• Journal of Microbiology and Biotechnology
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• v.24 no.8
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• pp.1096-1104
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• 2014

$\small{L}$-Asparaginase from gram-positive bacteria has been poorly explored. We conducted recombinant overexpression and purification of $\small{L}$-asparaginase from Staphylococcus sp. OJ82 (SoAsn) isolated from Korean fermented seafood to evaluate its biotechnological potential as an antileukemic agent. SoAsn was expressed in Escherichia coli BL21 (DE3) with an estimated molecular mass of 37.5 kDa, determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Consistent with asparaginases in gram-negative bacteria, size-exclusion chromatography determined SoAsn as a homodimer. Interestingly, the optimal temperature of SoAsn was $37^{\circ}C$ and over 90% of activity was retained between $37^{\circ}C$ and $50^{\circ}C$, and its thermal stability range was narrower than that of commercial E. coli $\small{L}$-asparaginase (EcAsn). Both SoAsn and EcAsn were active between pH 9 and 10, although their overall pH-dependent enzyme activities were slightly different. The $K_m$ value of SoAsn was 2.2 mM, which is higher than that of EcAsn. Among eight metals tested for enzyme activity, cobalt and magnesium greatly enhanced the SoAsn and EcAsn activity, respectively. Interestingly, SoAsn retained more than 60% of its activity under 2 M NaCl condition, but the activity of EcAsn was reduced to 48%. Overall, the biochemical characteristics of SoAsn were similar to those of EcAsn, but its kinetics, cofactor requirements, and NaCl tolerance differed from those of EcAsn.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.1162-1168
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• 2000

This study was designed to determine the seafood prcference of the 480 elcmentaty school children in Pusan. The survey was conducted from February 8 to February 22 in 2000. The correlation between nutrition knowledge and dietary attitude is highly significant. However there were no differences in nutrition knowledge and dietary attitude berween male and frmale students. Children's prefercnce is high in laver, crab, common squid, mackerel, hair tail, shrimp, but is low in oyster, warty sea squirt and salt-fermented seafood. The factors affected on the intake frequcncy of seafood and preference were dietary attitude of the children, cducation level of the mother and recommendation of the mother. Children's opinion on the intake of seafood was influenced by their nutrition knowledge and dietary attitude and the recommendation of the mother. Eating frequcncies of the seafood were not influenced by sex, family type, monthly food expenditure and dietary attitude of the mother.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.78-83
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• 2001

To use the by-products of whelk processing, whelk internal organ with the addition of bromelain were used to make jeotgal, Korean traditional salted and fermented seafood sauce. The products were prepared at different salt concentrations of 10, 15 and 20% with various bromelain contents 0, 0.01, 0.1 and 0.5%. The samples were stored at $10^{\circ}C$ and the chemical and microbiological analyses were evaluated for four weeks. The initial pH (near 6.1) in all conditions decreased in the beginning stage of aging, then gradually increased until three weeks and finally decreased to $5.6{\sim}6.0$. The sample with lower salt concentration showed less pH change For two weeks. The samples treated with higher bromelain in 10% and 15% salt concentration showed higher pH values after 4 weeks compared to the nontreated control. Amino nitrogen in the samples increased at lower salt concentration and at higher bromelain content. The amino nitrogen showed maximum value, 780 mg%, at 10% salt and 0.5% bromelain treatment. Total nitrogen contents increased with aging periods, especially increased rapidly in high concentrations of bromelain treated samples at early stages of aging. The higher salt concentrations in the product decreased the total microbial number and lactic acid bacterial number.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.84-90
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• 2015

Seventeen ampicillin-sensitive coagulase-negative staphylococci (CNS) isolates identified in jeotgal were subjected to assessments for antibiotic susceptibility and safety hazards. Fifteen of the 17 CNS strains exhibited phenotypic resistances to at least one antibiotic, and their prevailing resistance was to penicillin G. The dfrA gene for trimethoprim and tetK for tetracycline were amplified by PCR from the two strains, respectively. α-Hemolytic activity was not detected from the 17 strains, while five strains presented δ-hemolytic activity. Among the five strains, two strains exhibited β-hemolytic activity. Biofilm was formed from twelve strains. All of the tested phenotypic characteristics were expressed in a strain-specific manner.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.687-694
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• 2012

$Jeot-gal$ is a traditional Korean fermented seafood with a salt concentration of 15~20%. However, today's consumers prefer low-salted foods as they have become aware that high levels of salt cause hypertension and diabetes. In this study, the quality characteristics and shelf-life of low-salted squid $Jeot-gal$ were investigated at different fermentation temperatures and salt concentrations. The shelf-lives of 3%-salted squid $Jeot-gal$ fermented at -1, 4, and $10^{\circ}C$ were 45, 31, and 23 days, respectively, whereas those of 5%-salted squid $Jeot-gal$ were 52, 36, and 25 days. The DPPH radical scavenging activity of the ethanol extract of squid $Jeot-gal$ was stronger than that of the water extract. However, the other antioxidative activities, such as hydrogen peroxide and hydrogen peroxide radical scavenging activities, as well as enzyme inhibitory activities were very low at 20 mg/mL of water and ethanol extracts. Based on the results of the sensory evaluation, the quality of low-salted fermented squid $Jeot-gal$ was almost similar to that of commercial squid $Jeot-gal$ with a high salt concentration.

• Korean journal of food and cookery science
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• v.18 no.1
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• pp.1-7
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• 2002

A study on the seafood consumption was conducted from 1902 adolescent students (1110 boys and 792 girls) attending middle or high school to assess the attitude and degree of satisfaction for seafood being served in the school lunch program and ultimately to promote greater seafood consumption. A self-administered questionnaire was used to record the results. The results were as follows: Sixty percent of the respondents appeared to like or not to be reluctant to seafood. The main reasons for favoring seafood were its nutritious effect and taste. On the other hand, the reason for disliking seafood was due to its peculiar smell. In terms of cooking methods, the subjects preferred raw, fried, and grilled seafdod, whereas they disliked salt-fermented, seasoned and stewed dishes. The highly preferred seafood were crab, shrimp, tuna and squid. Only 6.6% of middle school students (MS) and 3.7% of high school students (HS) liked the seafood served in school lunch program, whereas the others responded 'so so'or disliked it. The reasons for disliking seafood being served in school lunch program were poor taste (14.7% of MS, 23.5% of HS), lack of freshness(6.3% of MS, 13.9% of HS) and unattractable cooking methods(3.4% of MS, 11.1% of HS). To promote seafood consumption in school lunch program, subjects anticipated the taste improvement (37.7% of MS, 48.5% of HS), use of a variety of seafood (19.8% of MS, 24.0% of HS) and cooking methods(12.6% of MS, 22.4% of HS). Above results suggested that further efforts are needed to provide preferred cooking methods and seafood items as a way of increasing seafood acceptability.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.297-301
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• 2002

To investigate changes of components in salt-fermented blenny, Enedrias nebulosus sauce during fermentation, various chemical properties were examined at 2$\~$3 months intervals during 18 months of fermentation. The degree of hydrolysis increased sharply until 6 months of fermentation and showed the gentle increasement after that. On the other hand, the contents of total and amino nitrogen, total ATP related compounds increased gradually during 18 months of fermentation, The hypoxanthine and uric acid were the most abundant in ATP related compounds, ranging from $80.1\% to $90.5\%. After 18 months of fermentation, sauce was rich in free amino acids such as glutamic acid, alanine, lysine, valine, leucine in that order.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.220-224
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• 2002

Alaska pollock roe is mainly used for the production of salt-seasoned and fermented seafood (Myungran-jeot). Alaska pollock roes with broken egg membrane are usually discarded as a waste product. In this study, the broken roes of Alaska pollock were salt-seasoned and stuffed into cellulose casing for commercial production. The chemical and microbial changes of the broken roes of Alaska pollock stuffed into cellulose casing fermented at 5 and $25^{\circ}C$, respectively, were analyzed at different ripening periods. On 5 week fermentation, pH decreased down to 5.60 and 5.10 at 5 and $25^{\circ}C$, respectively, but the amounts of lactic acid, amino-nitrogen, and volatile basic nitrogen increased continously as ripening period increased, higher at 25 than $5^{\circ}C$. The amounts of amino-nitrogen, 620 and 780 mg/100 g, were the highest on 3 week fermentation at $5^{\circ}C$ and on 1 week at $25^{\circ}C$, respectively. The numbers of total viable cell and lactic acid bacteria, $3.1{\times}10^6$ and $3.1{\times}10^5\;CFU/g$ at $5^{\circ}C$, and $1.9{\times}10^7$ and $2.8{\times}10^6\;CFU/g$ at $25^{\circ}C$, respectively, were the highest on 2 week fermentation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1265-1273
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• 2005

The purpose of this study was to prepare accelerated salt-fermented anchovy sauce using a shrimp processing byproducts (head, shell and tail) as a fermenting accelerator, and to investigate its physicochemical and enzymatic properties. Four types of sauces were prepared with 0, 10, 20, and 30$\%$ (w/w) addition of shrimp byproduct and fermented at 24$\pm$2$^{\circ}C$ for 360 days. During fermentation, all four type sauces decreased moisture content (67.5$\%$68.0$\%$ to 64.0$\∼$64.8$\%$) and pH (5.52$\∼$7.10 to 5.03$\∼$6.58), but showed increase in their crude protein (7.0$\∼$8.2 to 10.8$\%$) and volatile basic nitrogen contents (40$\∼$75 to 180$\∼$200 mg/100 g of sauce). The ratio of amino nitrogen to total nitrogen contents of control (0$\%$) and sauce with 10$\%$ shrimp byproducts (10$\%$ sauce) were maximized at 270 days, whereas 20$ \% $ and 30$\%$ added sauces were at 180 days. Endoprotease and exoprotease activities of anchovy sauces added with 20$\%$ and 30$\%$ of shrimp byproducts tend to be higher than those of control (0$\%$) and 10$\%$ addition. Proteolytic activities of sauces at pH 9 were about 2 times higher than those at pH 6. Amidolytic activities for LeuPNA decreased remarkably during fermentation, and control (0$\%$) almost lost their activity at 180 days, while additional sauces were relatively stable. These suggest that alkaline pretense of anchovy and shrimp byproducts as a endoprotease mainly contributed to the fermentation of salt-fermented sauces. The protein molecular weight distribution of sauces indicated 2 groups of peaks (peak 1,>70,000 da and peak 2, 3,000$\∼$29,000 da). As the fermentation proceeded, peak 1 tended to decrease in all of sauces, but peak 2 increased rapidly from 30 to 270 days. Optimum fermentation periods of control and 10$\%$ sauces were 270 days and those of 20$\%$ and 30$\%$ sauce were 180 days. The results suggest that shrimp byproduct can be used as accelerator of salt-fermented sauce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.721-729
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• 2013

To improve the quality and functionality of the low salt squid Jeot-gal, extracts from three types of medicinal and edible plants (bay leaf, green tea, pine needle) were added. The quality characteristics, bioactivities, and shelf-lives of these preparations were determined at three different fermentation temperatures. The pH decreased more rapidly at higher temperatures, while the amount of volatile basic nitrogen (VBN), total viable cells, and amino nitrogen ($NH_2$-N) increased. The shelf-lives of Jeot-gal with natural plant extracts at $10^{\circ}C$ were 34~35 days, similar to the control. The major free and compositional amino acids of Jeot-gal were glutamic acid, proline, and alanine, while the major nucleotides (and related compounds) were hypoxanthine and inosine. In bioactivity assays, samples supplemented with plant extracts showed higher bioactivities than the control. The DPPH radical scavenging activity of ethanol extracts from Jeot-gal were stronger than the water extracts; in contrast, the water extracts were stronger for hydrogen peroxide scavenging activity. However, superoxide dismutase (SOD)-like activity and ${\beta}$-glucuronidase inhibitory activity were moderately low at 20 mg/mL. Based on sensory evaluation results, the quality of low salt squid Jeot-gal with natural plant extracts is similar to the control. Therefore, low salt squid Jeot-gal with natural plant extracts can be commercialized as a functional fermented food.