• Food Science and Preservation
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• v.18 no.5
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• pp.643-650
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• 2011

This study was carried out to analyze the quality change of mackerel treated of green tea and lotus leaf boiled water extracts. And investigate the antioxidant effects of them on the lipid peroxidation of mackerel during storage at $4^{\circ}C$ for 28 days. It was estimated periodical measurements of proximate composition, pH, carbonyl, volatile basic nitrogen, trimethylamine-N, acid, peroxide and thiobarbituric acid values. It had no effect on proximate composition compared with non- treated control nearly but, pH of all the samples was increase during 28 days continuously. The contents of volatile basic nitrogen and trimethylamine-N lower than control during storage. Also, acid, peroxide and thiobarbituric acid values of mackerel treated of green tea and lotus leaf boiled water extracts were significantly lower than control throughout storage period. Especially, mackerel treated of 2% green tea and lotus leaf boiled water extracts shows that more effective than 1% of things in antioxidant during storage. Results indicate that the application of green tea and lotus leaf boiled water extract on the surface of mackerel may be useful to lower the rancidity degree and fish odor during storage.

• Food Science and Preservation
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• v.9 no.1
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• pp.19-27
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• 2002

The effect of gamma irradiation was investigated on the microbiological and physicochemical qualities of boiled-dried anchovies (large- and smallsized) packed in PVC film (0.06 ㎜) during storage at 15$\pm$1$\^{C}$ for 6 months. On the other hand, thermoluminescence characteristics of minerals extracted from the sample were analyzed to evaluate its possibility in detecting the irradiated anchovies. The samples were contaminated by microbial levels of 104∼106 CFU/g in total aerobic bacterial counts and negative in coliforms, which were different depending on the sample sizes. Gamma irradiation at 3 kGy was effective for improving the hygienic quality of both samples for 6 months, keeping the microbial population less than 20 CFU/g. Besides it was not detrimental to the quality attributes, such as instrumental color parameters L, a, b, ΔE), browning, TBA value, volatile basic nitrogen, trimethylamine-N and sensory properties(appearance, color, odor, tape, overall acceptability). However, storage conditions (time, temperature, packing) showed a critical factor nfluencing the quality changes of dried anchovies. Thermoluminscence analysis was prove to distinguish irradiated from non-irradiated anchovies by comparing both temperature at which glow curves appear and the curve intensity, that was possible even after 6 months at - 20$\^{C}$.

• The Korean Journal of Food And Nutrition
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• v.29 no.3
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• pp.371-381
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• 2016

The present study investigated the effects of processing parameters such as time (10, 20, 30, 40 min), pressure (25, 50, 75, 100 MPa), and the salinity of brine (0~10%(w/v)) on jacopever (Sebastes schlegeli Hilgendorf) in order to establish optimization of the three factors using a high hydrostatic pressure (HHP) machine. To do so, it analyzed the quality characteristics of volatile basic nitrogen (VBN), trimethylamine (TMA), total bacterial counts, dynamic viscoelasticities, and differential scanning calorimetry (DSC) properties. First, when the time increased to 40 mins, by 10 min intervals, the total bacterial counts in HHP groups under $25^{\circ}C$, 100 MPa, and 4%(w/v) brine were significantly decreased except for the first 10 min in comparison to the control group. In regards to DSC properties, the onset temperature ($T_O$) of the first endothermal curve was significantly reduced. Second, when the pressure level increased up to 100 MPa by 25 MPa increments, the total bacterial counts in the HHP samples significantly decreased for 20 min at 50 MPa or higher. As the pressure increased, G', G" and the slope of tan ${\delta}$ decreased (except for 50 MPa). Third, in regards to the salinities of brine, when the HHP processing was treated at 100 MPa, $25^{\circ}C$ for 20 min, the total bacterial counts of all the HHP groups significantly decreased in comparison to those of the control group. A significant difference was found in the enthalpy of the second endothermic curve in the 6~10%(w/v) (except 7%(w/v)) HHP groups. Therefore, the salinity of the immersion water under the HHP condition was appropriate when it was lower than 6%(w/v). The present study demonstrated that the optimum parameter condition according to/under the condition of the microbial inhibition and economic effects using an HHP would be the reaction time for 20 min, reaction pressure at 100 MPa, and the salinity of 4%(w/v) brine.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1515-1521
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• 2004

As one of the research series for the industrialization of sikhae, this study was evaluated the taste compounds present in different temperature conditions, $5^{\circ}C$, $20^{\circ}C$ and alternating temperature (stored at $5^{\circ}C$ after 10 days fermentation at $20^{\circ}C$), respectively. The changes in proximate compositions were negligible but the amounts of total sugar decreased during fermentation. The pH of sikhae products except the product fermented at $5^{\circ}C$, decreased during fermentation and was maintained at the rage of 3.8~4.4 after 10 days. The values of acidity, VBN and amino-N gradually increased with fermentation times and with increasing temperature condition in all products. Three organic acids (lactic, citric and malic acid) were disclosed as key compounds affecting the sourness in Alaska pollack sikhae. The result of taste value revealed that 6 amino acids having sweet and umami taste (aspartic acid, glutamic acid, alanine and lysine) and bitter taste (valine and methionine) as major amino acids affecting the taste of sikhae products, and increased with fermentation times. Hypoxanthine was the main component in ATP related compounds. Amino-N was comprised more over 50% of the Ex-N in sikhae products, and followed by total creatinine-N, TMAO-N and TMA-N in that order.

• 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.30 no.3
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• pp.459-465
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• 1997

In order to extend the shelf-life of the low-salted Myungran-Jeot, before immersing alaska pollack roe, the salt solutions was adjusted to pH 7.0 and 4.7, respectively. pH during ripening was somewhat constant, whereas the content of lactic acid was slightly increased, and especially, that of pH 4.7 Myungran-Jeot was increased rapidly in the begining of fermentation period. $NH_2-N$ content of pH 4.7 Myungran-Jeot was increased with increasing fermentation period, whereas those of control and pH 7.0 decreased except the begining of fermentation period. The contents of TMA, TBA, and VBN of pH 4.7 were lower than those of control and pH 7.0. In addition, the mirrobial growth was significantly inhibited in pH 4.7 Myungran-Jeot. The estimated shelflives of control, pH 7.0, and pH 4.7 Myungran-Jeots were about 12, 12, and 16 days, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.53-59
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• 2008

Salt is a major component in salt-fermented shrimp with 25% content. There are various types of salts that have different compositions, which may affect the quality of salt-fermented shrimp. We have investigated effects of various salts such as Korean solar salt (KSS), purified salt (PS), sea-concentrated salt (SCS), glasswort (Salicornia herbacea L.) spray solar salt (GSS), glasswort-sea-concentrated salt (GSCS) and spray-dried salt (SDS) on the physicochemical and sensory properties of fermented shrimps. Ammonia nitrogen content of the salted shrimp prepared with SDS was lower than others until 60 day fermentation. At 90 day fermentation, amino nitrogen contents of salted shrimps prepared with GSCS and GSS (980 mg%) were higher than those of the others while sample prepared with SDS showed the lowest amino nitrogen content (680 mg%). Volatile basic nitrogen content of salted shrimp prepared with SDS was also lower than those of the others between 14 and 60 day fermentation and there were differences among samples in the contents of trimethylamine at 180 day fermentation. Sensory evaluation results indicated significant differences in salty, overall taste and overall acceptance among samples. Overall acceptance was significantly higher in salt-fermented shrimp prepared with KSS, SCS, GSS, GSCS and SDS than in fermented shrimp with PS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.579-588
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• 2001

In order to investigate the composition and monthly variation of extractive nitrogenous components in the laver Porphyra dentata cultured at the south coast of Korea, the fresh laver was analyzed separately for the amounts of free amino acids, combined amino acids, ATP and its related compounds, and quaternary ammonium basis in fresh laver were measured. The extractive nitrogen contents of fresh laver extracts were 760~870 mg/100g (dry basis). Twenty-seven to thirty-one kinds of free amino acids were detected in the laver extracts and their total amounts were 2,404~3,966 mg/100g (on dry basis). The laver extracts showed rich in free amino acids such as alanine, taurine, glutamic acid, glutamine and aspartic acid. Sixteen to twenty-three kinds of combined amino acids were detected in the extracts and their total amounts were 1,429~2,692 mg/100g (on dry basis). Proline, glutamic acid, glycine, phosphoserine, serine were the amin combined amino acids in the extracts. The amounts of ATP and related compounds were 73.3~94.4 mg/100 g (2.04~4.43 $\mu$mol/g, on dry basis). Homarine and trigonelline were detected in all specimens but $\beta$-alaninebetaine, ${\gamma}$-butyrobetaine were found in some. Small amounts of trimethylamine were detected in all samples. Free and combined amino acids were occupying almost 90% of extractive nitrogen. Most of free and combined amino acids showed a marked monthly variation with a maximum in January and March, and a minimum in February and April. The fresh laver P. dentata did not differ much from the fresh laver P. yezoensis in qualitative com-position of extractive components, but their contents were generally low level.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.35-40
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• 2009

Lead free positive temperature coefficient of resistivity (PTCR) ceramics based on $BaTiO_3-(Bi_{0.5}Na_{0.5})TiO_3$ solid solution were prepared by a conventional solid state reaction method. The phase structure was showed single phase with perovskite structure regardless calcinations temperature and $Ba_{1-x}(Bi_{0.5}Na_{0.5})_xTiO_3$ structure was transformed from tetragonal to orthorhombic phase at $x{\geq}0.15$ mole. The XRD peaks with $45^{\circ}{\sim}46^{\circ}$ shifted in right the influence of crystal structure change and the intensity of peak was decreased with additive $(Bi_{0.5}Na_{0.5})TiO_3$. The curie temperature risen with additive $(Bi_{0.5}Na_{0.5})TiO_3$ but disappeared for $(Bi_{0.5}Na_{0.5})TiO_3$ addition more than 0.15 mole in TMA. In relative permittivity, the curie temperature by the transform of ferroelectric phase risen with additive $(Bi_{0.5}Na_{0.5})TiO_3$ but decreased in relative permittivity. Also, the peak of new curie temperature showed the sample containing $0.025{\sim}0.045$ mole of $(Bi_{0.5}Na_{0.5})TiO_3$ near $70^{\circ}C$ caused by phase transform from ferroelectric to ferroelectric and the peak of new curie temperature disappeared at 0.045 mole of $(Bi_{0.5}Na_{0.5})TiO_3$. In our study, it was found that the PTCR in $BaTiO_3-(Bi_{0.5}Na_{0.5})TiO_3$ system was possible for $0{\sim}0.025$ mole of $(Bi_{0.5}Na_{0.5})TiO_3$ and the maximum curie temperature by phase transition showed about at $145^{\circ}C$.