• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.753-758
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• 1997

Dried alaska pollack is one of the representatives among dried marine fish and shellfish products in our country. This study was performed to obtain the basic data about the effect of drying method on the formation of N-nitrosamine and its precursor to ensure the safety of dried alaska pollack. The contents of nitrate and nitrite were detected 1.5 and <1.0 mg/kg in raw samples, and $3.0\~4.2,\;1.4\~2.7mg/kg$ in dried products, respectively. There was no significant change of betaine contents during drying while TMAO decreased, TMA and DMA increased in alaska pollack during d교ing. N-nitrosodimethylamine (NDMA) was only detected in alaska pollack and its dried products, and recovery from above samples spiked with $10{\mu}/kg$ for N-nitrosodipropylamine was $87.2\~107.4\%$. The levels of NDMA were found to be $2.8{\mu}/kg$ on an average in raw samples, but the levels of NDMA increased remarkably during drying of alaska pollack and its content in dried products was $8.7\~51.4{\mu}g/kg$. Regardless of drying methods, NDMA tend to increased in dried products, and its contents were 15.5 times higher in hot-air dried than raw samples, 9.0 times in sun dried and 4.4 times in freeze dried products. less NDMA was produced in the freeze dried products, so it is believed that freeze drying method is effective to decrease the NDMA levels in the dried products of alaska pollack.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.439-444
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• 2012

We studied the characteristics of odor emitted from 40 swine facilities across the country under various conditions like rearing densities, management style, ventilation system and swine manure handling characteristics, based on the olfactory and analytical evaluation. Odor concentrations (D/T) measured from swine facilities were respectively an average 4,055 D/T at liquid manure storage tanks on aeration, an average 913 D/T at slurry manure storage, an average 506 D/T at finishing swine facilities and an average 201 D/T at composting facilities. The higher rearing densities and slurry accumulation volume in finishing swine house, the more odor concentration (D/T) was increased. But The odor concentration (D/T) in finishing swine house did not show significant difference according to application of microbial additives. 9 odor compounds ($NH_3$, $H_2S$, MM, DMS, DMDS, PA, n-BA, n-VA, i-VA) were detected at swine facilities and the main odor compounds were volatile sulfur compounds such as $H_2S$, MM and volatile fatty acids compounds such as n-BA, n-VA, i-VA. 97.5% of swine farms surveyed in this study is located within 300 m of residential area and it is easy to bring odor complaints.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.51-57
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• 1992

The preservative effect of chitosan film packing on quality of lightly-salted and dried horse mackerel was studied. In preparation of chitosan film, blue crab shell chitosan was dissolved in dilute acetic acid$(1.0\%,\;v/v)$, filtered, and spreaded on plastic plate and dried at $50\pm2^{\circ}C$. The chitosan film thus obtained was neutralized with 1.0N NaOH for 2 hrs and dried at room temperature after washing several times with distilled water. The lightly-salted and dried horse mackerel product was prepared by drying for 4 hrs at $40\pm2^{\circ}C$ in hot air dryer after packing with the chitosan film. During storage at $5.0\pm0.5^{\circ}C$, moisture content of the product was higher than that of the reference, but contents of VBN(volatile basic nitrogen) , amino nitrogen, and TMA of the product on dry basis were lower than those of the reference. Viable cell count, TBA value, and peroxide value of the product were also lower than those of the reference. Judging from the result of sensory evaluation, the chitosan film packing in the storage of lightly-salted and dried horse mackerel was remarkably elongated shelf-life of the product. From the results of chemical and sensory evaluation, it was concluded that chitosan film packing was an effective method for retaining the quality of lightly-salted and dried horse mackerel.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.215-222
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• 1994

Kang-Nung sik-hae is a traditional Korean fermented fish product which has remained in existence in Kang-Nung district. In order to preserve the traditional culture of Kang-Nung sik-hae and develop it as a commercial product, the property changes of sik-hae were investigated at different fermentation temperatures and periods. The chemical changes during the fermentation of squid(Todarodes pacificus) sik-hae were studied at different fermentation temperatures and periods. The amounts of proximate compositions and salinity did not change significantly at all fermentation temperatures and periods. The value of pH decreased with increasing storage period at all fermentation temperatures except at $5^{\circ}C$, whereas that of lactic acid at all fermentation temperatures increased. The amount of total arginine increased slightly up to 10-day of storage and decreased after that. The amount of $NH_2-N$ increased rapidly up to 15-day of storage at all temperatures and increased slightly after that. The amount of TMAO decreased significantly at $15^{\circ}C\;and\;20^{\circ}C$ and slightly at $5^{\circ}C\;and\;10^{\circ}C$, whereas that of TMA increased significantly at $20^{\circ}C$ up to 5-day of storage and decreased slightly after that. At all experimental temperatures except $5^{\circ}C$, the amount of TMA increased or fluctuated in proportion to the increase in fermentation periods. Inosine and hypoxanthine were the main components of nucleotides and their related compounds during the fermentation of sik-hae. Summarizing the above results, the optimum fermentation period of sik-hae was concluded to be 15-days at all experimental temperatures except $5^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.366-372
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• 1994

The effects of red pepper and grain contents on the properties of squid sik-hae fermented at $20^{\circ}C$ were investigated. The values of pH at $10\%$ red pepper contents and $30\%$ grain contents were lower at early stages of storage than $5\%\;and\;50\%$, respectively, and showed no significant differences at later stages of storage. The amounts of lactic acid and amino-N were not changed significantly at different red pepper contents where as, higher at $30\%$ grain content than at $50\%$ at early stages of storage. The amounts of total arginine were a little higher at $10\%$ red pepper and $30\%$ grain contents than at $5\%\;and\;50\%$, respectively. There were no significant effects of red pepper and grain contents on the amounts of TMAO and TMA during fermentation. Therefore, the effects of red pepper and grain contents on the chemical properties of squid sik-hae during fermentation were not significant.

• Korean journal of food and cookery science
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• v.2 no.1
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• pp.38-44
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• 1986

Effects of the kind and concentration of salt on oxidation of lipids and on formation of flavor components have been studied with four varieties of fermented anchovies prepared with 20％ sun-dried salt(sample B) , 12% refined salt (sample C), 16.5％ refined salt (sample D) and 16. 5% refined salt Plus 25％ brine (sample E). The sample B showed higher peroxide and TBA value and also higher content of TMA thar. those prepared with refined salt. The amounts of amino-N and VBN in sample B appeared larger than in sample D but was in a similar level with those in sample C. On the other hands, much smaller amounts of lactic and succinic acid were observed in sample B compared with in sample C and D. Sample C revealed the highest level of lactic acid among the samples tested. The changes in the amounts of each free amino acid displayed similar tendencies in all samples, except decreasing tendency of tyrosine in sample B and increasing tendency of aspartic acid in sample C. Also observed was lower IMP and inosine level in sample B than in C and D, but hypox-anthine level was higher in B. In general, sample I indicated remarkably lower values of experimental data in all cases mentioned above, but the highest TBA balue.

• Journal of IKEEE
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• v.11 no.1 s.20
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• pp.54-60
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• 2007

In this study novel ESD protection device, namely, N/P-type Low Voltage Triggered SCR, has been proposed, for high speed I/O interface. Proposed device could lower high trigger voltage($\sim$20V) of conventional SCR and reduce latch-up phenomenon of protection device during the normal condition. In this Study, the proposed NPLVTSCR has been simulated using TMA MEDICI device simulator for electrical characteristic. Also the proposed device's test pattern was fabricated using 90nm TSMC's CMOS process and was measured electrical characteristic and robustness. In the result, NPLVTSCR has 3.2V $\sim$ 7.5V trigger voltage and 2.3V $\sim$ 3.2V holding voltage by changing PMOS gate length and it has about 2kV, 7.5A HBM ESD robustness(IEC61000-4-2).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.529-536
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• 1986

By modified method yellow corvenia(called $Y_3$) was prepared with $4\%$ salt, $4\%$ KCl, $6\%$ sorbitol, $0.5\%$ lactic acid and $4\%$ alcohol extract of red pepper to improve the quality of fermented sea food. In this study, changes of volatile compounds and fatty acid composition obtained from modified fermented yellow corvenia($Y_3$) were experimented during fermentation, comparing with conventional fermented yellow corvenia(called $Y_1,\;20\%$ of salt contents). Total lipid of yellow corvenia was composed of $78.1\%$ of neutral lipid, $21.2\%$ of phospholipid and $0.7\%$ of glycolipid. And monoeonoic acid was held $37.4\%$ of fatty acid composition of total lipid and saturated fatty acid ($34.8\%$), polyenoic acid ($27.7\%$) were followed. Saturated fatty acid($C_{14:0},\;C_{16:0},\;C_{18:0}$) in $Y_1,\;Y_3$ increased, polyenoic acid ($C_{22:6}\;C_{22:5}\;C_{20:5}$) decreased while monoenoic acid($C_{16:1}\;C_{18:1}$) in those was little fluctuated during fermentation. Thirty-three kinds of volatile component in whole volatile compounds obtained from $Y_1,\;Y_3$ at 90 days fermentation were identified, and composed of some hydrocarbons (8 kinds), alcohols (7 kinds), acids (6 kinds), aldehydes(4 kinds), sulfides(2 kinds), ketones (2 kinds), one of phenol and 3 kinds of the other components. Among the whole volatile compounds 2-ethoxy ethanol and was held $79.35\%$ in $Y_3$, whereas nonadecane was held $75.85\%$ in $Y_1$. During fermentation 8 kinds of volatile acids, 5 kinds of amines and 9 kinds of carbonyl compounds were also detected. Those volatile acid such as acetic acid, isovaleric acid, n-caproic acid, n-butyric acid were the major portion of total volatile acids in $Y_3$ at 90 days fermentation. Meanwhile, carbonyl compounds such as ethanal, 2-butanone and butanal were the major ones, while TMA held the most part of volatile amines in $Y_3$ during fermentation. From the result of sniff test, the components which are believed to contribute to the characteristic flavor of fermented product $Y_1,\;Y_3$ are deduced to be volatile acid, carbonyl compounds and amines in order. Conclusively, there was little difference in composition of volatile components, but merely a little difference in content of those between $Y_3$ and $Y_1$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.131-138
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• 1985

The preservative effect of modified-atmosphere storage on the shelf-life of packed semi-salted and dried mackerel, Scomber japonicus, was examined. The semi-salted and dried mackerel fillets were packed in laminated plastic film bags (polyester/nylon/casted polypropylene: $12{\mu}m/15{\mu}m/60{\mu}m,\;15{\times}16cm$) filled with air (control, C), nitrogen gas (N), deoxygenized air (O) prepared by using free-oxygen absorber enclosed in the bag, in vacuum(V), and stored at $5^{\circ}C$. The quality of packed sample during the storage were examined in terms of viable cell counts of bacteria, thiobarbituric acid(TBA) value, perozide value(POV), volatile basic nitrogen(VBN), trimethylamine(TMA), adenosine triphosphate(ATP) and its related compounds and sensory evaluation. The results obtained are as follows: The pH of all the samples was in the range of $6.1{\pm}0.2$, and the contents of VBN and amino nitrogen of them increased during storage. In color values, L value(lightness) decreased while a and b values (red and yellow) revealed a tendency to increase during storage. The viable cell counts of the control sample(C) increased to $3.0{\times}10^6/g$ after 15 days storage but those of the other samples(V, N and O)were in the range of $2{\sim}6{\times}10^5/g$ after 20 days storage. The content of TMA increased during storage, but the histamine content showed a little change during storage and its content of all samples were less than 16 mg/100g. The inosinic acid(IMP) was rapidly degraded while inosine and hypoxanthine increased during storage. The TBA value of the control(C) reached a peak in 9 days and then decreased gradually while that of the sample(O) showed a little change during storage. The changes in POV of all the samples during storage showed a similar tendency to the TBA value. Fatty acid composition of raw mackerel consists of $35.6\%$ of saturated acid, $30.3\%$ of monoenoic acid and $34.2\%$ of polyenoic acid. The major fatty acid of the sample products were oleic acid($C_{18:1}$), palmitic acid($C_{16:0}$), docosahexaenoic acid($C_{22:6}$). The contents of polyenoic acid such as $C_{22:6},\;C_{20:5}$ decreased during storage while the other fatty acids showed a little change. From the results of sensory evaluation, the shelf-life of the control sample(C) was about 7 days and that of sample(V), (N) and (O) was about 15 days. It was concluded that deoxygenized atmosphere(free-oxygen absorber enclosed in the bag) was a good condition for preserving the quality of semi-salted and dried mackerel.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.321-329
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• 2003

In order to provide data on N-nitrosamine (NA) and sanitation in fish available in domestic markets, this study analyzed the levels of NA and its precursors in 9 samples of sea breams and yellow croakers, 12 samples of red-flesh fish, 38 samples of white fish, 5 samples of Alaska pollacks and cod, and 8 species of imported fish. Sea breams and yellow croakers had nitrite concentrations ranging from non-detectable (ND) to 7.4 mg/kg, red fish ND to 5.3 mg/kg, white fish ND to 18.7 mg/kg, Alaska pollacks 0.3 to 2.2 mg/kg, and imported fish from 0.4 to 12.8 mg/kg. Nitrates in sea breams and yellow croakers ranged from 1.2 to 41.19 mg/kg, red fish 0.6 to 26.1 mg/kg, white fish 4.3 to 75.9 mg/kg, Alaska pollacks 0.4 to 3.1 mg/kg, and imported fish ND to 16.0 mg/kg. DMA concentrations were 69.8 to 219.9 mg/l00 g in sea breams and yellow croakers, 4.1 to 336.3 mg/l00 g in red fish, 1.3 to 331.9 mg/l00 g in white fish, 15.7 to 312.3 mg/l00 g in Alaska pollacks, and 1.0 to 71.8 mg/l00 g in imported fish. TMA concentrations in sea breams and yellow croakers, red fish, white fish, Alaska pollacks and imported fish were 43.8∼496.2, 12.3∼127.0, 2.0∼525.9, 15.4∼122.4, and 4∼70.6 mg/l00 g, respectively. For NA in fish distributed in local markets, only N-nitro-sodimethylamine (NDMA) was detected, and its concentrations ranged from 4.7 to 73.7 $\mu\textrm{g}$/kg in sea breams and yellow croakers, 2.2 to 56.5 $\mu\textrm{g}$/kg in red fish, ND to 143 $\mu\textrm{g}$/kg in white fish, 3.8 to 33.3 $\mu\textrm{g}$/kg in Alaska pollacks, and 2.1 to 102.2 $\mu\textrm{g}$/kg in imported fish.