• Corrosion Science and Technology
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• 제21권1호
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• pp.32-40
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• 2022

The o-Vanillin - Glutamine Schiff base [2-Hydroxy-3-Methoxy BenzylidineCarbomyl) -2-Butanoic Acid] was examined for low carbon steel corrosion inhibition in acid media. Weight loss studies were carried out at three different temperatures to determine the inhibition efficiency (IE). Electrochemical impedance spectroscopy revealed that the charge transfer resistance controlled the corrosion reaction and Tafel polarization indicated that the Schiff base acts as mixed mode of inhibitor. SEM images were recorded for the surface morphology of the low carbon steel surface. DFT studies revealed corrosion control mechanisms using quantum chemical parameters such as E_HOMO, E_LUMO, energy gap (∆E), chemical Hardness (η), chemical Softness (σ), Electronegativity (χ), and the fraction of electron transferred (∆N), which is calculated using Gaussian software 09. The gas-phase geometry was fully optimized in the Density Functional Theory (DFT/B3LYP-6-31G (d)).The DFT results are in good agreement with the experimental results. All the results proved that the Schiff Base (2-Hydroxy-3-Metoxy BenzylidineCarbomyl) -2-Butanoic is a suitable alternative for corrosion inhibition of low carbon steel in acid media.

• 한국식품저장유통학회지
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• 제8권1호
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• pp.60-65
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• 2001

초산균을 달리하여 제조한 감자식초의 품질을 상호 비교하여, 초산균에 따른 품질 특성을 조사하였다. 3종의 감자식초에 대한 pH는 2.90∼3.09, 총산 함량은 5.30∼5.60%로 큰 차이를 나타내지 않았으나, Acetobacter sp. PA96을 이용한 감자식초(II)의 색상은 감자식초(I, III)과 구별되었다. 또한 acetic acid를 제외한 유기산 조성은 Acetobacter sp. PA97을 이용한 감자식초(I)에서 citric acid, oxalic acid, succinic acid, Acetobacter pasterianus JK99를 이용한(감자식초 III)에서 lactic acid, Acetobacter sp. PA96을 이용한 감자식초(II)에서 magic acid 비율이 높았다. 3종의 감자식초에서 유리아미노산은 glutamic acid, alanine, histidine, proline 등이 높은 함량을 나타내었으며, 주요 휘발성 성분으로는 acetic acid, isoamyl acetate, isobutyl acetate, 3-methyl-1-butanol, 3-methyl-butanoic acid, phenethyl alcohol 등이 확인되었고, 초산균에 따라 구성비율에 차이가 있었다.

• 한국식품과학회지
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• 제30권4호
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• pp.728-732
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• 1998

시판되고 있는 가공식품 중 이취(異臭) 미역 및 이취(異臭) 쌀엿의 냄새성분을 규명하고, 이의 발생원인을 밝히고자 하였다. 이취 미역에서는 naphthalene,2-methylnaphthalene, 1-methylnaphthalene, 2,6-dimethylnaphthalene, 1,5-dimethylnaphthalene, 1,8-dimethylnaphthalene, 2,7-dimethylnaphthalene, 1,4,6-trimethylnaphthalene, 2,3,6-trimethylnaphthalene 등 나프탈렌계화합물들이 검출되었으며, 이취 쌀엿에서는 butanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid,tetradecanoic acid 등 유리지방산 및 2-furanmethanol, 2-furancarboxaldehyde 이 검출되었다. 미역의 이취 생성원인은 채취선박의 페인트 오염으로부터, 쌀엿은 변패된 쌀을 당화의 원료로 사용한데 기인한 것으로 본다.

• 임산에너지
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• 제22권2호
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• pp.18-25
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• 2003

중국산 죽순대 (Phyllostachys pubescens)를 간이탄화로(400 - 500 ℃)에서 제탄하고 얻어진 죽초액에 대하여 그 특성을 검토하였다. 중국산 죽순대로부터 제조한 죽초액은 보매 비중 4.5, 유기산 함량 9.9%, pH 2.8, 용해타르함량 3.1%, 굴절률 13.1%를 나타내었다. 이들 죽초액의 구조 동정 및 정량 결과, acetic acid, 1-hydroxyl-2-propanone, methanol, 1-hydroxyl-2-butanone, propionic acid 등이 주요화합물로 국내산 죽순대 죽초액과 큰 차이가 없었다. 총 유기물 함량은 14.8% 이었으며 이중 유기산류 (acetic acid, formic acid, propionic acid, butanoic acid)는 9.0%로 전체 유기물 중 약 61%를 차지하였다. 페놀류와 중성류는 각각 0.8%와 4.5%로 전체 유기물의 약 6%와 31%를 차지하였다. 시판되고 있는 중국 재래식 죽초액의 경우 대부분의 물성치 및 유기물 함량이 낮은 것으로 보아 본 죽초액은 탄화 초기단계에서 포집하여 숙성시켰을 가능성이 높다고 생각되었다.

• Food Science and Biotechnology
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• 제14권2호
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• pp.238-241
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• 2005

Aroma-active compounds were evaluated from salt-fermented anchovy sauce by solid phase microextraction-gas chromatography-olfactometry (SPME-GC-O) based on sample dilution analysis (SDA). SPME extract from carboxen/polydimethylsiloxane (CAR/PDMS) fiber was the most similar to the original odor of salt-fermented anchovy sauce used for this experiment, followed by divinylbenzene/CAR/PDMS (DVB/CAR/PDMS) fiber. Because salt-fermented anchovy sauce contains 23% NaCl, NaCl concentration of diluent was considered when salt-fermented anchovy sauce was serially diluted. Linear relationship between GC response and sample concentration was observed when diluted with 23% NaCl solution, whereas not observed when diluted with deodorized distilled water. Eleven and 16 aroma-active compounds were detected by SPME-GC-O based on SDA using CAR/PDMS and DVB/CAR/PDMS fibers, respectively. Butanoic acid and 3-methyl butanoic acid showed the highest ${\log}_2SD$ factors for CAR/PDMS and DVB/CAR/PDMS fibers. Dimethyl trisulfide, methional, trimethyl amine, 1-penten-3-ol, and acetic acid were also detected as potent aroma-active compounds.

• 한국식품영양과학회지
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• 제36권7호
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• pp.874-880
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• 2007

품종에 따른 포도를 이용하여 3일 동안 $4^{\circ}C$와 실온에 각각 저장함에 따라 변화하는 전체적인 향의 패턴을 전자코를 통하여 분석하였고 SPME-GC/MS 분석 결과를 통하여 휘발성분을 분리 동정하였다. 대표적인 포도의 주요 휘발 성분은 alcohols, esters, acids, terpenes 등으로 GC/MS 분석 결과 butanoic acid/ethyl ester와 1-hexanol, hexanoic acid/ethyl ester, phenylethyl alcohol 등이 주요 성분으로 동정되었다. 캠벨은 다른 품종에 비해 다양한 휘발 성분이 동정되었고 레드글로브와 머루 품종에서는 1-hexanol, 2-decene, 8-methyl-(z)/1-dodecanol 등을 제외한 나머지 휘발 성분은 거의 나타나지 않았다. 또한 전자코를 이용하여 휘발성 향기성분 패턴 분석결과 $4^{\circ}C$와 실온 저장한 시료의 제 1주성분 값의 기여율은 각각 99.30, 99.36%로 품종에 따라 구분이 가능하였다. $4^{\circ}C$ 저장 시 저장 기간에 따른 제 1주성분 값의 변화 범위는 실온에서 저장한 것에 비해 적었음을 확인할 수 있었다.

• 한국산림과학회지
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• 제103권2호
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• pp.211-217
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• 2014

잣나무의 주요생장관련 대사물질 인자를 구명하기 위하여 3개 지역에 풍매차대 가계로 조성한 29년생 잣나무의 대사물질을 GC/MS을 이용하여 대사체분석을 실시하였다. 분리한 110종의 대사 물질 중 62종이 우수가계와 저조가계 간에 유의적 차이(p<0.05)가 있었으며 모두 상대적으로 우수가계에서 대사물질 함량을 높게 함유하고 있는 것으로 나타났다. Phosphoric acid, alanine, glycine, malic acid, sucrose, d-turanose, succinic acid 등 22종의 물질은 생장 저조 가계에 비해 생장 우수 가계에서 1.5배 이상 높게 함유되어 있었다. 한편 생장특성과 대사물질간의 상관관계를 분석한 결과 생장 우수가계와 생장 저조가계 그룹 간에 유의적 차이가 있었던 alanine, malic acid, sucrose, d-turanose, succinic acid 등 15종에서 고도의 정의 상관관계(p<0.01)가 있었다. 또한 생장과 유의적 상관관계(p<0.05)가 있으면서 지역간에 변이가 적어 환경에 영향을 적게 받고 있는 대사물질로는 acetic acid, succinic acid, butanoic acid, glutamic acid 및 inositol로 분석되었다. 이들 물질은 잣나무 생장 우수개체에 유의적으로 높게 함유하고 있는 대사물질 인자로 추정되었다.

• Preventive Nutrition and Food Science
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• 제13권1호
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• pp.12-17
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• 2008

Douchi, a popular seasoning agent in Chinese dishes prepared by the Aspergillus oryzae fermentation of black beans, was subjected to supercritical fluid extraction (SFE) and gas chromatography-mass spectrometry analysis for its volatile components. A total of 73 components were identified in two commercial brands, which were positively confirmed and quantified. Among the common components in the two brands were 18 acids, 12 alcohols, 11 aldehydes, 9 esters, 1 furan, 11 other oxygen-containing compounds, 4 pyrazines, 2 pyridines and 5 miscellaneous compounds. The most abundant components found were acetic acid, benzoic acid, 2,6-dimethylpyrazine, 2-piperidinone, 3-methylbutanoic acid, maltol, 4-ethylphenol, 2-methylpropanoic acid, butanoic acid, 2-pyrrolidinone, all fatty acids and some esters.

• Macromolecular Research
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• 제13권3호
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• pp.236-242
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• 2005

Three dithioester-derived carboxyl acid functionalized RAFT(reversible addition-fragmentation chain transfer) agents, viz. acetic acid dithiobenzoate, butanoic acid dithiobenzoate and 4-toluic acid dithiobenzoate, were used in the RAFT bulk polymerization of styrene, in order to study the effects of the R-group structure on the living nature of the polymerization. By conducting the polymerization with various concentrations of the RAFT agents and at different temperatures, it was found that the R-group structure of the RAFT agents plays an important role in the RAFT polymerization; the bulky structure and radical stabilizing property of the R-group enhances the living nature of the polymerization and allows the polymerization characteristics to be well controlled.

• Asian-Australasian Journal of Animal Sciences
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• 제19권8호
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• pp.1197-1205
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• 2006

This experiment was conducted to compare the effects of feeding DL-2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and DL-methionine (DLM) supplemented corn-soybean-cottonseed meal diets on growth performance, carcass composition, and muscle color of broilers. The trial was designed as a $2{\times}3{\times}2$ factorial experiment, including two methionine (Met) sources (HMTBA and DLM), three equimolar graded levels of Met supplementation (i.e., 0.08, 0.16, and 0.24% in the starter diet and 0.07, 0.14, and 0.21% in the grower and finisher diets, respectively), and two sexes (male and female). Additionally, one basal diet for each sex was formulated to be limiting in Met to test the dosage response of increasing supplemental Met levels. Four hundred and twenty 10-d-old broilers were randomly allotted to 14 treatments (seven each for males and females), with five replicate pens per treatment and six chicks per pen. There was no difference (p>0.05) between the two Met sources in growth performance and muscle deposition of broilers throughout the whole experimental period (d 10 to 49). With the increasing Met supplementation levels, average daily gain was increased (quadratic; p<0.01) during the starter, grower, and overall phases, average daily feed intake was increased (quadratic; p<0.01) during the starter phase, and feed:gain ratio was decreased (quadratic; p<0.05) during the grower and overall phases. At the end of finisher phase, Met supplementation increased breast muscle content (quadratic; p<0.01) and thigh muscle content (linear; p<0.05), and decreased abdominal fat content (quadratic; p<0.02). Compared to the broiler fed DLM, broilers fed HMTBA had superior breast and thigh muscle coloration (p<0.01). Male broilers had higher weight gain and feed intake and better feed conversion than female broilers (p<0.01). The fat content of thigh muscle in female broilers was higher than that of male broilers (p<0.03). The best fit comparison of HMTBA vs. DLM was determined by Schwarz Bayesian Criteria index, which indicated that the average relative bioefficacy of HMTBA vs. DLM was 120% with 95% confidence limit 67 to 172%. These results indicated that Met supplementation improved growth performance and carcass quality of broilers fed corn-soybean-cottonseed meal diets irrespective of Met sources. Compared to DLM, HMTBA has the same molar bioefficacy on improving the growth performance and carcass quality of broilers; however, HMTBA fed birds had superior meat color to DLM fed birds.