• Korean Journal of Microbiology
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• v.49 no.4
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• pp.403-414
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• 2013

This study evaluated the physicochemical and microbiological characteristics and antioxidant properties of yogurt samples fermented with lactic acid bacteria (LAB) obtained from pickled cabbage. API 50 CHL systems and 16S rRNA nucleotide sequence analyses revealed that the isolates were Lactobacillus casei PC05 and L. acidophilus PC16. Cell counts, titratable acidity, and viscosity of the yogurt samples fermented with L. acidophilus PC16 were significantly higher than those of the samples fermented with L. casei PC05 (P<0.05). The detected cell counts and physicochemical properties were significantly lower in plain yogurt than in soy yogurt (P<0.05). Yogurt samples fermented with L. acidophilus PC16 exhibited higher antioxidant activity, measured as ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and chelate ferrous ions, than those fermented with L. casei PC05. However, the ability to scavenge superoxide anions and superoxide dismutase (SOD) activity were significantly (P<0.05) higher in yogurt samples fermented with L. casei PC05 compared to those in samples fermented with L. acidophilus PC16. The antioxidant activity of soy yogurt was significantly (P<0.05) higher than that of plain yogurt. The antioxidant activity of the tested strains resulted in lipid peroxidation inhibition (in vitro), which may be related to the elimination of free radicals, chelating ability, and reducing power. There were no significant differences in the physicochemical properties and antioxidant activities of the yogurt samples during cold storage.

• Korean Journal of Poultry Science
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• v.45 no.1
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• pp.29-39
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• 2018

The goal of the present work was to determine the optimal addition amounts of liquid smoke and curing mixture to develop Chuncheon Dakgalbi with improved preference and shelf-life. In the first experiment, Chuncheon Dakgalbi was prepared with different amounts of liquid smoke. In the second experiment Chuncheon Dakgalbi was prepared with various amounts of curing mixture and 0.1% (w/w) liquid smoke. Different amounts of liquid smoke resulted in different aroma patterns, which were observed using an electronic nose, and Dakgalbi with 0.1% (w/w) liquid smoke had the highest score in overall acceptability. The addition of liquid smoke and curing mixture inhibited the growth of bacteria, slowed down the decline in pH, and delayed increased in volatile basic nitrogen contents and lipid oxidation. However, no clear effects were observed on instrumental color. From a consumer preference test, the highest preference score was achieved by added 0.2% (w/w) curing mixture. Liquid smoke and curing mixture extended shelf-life and improved preference of Chuncheon Dakgalbi. Considering the physicochemical, microbiological and consumer preference, it was recommended to add 0.1% (w/w) liquid smoke and 0.2% (w/w) curing mixture to Chuncheon Dakgalbi to enhance shelf-life and preference.

• Food Science and Preservation
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• v.11 no.3
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• pp.417-423
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• 2004

Botanical antimicrobial agent-grapefruit seed extract mixture (BAAG) have an unknown compounds which exhibit the antibiotic activities aganist microorganisms including bacteria and fungi. We have examined the effects of BAAG on the physiological function of Botrytis cinerea which was isolated from necrotic lesions of decayed fruits and vegetables such as cucumbers, grapes, tomatoes, and red peppers during storage. In the results of enzymatic activities related to the energetic metabolism there was no inhibitory effect of BAAG on the activities of several enzymes in vitro including glucose 6-phosphate dehydrogenase and malate dehydrogenase, while there was inhibitory effect of BAAG on the activities of hexokinase and succinate dehydrogenase. O-nitrophenyl-$\beta$-D-galactopyranoside(ONPG), the artificial substrate of $\beta$-galactosidase was hydrolyzed in the presence of BAAG, indicating that the membrane was pertubated by the BAAG. From the results we suggested that the antibiotic activity of BAAG is due to the change of membrane permeability of the cell. BAAG was fractionated and purified by silica gel and sephadex column chromatography. Among active fractions two peaks were identified as naringin and limonin when they were analyzed by by NMR and Fast atomic bombardment.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.132-140
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• 2017

Nuruk, a traditional Korean alcoholic beverage starter, was evaluated as an additional saccharifying agent comprising up to 1.5% (w/w) of malt weight in ale-type beer processing. Sample characteristics were monitored during fermentation, ripening, and storage. Beer containing nuruk showed higher numbers of total viable bacteria and yeast cell counts. Additionally, ethanol (6.19-6.35%), color (Standard Reference Method), foam stability ($228.49-368.24{Sigma}$), saccharogenic power (307-417), and reducing sugar (3.83-5.25%) increased as the amount of nuruk was increased, while viscosity (3.13-2.07 cP) and bitterness unit (19.68-13.13) were lower than in samples without nuruk. Overall acceptance and aftertaste of the beer were significantly higher in a preference test. These results demonstrate that nuruk can be used to produce a new type of ale.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.117-122
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• 2017

The aim of this study was to evaluate the quality characteristics of fresh red paprika treated by electron-beam irradiation at quarantine doses. The initial microbial loads were low with $10^4$ and $10^2$ colony-forming units/g for total aerobic bacteria and coliform, respectively; however, a dose of 1 kGy resulted in load reduction of 1 log cycle. A dose level of more than 1 kGy caused significant decreases in the hardness and carotenoid content parameters. An applied dose level of less than 2 kGy did not affect vitamin C content; however, a decrease of 87-90% was observed after 40-day storage. Samples treated with 2 kGy showed significantly lower acceptance compared to the control, with lower sensory evaluation scores for color and texture. Therefore, e-beam irradiation at dose range of 0.4 and 1 kGy was found to be appropriate for quarantine applications for microbiological control and quality maintenance of paprika.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.767-772
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• 2006

In this study, we sought to produce a double layer microcapsule containing Lactobacillus sp. as the core material. The conditions for this microencapsulation process were optimized for the formation of a microcapsule with high storage stability. The effects of the ratio of[core material] to [wall material], the type and concentration of emulsifier used, the stirring rate(dispersibility) and the temperature of the dispersion fluid on the microencapsulation yield were studied. The optimal concentration and type of emulsifier required in order to allow for the stable formation of a W/O type emulsion (a primary process in double layer microencapsulation) were 1.00% (w/w) and polyglycerol polyricinileate (PGPR, HLB 0.6). However, the optimal concentration and type of emulsifier required to construct a W/O/W type emulsion (a secondary process in double layer microencapsulation), were 0.65% (w/w) and polyoxyethylene sorbitan monolaurate (PSML, HLB 16.7). Finally, we obtained a maximum yield of microencapsulation with a dispersion fluid stirring rate of 270rpm and a dispersion fluid temperature of 10$^{\circ}C$ after spraying a W/O/W type emulsion into the dispersion fluid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.1
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• pp.7-11
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• 1990

As the putrefaction of fish is greatly relied on the microorganisms inhabited in the viscera of them, we investigated the microfloral changes in the viscera of sardine, Sardinops melanosticta, which has been caught a lot in adjacent sea of Korea but showed rapid spoilage, after storages with various temperature. The following results were obtained. Viable cell counts at $25^{\circ}C$ of the viscera of sardine were $1.6\times10^5/g$ at the fresh sample, $1.5\times10^5/g$ at the frozen sample, $2.9\times10^8/g$ at the spoiled samples. The most predominant microbial genera from the fresh sardine were Moraxella spp.($31.4\%$) and Pseudomonas spp.($28.6\%$), but Enterobacteriaceae($83.1\%$) was in spoiled sample. While Moraxella spp.($46.2\%$) and Flavobacterium-Cytophaga($21.0\%$) were predominant in the frozen sample and Enterobacteriacear($69.6\%$) was in the thawed-spoiled sample. The rates of proteolytic enzyme producing bacteria were $20\%$ in the fresh sample, $22\%$ in the frozen sample but the rates were increased to $52\%,\;29\%$ in the spoiled sample and the thawed-spoiled sample respectively.

• Journal of Dairy Science and Biotechnology
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• v.37 no.4
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• pp.237-246
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• 2019

In this study, quality characteristics of yogurt supplemented with Angelica gigas Nakai leaf extract were examined. The pH of the yogurt ranged from 4.40 to 4.45 and the titratable acidity ranged from 0.96% to 0.98%. The viscosity tended to decrease with the addition of the Angelica gigas Nakai leaf extract, but did not affect stability during storage. In the range of 0.1% to 0.3%, lactic acid bacteria were present in the range of 1.9×10⁹ to 3.2×10⁹ CFU/mL. The decursin content in yogurt was quantitatively analyzed, depending on the addition of 0.1% to 0.3% of Angelica gigas Nakai leaf extract and was found to be 0.26 ㎍/g, 15.23 ㎍/g, and 23.57 ㎍/g respectively. Organic acid showed the highest generation of lactic acid. The antioxidant properties of yogurt were shown to increase with the addition of the Angelica gigas Nakai leaf extract. The sensory score of yogurt supplemented with 0.1% of the Angelica gigas Nakai leaf extract was highly valued, at a level similar to that of plain yogurt. Yogurt supplemented with 0.2% of the extract was rated above the normal score of 6.31 to 6.50. As shown by the results, the optimal concentration of Angelica gigas Nakai leaf extract for addition to yogurt was within 0.2%.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1285-1291
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• 2005

In this study, we isolated bacteria from petroleum contaminated soil which were near to underground storage tanks(UST). Through the screen test, we selected high efficiency bacterium, KDi19, for biodegradation of diesel. KDi19 was identified as Pseudomonas sp. by 16S rDNA, fatty acid, and morphological physiological characteristics. KDi19 degraded 956.3 mg/L(95.6%) of 1,000 mg/L diesel for 48 hours(incubation condition : temperature; $30^{\circ}C$, cell concentration; 1.0 g/L, pH 7). At low temperature, $20^{\circ}C$, $15^{\circ}C$, $10^{\circ}C$, KDi19 respectively removed 63.9%, 18.5% and 17.0% of 1,000 mg/L diesel for 48 hours(cell concentration 1.0 g/L, pH 7). At low concentration of diesel, 50 mg/L and 100 mg/L, KDi19 degraded 97.9% and 96.2% of diesel for 24 hours(temperature; $30^{\circ}C$, cell concentration: 1.0 g/L, pH 7), respectively.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.265-270
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• 1993

In order to retain the freshness of fruits and vegetables and to reduce the rate of disease damage, grafruit seed extract (GPSE), natural microorganism control agent, was applied during the preservation process of fresh fruits and vegetables. GFSE showed an effective inhibitory action against plant putrefactive bacteria and fungi which were involved in the decay of fruits and vegetables. Minimal inhibitory concentrations for GFSE against the microbes were in the range of 50 to 2,000 ppm. Direct observation of microbial cells and spores using electron microscopy showed their function was destroyed by the treatment of the dilute solutions of GFSE. Fresh Welsh onions, onions and red peppers treated with GFSE and stored in polyethylene film (0.1 mm) retained better quality in color and texture than the non-treated control. GFSE was efficient in controlling the germination of potatoes. It was observed that GFSE would reduce disease damages and have bactericidal and fungicidal properties during the storage of such fruits and vegetables as zucchinis, cucumbers, tomatoes and mandarin oranges.