• Food Science of Animal Resources
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• v.39 no.4
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• pp.601-609
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• 2019

Bifidobacterium longum KACC 91563 secretes family 5 extracellular solute-binding protein via extracellular vesicle. In our previous work, it was demonstrated that the protein effectively alleviated food allergy symptoms via mast cell specific apoptosis, and it has revealed a therapeutic potential of this protein in allergy treatment. In the present study, we cloned the gene encoding extracellular solute-binding protein of the strain into the histidine-tagged pET-28a(+) vector and transformed the resulting plasmid into the Escherichia coli strain BL21 (DE3). The histidine-tagged extracellular solute-binding protein expressed in the transformed cells was purified using Ni-NTA affinity column. To enhance the efficiency of the protein purification, three parameters were optimized; the host bacterial strain, the culturing and induction temperature, and the purification protocol. After the process, two liters of transformed culture produced 7.15 mg of the recombinant proteins. This is the first study describing the production of extracellular solute-binding protein of probiotic bacteria. Establishment of large-scale production strategy for the protein will further contribute to the development of functional foods and potential alternative treatments for allergies.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.6
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• pp.911-917
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• 2011

This study was to investigate the characteristics of the Yakju fermented with differently-processed lotus leaves such as blanching, steaming, roasting, and drying, and fresh one for control. The total acid content was high (0.82~1.22%) in the lotus leaf Yakju, and lactic acid was the main compound among organic acids. Volatile acid content was high (200~500 mg/L) compared to the results of organic acid composition, and the main volatile acid in lotus leaf Yakju was acetic acid. Though the polyphenol content (616.5~693.1 mg/L) was similar among the Yakju, the Hunter's color value of those were quite different and also had a big impact on the sensory evaluation of color. Therefore, it seems that the enzyme activity of polyphenol oxidase in differently-processed lotus leaves may have an influence on the color of lotus leaf Yakju. In a sensory evaluation of color and aroma, lotus leaf Yakju fermentaed with fresh leaves and roasted ones were preferred to the others, and steamed leaves and roasted ones were the best in taste and overall acceptability.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.245-253
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• 2014

A fibrinolytic enzyme was produced by an edible mushroom of Pleurotus ostreatus using submerged culture fermentation. The enzyme was purified from the culture supernatant by applying a combination of freeze-thaw treatment, ammonium sulfate precipitation, hydrophobic interaction, and gel filtration chromatographies. The enzyme was purified by a 147-fold, with a yield of 7.54%. The molecular masses of the enzyme an determined by gel filtration and SDS-PAGE were 13.6 and 18.2 kDa, respectively. The isoelectric point of the enzyme was 8.52. It hydrolyzed fibrinogen by cleaving the ${\alpha}$ and ${\beta}$ chains of fibrinogen followed by the ${\gamma}$ chains, and also activated plasminogen into plasmin. The enzyme was optimally active at $45^{\circ}C$ and pH 7.4. The enzyme activity was completely inhibited by EDTA, whereas protease inhibitors of TPCK, SBTI, PMSF, aprotinin and pepstatin showed no inhibition on its activity. The partial amino acid sequences of the enzyme as determined by Q-TOF2 were ATFVGCSATR, GGTLIHESSHFTR, and YTTWFGTFVTSR. These sequences showed a high degree of homology with those of metallo-endopeptidases from P. ostreatus and Armillaria mellea. The purified enzyme can also be applied as a natural agent for oral fibrinolytic therapy or prevention of thrombosis.

• Journal of Food Hygiene and Safety
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• v.23 no.1
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• pp.19-25
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• 2008

We analyze the HACCP Prerequisites of National Veterinary Research and Quarantine Service (NVRQS), Korea Food and Drug Administration(KFDA), and US Food Safety and Inspection Service (FSIS) and recommend contents and ranges to be complemented and used for the preparation of guidelines. We used the HACCP Notice of the Processing Livestock Act, the HACCP Application Manual for Livestock Processing Plants, the HACCP Notice of the Food Sanitation Act, US GPO 9 CFR and 21 CFR, US FSIS Directive 11,000.1, and HACCP-based Inspection reference guide of Consumer Services, North Carolina Department of Agriculture. The Prerequisites of NVRQS and KFDA are composed of 66 and 84 items respectively, without detailed guidelines for their application. This may decisively affect the application in the field and the evaluation activities. Water supplies, washing and disinfection monitoring tools, and examining and correcting plan are required to be improved. If the standards of compliance of each Prerequisite item as well as performance guidelines are given, the application and evaluation will be performed more effectively. The evaluation items should be associated with Prerequisite operations such as non-compliance complement, self-evaluation, and record keeping. Hazards found during official inspection should be promptly controlled not to contaminate the work places and processing items. As the HACCP is expected to spread from farms to tables, the standardized Prerequisite program among the official governments should be prepared.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.460-466
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• 2016

From 2013 through 2015, we investigated the contamination status and antimicrobial resistance patterns of pathogenic Vibrio parahaemolyticus in commercially valuable seawater and shellfish (Oyster Crassostrea gigas, short-neck clam Venerupis philippinarum, ark shell Scapharca broughtonii and mussel Mytilus galloprovinciallis) from the southern coast of Korea. The detection rate of V. parahaemolyticus was highest in short-neck clams (23.7%), followed by ark shells (19.2%), oysters (15.9%), mussels (13.6%), and seawater (8.6%). The following percentages of PCR assays of shellfish were positive for the thermostable direct hemolysin-related hemolysin gene (trh) : oysters (12.8%), short-neck clams(11.8%), and ark shells (3.4%). Similar assays for the thermostable direct hemolysin gene (tdh) resulted in positive results for short-neck clams (5.9%) and ark shells (3.4%). Antimicrobial resistance was present in 100% of 8 tdh (+) and 2 trh (+) V. parahaemolyticus isolates challenged with ampicillin. However, all pathogenic V. parahaemolyticus were sensitive to 14 other antibiotics. To ensure the safety of shellfish consumption, the continuous monitoring of the prevalence and distribution of virulence factors of V. parahaemolyticus in shellfish farms is needed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.898-903
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• 2015

Noroviruses (NoV) are known to cause acute epidemic gastroenteritis worldwide. Outbreak strains are predominantly genogroup I (GI) and genogroup II (GII) in oysters Crassostrea gigas. We investigated the changes in concentration of male specific coliphage (MSC) and NoV under heat treatment of the naturally contaminated oyster, Crassostrea gigas. After heat treatment for 5 min in $85^{\circ}C$, no viable MSC was detected. The concentrations of GI and GII NoV decreased by 1.65 log and 2.25 log, respectively, following heat treatment for 5 min at $100^{\circ}C$. Moreover, both GI and GII NoV were completely deactivated by heat treatment for 10 min at $100^{\circ}C$. Therefore, in order to reduce the risk of norovirus infection from contaminated oysters, immersion in boiling water for at least 10 min is recommended.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.1-7
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• 2017

The elimination of harmful heavy metals (Cd, Cr, and Pb) from sea lettuce Enteromorpha sp. was evaluated in filtered seawater over a pH range of 2.0-4.0 using citric, hydrochloric, and nitric acids. We also evaluated the quality of sea lettuce samples after release of their internal constituents into seawater solutions containing acids. The heavy metals that accumulated in raw sea lettuce after incubation for 3 days in seawater containing Cd, Cr, and Pb were, in descending order, Pb ($120.45{\mu}g/g$), Cr ($86.04{\mu}g/g$), and Cd ($18.35{\mu}g/g$). The rate of elimination of heavy metals from sea lettuce was higher at lower pH for all of the acids used. However, the color of the sea lettuce changed adversely at below pH 2.5. The heavy metals in sea lettuce samples after 10 min in seawater at pH 3.0 containing the three acids were eliminated in the order Pb (42.2-78.0%), Cd (51.8-55.3%), and Cr (14.0-32.8%). The quality of the sea lettuce was not affected when it was incubated for 30 min at pH above 3.0. The maximum elimination of heavy metals from sea lettuce occurred when it was soaked for 10 min in seawater at pH 3.0 containing citric acid.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.157-165
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• 2017

Being a staple food for more than half of the population of the world and South Korea, rice is an important crop. For the past 20 years, global paddy rice cultivation area and production have shown an annual growth of 0.46% and 1.61%, respectively. Global rice consumption for food and processing has increased by 1.37% and 3.68%, respectively. Due to the main reason for such increasing human population, it is expected that from 439 million tons in 2010, additional 116 million tons will be needed in 2035. Global rice imports and exports have doubled in the last 20 years. However, in spite of such increment, global rice exports in 2013 were 8.4% of the total production. It is thought that rice protection policies in the producing countries are the main reason for such small scale of rice trading. In the past 5 years, India recorded the largest growth rate in rice exports (51.4%), whereas China showed the largest growth rate in imports (61.0%). For global utilization of milled rice during the same period, approximately 79.4% was used as food, 7.2% as animal feeds, and 1.4% for processing. Regionally, Asia has shown a similar pattern to the global rice usage, whereas utilization for processing in America, for food in Africa, and for animal feed in Europe was relatively higher than the global rice usage. Korea's cultivation area and production since the last 5 years, are 0.5% and 0.8% of those of the world, respectively. Its annual rice export is approximately 3,000 tons, which is 0.01% of the global rice export. Korea's rice utilization is high for food and low for feed and for processing relative to global rice utilization. Therefore, a review must be conducted to increase Korea's utilization of rice for processing and for feed production.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.103-109
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• 1994

Changes in the rheological properties and the linear viscoelasticity of fish protein gel upon the thermal processing were studied by using mathematical models with stress-relaxation data. The linear viscoelasticity of surimi gel was observed in the range of the true strain $0.105{\sim}0.693$ and cross-head speed $50{\sim}250\;mm/min$ applied in this study. The results of the generalized Maxwell analysis showed that the magnitudes of elastic elements $(E,\;E_e)$ were increased, but the viscous element $({\eta}) $was decreased, as the cross-head speeds and strain levels were increased. Compared to the protein gel heated directly at $90^{\circ}C$ without preheating, the protein gel pretreated at $4^{\circ}C$ and $40^{\circ}C$ showed the higher elastic modulus, but showed different trends in the viscous component, depending on the rheological model applied. Thus, the approaching methods and curve fitting of two mathematical models of stress-relaxation to describe the viscoelastic properties of fish protein gel were discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.779-784
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• 2016

We evaluated seasonal variations in the proximate, fatty acid and total amino acid compositions and mineral content of the muscles of wild and cultured Korean bullhead Pseudobagrus fulvidraco. The wild and cultured samples showed a significantly higher proportion of crude lipids than other components. Crude lipid content was highest in May in wild fish but lowest in May in cultured fish. We found no significant difference between wild and cultured samples in terms of fatty acid and total amino acid compositions and mineral content. The levels of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) as well as n-6/n-3, were higher in the muscles of wild fish compared with those of cultured fish. However, monounsaturated fatty acids (MUFA) levels were higher in cultured fish. Both wild and cultured fish were good sources of eicosapentaenoic acid (EPA) and docosa hexaenoic acid (DHA). In wild fish, the Mg and Zn contents were highest in August, while the Ca, P, Na, K, Fe, and Cu contents were highest in May. However, the mineral content of the cultured fish did not exhibit significant seasonal variation.