• Journal of the East Asian Society of Dietary Life
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• v.10 no.2
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• pp.153-159
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• 2000

The effect of boiling with apple vinegar and citric acid on the dissolution of Ca, Mg, and P out of pork rib bone during stew preparation was investigated. As the concentration (0, 1, 2. 4%) of apple vinegar and citric acid increased, the amount of Ca, Mg, and P dissolved out of the rib bone increased compared with the control. The increase in boiling time(3, 6, 9, 12 hour) also showed the same result. Between the two acid condiments citric acid extracted more Ca, Mg, and P than the apple vinegar at the same concentration. The pH of the pork rib bone stew added with the acid condiments increased gradually during the boiling process. Between the two acid condiments the apple vinegar extracted more amino acids and protein than citric acid at the same concentration.

• Food Science and Preservation
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• v.21 no.5
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• pp.652-660
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• 2014

To maintain the microbiological safety of Prunus mume fruit before it is processed, it was treated with a combination of 0.5% citric acid and 0.1% Tween 20, and stored at $4{\pm}1^{\circ}C$ for seven days. The combined treatment reduced total aerobic bacteria, yeast, and mold populations in the fruit by 2.20 and 1.70 log CFU/g, respectively, compared to those in the control. Organic acid contents and the Hunter $L^*$, $a^*$, and $b^*$ values were not affected by the treatment during the storage. In addition, the dried Prunus mume fruit prepared with 40% red algae extract (RAE) or maltodextrin (MD) treatment and hot-air drying were compared with respect to the fruit's physicochemical properties such as color, total phenolic and flavonoid content, and microstructure. The hot-air dried samples had undesirable color changes and inferior textures. The RAE-treated samples had a higher total phenolic content (225.15 mg gallic acid equivalent (GAE)/100 g) and total flavonoid content (49.25 mg quercetin equivalent (QE)/100 g) than the other treatments. The treatment of Prunus mume fruit with RAE can provide better-dried products than can MD treatment or hot-air drying. These results suggest that the combined treatment with citric acid and Tween 20 can be effective in preserving the microbiological safety of Prunus mume fruit, and its dehydration using RAE is an efficient drying method.

• Food Science of Animal Resources
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• v.35 no.6
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• pp.721-730
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• 2015

The objective of this study was to examine the effect of ginger extract (GE) combined with citric acid on the tenderness of duck breast muscles. Total six marinades were prepared with the combination of citric acid (0 and 0.3 M citric acid) and GE (0, 15, and 30%). Each marinade was sprayed on the surface of duck breasts (15 mL/100 g), and the samples were marinated for 72 h at 4℃. The pH and proteolytic activity of marinades were determined. After 72 h of marination, Warner Bratzler shear force (WBSF), myofibrillar fragmentation index (MFI), pH, cooking loss, moisture content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein solubility were evaluated. There was no significant (p>0.05) difference in moisture content or cooking loss among all samples. However, GE marination resulted in a significant (p<0.05) decrease in WBSF but a significant (p<0.05) increase in pH and MFI. In addition, total protein and myofibrillar protein solubility of GE-marinated duck breast muscles in both WOC (without citric acid) and WC (with citric acid) conditions were significantly (p<0.05) increased compared to non-GE-marinated duck breast muscles. SDS-PAGE showed an increase of protein degradation (MHC and actin) in WC condition compared to WOC condition. There was a marked actin reduction in GE-treated samples in WC. The tenderization effect of GE combined with citric acid may be attributed to various mechanisms such as increased MFI and myofibrillar protein solubility.

• The Korean Journal of Food And Nutrition
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• v.13 no.4
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• pp.328-333
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• 2000

The spore of Aspergillus niger KCTC-6144 was immobilized on alginate gel beads. When pumpkin powder was used with glucose for a medium of citric acid fermentation by Aspergillus niger beads, the beaded Aspergilus niger grew up inside the bead and mycelia penetrated through the pore of the bead membrane. The bead size became largely from 2.0∼2.5mm to 6∼8mm after growing at 30$\^{C}$ for 4 days. Studies of optimum culture conditions on citric acid fermentation using Aspergillus niger beads on pumpkin medium (pumpkin powder 1% +glucose 7%, pH 6.0) were carried out in submerged cultures on 250m1 Erlenmeyer flask. As a result, it was found that to reinforce 12% as carbon source was good for citric acid production and that 1% pumpkin powder was good as nitrogen and mineral source in orbital shaker (150rpm) at 30$\^{C}$ for 5 days. The optimum initial pH on citric acid production was pH 6.0 and it was found that 100 beads of immobilized Aspergillus niger was adequate for citric acid production in a 250ml Erlenmeyer flask containing 50m3 of pumpkin medium solution with orbital shaker at 30$\^{C}$ for 5 days. We also found that maximal production of citric acid was 23.5g/ℓ at optimal condition (at 30$\^{C}$ for 5 days, pH 6.0, and 100 beads and medium containing 1% pumpkin powder plus 12% glucose).

• KSBB Journal
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• v.14 no.6
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• pp.672-676
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• 1999

Encapsulated Aspergillus niger was prepared in order to inspect the effect of oxygen supply on the production of citric acid. A. niger cells which had been immobilized in the calcium alginate capsule grew and mycellia penetrated through the capsule membrane after two days of cultivation and covered over all of the capsule after eight days. The mycellia became loose when the nitrogen source was sufficient of oxygen was deficient. The larger amount of encapsulated cells were put into a given growth medium, the smaller quantity of citric acid was produced. The increase of volumetric oxygen transfer coefficient from 1.8 $hr^-$ to 2.55 $hr^-$ in the flask culture accelerated cell growth rate but did not influence the production of citric acid. The high oxygen supply rate($k_La:\;150\;hr^-$) in the concentric air lift reactor hastened the growth of cells and hindered the production of the citric acid. The reduction of nitrogen source level in the growth medium in the concentric air lift reactor increased citric acid production by 40 percent of that of flask cultivation and the culture period was shortened by 3 days. The variation of the geometry of the concentric air lift reactor did not influence the growth rate of encapsulated cells and production rate of citric acid.

• Korean journal of food and cookery science
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• v.3 no.1
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• pp.78-85
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• 1987

2M D-glucose and 2M D-glucose with 0.4M citric acid were heated at $100^{\circ}C$ for 12, 24, 48hours. The color intensity of these browning reaction products and the fractionated materials by Sephadex G-15 were measured as absorbance at 490nm with a spectrophotometer. The control (soybean oil) and the soybean oil substrates containing equal amounts of ethanol extracts taken from each fraction group were stored at $40.0\pm$1.0^{\circ}C$$ in an incubator for 30 days Antioxidant activities of browning reaction products determined by peroxide value and TBA value the soybean oil. The results were as follows. 1. According to increase heating time and to add citric acid, color intensity was increased. Color intensity of Fraction II(fraction 10~18 high molecular weight) was higher than other fraction group, especially Fraction II of sample F (glucose with citric acid, heated at $100^{\circ}C$ for 48hours) was the highest. 2. All of the fractionated material was showed antioxidant effect but Fraction I (high molecular weight) was more oxidized than the control Fraction IV, V (fraction 28~45; low molecular weight) was showed the highest antioxidant effect.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.307-310
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• 2004

Micellar enhanced ultrafiltration (MEUF) is a surfactant-based separation process and it can remove heavy metal ions from aqueous stream effectively. However, it is necessary to recover and reuse surfactants for economic feasibility because surfactant is expensive. Foam fractionation was investigated for both anionic and cationic surfactant recovery. Chelating agent such as ethylenediaminetetraacetic acid (EDTA) was studied for the separation of heavy metals from surfactant solution. Anionic surfactants bound with heavy metals can be recovered by lowering pH (acidification). In this study, citric acid and imminodiacetic acid (IDA) were applied to release copper from sodium dodecyl sulfate (SDS) micellar solution and compared with EDTA. Precipitation of copper by ferricynide and sodium sulfide were also investigated. As a result, ca. 100 % of copper was released from SDS micellar solution by 5 mM of EDTA and citric acid. And 3.3 mM of ferricyanide formed precipitate with 82.7 % of copper. 5 mM of IDA and sodium sulfide released or formed precipitate 82.5 % and 58.9 % of copper, respectively. Citric acid is harmless to environments and ferricyanide precipitates with Cu easily. Therefore, it is considered that citric acid and ferricyanide have competiveness over a famous chelating agent, EDTA, for the separation of Cu from SDS solution.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.4
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• pp.475-482
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• 1999

The effect of boiling with grain vinegar and citric acid on the dissolution of Ca. Mg and P out of beef rib bone during stew preparation was investigated. As the concentration (0, 0.5, 1.0, 2.0%) of grain vinegar and citric acid increased, the amount of Ca, Mg and P dissolved out of the rib bone increased compared with the control. The increase in boiling time(1, 2, 4, 8, 12 hour) also showed the same result. Between the two acid condiments citric acid extracted more Ca, Mg. P compared with the grain vinegar at the same concentration. The pH of the rib bone stew added with the acid condiments increased gradually during the boiling process. In sensory evaluation. the rib bone stew boiled for 12 hours with 2% grain vinegar was highly evaluated compared to the stew prepared with citric acid.

• Culinary science and hospitality research
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• v.4
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• pp.413-436
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• 1998

In order to guarantee the safety of Korean Naeng Myon Broth in summer, pH and micrological quality of iced noodle gravy which is cooked and sold in public restaurant were investigated. And the variations of pH, taste and microorganism were studied with organic acid treatment during storage period. The micrological status of iced noodle gravy showed that average number of total aerobic bacteria was 2.7${\times}$105CFU/$m\ell$ and fecal coliform was 8.3${\times}$103CFU/$m\ell$ respectly. Food poison microorganisms not detected and average of pH was 4.8. pH changed slightly during storage period and deceased with increasement of organic acid added. Sour taste of organic acid increased acetic acid, citric acid, lactic acid order and there was no organic acid having with more sour taste than iced noodle gravy which is cooked and sold in public restaurant. Salmonella was destroyed when treated with 1% of acetic acid and lactic acid and Escherichia coli became extinct at treatment with 0.8% acetic acid and 1% lactic acid. in case of same concentration, inhibition effects to Escherichia coli multiplication show citric acid, lactic acid, acetic acid order. In conclusion, treatment with more than 0.8% acetic acid and above 1.0% lactic acid or more than 1.0% citric acid in case of production and consumption a day can prevent from Escherichia coli pollution in Korean Naeng Myon Broth.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.83-95
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• 2004

The removal efficiency of several washing agents on the $Cs^+$ ion was investigated. Leaching of $Cs^+$ ion from the soil surface by washing agents is affected by the exchange capability of the washing solution. Reuse tests of the effective soil washing agents such as $BaCl_2$, NaOH, citric acid＋ $HNO_3$ and oxalic acid were performed. NaOH, citric acid ＋ $HNO_3$ and oxalic acid solutions can be reused after passing through the ion exchange column. Among the tested solutions, both of citric acid＋ $HNO_3$ and oxalic acid were effective for the decontamination of TRIGA research reactor soil. The radioactivity of soils can be reduced to a release level by the successive application.