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Stability Constants for Transition Metal ions of Hexadentate $N_6$ Ligands Containing Two Pyridyl Groups (피리딘을 포함하는 여섯자리 $N_6$ 리간드와 전이금속 이온 착물의 안정도상수)

  • Kim, Sun-Deuk;Kim, Jun-Kwang;Park, Yoon-Yul
    • Analytical Science and Technology
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    • v.12 no.5
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    • pp.397-402
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    • 1999
  • The open-chain hexadentate $N_6$, ligand containing two pyridyl groups, 1,15-bis(2-pyridyl)-2,6,10,14-tetraazapentadecane (bpyped) has been synthesized as its tetrahydroehloride salt and characterized by EA, IR, NMR, and Mass. Its proton dissociation constants($logK{^n}_H$) and stability constants ($log\;K_{ML}$) for Co(II), Ni(II), Cu(II) and Zn(II) ions were determined at $25^{\circ}C$ and ionic strength 0.10 M($KNO_3$) in aqueous solution by potentiometry and compared with those or analogous $N_6$ ligands contain one or two propylenic spacers, which make six-membered chelate rings, between the aliphatic nitrogen atoms.

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Leakage-reduction Measures at a Joint between CPVC Piping for a Sprinkler System and a Pipe Expansion (스프링클러설비용 CPVC관과 신축배관 접속부분에서의 누수저감 대책에 관한 연구)

  • Lim, Chun-Ki;Lim, Yun-Tack;Baek, Eun-Sun
    • Fire Science and Engineering
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    • v.29 no.3
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    • pp.21-30
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    • 2015
  • In this study, we try to suggest measures to reduce leakage at a joint between CPVC piping for a sprinkler system and a pipe expansion through reviews of domestic and foreign standards and related tests. The quality of the waterproof rubber packing material between a valve socket and pipe expansion nut was examined. In the leak test, the valve socket material over the expansion part of the metal pipe nut was found to use a metal part or a schlorinated polyvinyl chloride pipe nut part. In addition, the KS B 0221 standard for parallel pipe threads with threaded and thread inspection criteria and inspection standards in order to ensure an acceptable quality of valve socket, there is a need to amend the regulations to comply with the KS B 5223 (screw thread limit gauges parallel pipe threads). We do not have detailed standards for expansion piping nuts for waterproof rubber ring material, so we need to amend the relevant criteria for EPDM material to be used with excellent waterproofing, for which both NBR and EPDM are currently used.

Physico-chemical Changes of Commercial Ssamjang during Storage (공장식 쌈장의 저장기간에 따른 이화학적 성분변화)

  • Kim, Yong-Kook;Kim, Seong-Ju;Han, Min-Soo;Chang, Young-Il;Chang, Kyu-Seob
    • Korean Journal of Food Science and Technology
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    • v.37 no.3
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    • pp.389-396
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    • 2005
  • Physico-chemical properties of ssamjang prepared by industrial process were investigated. Overall experiments were planned by central composite design for five independent variables, kochujang mash aging period $(X_{1})$, doenjang aging period $(X_{2})$, doenjang content $(X_{3})$, sterilization temperature $(X_{4})$, and storage temperature $(X_{5})$. Storage period had no consistent effect on moisture content of ssamjang. Doenjang having longer aging period showed lower moisture content than that having shorter aging period. Titratable acidity and pH of ssamjang gradually increased and decreased with storage period, respectively, with pH of ssamjang significantly affected by aging period of doenjang and kochujang mashes, and sterilization and storage temperatures. Amino nitrogen contents of ssamjang increased during storage and were more affected by sterilization temperature than by aging period and content of doenjang, and storage temperature. Crude protein content of ssamjang irregularly changed during storage, and was slightly affected by content of doenjang.

Flavour Improvement of Soybean Pastes by the Addition of Bacillus licheniformis and Saccharomyces rouxii (Bacillus licheniformis 와 Saccharomyces rouxii 첨가에 의한 된장의 풍미향상)

  • Shin, Soon-Young;Kim, Young-Bae;Yu, Tae-Jong
    • Korean Journal of Food Science and Technology
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    • v.17 no.1
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    • pp.8-14
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    • 1985
  • In order to give the unique flavour of traditional Doenjang (Korean-style soybean paste) to commercially manufactured soybean paste, the addition of Bacillus licheniformis and Saccharomyces rouxii was tried and their influences were investigated. The addition of B. licheniformis and S. rouxii in soybean paste decreased the content of reducing sugars. By the addition of B. licheniformis, the contents of amino type nitrogen and titrable acidity were increased. The content of ammoniacal nitrogen was reduced and ethyl alcohol production was increased by the addition of S. rouxii. The viable counts of molds showed the decreasing tendency during the aging and it was accelerated by the addition of B. licheniformis and S. rouxii. Acetaldehyde, acetone, ethylacetate, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol and isopropyl alcohol were detected from the vapor of all tested ripen soybean pastes, while in a traditional Doenjang, isoamyl alcohol and isobutyl alcohol were not. The B. licheniformis and S. rouxii added sample showed richest free amino acid content. In organoleptic test the B. licheniformis and S. rouxii added sample showed the most excellent overall acceptability.

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Effects of Freezing Pretreatment on Juice Expression and Drying Characteristics of Prunus mume Fruit (동결 전처리가 매실의 착즙과 건조 특성에 미치는 영향)

  • Chung, Hun-Sik;Kim, Han-Soo;Lee, Young-Guen;Seong, Jong-Hwan
    • Food Science and Preservation
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    • v.17 no.4
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    • pp.507-512
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    • 2010
  • The effects of pretreatment by freezing on juice expression and drying characteristics of Prunus mume fruit were investigated. Fresh fruit slices were frozen at $-20^{\circ}C$, thawed, and then either pressed (to yield juice) or dried. Fresh fruit slices were used as controls. Both juice yield and drying rate were higher when pre-frozen fruit was tested, compared to fresh fruit. The L and b color values were lower in the juice and dried powder of pre-frozen compared to fresh fruit. The a color value was higher in juice and powder prepared from pre-frozen fruit compared to fresh fruit. There was no significant difference in free sugar or organic acid content between juices and powders from pre-frozen and fresh fruit. None of soluble solid content, titratable acidity, or juice pH was affected by freezing pretreatment. The results suggest that such pretreatment may be useful to increase juice yield and drying rate. However, browning of juice and powder may be elevated.

A Study on the Housewives' Purchase Behaviors of Pork (주부의 돼지고기 구매행태에 관한 연구)

  • Kim, Gye-Woong;Kim, Min-Su;Kim, Seok-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.12
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    • pp.3910-3918
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    • 2009
  • This study was carried out to investigate consumer's purchase behaviors of pork. Questionnaires from a total of 253 housewives were analyzed Jan. to Feb. 2008. The average of preferences for domestic and imported pork were $4.07{\pm}0.81$ and $2.21{\pm}0.96$ scores of 5 points, respectively. Consumers (56.4%) liked belly of pork very much. Consumers (45.4%) purchased a great deal of pork in big discount mart. Consumers (40.2%) responded that they indicated quality reliability as the choice factors for determination of purchasing pork. Respondents (54.6%) hoped the wrapping pork pack of 600 g. The evaluation of the perception for carcass grading system and quality reliability for brand-pork averaged $2.97{\pm}0.88$ and $3.47{\pm}0.60$ scores of 5 points, respectively.

Changes of Properties in Cinnamon Extracts Prepared by Enzyme Hydrolysis and Addition of Salts, Sugars and Antioxidant Synergists (효소분해와 염과 당 및 항산화 작용 상승제의 첨가에 의한 계피 추출액의 특성 변화)

  • Kim, Na-Mi;Do, Jae-Ho;Lee, Jong-Soo;Kim, Woo-Jung
    • Applied Biological Chemistry
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    • v.37 no.4
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    • pp.272-276
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    • 1994
  • The dried cinnamon was extracted with enzymes, salts, sugars and additives in order to find the most effective extraction material. Enzymatic hydrolysis of cinnamon suspension with cellulase, hemicellulase, pectinase, ${\beta}-1.4-glucosidase$, tannase and lipase showed a little increase of their cinnamic aldehyde contents. Solid yield, antioxidant activity and degree of browning were increased in hemicellulase treatment. Acid and alkali extraction of cinnamon showed a some increase in solid yields and antioxidant activity was increased by addition of glucose and Na-ascorbate. Cinnamic aldehyde contents and degree of browning were increased in extraction with Na-citrate addition.

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Quality Characteristics of High-Fiber Breads Added with Domestic Wheat Bran (국산밀 제분부산물을 첨가한 고식이섬유빵의 품질 특성)

  • Lee, Young-Tack
    • Applied Biological Chemistry
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    • v.46 no.4
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    • pp.323-328
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    • 2003
  • Wheat bran, a milling by-product of domestic wheat grains, containing approximately 42% of the total dietary fiber, was tested for the effects on bread-making properties. The amylograph peak viscosity and set bark values considerably decreased with increasing levels $(0{\sim}30%)$ of wheat bran. Adding wheat bran somewhat increased water absorption and showed no consistent effect on mixing time. Yeast-leavened breads were baked with wheat flour with up to 30% of the flour substituted with domestic wheat bran. Adding domestic wheat bran exerted detrimental effect on loaf volume and decreased sensory acceptability such as crust and crumb color, crumb grain, texture, and flavor. Wheat bran decreased lightness and imparted red and yellow tint. It was suggested that domestic wheat bran could be substituted for wheat flour at levels up to 15% without significantly depressing bread quality in the preparation of high-fiber bread. Crumb firmness of bread containing 15% wheat bran was significantly higher than that of the control bread (100% wheat flour) and increased rapidly at $2{\sim}3$ days during storage.

Understanding Soil by Cartoons (카툰(Cartoon)을 통한 토양의 이해)

  • Kim, K.H.;Hyun, H.N.
    • Korean Journal of Soil Science and Fertilizer
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    • v.42 no.spc
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    • pp.51-56
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    • 2009
  • Numerous methods can be employed to teach students and farmers on soil science and fertilizer. The cartoon is one of the most effective teaching aids both for instructors and students. Instructor becomes a director of the cartoon to organize the framework of story based on the chapter of lecture. Director should adapt the regular sentence on soil science into the short and concise scenario suitable for the visual expression of the cartoon, followed by the selection of the scene for drawing. Next is to cast the instructor for the role of actor or sometimes supporter. After casting, the director starts to draw each cut of the cartoon in sequence. I published the cartoons in weekly serials in the farmer's newspaper for three years. Each cartoon was composed of eighteen cuts and formatted with the introductory, main and conclusive issues. Cartoon started with dialogues between the cast on subject to stimulate the interest by farmers, inserted the tables and graphs for the scientific knowledge and summarized the chapter. Major contents covered in the cartoons were glossary, nutrient uptake, pH, salt accumulation, moisture, pollution, chemical fertilizer, compost and other general aspects of soils. Cartoons had been very popular serial of the newspaper and are archived in the web for reviewing.

Quality Characteristics of Modified Doenjang and Traditional Doenjang (개량된장과 전통된장의 품질 특성)

  • Jeon, Hyeonjin;Lee, Sanghoon;Kim, Sangsook;Kim, Yoonsook
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.7
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    • pp.1001-1009
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    • 2016
  • This study was conducted to investigate the relationship between quality factors and palatability of modified Doenjang and traditional Doenjang. Fourteen types of Doenjang, including three modified Doenjang and 11 traditional Doenjang samples, were analyzed to evaluate their physicochemical and sensorial properties. There were differences in e-tongue, which indicates overall acceptability. Water contents, minerals, total sugar contents, salt contents, pH, titratable acidity, and free amino acids of Doenjang did not show significant differences. From the correlation and regression analysis, palatability was closely related to the e-tongue sensor such as $X_1$ (sourness), $X_3$ (saltiness), and $X_4$ (umami) to -0.772, -0.642, and 0.678, respectively. The regression equation for sensorial palatability (Y) was Y=$45.356-0.008X_1-0.010X_3$ with a coefficient of 0.882.