• Korean Journal of Soil Science and Fertilizer
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• v.49 no.3
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• pp.265-270
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• 2016

Accumulated Phosphate can be released by ligand exchange reaction of organic acids. The objective of this study was to evaluate effects of the organic acids on the availability of phosphate and the growth of crop in phosphate and salts accumulated soil. Soil samples were collected from farmer's plastic film house. Available phosphate and electrical conductivity of soil were $3,005mg\;kg^{-1}$ and $16.63mg\;kg^{-1}$ which were 6 and 8 times higher than the optimum range of soil for crop growth, respectively. Corns were cultivated in pots for 2 months. Treatments were no treatment (control), phosphate fertilizer (P), citric acid (CA) 1, 5, 10 mM, and oxalic acid (OA) 1, 5, 10 mM. Water soluble phosphorus, available phosphate, corn growth and uptake were determined after cultivation. Results showed that organic acids increased water soluble phosphorus and available phosphate. For the level of 10 mM, the order of effectiveness of organic acids for water soluble P was citric acid (44%) > oxalic acid (32%). Height and dry weight of corns were increased significantly by the treatment of citric acid 1 and 5 mM. Also, corn absorbed more phosphorus, nitrogen, potassium, calcium and magnesium in the treatment of citric acid 1 mM than these of other treatments. Even though phosphate availability of soil was enhanced by addition of citric acid 10 mM, the growth of corns decreased because high concentration of citric acid caused salt damage by increasement of electrical conductivity. Thus, the citric acid of 1 mM has the potential to improve the availability of phosphate and the healthy growth of corns.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.310-313
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• 2003

The precipitation of heavy metals within the region of pH jump is inevitable in the conventional electrokinetic remediation technology. This study prevents the interest species from precipitating through the injection of flushing solutions in which HCl, acetic acid, citric acid, EDTA and SDS dissolved. The cumulative flow resulted from electroosmosis appear in order of Citric acid

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1269-1274
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• 1999

Four dimensional response surface methodology was applied to determine the optimum conditions on organoleptic properties to develop red pepper jam into Korean type jam. The organoleptic color of red pepper jam showed maximum score of 8.08 in 14.24g pectin, 256.2g sucrose and 8.31ml citric acid(50% citric acid solution). The organoleptic taste of red pepper jam showed maximum score of 6.77 in 14.23g pectin, 202.1g sucrose and 8.19ml citric acid. Optimum conditions on the organoleptic mouth feel of red pepper jam were 14.34g in pectin, 255.6g in sucrose and 8.39ml in 50% citric acid solution. Maximized overall palatability of red pepper jam was 7.25 in 14.15g pectin, 257.08g sucrose and 8.19ml of 50% citric acid solution. The optimum preparation condition ranges on organoleptic properties of red pepper jam were 14.0~15.5g pectin, 225.0~257.0g sucrose and 8.0~8.2ml of 50% citric acid solution.

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.121-125
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• 2004

Effects of chemical treatment with a citric acid solution or ozonated water on microbiological changes in lettuce and cabbage during storage were studied. Fresh lettuce and cabbage samples were cut into small pieces and treated by soaking in either ozonated water or a citric acid solution. After treatment, populations of total bacteria, yeast and mold, and E. coli were determined. Numbers of microorganisms increased during storage, but ozonated water and citric acid treatments retarded the increase in microbial growth. Among treatments, 1 % citric acid treatment was the most effective in terms of microbiological change and inhibition of polyphenoloxidase (PPO). For lettuce, citric acid treatment decreased the microbial growth overall by 1.5 log CFU/g and inhibited the PPO activity by 80%. These results indicate that chemical-treated lettuce and cabbage retained a better quality than those of the control during storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.790-795
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• 2000

To establish the optimum conditions for the extraction of anthocyanin pigment from purple-fleshed sweet potato, a suitable extraction solvent with the optimum citric acid concentration for acidification of the solvent, and the optimum extraction time and temperature were determined. Twenty percent ethanol solution acidified with citric acid was found to be a good solvent for the extraction of the pigment from purple-fleshed sweet potato. About 10 hour extraction at room temperature was appropriate for the extraction. pH of the extract was below 3 when more than 0.7% citric acid was added. The higher the concentration of citric acid added was, the higher the total optical density (TOD) of the extract was. However, the increase in TOD of the extract was insignificant when more than 1% of citric acid was added. Therefore, addition of 1% citric acid was determined for acidification of the extracting solvent. Though the initial rate of the pigment extraction increased as the extracting temperature increased, extraction at higher temperatures of 60 or 8$0^{\circ}C$ for an extended time caused a decrease in the extraction yield due to degradation of the pigment. The optimum extraction temperature for the anthocyanin pigment from purple-fleshed sweet potato with the solvent used was determined as 4$0^{\circ}C$.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.3-9
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• 1986

A yeast strains, CJ 2, CJ 7 and CJ 8, isolated from soil and contaminated choose, mated with authentic strains of Saccharomycopsis lipolytica and were identified as Saccharomycopsis lipolytica with mating A, B and B, respectively. The strain CJ 7 produced large amount of isocitric acid in glucose and n-hexadecane medium as compared with another strains. All strains produced larger amount of citric acid in n-hexadecane medium as compared with glucose medium, and citric acid production of diploids was greater than that of the parental haploid strains. The specific activity of isocitrate lyase in n-hexadecane grown cells was $15{\sim}20$ times greater than that in glucose-grown cells, but the specific activity of citrate synthetase was not so influenced by carbon source. Little correlation between citric acid production and the specific acitivity of these enzymes was noticed irrespective of strains and ploidy.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.209-213
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• 2009

This study was carried out to investigate the distribution of V. parahaemolyticus in Incheon adjacent sea, and anti-microbial effect on growth of V. parahaemolyticus in organic acid. The detected strains were compared for geography, months and sample types. V. parahaemolyticus was detected form 28.5 percent of 287 samples collected from Incheon area, and 34.7 percent of 91 samples collected in the months of July through September, and 24.7 percent of 279 shellfish samples respectively. The minimun inhibitory concentration(MIC) of organic acid in V. parahaemolyticus were 1,250ppm at propionic acid, citric acid and acetic acid, 2,500ppm at vanillic acid, respectively. MICs of combined treatment of acetic acid and vanillic acid, citric acid and vanillic acid, propionic acid and vanillic acid were 1,250 ppm. MICs of combined treatment of citric acid and acetic acid, propionic acid and acetic acid, propionic acid and citric acid was 12.5ppm. The antimicrobial effect of organic acid in V. parahaemolyticus was confirmed from the result of this experiment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.3
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• pp.529-534
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• 1996

Using cystine, ascorbic acid and citric acid, retarding and synergistic effect on the browning reaction of onion juice concentrate was evaluated. Cysteine retarded the browning reaction most effectively followed by citric acid ; on the contrary, ascorbic acid accelerated rather than retarded the reaction at the concentration of 0.1%. The retarding effect of cysteine increased abruptly up to concentration of 0.3% and remained unchanged. Citric acid acted more effectively than ascorbic acid in terms of synergism. The browning reaction of onion juice concentrate exhibited activation energies of 62J/mol with cysteine and citric acid as compared to 73J/mol for control. $Q_{10}$ was determined to be 2.52 and 2.38 for control, 2.2 and 2.09 for treatment in the temperature range of 30~4$0^{\circ}C$ and 40~5$0^{\circ}C$, respectively.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.100-105
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• 1988

Composition of organic acids and fatty acids in three edible mushrooms, Pleurotus ostreatus, Lentinus edodes and Agaricus bisporus were analyzed by gas-liquid chromatography and compositional differences of these components depending on species, sizes and portions (pileus and stipe) were investigated. Lactic, oxalic. fumaric. citric and pyroglutamic acid were identified in each of the three mushrooms and the major organic acids were malic, citric and pyroglutamic acid, respectively. The total organic acid contents were in the range of 2.4-4.0% in Pleurotus ostreatus, 1.7-3.6% in Lentinus edodes and 1.9-3.1% in Agaricus bisporus. Especially oxalic and pyroglutamic acid in Pleurotus ostreatus, malic and citric acid in Lentinus edodes and fumaric acid in Agaricus bisporus were higher in pileus than stipe. The total organic acid contents decreased as the size of pileus developed and especially the decrease of citric acid were marked. On the other hand, the major fatty acids in three mushrooms were linoleic, palmitic and oleic acid. But fatty arid compositions were not significantly different depending on species, sizes and portions.

• Korean journal of food and cookery science
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• v.19 no.6
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• pp.777-782
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• 2003

This study was carried out to investigate the characteristics of mulberry fruit seolgidduk. Four percent additions of mulberry were evaluated as the most suitable concentration for seolgidduk, in order to improve the color of gum metal gray and sour smell. Therefore, in order to improve the preference, citric acid was added. The acidity of mulberry fruit seolgidduk increased and its pH decreased significantly by increasing the amount of citric acid. The moisture content of mulberry fruit seolgidduk showed no significant difference between the groups with added citric acid and the control group. The L value decreased as the citric acid concentration increased. Color a and b (Ed-define 'a' and 'b') values increased significantly by increasing the mont of citric acid. The hardness, cohesiveness, springiness, gumminess and brittleness decreased as the citric acid was added. From the sensory evaluation, mulberry fruit seolgidduk with 0.01％ citric acid added was the most preferred in taste, chewiness and overall acceptability. These results indicated that mulberry fruit stolgidduk with 0.01％ citric acid added showed the best quality.