• Food Science of Animal Resources
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• v.23 no.1
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• pp.50-55
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• 2003

Fresh ground pork was irradiated with the electron beam(3.0 and 5.0 kGy) using 2 different conveyer speeds (10 and 20 ㎐), respectively, in order to determine the effect of conveyer speeds on the development of lipid oxidation and microbial stability. During refrigerated storage, the development of lipid oxidation decreased significantly (p<0.05) with the increase in the electron beam conveyer speed from 10 to 20 ㎐. The ground pork with electron beam inhibited the growth of total aerobic bacteria and mesophiles. The inhibitory effect increased when the electron beam dose increased from 0 to 5.0 kGy. The finding that higher speed(20 ㎐) of electron beam had some antioxidative effect is very promising, however, other means to control the lipid oxidation must also be employed to fully utilize the sterilization effect of electron beam in ground pork.

• Food Science of Animal Resources
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• v.37 no.3
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• pp.429-439
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• 2017

This study investigated the antioxidative and functional effects of a curing agent containing grapefruit seed extract (GSE) on the quality and storage characteristics of chicken breast. The total polyphenol and total flavonoid contents of GSE were 45.06 mg/g and 36.06 mg/g, respectively. The $IC_{50}$ value of 2,2-diphenyl-1-picrylhydrazyl hydroxyl scavenging of GSE was $333.33{\mu}g/mL$. The chicken breast comprised six groups: no-treatment (N), 0.2% ascorbic acid + 70 ppm sodium nitrite (C), 0.05% GSE (G0.05), 0.1% GSE (G0.1), 0.3% GSE (G0.3), and 0.5% GSE (G0.5). The pH and cooking loss of cured chicken breast decreased with increasing GSE levels, and the water holding capacity increased with increasing GSE levels. The hardness and chewiness of GSE-treated chicken breast were higher than those of N and C. Hunter's L and a color values increased significantly after GSE addition. Moreover, 0.1% GSE (G0.1) increased the flavor and total acceptability scores. The 2-thiobarbituric acid and volatile basic nitrogen values of the 0.5% GSE group decreased significantly compared with those of C group. Total microbial counts of GSE-treated chicken breast were higher than those of C, but that lower than those of N. Adding GSE to chicken breast delayed lipid peroxidation and had antimicrobial effects during cold storage. GSE improved shelf life and palatability; therefore, it could be used as a natural antioxidant and functional curing agent ingredient in meat products.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.865-871
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• 2011

This study was conducted to evaluate the antioxidant effects of pumpkin leaf extracted using a 50% ethanol on ground pork during storage. The pumpkin leaf extracts were added at concentrations of 0.05 (PE-0.05), 0.1 (PE-0.1), and 0.2% (PE-0.2) to ground pork, and 0.05% of ascorbic acid (As-0.05) was added as a control. Each sample was collected after 1, 4, 7, and 10 d of storage and the pH, total viable counts (TVC), conjugated dienes (CD), free fatty acids (FFA), and thiobarbituric reaction substance (TBARS) values were measured. The pH of the pork samples decreased until day 7, and then increased thereafter, except for the control and PE-0.05 sample. Lower CIE $a^*$ values were observed for pork samples containing PE relative to As-0.05 at increasing storage time (p<0.05). The addition of PE decreased the TVC, CD, FFA and TBARS values levels in the ground pork when compared to the control during 10 d of storage. These results indicate that PE can produce notable effects on meat products, such as inhibiting lipid oxidation and discoloration.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.116-121
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• 2008

In my search of microbial source of novel enzymes, a marine actinomycetes, A1460, producing haloperoxidase was isolated from macroalgae from south sea, Korea and studied for physiological and biochemical properties. The haloperoxidation reaction was followed by the bromination of phenol red in the presence of hydrogen peroxide and potassium bromide. The haloperoxidase was partially purified from the cell extract with $35\sim75%$ ammonium sulfate precipitation, High-Q anion exchange chromatography, gel filtration chromatography, hydroxyapetite chromatography and hydrophobic interaction chromatography to a yield of 42% and purification fold of 70. This enzyme showed relatively high heat stability without losing 50% of activity after 1 hr incubation at $60^{\circ}C$. The highest activity was found at $45^{\circ}C$, and the optimal pH was about pH 7, but higher stability was observed at pH 8. Azide and cyanide ion showed strong inhibition at less than 1 $\mu M$ level suggesting that the enzyme was Fe ion dependent haloperoxidase.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.207-214
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• 2014

PURPOSE. This study characterized the synthesis of a modified PMMA (Polymethyl methacrylate) denture acrylic loading platinum nanoparticles (PtN) and assessed its bacterial inhibitory efficacy to produce novel antimicrobial denture base material. MATERIALS AND METHODS. Polymerized PMMA denture acrylic disc ($20mm{\times}2mm$) specimens containing 0 (control), 10, 50, 100 and 200 mg/L of PtN were fabricated respectively. The obtained platinum-PMMA nanocomposite (PtNC) was characterized by TEM (transmission electron microscopy), SEM/EDX (scanning electron microscope/energy dispersive X-ray spectroscopy), thermogravimetric and atomic absorption spectrophotometer analysis. In antimicrobial assay, specimens were placed on the cell culture plate, and $100{\mu}L$ of microbial suspensions of S. mutans (Streptococcus mutans) and S. sobrinus (Streptococcus sobrinus) were inoculated then incubated at $37^{\circ}C$ for 24 hours. The bacterial attachment was tested by FACS (fluorescence-activated cell sorting) analysis after staining with fluorescent probe. RESULTS. PtN were successfully loaded and uniformly immobilized into PMMA denture acrylic with a proper thermal stability and similar surface morphology as compared to control. PtNC expressed significant bacterial anti-adherent effect rather than bactericidal effect above 50 mg/L PtN loaded when compared to pristine PMMA (P=.01) with no or extremely small amounts of Pt ion eluted. CONCLUSION. This is the first report on the synthesis and its antibacterial activity of Pt-PMMA nanocomposite. PMMA denture acrylic loading PtN could be a possible intrinsic antimicrobial denture material with proper mechanical characteristics, meeting those specified for denture bases. For clinical application, future studies including biocompatibility, color stability and warranting the long-term effect were still required.

• Korean journal of food and cookery science
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• v.24 no.1
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• pp.92-98
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• 2008

In this study, salad dressing was prepared with added soypaste and its quality characteristics were evaluated. In terms of nutrient composition, the soypaste dressing contained higher levels of protein, minerals, and vitamins, and fewer calories, as compared to commercial mayonnaise. In addition, sensory evaluations revealed that the soypaste dressing received higher scores for flavor, taste, viscosity, and over-all preference than the commercial mayonnaise. The viscosity and emulsion stability of the freshly made soypaste salad dressing were 2,400 cP and 80%, respectively. And during 8 weeks of storage at $5^{\circ}C$, the viscosity and emulsion stability values remained similar to those of freshly made dressing. With prolonged storage time, the Hunter's color b-value slightly increased, whereas the L- and a-values slightly decreased. In terms of antioxidant activity, DPPH radical scavenging activity and lipid peroxidation inhibition were 2- to 3-fold higher in the soypaste salad dressing as compared to the commercial mayonnaise. And the soypaste dressing's antioxidant activity increased according to the storage temperature and time. Total microbial numbers increased to 6.2 log CFU/mL in the soypaste dressing, but E. coli was not detected. Overall, the results suggest that soypaste salad dressing could be introduced as a commercial product.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.818-825
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• 2012

Keratinases are exciting keratin-degrading enzymes; however, there have been relatively few studies on their immobilization. A keratinolytic protease from Chryseobacterium sp. kr6 was purified and its partial sequence determined using mass spectrometry. No significant homology to other microbial peptides in the NCBI database was observed. Certain parameters for immobilization of the purified keratinase on chitosan beads were investigated. The production of the chitosan beads was optimized using factorial design and surface response techniques. The optimum chitosan bead production for protease immobilization was a 20 g/l chitosan solution in acetic acid [1.5% (v/v)], glutaraldehyde ranging from 34 g to 56 g/l, and an activation time between 6 and 10 h. Under these conditions, above 80% of the enzyme was immobilized on the support. The behavior of the keratinase loading on the chitosan beads surface was well described using the Langmuir model. The maximum capacity of the support ($q_m$) and dissociation constant ($K_d$) were estimated as 58.8 U/g and 0.245 U/ml, respectively. The thermal stability of the immobilized enzyme was also improved around 2-fold, when compared with that of the free enzyme, after 30 min at $65^{\circ}C$. In addition, the activity of the immobilized enzyme remained at 63.4% after it was reused five times. Thus, the immobilized enzyme exhibited an improved thermal stability and remained active after several uses.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.754-762
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• 2012

Colbricon Superiore and Inferiore are two small adjacent high-mountain lakes located in the Paneveggio Natural Park (Italy) that offer the rare opportunity to study two iso-ecologic water environments differing only by area and volume in a ratio of 2:1 and 3:1, respectively. We took advantage of this setting to investigate phytoplankton dynamics, compare variability and productivity differences between the two basins, and assess size-dependent issues. The phytoplankton group of the Dinophyceae was chosen as the indicator organisms of ecological perturbation owing to their high sensitivity to environmental variations, as well as their acknowledged nature of versatile proxy to report global climatic changes. The study was conducted for over 10 years with fortnightly samplings. Results indicated that (a) the Dinophyceae communities in the smaller lake were significantly more resistant to changes exerted by the fluctuation of lakewater transparency and pH; and (b) the smaller lake sustained a consistently higher production with an average Dinophyceae density 1.73 fold higher than that of the larger lake. The coefficients of variation show that the chemical parameters in the smaller lake display higher time-related fluctuation while being spatially homogeneous and that such conditions correlate with a higher stability of the Dinophyceae assemblage. The use of this setting is also proposed as a model to test relationships between ecosystem production and physical stability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.880-884
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• 2005

Yellow pigment of Gardenia jasminoides was converted into new pigment by whole-cell biotransformation of thirteen different microbial species. The color value of the biotransformed pigment, which was produced by Streptococcus mutans MK-34, was higher than those of other biotransformed pigments. The biotransformed pigment produced by S. mutans MK-34 dispalyed an characteristic absorption peak at 588 nm and the absorption value increased during the incubation in a jar fermentor. The effects of light and temperature $(60^{\circ}C)$ on storage stability of the biotransformed pigment were investigated. As a result, the biotransformed pigments produced by Streptococcus mutans and Bacillus subtilis were more stable than Gardenia jasminoides yellow pigment during storage.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.12-17
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• 2007

A biosurfactant-producing strain, Bacillus subtilis TBM 3101 was isolated from the soil sample at Tae-Baek Mountain through an antifungal test and emulsification assessment. The strain was assessed, regarding to the microbial growth, by physical and chemical test, surface tension, emulsification activity and stability. The surface tension of the isolate sharply decreased to the minimum 29mN/m at 48 h growth. Of note, its emulsification was stabilized to the highest degree when tributyrin was utilized as a substrate, indicating that in comparison to a variety of synthetic surfactants, the biosurfactant produced by the isolate was significantly similar to synthetic surfactant, tween 20. In addition, the biosurfactant showed high emulsification activity when soybean oil, crude oil and tetradecane were used as a substrate. Thus, these studies could contribute to the detection and development of biosurfactant beneficial to the environment and humans.