• 분석과학
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• 제8권4호
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• pp.877-880
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• 1995

The determination of fluoride and the nutritious calcium in infusion of teas are explained. Tea leaves were pulverized and were immersed in boiling water. The solution was filtered and fluoride, calcium and oxalic acid were determined by the ion chromatography. The quantities of fluoride, calcium and oxalate ions extracted from 100 g of tea leaves were calculated. Tea leaves were also immersed in 0.5 M hydrochloric acid and extracted oxalate and calcium ions were analyzed. The free oxalic acid and calcium were extracted in boiling water and the total ones were extracted in hydrochloric acid. The quantity of calcium oxalate was calculated from the total and the free oxalic acids. The free calcium was estimated to be nutritious.

• 미생물과산업
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• 제26권1호
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• pp.18-30
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• 2000

질소 고정능이 있는 Nostoc pruniforme를 재료로, 3종의 유기물, glucose, oxalic, 및 ethanol을 N-free medium과 NO$^{[-993]}$ riched medium에 처리해 주었을 때 다음과 같은 효과를 얻었다. 1)N-free medium과 NO$^{[-993]}$ riched medium에서 위의 유기물 모두가 질소 고정과정의 energy원으로서 또는 substrate로서의 유효한 결과를 얻었다. 3)oxalic acid를 처리한 실험에서는NO$^{[-993]}$ richedmedium의 경우 고농도 처리구에서 질소고정량이 많았고 N-free medium은 그 반대의 결과였다. 4)비교구인 control의 질소 고정량은 일예를 제회하고는 전반적으로 고농도 처리구와 저농도 처리구의 중간에 위치했다.

• 분석과학
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• 제8권4호
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• pp.855-858
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• 1995

Vegetables contain more or less calcium. By the traditional method the total calcium in the vegetable was analyzed. A part or calcium in the vegetable is fixed as calcium oxalate and the calcium does not utilize for nutrition. In this investigation the free calcium was determined by extraction in boiling water, the combined calcium with oxalic acid was determined by extraction in 0.1 M hydrochloric aci and the other calcium combined with protein, amino acid etc. was estimated. The amount of calcium obtained from the difference between the total calcium and calcium exmtaining in calcium oxalate was estimated to be nutritious.

• 한국식품저장유통학회지
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• 제6권4호
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• pp.495-499
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• 1999

민들레 잎과 뿌리의 유리당은 sucrose, glucose, fructose 3종이 분리되었으며, 총 유리당의 함량은 잎에 비해 뿌리에서 높았다. 잎의 유기산 함량은 oxalic acid, citric acid, malic acid이 각각 45.4, 3.6, 2.7mg/100g-f.w.이었고, 뿌리의 경우에는 각각 34.6, 2.1, 1.6mg/100g-f.w.이었다. 총 유기산의 함량은 잎과 뿌리에서 각각 51.7, 38.3mg/100g-f.w.이었는데 뿌리에 비해 잎에서 그 함량이 높았다. 민들레의 잎과 뿌리의 유리아미노산 중에 aspartic acid, serine, asparagine, glutamic acid, glycine, valine, isoleucine의 함량이 높았고, 특히glutamic acid의 함량이 높았다. 민들레의 비타민 A 함량은 잎과 뿌리에서 각각 135.4, 34.1$\mu\textrm{g}$/100g-f.w.이었고, 비타민 C의 함량은 각각 67.4, 4.6mg/100g-f.w.이었다.

• 한국식품영양과학회지
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• 제5권1호
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• pp.61-64
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• 1976

P. edulis순(荀)의 free amino acid 및 organic acid의 종류(種類)와 함량(含量)을 측정(測定)한 결과(結果)는 다음과 같다. (1) Free amino acid는 18종(種)이 검출(檢出)되었는데, lysine histidine arginine tryptophan aspartic acid glutamic acid threonine serine proline glycine alanine valine methionine isoleucine leucine tyrosine phenylalanine 등 17종(種)이 정량(定量)되었으며 이들 중 serine이 가장 많았고, 1종(種)은 미확인(未確認)되었다. (2) Organic acid는 11종(種)이 검출(檢出)되었으며 이들 중 formic acid acetic acid oxalic acid maleic acid succinic acid fumaric acid citric acid tartaric acid sorbic acid 등 9종(種)이 확인(確認)되었고, 이들 중 oxalic acid가 가장 많아 291.14mg%이었으며, 2종(種)은 미확인(未確認)되었다.

• 한국식품영양과학회지
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• 제6권1호
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• pp.17-20
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• 1977

A. altissima 엽(葉)의 free amino acid 및 free organic acid의 함량(含量)을 측정한 결과는 다음과 같다. 1. free amino acid는 lysine, histidine, arginine, tryptophan, aspartic acid, glutamic acid, threonine, isoleucine, leucine, tyrosine, phenylalanine 등 17종(種)이 정량(定量)되었으며 이들 중 glutamic acid가 가장 많아 전(全)아미노산량의 48.3%를 차지하였다. 2. free organic acid는 formic acid, acetic acid, oxalic acid, maleic acid, succinic acid, fumaric acid, citric acid, tartaric acid 등 8종(種)이 정량되었고 sorbic acid는 미량(微量)이었으며, 이들 중 fumaric acid가 가장 많았다.

• 한국식품과학회지
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• 제30권2호
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• pp.306-312
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• 1998

대표적인 제주산 감귤류인 하귤, 당유자, 병귤, 스타치, 지각, 궁천조생, 6품종을 수확시기에 따라 유리당, 유기산, 헤스페리딘, 나린진, 무기물을 각각 분석하였다. 수확시기별 유리당의 함량에는 조금씩 차이를 보였으나 모든 품종에 있어서 과즙내 유리당 중에서 sucrose가 $44.9{\sim}66.0%$로 가장 많이 함유되어 있었고 glucose와 fructose는 $15.7{\sim}25.7%,\;17.5{\sim}30.1%$로 서로 비슷하게 함유되어 있었다. 유리당의 함량은 성숙함에 따라 계속적으로 증가하는 경향을 보였다. 유기산 함량은 감귤이 성숙됨에 따라 점차적으로 감소되며, 이는 산 함량의 변화와 비슷한 경향을 보였다. 감귤과즙에서 검출된 주요한 유기산은 citric acid, malic acid, oxalic acid였으며 전체 유기산 중에 citric acid가 90%이상으로 대부분을 차지하고 있었고, 그 외로 malic acid가 $0.98{\sim}9.45%$ 내외로 함유되어 있었고 oxalic acid가 3.58% 이하로 미량 함유되어 있었다. 품종별 과즙과 과피내의 flavonoid계 성분인 naringin과 hesperidin의 함량을 분석한 결과 이 두 성분은 과피 중에서 월등히 많이 함유되어 있었고 미숙과일 때 그 함량이 높았으나 착색이 진행됨에 따라 점차적으로 감소하는 경향을 보였다. 감귤을 이용한 가공품 제조시에는 완숙과를 사용해야 가공품의 혼탁과 쓴맛이 적을 것으로 예상되었다.

• 펄프종이기술
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• 제33권1호
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• pp.73-79
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• 2001

Stricter environmental demands have increased the need to replace conventional C/D bleaching sequence by chlorine-free sequence. Permanganate is well known as a powerful oxidant and have been used industrially in variable fields. However, it has considered to be difficult to use permanganate as a bleaching reagent because of its strong oxidative effect decreasing the viscosity of pulps extremely. We have tried to use permanganate as a bleaching reagent for KP under the mild condition and it was clear that pernanganate oxidized lignin remained in pulps selectively and increased pulp brightness decreasing K number of pulps with small degradation of cellulose. We have employed the neutral condition in the permanganate bleaching process in this study. In this case, permanganate was converted to manganese dioxide after bleaching reaction. The manganese dioxide is remained in the treated pulp fibers because of its insolublity in water. So it was required to reduction the manganese oxide to manganese ion by using reductants with acid. In this paper, we proposed to use oxalic acid as a reducing reagent converting manganese oxide to manganese ion after bleaching reaction. Oxalic acid plays the role as a reductant and a acid, so post-treatment after bleaching became to be easy by using oxalic acid. On the study using lignin model compounds, it was clear that permaganate react with phenols firstly, after that oxalic acid reduce the manganese oxide to manganese ion in the mixture of permanganate, phenols and oxalic acid. Several lignin model compounds ($\textit{p}$-hydroxybenzaldehyde, vanillin, syringaldehyde, veratraldehyde) are selected to elucidate the effect of substituents on reaction rate and its mechanism with permanganate including oxalic acid in this study. Except for veratraldehyde, the rate of oxidative degradation of phenolic compounds by permanganate with oxalic acid are higher than neutral condition. Especially, the degradation rate of $\textit{p}$-hydroxybenzaldehyde are strongly dependent on pH of reaction mixture. On the other hand, the degradation rate of veratraldehyde are decreased with decreasing pH and main degradation product is veratric acid. This result indicate that pH of bleaching liquor should be kept over 2 to degrade of non-phenolic lignin in the pulps effectively in permanganate bleaching.

• 미생물학회지
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• 제11권2호
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• pp.51-58
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• 1973

Three kinds of organic matter such as glucose, oxalic acid, and ethanol were added to the media(N-free or $NO_{3}$-riched) and their effects on the nitrogen fixation of Nostoc pruniforme were measured by manometric technique through the experiments in vivo. 1) The organic matters used in this experiments showed effective results as a role of substrate for the fixation of atmospheric nitrogen. 2) In the nitrogen-free medium treated with the both of flucose nad ethanol, the highest nitrogen uptakes were detected in the treated of low concentrations (glucose ; 0.1%, 0.5%, ethanol : 0.1%, 0.5%). On the contrary, the highest nitrogen uptakes in $NO_{3}$-riched medium were measured at the treated of high concentrations (glucose ; 2%, 1%, ethanol ; 1.5%, 1.0%). 3) The highest nitrogen uptakes in N-free medium treated with oxalic acid were measured at the concentration of 2% and 1%, respectively. In the medium of $NO_{3}$-riched, the nitrogen uptakes were in the opposite directions.

• Journal of Microbiology and Biotechnology
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• 제3권4호
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• pp.266-269
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• 1993

The production of free non-volatile and volatile organic acids in Kimchi during fermentations at 30, 20 and $5^{\circ}C$, were determined by gas chromatography. The order in the amount of non-volatile organic acid, soon after preparation, was malic, citric, tartaric, pyroglutamic, oxalic, lactic, succinic and ${\alpha}-ketoglutaric$ acids. The major non-volatile acids at the optimum ripening time were malic, tartaric, citric and lactic acids, and as the temperature was lowered, the amount of lactic, succinic, oxalic, pyroglutamic and fumaric acids increased, while that of malic and tartaric acids decreased. The order in the amount of volatile acids at the beginning was acetic, butyric, propionic and formic acids. Among these acids, acetic acid was significantly increased in its amount during fermentation and the Kimchi fermented at low temperature produced more acetic acid than that fermented at high temperature.