• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.772-779
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• 2005

Ammonia-oxidizing bacteria (AOB) were enriched by repeating fed-batch cultivations in an AOB-selective medium of activated sludges from a domestic wastewater treatment plant. Enriched culture showed strong capabilities of ammonia oxidation [0.810 mg $NH_4^+$-N/mg mixed liquor suspended solids (MLSS)$\cdot$day] as well as $NO_x^-$-N production (0.617 mg $NO_x^-$-N/ mg MLSS$\cdot$day). Degree of enrichment was examined through fluorescent in situ hybridization (FISH) analyses using an AOB-specific Cy3-labeled oligonucleotide probe (NSOl90) and terminal-restriction fragment length polymorphism (T-RFLP) analyses. FISH analyses confirmed that the fraction of AOB among 4',6-diamidino-2-phenylindole (DAPI)-stained cells increased from about less than $0.001\%$ to approximately $42\%$ after enrichment of AOB, and T-RFLP analyses showed that bacterial community became simpler as enrichment was continued. When the enriched culture of AOB was added (150 mg/l as dry suspended solid) to the normal activated sludge (3,000 mg/l as dry suspended solid), nitrification efficiencies were improved from 0.020 mg $NO_x^-$-N/mg MLSS$\cdot$day to 0.041 mg $NO_x^-$-N/mg MLSS$\cdot$day in a synthetic wastewater and also from 0.0007 mg $NO_x^-$-N/mg MLSS$\cdot$day to 0.0918 mg $NO_x^-$-N/mg MLSS$\cdot$day in a real domestic wastewater. Therefore, it is expected that this enrichment method could be used for improving efficiency of nitrification in wastewater treatment plants.

• Journal of the Korean Society of Food Culture
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• v.30 no.1
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• pp.77-85
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• 2015

This study investigated the physicochemical properties and antioxidative activity of soymilk added with buckwheat sprout (SBS), and sensory properties of SBS were analyzed with control soymilk (CS). Moisture content decreased while protein, ash, and lipid contents increased according to content of buckwheat sprout. Solids content and viscosity tended to increase with addition of buckwheat sprout from 0% (CS) to 2.5% (2.5SBS), 3.5% (3.5SBS), and 4.5% (4.5SBS). SBS was found the significant pH drop from 7.08 to 6.43, 6.34, and 6.21. Suspension stability of soymilk slightly decreased with addition of buckwheat sprout. Hunter's color value L of SBS decreased while a and b values increased in comparison with CS. Rutin content was measured 23.78 mg/100 g (2.5SBS), 39.68 mg/100 g (3.5SBS), and 44.80mg/100 g (4.5SBS). Vitamin C content in SBS was higher than CS. Daidzin content increased as buckwheat sprout was added. Total phenolic content increased from 100.95 mg/100 g (CS) up to 315.71 mg/100 g (4.5SBS). For free radical scavenging activity, SBS was significantly higher than CS. In conclusion, SBS can be used as a functional food with higher amounts of rutin, vitamin C, total phenolics, and daidzin. 2.5SBS and 3.5SBS also showed better overall quality characteristics.

• Journal of the Korean Society of Food Culture
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• v.31 no.6
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• pp.597-604
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• 2016

This study was performed to investigate the quality characteristics of lotus root tea (LT) prepared with Gardenia jasminoides powder (GLT) and Rubus coreanus Miquel powder (RLT). The proximate compositions, physicochemical properties, mineral contents, and sensory evaluations of samples were measured. GLT sample showed higher contents of crude protein, crude fat, crude ash, and moisture (p<0.001) as well as pH (p<0.001) compared to LT and RLT. In terms of color, lightness (L) and yellowness (b) of GLT were the highest among the samples, whereas redness (a) of GLT was the lowest. The results of mineral analysis showed that the mineral contents of K, Ca, and Fe of LT were the highest, whereas the content of Mg of GLT was the highest. The results of browning color intensity of all samples showed that LT had the lowest. GLT showed higher contents of water soluble solids than LT and RLT. In the sensory evaluation, the scores of color, flavor, aftertaste, feeling of throat, and overall preference of LT and GLT were significantly higher than those of RLT. From the findings, this study suggests that addition of Gardenia jasminoides powder was effective for preparation of lotus root tea in the aspects of consumer acceptability.

• Journal of the Korean Society of Food Culture
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• v.36 no.1
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• pp.84-91
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• 2021

The oriental plum (Prunus salicina) is one of the most popular fruits in Korea due to its sweet taste and pleasant aroma. The objective of this study was to analyze the quality characteristics and antioxidant activities of a puree made using plums stored at low-temperatures. The quality characteristics were determined by estimating total soluble solids (TSS, °Brix), titratable acidity (TA, % citric acid), TSS/TA ratio, pH, colors, sugar content, and sensory profiles. The antioxidant effects were estimated by total polyphenol and flavonoid content and radical scavenging activity. The results showed that the plum puree containing both the flesh and the peel had markedly higher red coloration (a⁎ value) than the puree without the peel, while yellow coloration (b⁎ value) and lightness (L⁎ value) were lower in the puree without the peel than with the peel. The sensory qualities including the plum taste and flavor, texture as well as overall acceptance showed no significant variation between the samples. Meanwhile, the total polyphenol/flavonoid content and radical scavenging activities were significantly improved by the presence of fruit peel and by frozen storage. These findings suggest that frozen plums could be a suitable ingredient for making a puree and concentrate for the food manufacturing industry.

• Journal of the Korean Society of Food Culture
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• v.37 no.6
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• pp.555-563
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• 2022

The purpose of this study was to confirm the quality characteristics of distilled soju with different rice pretreatment processes. The non-steamed fermentation method is a technology that uses starch to produce saccharification and alcohol without going through the steaming of raw materials. It has advantages such as reduction of manpower and cost, prevention of nutrient loss, and minimization of waste water. In this study, rice used were non-steamed and pulverized 'Baromi2', nonsteamed and steamed 'Samgwang', and puffed rice. As the fermenting agent, koji, modified nuruk, N9 yeast, and purified enzyme were used, and lactic acid was added to prevent contamination during fermentation. The amount of water was 300% in total, and after the first watering, 5 days after fermentation, the second watering was carried out. As a result of the study, it was confirmed that the non-steamed fermentation method using 'Baromi' was superior to the existing fermentation method in terms of temperature during fermentation, final alcohol content, soluble solids, and pH. By expanding the stability of the production technology of non-steamed fermentation technology, product quality improvement can be expected.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.626-632
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• 2005

A new bacterium BL-2 excreting a novel cationic polyglucosamine biopolymer was isolated from the spoiled leaves of Chinese cabbage and identified as Enterobacter sp. BL-2. The isolated Enterobacter sp. BL-2 was cultivated in pH-stat fed-batch culture using acetic acid as the feeding stock at pH 8.0, resulting in 17.11 g/l of cells and 1.53 g/l of an extracellular biopolymer after 72 h. The excreted biopolymer was purified by a three-step procedure, involving ethanol precipitation and deproteinizations, to a nearly homogeneous state, and its molecular weight was found to be 106 kDa. It was composed of glucosamine, rhamnose, and galactose at a molar ratio of 86.4:1.6:1.0, respectively, indicating a rarely found novel high-glucosamine-containing biopolymer. The FT-IR and $^{13}C-NMR$ spectra of the novel cationic polyglucosamine biopolymer PGB-l revealed a close identity with chitosan from crab shell. It can effectively flocculate various suspended solids, including kaolin clay, $Ca(OH)_2,\;Al_{2}O_3$, active carbon, microbial cells, and acidic dyes.

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.317-323
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• 2009

Waste products were biologically estimated from juvenile flounder (Paralichthys olivaceus) on three diet types-raw fish-based moist pellets, moist pellets, and extruded pellets. Total solid and soluble wastes were estimated by determining nutrient digestibility and accumulation in juvenile flounders through growth trials. Total solid wastes produced were 20%-23% of the organic matter supplied. Soluble excretions ranged from 45% to 49%. Soluble nitrogenous excretions ranged from 36.4% to 46.2%. These results indicate that about 30.2%-35.9% of supplied feed is retained in the fishes' bodies while the remainder of feed is excreted into culture systems or the surrounding environment.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.19-26
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• 2010

Batch experiments were conducted to investigate growth and nutrient removal performance of microalgae Chlorella vulgaris by using piggery wastewater in different concentration of pollutants and the common growth models (logistic, Gompertz and Richards) were applied to compare microalgal growth parameters. Removal of nitrogen (N) and phosphorus (P) by Chlorella vulgaris showed correlation with biomass increase, implying nutrient uptake coupled with microalgae growth. The higher the levels of suspended solids (SS), COD and ammonia nitrogen were in the wastewater, the worse growth of Chlorella vulgaris was observed, showing the occurrence of growth inhibition in higher concentration of those pollutants. The growth parameters were estimated by non-linear regression of three growth curves for comparative analyses. Determination of growth parameters were more accurate with population as a variable than the logarithm of population in terms of R square. Richards model represented better fit comparing with logistic and Gompertz model. However, Richards model showed some complexity and sensitivity in calculation. In the cases tested, both logistic and Gompertz equation were proper to describe the growth of microalgae on piggery wastewater as well as easy to application.

• Food Science of Animal Resources
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• v.38 no.6
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• pp.1160-1167
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• 2018

The objective of this study was to evaluate the composition, pH, titratable activity, microbial properties, and antioxidant effect of yogurt using ginseng extract powder (GEP), Lactobacillus plantarum NK181, and Streptococcus thermophilus as the starter culture. Different concentration of GEP (0%, 0.5%, 1%, 1.5%, and 2% (w/v)) were used in the yogurt. During yogurt fermentation, pH was decreased; however, titratable acidity and viable cell counts were increased. The addition of GEP to yogurt led to a decrease in moisture content and an increase in the fat, ash, and total solids content. The antioxidant effect using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ${\beta}$-carotene bleaching, and ferric reducing antioxidant power (FRAP) assay gradually increased with added GEP. Overall, yogurt fermented with 1% GEP was acceptable in terms of cell viability and antioxidant effect. These results might provide information regarding development of ginseng dairy products with enhanced antioxidant activities and probiotic properties.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1470-1475
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• 1998

Two kinds of Korean rice-wine (Yakju) with different process and ingredients, and Japanese rice-wine (Sake) were chosen for this study, and throughly dried and solubilized in water or cell culture medium. In vitro cytotoxicity assays of the solubilized wine solids exhibited that maximum dilution factors for inhibition of B 16BL6 mouse melanoma cell growth were 16X for herbal medicine-added rice-wine (Korean rice-wine I) and typical Korean rice-wine (Korean rice-wine II), and 8X for Japanese rice-wine. Their cytotoxic effects on HRT18 human colon adenocarcinoma cells were even lower than those on B16BL6 cells. The morphology of the tumor cells were changed by addition of the solubilized wine solids. Inhibitory effect of the rice-wine on in vivo tumor growth and metastasis were monitored after implantation of B16BL6 cells into C57BL/6 mice with daily feeding the solubilized wine solids. Compared to non-fed control groups, B16BL6 tumor growth and metastasis to lung were clearly inhibited by feeding the wine solids, in order of Korean rice-wine I > Korean rice-wine II > Japanese rice-wine. The data of in vitro cytotoxicity and the cell shape changes indicate that the inhibitory effect of tumor progression may be attributed to tumor cell differentiation or immune stimulation induced by certain components in the rice-wine, rather than direct cytotoxicity of the components.