• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.574-579
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• 2004

Quality characteristics of citron-treated mackerel oil and fillet during refrigerated storage were evaluated. Citron-treated and non-treated mackerel oil and fillet were estimated by periodical measurements of acid, peroxide, carbonyl, volatile basic nitrogen, trimethylamine-N, and thiobarbituric acid values. Volatile basic nitrogen and trimethylarnine-N values in mackerel fillet treated with citron for 25 days during refrigerated storage were significantly lower than those of citron non-treated mackerel fillet, with those of boiled citron water-treat group significantly decreasing compared to 1 and 2% citron extract groups. Acid, peroxide, carbonyl, and thiobarbituric acid values of citron-treated mackerel oil were significantly lower than those of citron non-treated mackerel oil throughout storage period. Overall acceptability of salted mackerel fillets treated with boiled citron water and 1% citron extract was significantly than those of control and 2% citron extract. Results indicate application of citron juice on mackerel surface may be useful to lower rancidity degree and fish odor during refrigerated storage.

• Membrane Journal
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• v.18 no.2
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• pp.138-145
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• 2008

A series of anion exchange composite membranes were prepared and characterized for electro-dialysis process used in the removal of toxic anion and cation polutants in groundwater or wastewater. The membranes were prepared as follows; first, porous poly(ethylene) (PE) substrates were fully impregnated with monomer mixtures with various ratio of vinylbenzylchloride (VBC), divinylbenzene (DVB) and ${\alpha},\;{\alpha}$-azobis(isobutyronitrile) (AIBN). Second, they were thermally polymerized to yield crosslinked poly(VBC-DVB)/PE composite membranes. Finally, the membranes were treated in trimethylamine (TMA)/acetone to give $-N^+(CH_3)_3$-containing poly(VBC-DVB)/PE membranes. The basic membrane properties such as ion exchange capacity (IEC), electric resistance and water content of the resulting membranes were measured as a function of VBC/DVB and TMA/Acetone content. As a result, the composite membranes showed lower electric resistance, lower water content and higher IEC than commercial anion exchange membranes (AMX, Astom) due to thin PE substrates, indicating that the composite membranes could be successfully applied to the electrodialysis for water treatment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.259-264
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• 1994

The possibility of shellfish utilization of juice as seasoning materials was examined through the analyzing proximate compositions and N-containing materials. The amounts of the sucking liquid wastes were estimated as 58,819 tons for oyster, 764 tons for pen-shell, 604 tons for cockle and 3,896 tons for blue-mussel from 1985 to 1990 in Korea. Water contents ranged from 95.2 to $97.4\%$ and crude protein level was $1.0{\sim}1.4\%$. Taurine was the most abundant nitrogenous compound($40{\sim}56\%$) in extracts, and glycine($10.4{\sim}36.1\%$), alanine($4.8{\sim}8.6\%$) and glutamic acid($3.1{\sim}5.3\%$) followed. More than $40\%$ of ADP and AMP as mucleotide were contained in all shellfish samples but pen-shell and cockle had $20\%$ of inosine, also. Glycinebetaine was present in corcentrations of 139.8mg/g in oyster and $45.5{\sim}61.9mg/100g$ in pen-shell, cockle and blue-mussel. Total creatinine and trimethylamine oxide levels were $30.4{\sim}59.1mg/100g$ and $0.82{\sim}47.2mg/100g$, respectively.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.200-207
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• 1991

Jariieot is a local food prepared by fermentation of salted fish, Chromis notatus. Since its NaC' content is around 20% like other fermented seafoods, reduction NaCl concentration is desirable to minimize the risk of health hazard. Addition of KCl and enrichment of lactic acid fermentation were attempted to solve the problems resulting from low salt concentration. NaCl and KCl were added to a fish, Chromis notatus simultaneously at concentrations of 10 to 4% and 5 to 2%, respectively. Lactic acid bacteria and glucose at final concentration of 2% were also mixed with the above-salt treated fish to prepare jarijeot. The jarijeot was examined periodically for chemical changes during aging and compared with reference jarijeot containing only 20% of NaCl to find out an appropriate method for quality improvement. The content of ATP and its related compounds was not affected by the concentration of NaCl or the presence of lactic acid bacteria. Nearly no difference in contents of free amino nitrogen, trimethylamine oxide, trimethylamine and volatile basic nitrogen was observed between the jarijeot containing 20% of NaCl only and that containing 10% of NaCl, 5% of KCl, 2% of glucose and cells of Pediococcus halophilus. Moreover, sensory evaluation of both kinds of jarijeots revealed almost the same scores. The number of cells of P. halophilus was maintained at concentration of $10^5$cell/ml for 60days' fermentation in the above mentioned jarijeot containing 10% of NaCl. Its pH was dropped down to 4.2. Accordingly it is possible to prepare jarijeot enriched with lactic acid bacteria if KCl and glucose are added at concentration of 5% and 2%, respectively, in addition to NaCl at a final concentration of 10%.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.437-441
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• 1985

In order to elucidate the flavor compounds of fermented big eyed herring, Harengula zunasi (BLEEKER), and slimy, Leiognathus nuchalis (TEMMINCK et SCHEGEL), the volatile constituents of products were analysed by GLC. In the volatile compounds of fermented big eyed herring, eight kinds of volatile fatty acids, nine kinds of volatile carbonyls, and five kinds of volatile amines were identified. While in the fermented slimy, seven kinds of volatile fatty acids, six kinds volatile carbonyls, and five kinds of volatile amines were also identified. In the volatile fatty acids and volatile amines, n-butyric acid and trimethylamine were the most dominant component in both fermented products. In the fermented big eyed herring 2-methylpropanal, ethanal, and propanal were abundant holding 36.2%, 28.5%, and 16.2%, while in the fermented slimy ethanal, 2-methylpropanal, and propanal were abundant holding 44.7%, 24.1%, and 14.4% of total volatile carbonyls, respectively. From the experimental results, it was concluded that n-butyric acid, trimethylamine and volatile carbonyls such as 2-methylpropanal, ethanal and propanal played an important role in the flavor of the fermented big eyed herring and slimy.

• Applied Biological Chemistry
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• v.24 no.2
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• pp.126-131
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• 1981

General composition, amines, and flesh tissue of boiled-dryed abalone and sea cucumber were compared with those of the freeze-dried abalone and sea cucumber. No significant differences were found in the general composition between the boiled-dried and freeze-dried, but the slight amount of soup flowed out from the boiled-dried. A specific feature is that 28.24% of ash was found in the boild-dried sea cucumber and 33.99% of ash in the freeze dried one in order of Na, K, Mg, Ca. Such contents of ash are considered to be due to salt and soft bone of samples. In the changes of amines in abalone and sea cucumber, trimethylamine oxide (TMAO) showed no great difference between raw samples and the dried ones, but showed the decrease of 43% to 54% in the boiled-dried ones, compared with raw ones. Trimethylamine (TMA) was richer in the boiled-dried than in the dried. Dimethylamine (DMA) which has tendency of causing cancer in the human body showed 14 times of content in the freeze boiled-dried abalone, 18.5 times in the boiled-dried sea cu cumber and also showed 4.7 to 6.7 times of increase in the freeze dried, respectively compared with raw ones. The muscular change of abalone was not found in at freeze dried samples, but a considerable change in sea cucumber.

• Membrane Journal
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• v.20 no.2
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• pp.142-150
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• 2010

A series of anion exchange composite membranes were prepared and characterized for electrodialysis processes used in the removal of nitrate nitrogen and ions in groundwater. The membranes were prepared as follows; first, fabric substrates were fully impregnated with monomer mixtures of vinylbenzylchloride (VBC), divinylbenzene (DVB), Styrene (ST) and $\alpha,\alpha$-Azobis(isobutyronitrile) (AIBN). Second, they were thermally polymerized to yield crosslinked poly (VBCST- DVB)/fabric composite membranes. Finally, the membranes were treated with trimethylamine (TMA) / acetone to give $-N^+(CH_3)_3^-$-containing poly(VBC-ST-DVB)/fabric membranes. The basic membrane properties such as ion exchange capacity (IEC), electric resistance and water content of the resulting membranes were measured as a function of VBC/DVB and TMA/Acetone content. As a result, the composite membranes showed lower electric resistance and higher IEC than commercial anion exchange membranes (AMX, Astom). Electrodialysis tests using the prepared membranes were carried out for the removal of various ions such as $NaNO_3$, $MgSO_4$ and NaF for 60 minutes. The results showed that the ions were removed below 1 mg/L within about 15 minutes which indicates that the anion exchange membranes prepared here could be applied to the electrodialysis process. as can be seen in the following that the ion conductivity values were almost no change after 15 minutes electrodialysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.271-282
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• 1982

The browning development, mainly through the Maillard reaction, occurring in the dried fish meat products during storage causes reduction of the nutritional value due to the loss of the essential amino acid such as available lysine as well as off -flavor resulting in the deterioration of the food quality thus shortening the shelflife. In the work, the changes in the amount of available lysine, extractable nitrogenous compounds (nonprotein-N, amino-N, trimethylamine oxide, trimethylamine, and free lysine) and development of browning were measured to assess the relationship between the shelflife and the quality loss in dried filefish under the steady state conditions (35,45, and $55^{\circ}C;a_{w}'s$ of 0.44 0.52, 0.65 and 0.75 at each temperature) and fluctuating temperature condition of $35/55^{\circ}C$ will. alternating 7 day periods at each water activity. The results indicated that the amount of available lysine and extractable nitrogenous compounds except TMA decreased rapidly with increasing temperatures and water activities while the rate of available lysine and extractable nitrogenous compounds must be involved in the initial stage of brown pigment formation. The available lysine loss of the dried filefish products stored under the fluctuating temperature conditions was greater than that stored under its fixed mean temperature, $45^{\circ}C$. The activation energies for lysine loss obtained from the Arrhenius plot ranged 6.9 to 4.4 Kcal/mol and $Q_{10}$ values at $40^{\circ}C$ were 1.4 to 1.2. The values for browning were 15.7 to 14.4 Kcal/mol and 2.2 to 2.0 respectively. Shelf-life, defined as the time to reach 0.15 O. D./g solid or the limit of off-color deterioration by browning reaction, was extented longer than the halflife of Iysine loss, actually corresponding $75\%$ loss of available lysine. This suggested that the halflife of lysine loss might not be adequate to assess the shelf-life of the food system with high potential of protein, nonproteinous nitrogen compounds, and lipids.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.69-76
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• 1990

To substitute the soy-sauce 'koji' used in fish sauce processing with molded sardine meal(MSM) 'koji', the culture conditions of MSM be inoculated with Aspergillus spp. were investigated. To prepare the MSM, Asp. awamori(KFCC. 11439), Asp. guercinus (KFCC. l1595), Asp. niger(KFCC. 11239), Asp. oryzae(KFCC. 32343), and Asp. sojae(KFCC. 11559) were inoculated upon the chopped sardine with $20\%$ (w/w) corn starch after steriling it at $121^{\circ}C$ for 15min. Sporulation time cultured with Asp. spp. at $30^{\circ}C$ was 48hrs and color of mycelium on the surface of MSM inoculated with Asp. awamari and Asp. oryzae were black, that of MSM inoculated with the other strains were yellowish brown. The activity of protease and lipase from the MSM were increased till the 72hrs of culture at $30^{\circ}C$, while the content of trimethylamine was decreased after 96hrs of culture period at same condition with exception of Asp. niger. Asp. oryzae and Asp. sojae showed superior in pro-tease and lipase activity in comparison with the other strains, and maximum activity of protease and lipase of MSM was observed after 72hrs of culture period. The optimum pH and temperature for the activity of MSM inoculated with Asp. oryzae and Asp. sojae were pH 9.0, $30\~35^{\circ}C$ and pH $6\~7$, $35^{\circ}C$, respectively.

• Journal of Sensor Science and Technology
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• v.9 no.1
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• pp.36-43
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• 2000

In oder to enhance the selectivity of TMA(trimethylamine) gas, the ZnO-based films which were doped with $Al_2O_3$, $TiO_2, $In_2O_3$ and $V_2O_5$ catalysts with various weight percents were deposited in oxygen by RF magnetron sputtering method. To improve electrical stability of sensors, the ZnO-based films were annealed in oxygen at $700^{\circ}C$ for 1 hour. The TMA selectivity of sensors was defined by the magnitude($S_{TMA}/S_{DMA}$ and $S_{TMA}/S_{NH3}$) of TMA sensitivity relative to DMA and sensitivity ammonia($NH_3$) sensitivity, respectively. The $ZnO+Al_2O_3(4\;wt.%)+TiO_2(1\;wt.%)+In_2O_3(1\;wt.%)$ sensor showed high $S_{TMA}/S_{DMA}$ of 5.9 and $S_{TMA}/S_{NH3}$ of 26 to 160 ppm at the working temperature of $300^{\circ}C$ respectively.