• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.40-44
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• 1988

This paper was carried out to investigate the relation of pH, aciidity and sourness during Kimchi fermentation and preservatives on Kimchi fermentation. Na-acetate, Na-malate, K-sorbate and K-sorbate+acetic acid were added to Kimchi samples. These Kimchi samples were fomented for 7 days at $37^{\circ}C$ and $20^{\circ}C$. In the experiment about the sourness and buffer action by organic salts which showed that the intensity of sourness was differented by the difference of pH in the same acidity. Na-acetate (0.3%) and Na-malate (0.3%) acted as good buffer, whereas K-sorbate (0.1%) and K-sorbate (0.1%)+acetic acid (0.05%) acted as lactobacilli growth enhancer in the fermentation.

• Korean Journal of Food Science and Technology
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• v.14 no.1
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• pp.6-10
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• 1982

To investigate the effect of organic acids on suppression of fishy odor, the change of the odor and the remaining amount of trimethyamine (TMA), selected as the representative component of fishy odor in clam pickle (15.5% NaCl) were examined by sensory evaluation and gas chromatography. The fishy odor linearly decreased as the amount of vinegar increased at ${\alpha}=0.01$, but there was no significant difference of fishness score for the changes of storage period and kinds of acid. Overall acceptability score was found to be the best when 8 ml vinegar added to 100g clam pickle. The remaining amount of TMA showed the tendency to decrease as the amount of acetic acid and storage time increased and kinds of acid were changed in order of acetic, malic and citric acid. However when $4\;{\mu}l/ml$ acetic acid (=8 ml vinegar/100g clam pickle) was added, the percentage of the remaining amount of TMA showed little decrease from about 95% for 72 hours of storage time. From the results of sensory evaluation and gas chromatography, it was considered that acids have the effect on suppression of fishy odor by producing non-volatile salts by combining with TMA chemically and that the effect of acids on suppression of fishy odor is mainly due to the masking effect at the concentration commonly used.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.983-987
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• 1998

Effects of sugars, temperature, pH and some chemicals on caramelization were investigated for improving of its reaction rates. Among the sugars tested, fructose showed the fastest reaction rate, followed by sucrose, glucose, starch syrup and maltose. As the reaction temperature increased from 80 to $110^{\circ}C$, the rate greatly increased by the range of $150{\sim}8000$ folds depending on sugars. It was indicated that pH 10 resulted in the highest reaction rate in the range of $pH{\;}4{\sim}10$. When several chemicals, such as phosphates and organic acid salts, were added to starch syrup, the rate increased by more than 10 folds, in particular effects of $K_2HPO_4$ and sodium salts of citrate, oxalate and succinate were significant.

• Journal of Animal Science and Technology
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• v.61 no.6
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• pp.313-323
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• 2019

The interactive effect of dietary fat supplementation and milk yield level on dairy cows performance under heat stress has not been thoroughly investigated. The purpose of this study was to evaluate the effect of production level, the source of fat supplements and their interaction on dairy cows performance under heat stress. In this study, 64 Holstein multiparous cows were divided into 2 groups and received one of two rations having either calcium salts of fatty acids (Ca-FA) or high-palmitic acid (PA) supplements (2.8% of DM; dry matter). After completing the experiment and based on maturity-equivalent milk, cows were divided into two groups of high-yielding (14,633 kg) and medium-yielding (11,616 kg). Average temperature humidity index (THI) was 71 during the trial period. Apparent digestibility of dry matter (p = 0.04), organic matter (p = 0.05), and neutral detergent fiber (NDF; p = 0.04) for cows fed Ca-FA were greater than cows fed PA. The milk fat content in high-producing cows was 0.3% greater than medium-producing cows (p = 0.03). The milk protein content in cows fed Ca-FA was greater than cows fed PA (p < 0.01). High-producing cows had greater serum cholesterol (p = 0.02) than medium-producing cows. The cows fed PA tended to have a greater BUN than cows fed Ca-FA (p = 0.06). Alanine aminotransferase and aspartate aminotransferase tended to be increased by PA, which indicates that cows in PA treatment may have experienced more adverse effect on the liver function than cows on Ca-FA. Therefore, under heat stress and in 90 d trial, milk production level does not affect the cows' response to PA or Ca-FA. Although cows fed Ca-FA received lower energy than those fed PA, they compensated for this shortage likely with increasing the digestibility and produced a similar amount of milk.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.49-54
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• 2004

Biotransformation process using microorganisms was examined to improve the bioconversion rate for the production of sotolon from the raw material. First, the extraction condition was optimized with regard to solvent type and pretreatment conditions. Dichloromethane was selected as a suitable solvent for the extraction of sotolon and sotolon-related compounds. Second, various microorganisms such as lactic acid-producing bacteria, yeast and fungi were tested for the biotransformation. Among the tested microbes, Agaricus blazei showed the highest conversion rate. Additives including amino acids, salts, and organic acids were investigated to test their effects on bioconversion. When the solution was added by isoleucine, ${\alpha}-ketoglutaric\;acid$, ascorbate, and $FeSO_4$ and later incubated by culture broth containing the mycelium of Agaricus blazei, the sotolon content increased up to about 77 times as compared to that of the raw material.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.53-56
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• 2000

Two-stage fed-batch culture was peformed to improve the volumetric productivity of erythritol. In the growth phase dissolved oxygen was maintained to 20% and the feed medium was automatically supplied to the fermenter by pH-stat mode. The cell yield was 0.76 g-cell/g-glucose. In two-stage fed-batch culture, 41% of total erythritol conversion yield with 187 g/L of erythritol concentration and 2.79 g/L-h of maximum erythritol Productivity were obtained when 400 g/L of glucose was directly added in the form of non-sterile powder at production phase. The erythritol productivity increased in parallel with cell mass. The metabolic shift in the biosynthetic pathway of erythritol was caused by dissolved oxygen concentration. The production of gluconic acid was observed when the dissolved oxygen in the medium was maintained over 40% during the production phase, whereas the dissolved oxygen concentration lower than 40% caused the production of citric acid. But the butyric acid was produced independently with dissolved oxygen concentration in the medium. The production of organic acids such as gluconic acid, citric acid, and butyric acid was decreased by addition of mineral salts.

• International Journal of Concrete Structures and Materials
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• v.18 no.1E
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• pp.3-9
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• 2006

Five slab specimens with predefined cracks are examined to evaluate the corrosion behavior of epoxy-coated bars in chloride contaminated concrete, using linear polarization method. The test specimens were subjected to alternating weekly cycles of ponding in a salt solution and drying for 48 weeks. Test results show that the current density of the specimen of normal steel bars becomes 0.715 ${\mu}A/cm^2$ indicating that the steel bars are in moderate or high corrosion condition. However, the corrosion rates of the specimens with damaged epoxy-coated bars are significantly below 0.1 ${\mu}A/cm^2$ and the bars appears to be in passive condition. The damaged epoxy-coated bars with a corrosion inhibitor of calcium nitrite showed a corrosion rate of 0.110 ${\mu}m/year$ or 56 percents of the corrosion rate of damaged epoxy-coated specimen without such an inhibitor, 0.195 ${\mu}m/year$. However, the corrosion rates of specimens containing the other two corrosion inhibitors, a combination of amines and esters or mixtures of organic alkenyl dicarboxyl acid salts are quite equivalent to the control specimen. The research technique of linear polarization resistance method has proven itself to be useful in measuring corrosion rates of reinforcement in concrete.

• Journal of Powder Materials
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• v.9 no.6
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• pp.449-454
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• 2002

$MnxZn_{1-x}Fe_2O_4$ (x=0.69~0.74) powders synthesized by the thermal decomposition of organic acid salts. The obtained powders were uniform in composition and ultra-fine particle with about 400 nm. The amount of spinel phase of these powders was about 50% in X-ray diffraction patterns. The calcination of powder was carried out at $900^{\circ}C$ for 2 hours in air. After the powders were calcined. the mean size of powder was about 500 nm and the amount of spinel phase was increased over about 65%. The maximum amount of spinel phase was about 75% in the specimen of X=0.72. The magnetic properties of calcined $Mn_{0.72}Zn_{0.28}Fe_2O_4$ powders were the best among the different among the different compositions.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.56-56
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• 2001

Ni-W alloy deposit is one of the best alternatives to hard chromium plating because of its good mechanical properties (high hardness, high strength, and good wear resistance). Ni-W alloy is deposited from weakly acidic or alkaline electrolytic bath with nickel sulfate, sodium tungstate or APT, and some kinds of organic hydroxy-acid complex and ammonia salts. W content of the deposit can be changed from 0 to 5Owt% and the coating with high W content is more attracted. But, meanwhile, the deposited layers are always found high internal stress, which cause them to become brittle and to bond insufficiently with the substrate. On the second hand, as the W content is incresed, the current efficiency reduced, which results in large quantities of hydrogen evolution and then produces bubbles on surface and pitting appearance In this paper, the influence of some additives on Ni-W alloy electroplating was investigated by means of compositional analysis and SEM. The initial results showed that 2-butyne-1,4-diol was the best brightener for Ni-W plating process. It could brighten and level deposit, but decreased the cathodic current efficiency. Its optimum concentration range is from O.lgjL to 0.5gjL. Besides, three kinds of additives including 2-butyne-1,4-diol were examined with Dagguchi method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.4
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• pp.496-501
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• 1995

The N $O_{2}$ gas-detection characteristics were investigated using the functional organic Langmuir-Blodgett (LB) films of Copper-tetra-tert-butylphthalocyanine (CuTBP), Dilithium phthalocyanine (Li$_{2}$Pc), N-docosylpyridinium TCNQ(C$_{22}$Py(TCNQ)), Polyamic acid alkylamine salts (PAAS). The optimum conditions for a film deposition were obtained through a study of .pi.-.ALPHA. isotherms and the deposited film status was confirmed by electrical and optical methods such as UV/visible absortion spectra, thickness measurements by ellipsometry, and electrical capacitances. A response of the LB films to the N $O_{2}$ gas was measured by a change of the electrical conductivities when the film is exposed to the gases. The CuTBP LB film shows the biggest change of the electrical conductivities when it is exposed to the N $O_{2}$ gases. And the order of gas-detection performance is the following;Li$_{2}$Pc, $C_{22}$Py(TCNQ), and PAAS LB films. Especially, the CuTBP and Li$_{2}$Pc LB films not only show the bigger change in the electircal conductivities when exposed to the gas, but return to the original state when the gas is desorbed.d.