• Applied Biological Chemistry
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• v.47 no.4
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• pp.409-413
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• 2004

We have studied quality changes of fully ripe fruit of Korean native pumpkin 'Yangsan' regarding the following parameters: pH, sugar content, weight, water content, contents of crude protein and amino acids during 60 days storage at room temperature. As the results, there was no changes in sugar contents according to the storage period, but pH was changing to a little acidic direction with slight decrease in weight and water content. Contents of total crude proteins and comprising amino acids were increased during the storage period. The main contents of amino acids of the Korean native pumpkin, Yangsan, were glutamic acid (15.5%), aspartic acid (10.1%), lysine (8.7%), valine (7.5%), leucine (7.1%) and alanine (6.6%), which were not highly influenced during storage period. Additionally we have investigated the content of free amino acids and color changes during processing of Yangsan under high temperature at $121^{\circ}C$ and high pressure at $1\;kg/cm^2$. In fully ripe fruits, a total of 29 kinds of free amino acids were detected including 8 kinds of essential amino acids (histidine, isoleucine, leucine, lysine, phenylalanine, methionine, threonine and valine). More than 35% of total free amino acids were aspartic acid (20.3%) and asparagine (15.4%); ornithine, citrullin, and arginine, which are related to Ornithine cycle, were also detected in fully ripe fruits. But when treated with high temperature and high pressure, glutamic acid and arginine were decreased rapidly whereas ammnonium chloride was relatively increased. Moreover "b" value as yellow color indicator was decreased from 17.45 to 9.14 while treated for 60 minutes with high temperature and pressure, caused by the degradation of ${\beta}-carotene$ and other yellowish pigments in Yangsan.

• Food Science and Preservation
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• v.18 no.5
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• pp.729-738
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• 2011

This study was conducted to investigate the effect of extruded pellets (EP) containing different levels of protein (51%-55%) and lipid (9%-15%) on flesh quality of flounder (Paralichthys olivaceus) comparing with raw fish-based moist pellet (MP). Two replicate groups of 40 fish per each tank (initial mean weight 106 g) were fed one of three experimental EP (EP1, EP2 and EP3) containing different protein and lipid levels, a commercial EP (EP4) and MP for 16 weeks. Moisture content of fish fed MP was significantly higher than that of fish fed all EP. Significantly higher contents of 16:1n-7, 20:4n-6, 20:5n-3 and lower 18:2n-6 were observed in fish fed EP4 and MP compared with fish fed EP1, EP2, EP3. The 22:6n-3 content was not significantly different among all groups. Taurine content of fish fed MP was significantly higher than that of fish fed all EP. Asparagine content of fish fed EP1 was significantly higher than that of fish fed EP2, EP, EP4 and MP. Significant difference were observed in lysine and serine contents of fish fed experimental diets. In nucleotides and their related compounds, ATP and AMP content was not affected by diets. Significant difference were observed in IMP contents of fish fed experimental diets. Textural properties, no significant difference was observed among the fish groups fed different diets.

• Journal of Life Science
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• v.18 no.3
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• pp.387-394
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• 2008

This research was performed to determine the proximate compositions, mineral contents, alginic acid, antioxidative activities and amino acids of sea mustards (Miyeok: Undaria pinnatifida) collected from Gijang and Wando area. Ash content was higher in Gijang samples, whereas carbohydrate and moisture were higher in Wando Sil Miyeok. General compositions of dried sea mustard showed different contents as manufacture's company and places. The major free amino acids were hydroxyproline, alanine, glutamic acid and asparagine in Gijang samples. Both Gijang and Wando Sil Miyeok showed lower contents comparing with Gijang Gadak Miyeok. Major mineral content was Na, K, Ca, Mg and P, and especially, Na and K were the most abundant in both Gijang and Wando sea mustards. Alginic acid content was almost similar in both sea mustards. Antioxidative activity of methanol extract of sea mustards was measured by using DPPH radical scavenging and SOD-like activity. DPPH radical scavenging activity was 45.5% $(40\;{\mu}g/ml)$ in Gijang Gadak Miyeok and 37.0% and 26.0% $(40\;{\mu}g/ml)$ in Gijang and Wando Sil Miyok, respectively. SOD-like activity of Gijang and Wando Sil Miyok was 63% and 71% $(10\;{\mu}g/ml)$, respectively. These results show that biological activities depend on Miyeok manufacture's process. When stimulated macrophages RAW264.7 cells with lipopolysaccharide (LPS), inhibition of NO production in Gijang Sil Miyeok (44.2%) was 9% high comparing with that of Wando Sil Miyeok (35.7%).

• Food Science and Preservation
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• v.15 no.3
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• pp.461-468
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• 2008

To obtain basic da1a on the preparation of Cudrania tricuspidata leaves tea, the quality and anti-oxidative characteristics of dried raw leaves (RT), pan-fired leaves tea (PT) and fermented leaves tea (FT) were investigated. General characteristics of RT, PT and FT, respectively, were: moisture content 18.47, 6.23 and 8.50%; crude protein content 17.77, 20.46 and 19.13%; and carbohydrate content 54.42, 62.52 and 61.96%. The crude lipid and ash contents were in the range 0.05 - 0.07% and 9.27 -10.74% respectively; the water soluble solid content was in the order FT > PT > RT and ranged from 23.10 - 37.38%; there were no significant differences in the total polyphenol content (815.24 - 835.16 mg%). Although $L^*$ values of PT (20.94) and FT (20.85) were lower than those of RT (34.71), the $a^*$ value in PT and the $b^*$ value in FT were highest. In all ethanol extracts the reducing power, electron-donating ability and superoxide dismutase (SOD)-like activity increased in a concentration-dependent manner. Furthermore, the activity in FT was higher than in PT or RT. The total free amino-acid content was higher in FT (1429.93 mg%) than RT (1108.94 mg%) or PT (833.13 mg%). The major amino acids were L-asparagine and L-valine in RT, L-cysteine and L-glutamic acid in PT and L-proline in FT. In a sensory evaluation of PT and FT, bitter and astringent tastes were decreased relative to RT, while sweet and savory tastes, flavor, color and overall acceptability were increased. These results indicate that FT bas a higher antioxidant effect and free-amino-acid content than PT, while the sensory quality of FT is similar to that of PT.

• Journal of Life Science
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• v.16 no.4
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• pp.683-690
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• 2006

The chemical compositions of amino acids, minerals, betaine, and polyphenolic compounds from Salicornia herbacea (Hamcho) according to harvest periods were analyzed. Changes of chemical characteristics in water and ethanol extracts from Hamcho were evaluated for titratable acidity, pH, soluble solid, and Hunter's color values. The antioxidative activity of water extract from Hamcho was also determined by DPPH $({\alpha},{\alpha}'-diphenyl-{\beta}-picrylhydrazyl)$ scavenging radical activity. Total polyphenolic compounds of Hamcho were shown the highest in August harvested by 201.6 ppm. The betaine of Hamcho water-extract was identified by high performance liquid chromatography (HPLC), which content was 0.248%, 0.269% and 0.204% in June, August, and October, respectively. Major compositional amino acids (mg%) were glutamic acid (582: 519: 664), proline (552: 471: 322), phenylalanine (480: 431: 424), aspartic acid (322: 297: 330), and arginine (282: 321: 483) in June, August, and October, respectively, and major free amino acids (mg%) were proline (9.7: 3.4), asparagine (6.7: 1.4), hydroxyproline (6.4: 2.8), valine (3.9: 2.5), arginine (1.7: 3.0) in June and August, respectively. Mineral contents (mg%) were Na (5,695: 7,536: 5,529), K (1,640: 963: 931), Mg (359: 428: 348), Ca (221: 234: 251), and P (207: 189: 259) in June, August, and October, respectively. Especially, K was high in June, Na and Mg were high in August, and Ca and P were high in October, respectively. DPPH scavenging radical activity was shown in the following order; 0.05% butylated hydroxytoluene (BHT)> August> June> October harvested Hamcho. The chemical components of polyphenolic compounds, betaine, amino acids and minerals were changed by harvest periods according to the growing season, and the highest concentrations of polyphenolic compounds and betaine of Hamcho were shown in August harvested.

• Food Science and Preservation
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• v.15 no.5
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• pp.711-718
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• 2008

Dombaeki, a traditional salted shark meat, has been widely used as a customary religious food in the Daegu-Gyeongbuk area of Korea. Two different sharks, Sphyrna zygaena (SZ) and Isurus oxyrinchus (IO) are traditionally used to prepare Dombaeki. Chemical components, lipid classes, fatty acid levels, and sterol compositions of meats prepared from the two sharks were investigated. There were no significant differences in chemical composition between the two dried shark meats. Major amino acids in shark meat were leucine, lysine, arginine, proline, isoleucine, valine, phenylalanine, glutamic acid, and asparagine, which together accounted for about 40% of total amino acids. Levels of amino acids in IO meat were higher than in SZ meat. Major fatty acids in the two shark meats were palmitic ($C_{16:0}$), stearic ($C_{18:0}$), oleic ($C_{18:1}$), arachidonic ($C_{20:4}$), and docosahexanoic (DHA, $C_{22:6}$) acids, which accounted for about 80% of total fatty acids. Notably, IO meat showed higher amounts of DHA (31.8%) and eicosapentanoic acid (EPA, 1.8%) than did SZ meat. The two shark meats showed similar dry weight levels of total lipids, with triacylglycerols, free fatty acids, sterols, and phospholipidscomprising on average 5.0, 2.0, 13.0 and 63.0% of total lipids, respectively. The dominant classes of phospholipids were mainly phosphatidylcholine (PC) and phosphatidylethanolamine (PE). PC content in the two shark meats was higher than that of PE, although the differencewas not great. The major fatty acids in phospholipids were myristic, palmitoleic, stearic, and docosanoic acids. Total volatile basic nitrogen content and the pH of SZ meat were lower than those of IO meat, whereas the Hunter's 'a' and 'b' values of SZ meat were higher than those of IO meat. These results suggest that shark meat may be useful as a functional food to prevent several degenerative diseases.

• Journal of Mushroom
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• v.22 no.2
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• pp.60-66
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• 2024

This study was conducted to selection and investigate appropriate conditions for mass production of antagonistic microbes to control cobweb disease caused by Cladobotryum mycophilum. A grampositive bacterium was isolated from spent substrate of Agaricus bisporus and showed significant antagonistic activity against Cladobotryum mycophilum. The bacterium was identified as Bacillus altitudinis. based on the cultural, biochemical and physiological characteristics, and 16S rRNA sequence. The isolate is saprophytic, but not parasitic nor pathogenic to cultivated mushroom whereas it showed strong inhibitory effects against C. mycophilum cells in vitro. The control efficacy of B. altitudinis HC7 against cobweb disease of C. mycophilum was up to 78.2% on Agaricus bisporus. The suppressive bacterium may be useful for the development of biocontrol system. To define the appropriate conditions for the mass production of the Bacillus altitudinis HC7, we have investigated appropriate culture conditions and effects of various nutrient source on the bacterial growth. The appropriate initial pH and temperature were determined as pH 6.0 and 30℃, respectively. The appropriate concentration of medium elements for the growth of pathogen inhibitor bacterium(Bacillus altitudinis HC7) was determined as follows: 3.0% soluble startch, 10% soytone, 1.0% (NH₄)₂HPO₄, 1.0 mmol KCl, and 0.5% L-asparagine.

• Applied Biological Chemistry
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• v.13 no.2
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• pp.111-129
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• 1970

As a series of studies on the nucleic acids and their related substances 210 samples were collected from 76 places such as farm soil, compost of heap, nuruk and meju to obtain microbial strains which produce 5'-phosphodiesterase. From these samples total of 758 strains were isolated by the use of dilution pour plate method. For all isolated strains primary screening of the productivity of RNA depolymerase was performed and useful strains with regard to 5'-phosphodiesterase productivities were identified. For these useful strains optimum condition, the effect of various compounds on the activity of 5'-phosphodiesterase, and the optimum condition for enzyme reaction were discussed. The quantitative of 5'-mononucleotides produced by the action of 5'-phosphodiesterase was performed using anion-exchange column chromatography and their identified was done by paper chromatography, thinlayer chromatography, ultra violet spectrophotometry, and characteristic color reaction using carbazole and schiff's reagent. (1) Penicillium citreo-viride PO 2-11 and Streptomyces aureus SOA 4-21 from soil were identified as a potent 5'-phosphodiesterase producing strains. (2) Optimum culture conditions for Penicillium citreo-viride PO 2-11 strain isolated were found to be pH 5.0 and $30^{\circ}C$, and the optimum conditions for enzyme action of 5'-phosphodiesterase were pH 4.2 and $60^{\circ}C$. Best carbon source for the production of 5'-phosphodiesterase was found to be sucrose and ammonium nitrate for nitrogen source. Addition of 0.01% corn steep liquor or yeast extract exhibited 20% increase in the amount of 5'-phosphodiesterase production compared to the control. 5'-phosphodiesterase produced by this strain was activated by $Mg^{++},\;Ca^{++},\;Zn^{++},\;Mn^{++}$ and was inhibited by EDTA, citrate, $Cu^{++},\;CO^{++}$. 5'-phosphodiesterase produced 5'-mononucleotide from RNA at a rate of 65.81%, and among the 5'-mononucleotides accumulated 5'-GMP only was found to have flavorous and the strain was also found lack of 5'-AMP deaminase. Productivity of flavorous 5'-GMP was found to be 186.7mg per gram of RNA. (3) Optimum culture canditions for the isolated Streptomyces aureus SOA 4-21 strain were pH 7.0 and $28^{\circ}C$, and the optimum conditions for the action of 5'-phosphodiesterase were pH 7.3 and $50^{\circ}C$. The best carbon source for 5'-phosphodiesterase production was found to be glucose and that of nitrogen was asparagine. Addition of 0.01% yeast extract exhibited increased productivity of 5'-phosphodiesterase by 40% compared to the non-added control. 5'-phosphodiesterase produced by this strain was activated by $Ca^{++},\;Zn^{++},\;Mn^{++}$ and was inhibited by citrate, EDTA, $Cu^{++}$. It was also found that the strain produce 5'-AMP deaminase in addition to 5'-phosphodiesterase. For this reason although decomposition rate was 63.58% the accumulation of 5'-AMP, 5'-CMP, 5'-GMP and 5'-UMP occurred by the breakdown of RNA. In the course of these reaction 5'-AMP deaminase converted 60% of 5'-AMP thus produced into 5'-IMP and flavorous 5'-mono nucleotide production was significantly increased by this strain over the above mentioned one. Production rates were found to be 171.8mg per grain of RNA for 5'-IMP and 148.2mg per gram of RNA for 5'-GMP, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.2
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• pp.240-248
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• 1996

To clarify the potentiality of sea cucumbers as dietary food, the effects of those glycoprotein on dietary proteins and physicochemical properties of those proteins were studied. Crude glycoprotein was efficiently extracted using 20mM sodium phosphate beffer(pH 7.0) and by salting out with 80% ammoniym sulfate saturation. The fractions obtained through the DEAE-cellulose ion exchange chromatography was identified as glycoprotein by Schiff's reagent and SDS polyacrylanide gel electro-phoresis. The yields of each glycoprotein from the three kinds of sea cucumbers were 0.814(red), 0.184(blue) and 0.232(black) and the molecular weights of the glycoproteins subunits were ranged from 20,000 dalton(blue and black) to 29,000 dalton(red), respectively. The electrophoretic patterns of the glycoprotein isolates were similar to each other and any significant difference in amino acid pattern was observed. Predominant arnino scids were Asx(aspartic acid and asparagine) and Glx(glutamic acid and glutamine) ; in contrast, histidine and methionine were below 2% as compared to total amino acids. water holding capacities of the glycoprotein isolates from red, blue and black cucumbers were equally 100% and emulsion activities ranged from 53% to 64%. In addition the emulsion stabilities were 7.04, 1.37 and 2.44, respectively. In vitro digestibility of some proteins(casein, SPI and squid) was decreased as increasing the level of the freeze dried sea cucumber powder and glycoprotein isolates. But squid protein was not affected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.744-750
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• 2017

Acrylamide is a probable human carcinogen and can be formed during frying of starchy foods. The objective of this study was to investigate the effects of acrylamide reduction in storage potato chips by fermentation of Bacillus subtilis and compare its usefulness with four different cultivars of storage potatoes (Goeun, Atlantic, Saebong, and Jinsun). Potato slices were fermented by B. subtilis at $37^{\circ}C$ for 0, 2, and 4 h and fried at $180^{\circ}C$ for 115 s. The total sugar contents of the fermented potato slices did not change compared to the control. However, reducing sugar contents increased in the fermentation solution containing potato slices. Asparagine contents of Saebong and Jinsun potato slices decreased with fermentation time. Color values of the fermented potato chips were improved compared to those of non-fermented potato chips. The highest $L^*$ value was found in Saebong (57.4), followed by Goeun (56.7), Jinsun (52.5), and Atlantic (48.8) after 4 h of fermentation. Potatoes stored for 240 days generated considerable amounts of acrylamide, ranging from 4.99 to 10.38 ppm, after frying. Four hours of fermentation reduced acrylamide formation in all potato chips. The lowest acrylamide content was found in Saebong (0.77 ppm), followed by Jinsun (1.21 ppm), Goeun (1.76 ppm), and Atlantic (4.09 ppm). In conclusion, fermentation of storage potatoes by B. subtilis can effectively lower acrylamide formation during frying of potato chips.