• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.302-305
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• 1991

Six low-molecular-weight organic acids from decomposing plant residues were analyzed, which were formic, acetic, succinic, malic, tartaric, and citric acids. Straws of rice, barley, wheat, and rye were put under acid- hydrolysis after decomposition for different periods of time. The contents of organic acids in the hydrolysates were determined. 1. The relative molarity of a low-molecular-weight organic acid varies with the passage of the time of decomposition. 2. In general, formic and acetic acids were the major low-molecular-weight organic acids in all samples. 3. Malic acid was found to be only in a trace amount in rice and barley straws, and in their decomposed residues. 4. The relative molarities of total monocarboxylic acids(formic and acetic) increased with the progressing time of decomposition, far exceeding those of dicarboxylic and tricarboxylic acids combined together. 5. Formic and acetic acids were compensatory for each other and they were supposed to persist for a long time in soil environment.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.2
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• pp.75-80
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• 1982

During the process of curing of the tobacco (Nicotiana tabacum L. ) leaves the concentration change of Nonvolatile organic acids and Higher fatty acids of the flue-cured tobacco leaves was observed. The contents of Nonvolatile organic acids in flue-cured tobacco leaves were as follows, malic> oxalic>malonic>citric>succinic acid. Higher fatty acids was linolenic>Palmitic>oleic >stearic$\geqq$linoleic acid, Citric acid content of last curing time was increased about 4~5 times in compare to before curing tobacco. It was concluded that significant changes of three variety flue-cured tobacco but a significant difference was observed in the composition of Daegu gold variety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.950-953
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• 1994

This study was carried out to investigate the proximate composition , free sugars,amino acids, organic acid, minerals and extracted color of the fruit of paper mulberry (Broussonetia Kazinoki Siebold) . the proximate compositins were 6.1% of moisture, 15.9% of crude protein, 28.5% of crude fat, 8.9% of crude ash and 40.6% of carbohydrates in the fruit of paper mulberry. Free sugars showed low content as 0.1% of glucose , 0.1% of sucrose, 0.1% of fructose and 0.01% of sorbitol, respectively. In amino acid composition of the fruit of paper mulberry, glycine was the highest in the content, followed by methionine, aspartic acid and alanine, The ratio of essential /total mino acids was 0.43 . The richestmineral contained in the fruit of paper mulberry was Ca and followed by K and Mg. Optical density (490-500nm) of the extracted color with 50% ehtanol and 80 % ethanol were 0.75 and 0.30 , respectively.

• Journal of the Korean Home Economics Association
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• v.23 no.3
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• pp.75-84
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• 1985

This studies was conducted to elucidate the taste components of shellfishes, producted in Korea. Four kinds of shellfishes including sea mussel, short-necked clam, corb shell and ark ahell were selected according to the higher sales order and cheaper retail price at 50 fish markets in Seoul in August 1982. The results are : Palatable taste of shellfishes should be caused by nucleotide related products, organic acids and free amino acids. Thus taste components found in four shellfishes were succinic, fumaric, and lactic acids as organic acids, glycine, alanine and glutamic acid as free amino acids.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.11
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• pp.1600-1607
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• 2014

A total of 120 finishing pigs ([Yorkshire${\times}$Landrace]${\times}$Duroc) with an average body weight (BW) of $49.72{\pm}1.72kg$ were used in 12-wk trial to evaluate the effects of protected organic acids on growth performance, nutrient digestibility, fecal micro flora, meat quality and fecal gas emission. Pigs were randomly allotted to one of three dietary treatments (10 replication pens with 4 pigs per pen) in a randomly complete block design based on their initial BW. Each dietary treatment consisted of: Control (CON/basal diet), OA1 (basal diet+0.1% organic acids) and OA2 (basal diet+0.2% organic acids). Dietary treatment with protected organic acid blends linearly improved (p<0.001) average daily gain during 0 to 6 week, 6 to 12 week as well as overall with the increase in their inclusion level in the diet. The dry matter, N, and energy digestibility was higher (linear effect, p<0.001) with the increase in the dose of protected organic acid blends during 12 week. During week 6, a decrease (linear effect, p = 0.01) in fecal ammonia contents was observed with the increase in the level of protected organic acid blends on d 3 and d 5 of fermentation. Moreover, acetic acid emission decreased linearly (p = 0.02) on d7 of fermentation with the increase in the level of protected organic acid blends. During 12 weeks, linear decrease (p<0.001) in fecal ammonia on d 3 and d 5 and acetic acid content on d 5 of fermentation was observed with the increase in the level of protected organic acid blends. Supplementation of protected organic acid blends linearly increased the longissimus muscle area with the increasing concentration of organic acids. Moreover, color of meat increased (linear effect, quadratic effect, p<0.001, p<0.002 respectively) and firmness of meat showed quadratic effect (p = 0.003) with the inclusion of increasing level of protected organic acid in the diet. During the 6 week, increment in the level of protected organic acid blends decreased (linear effect, p = 0.01) Escherichia coli (E. coli) counts and increased (linear effect, p = 0.004) Lactobacillus counts. During 12-wk of experimental trial, feces from pigs fed diet supplemented with organic acid blends showed linear reduction (p<0.001) of E. coli counts and the tendency of linear increase (p = 0.06) in Lactobacillus count with the increase in the level of organic acid blends. In conclusion, 0.2% protected organic acids blends positively affected growth performance, nutrient digestibility, fecal gas emission and meat quality in finishing pigs without any adverse effects on blood parameters.

• Journal of Soil and Groundwater Environment
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• v.27 no.5
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• pp.10-17
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• 2022

Inorganic acids such as HCl, HNO₃, and H₂SO₄ have been commonly applied to soil washing of heavy metals-contaminated soil due to their cost-effectiveness. However, implementing the 'Chemical Substance Control Act' requires off-site risk assessment of the chemicals used in the soil washing. Therefore, in this study, organic acids or Fe(III)-based washing agents were evaluated to replace commonly used inorganic acids. Ferric removed heavy metals via H⁺ generated by hydrolysis, which is similar to the HCl used in the control group. Oxalic acid and citric acid were effective to remove Cu, Zn, and Cd from soil. Organic acids could not remove Pb because they could form Pb-organic acid complexes with low solubility. Furthermore, Pb could be adsorbed onto the iron-organic acid complex on the soil surface. Ferric could remove exchangeable-carbonate, Fe-Mn hydroxide, and organic matter and sulfides bound heavy metals (F1, F2, and F3). Organic acids could remove the exchangeable-carbonate and Fe-Mn hydroxide bound metals (F1&F2). Therefore, this research shows that the fractionation of heavy metals in the soil and the properties of washing agents should be considered in the selection of agents in the process design.

• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.279-284
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• 2008

We investigated whether carboxylate exudation of Brassica pekinensis Rupr. was affected by nitrate deposition from simulated acid rain. A gas chromatographic (GC) analysis was employed for the determination of low molecular weight organic acids (LOA) in rhizosphere soils, bulk soil, roots and leaves of Brassica pekinensis Rupr.. Rhizosphere soils were collected after 8 weeks of plant growth by first removing the bulk soil from the root system and then by mechanical move off the rhizosphere soil that adhered to the root surface with soft brush. Soil and plant materials were simultaneously extracted with the mixture of methanol and sulfuric acid (100:7, v/v). Seven organic acids, oxalic, malonic, fumaric, succinic, maleic, L-malic and citric acid were identified and quantified by GC equipped with FID. Oxalic, L-malic, and citric acids were found in both the bulk and rhizosphere soils, while most LOAs were not detected in the control treatment. On the contrary, except maleic acid, all other organic acids were detected in the leaves and roots of cabbages treated with nitrate deposition.

• Fire Science and Engineering
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• v.27 no.3
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• pp.47-51
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• 2013

The explosion limit is one of the major combustion properties used to determine the fire and explosion hazards of the flammable substances. The explosion limit of organic acids have been shown to be correlated the heat of combustion and the chemical stoichiometric coefficients. In this study, the lower explosion and upper explosion limits of organic acids were predicted by using the heat of combustion and chemical stoichiometric coefficients. The values calculated by the proposed equations agreed with literature data within a few percent. From the given results, using the proposed methodology, it is possible to predict the explosion limits of the other organic acids.

• Korean journal of food and cookery science
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• v.7 no.1
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• pp.27-34
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• 1991

This study attempted to set up reasonable extraction time of Omija that was put in water for the various components to soak out. Changes of free sugars, organic acids, reducing sugar, total acid and tannin in Omija with various extraction times were investigated (together with the analysis of each components in Omija fruit). 1. High Performance Liquid Chromatography showed fructose, glucose, and sucrose to be the major free sugars of the Omija fruit. Free sugars and reducing sugar value in Omija beverage increased gradually in according with the extraction time, and marked 75.6% per total free sugars and 82.1% per total reducing sugar at 12 hours. 2. Gas Chromatography showed lactic acid, oxalic acid, fumaric acid, levulinic acid, succinic acid, malic acid, citric acid and pyroglutamic acid to be the major organic acids of the Omija fruit. Organic acids and total acids value in Omija beverage increased gradually on proportion to extraction time, and marked 97.0% per total organic acids at 9 hours and 79.0% per total acids at 12 hours. 3. Tannin content in Omija beverage was increased when extraction time was longer but it showed a low percentage as compared with the reducing sugar and total acid. Tannin content marked 48.8% per total tannin at 12 hours. 4. Sensory evaluation revealed that !1 hours of extraction produced the best quality products based in taste, flavor, color and over-all acceptability, considering the data, it seems possible to conclude that the optimum of time for extraction of Omija to water is 9 hours.

• Macromolecular Research
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• v.17 no.1
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• pp.14-18
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• 2009

The acceleration effect of various organic acids, such as methanesulfonic acid (MSA), ethanesulfonic acid (ESA), 4,4'-sulfonyldibenzoic acid (SDA), diphenylacetic acid (DPAA), and $\rho$-toluenesulfonic acid (TSA), on the rate of styrene bulk polymerization with 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) and benzoyl peroxide (BPO) was investigated. The addition of organic acids significantly accelerated the rate. Among these organic acids, DPAA showed an efficient rate-accelerating effect with living nature of polymerization. When DPAA was used as a rate-accelerating additive for TEMPO-mediated living free radical polymerization (LFRP), the rate of polymerization was dramatically enhanced, the linearity of reaction kinetics was successfully maintained, and the polydispersity was effectively controlled.