesting the possibility of fermentation even at low salt concentration, but was still active even at 1$0^{\circ}C$. The time to reach pH 4.0 during fermentation of juice of 1% salt concentration was 281~301 hrs at 1$0^{\circ}C$ and 50-73 hrs at 3$0^{\circ}C$. The concentrations of sucrose and glucose in the fermented juice were low at high temperatures and were the lowest at a 1.0% salt concentration. However, the content of mannitol showed the opposite trend. Although sour taste, ripened taste, and acidic odor of the fermented juice showed no significant differences among various temperatures and salt concentrations, sensory values of ripened taste and sour acidic were high at high temperatures. The overall quality was the best at 1.0% salt concentration, irrespective of the temperature.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.340-345
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• 2010

The culture variables were optimized to increase 1,3-dihydroxyacetone (DHA) production by Gluconohacter oxydans ZJB09112 in shake flasks and bubble column bioreactors. After fermentation in the optimized medium (g/l: yeast extract 5, glycerol 2.5, mannitol 22.5, $K_2HPO_4$ 0.5, $KH_2PO_4$ 0.5, $MgSO_4{\cdot}7H_2O$ 0.1, $CaCO_3$ 2.0, pH 5.0), when five times of glycerol feeding were applied, $161.9{\pm}5.9\;g/l$ of DHA was attained at a $88.7{\pm}3.2%$ conversion rate of glycerol to DHA.

• Food Science and Preservation
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• v.23 no.5
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• pp.718-726
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• 2016

Sweet pumpkin paste (SPP) was fermented by Leuconostoc mesenteroides SM at $25^{\circ}C$ for 3 days for enhancing its physicochemical properties. SPPs with 5%, 10%, and 15% solid contents (SC) were fortified with 20% sucrose and 0.5% yeast extract. The unfermented SPP with 15% SC indicated L, a, and b color values of 25.02, 4.66, and 13.35, respectively, and a consistency index of $48.6Pa{\cdot}s^n$. During the 3 days of fermentation, both the a and b color values decreased slightly, whereas the consistency index increased to $188.8Pa{\cdot}s^n$, giving the fermented product a pudding-like consistency. This fermented SPP (15% SC) showed the highest acid production and viable cell counts among samples, indicating pH 3.85, 1.30% acidity and $9.2{\times}10^8CFU/mL$ respectively. The added sucrose was completely utilized after 1 day of fermentation. After 3 days, the insoluble and soluble dextran contents were 8.9% and 4.5%, respectively. Furthermore, the contents of mannitol and fructose were 3.11% and 1.76%, respectively. Regarding the sensory evaluation, this fermented sample also indicated the highest color, taste and texture scores, and was the overall preferred sample. In conclusion, the fermented SPP with 15% SC was carotinoid-rich a wholesome pumpkin-based product that is rich in probiotics and lactic bacteria-produced mannitol and dextran, which gave the product an acceptable viscous pudding-like consistency and good organoleptic properties.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.8-13
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• 1991

Bacteriocin-producing microorganisms were screened from raw milk and tested their antimicrobial activities against Lactobacillus plantarum ATCC 8014 as target organism, Antimicrobial substances isolated showed broad antimicrobial spectra against Gram positives and negatives. Strain 1112-1 was selected as a test organism due to its highest antimicrobial activity among the isolates. Antimicrobial substance produced by 1112-1 completely suppressed the growth of Lactobacillus plantarum at 230 IUIml and showed 11% growth inhibition of E. coli at 500 IUIrnl level. The antimicrobial substance was found to be proteinaceous material which was inactivated by carboxypeptidase, elastase, alpha amylase, amyloglucosidase, pronase, protease IV, alpha chymotrypsin, ficin, cellulase, phosphatase and lipase. The molecular weight was estimated by SDS-PAGE as 5,900. The isolate 1112-1 was identified as one of the related strains of Lactococcus sp. The strain was different from Lactococcus lactis in the following characteristics: late positive in maltose and sucrose fermentation; positive in mannitol and salicin fermentation; negative in lactose fermentation.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.514-520
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• 2021

This study identified and quantified the sugar-related metabolites and analyzed the structural features of starch in kimchi added with various concentrations of glutinous rice paste during fermentation. The pH values and total bacterial counts indicated that the fermentation of kimchi with 10% glutinous rice paste progressed more quickly than that of kimchi with other rice paste concentrations. The addition of glutinous rice pastes to kimchi resulted in increased glucose and decreased fructose contents during fermentation compared to the control kimchi. Maltose content increased significantly with increasing glutinous rice paste concentrations. The average chain length distribution of starch in kimchi decreased with increasing proportions of short chains as fermentation progressed. However, the average chain length distribution of starch increased with increasing glutinous rice paste concentration in kimchi. Our results confirmed that the sugar-related metabolites and starch structural changes were highly influenced by the added starch paste concentration.

• The Journal of the Korean Society for Microbiology
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• v.8 no.1
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• pp.13-17
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• 1973

To understand the characteristics of 29 toxigenic strains of Corynebacterium diphtheriae isolated in Seoul area, type classification, biochemical properties and antibiotic susceptibility pattern to 9 kinds of antibiotics were investigated. The results obtained were summerized as follows; I. Among the 29 strains, gravis type was the overwhelming majority(24 strains), followed by intermedius type(3 strains) and mitis type(2 strains). II. Fermentation of glucose, maltose, lactose, trehalose and mannitol, nitrate reduction and urease were tested. All strains fermented glucose, but not sucrose, lactose, mannitol and trehalose. 9 strains fermented maltose and 20 strains did not. Nitrate was reduced by 28 strains but not by one strain. In urease test one strain showed positive, 28 strains negative. III. Antibiotic susceptibility test to penicillin G, chloramphenical, kanamycin, lincomycin, streptomycin, terramycin, erythromycin and gentamycin were carried out. The MIC of erythromycin(0.025 ${\mu}g/ml$ 26 strains and 0.05 ${\mu}g/ml$ 3 strains) was the lowest, followed by ampicillin, lincomycin and penicillin G. Streptomycin showed the highest MIC.

• Korean Journal of Food Science and Technology
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• v.44 no.2
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• pp.173-178
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• 2012

The water extract of the fermented $Rhus$ $verniciflua$ stem bark (FRVSB) was prepared by hot water extracting at $100^{\circ}C$ for 8 h. The urushiol content of the FRVSB water extract was determined by HPLC. The urushiol was not contained in FRVSB water extract, whereas $Rhus$ $verniciflua$ stem bark (RVSB) water extract contained 3.4 mg%. At the lab scale size, suitable water extraction condition for a total solid, polyphenol and flavonoid from FRVSB was at over $100^{\circ}C$ for 6-8 h. The total solid contents was reduced in pilot scale processing system, with 5.7% of the extraction yield. The proximate composition (%) of FRVSB water extract obtained from industrial installation was moisture 4.34, crude fat 1.69, crude protein 10.21, and crude ash 15.80. Gallic acid (1,090.5 mg%) was the most abundant compound in phenolic acids, while fisetin (135.7 mg%) was the predominant flavonoid. The free sugar content was mannitol of 3.48%, glycerol of 0.19%, and glucose of 0.19%. Alanine (244 ppm), serine (231 ppm), and leucine (218 ppm) were predominant amino acids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.137-144
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• 2015

Kyejang is a Korean traditional beverage manufactured from medicinal plants and fruits using honey, sugar, or starch in cold water. In this study, cinnamon-containing kyejang, which is a type of beverage Jang, was reproduced based on Imwonsibyukji's method published in 1827 in the Korean literature. Kyejang made by nuruk, cinnamon, and medicinal plants was prepared at various temperatures and periods. Kyejang was assayed for physiochemical properties (pH and acidity), contents of metabolites (organic acids, sugars, and amino acids), and sensory characteristics (aroma and taste). During fermentation, content of organic acids (e.g. lactic acid, acetic acid, and shikimic acid) increased, which lowered pH, increased acidity, and increased intensity of sour taste. In the case of free sugars, fructose and maltose levels decreased while glucose and mannitol levels increased during fermentation periods, and sweetness decreased. The main amino acid in kyejang was tryptophan, followed by asparagine, proline, and arginine. The sensory evaluation score of overall preference was highest for kyejang which was fermented at $20^{\circ}C$ for 3 days. The results will be provide the basic data of fermentation conditions for standardized manufacturing process of kyejang.