• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.265-272
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• 2011

Even though concrete is the most important material for building structures, its intrinsic gray color degrades urban esthetics. In order to improve this problem, coloring methods of mixing pigment in concrete batch and painting the surface of concrete surface have been tried. However, applications of the coloring methods in construction field are difficult due to high cost and low durability. Recently, acid stain agent is emerging as a new coloring method for concrete. It is able to apply a remarkably thin colored layer on a concrete surface from chemical reaction between acid and alkaline solutions. This study has examined the changes and variations of the surface layer of mortar specimen from chemical reaction of acid stained agents. The colors were changed into natural irregular stains according to aging. After the staining, no shape change was found from visible inspections. Microstructure of the colored surface applied with acid stained agent was much rougher than that of original mortar. When the colored layer was compared to original surface, crystals of hydrate such as $Ca(OH)_2$ and C-S-H gel were observed. Surface hardness was same or slightly higher in the colored layer. The value of pH was reduced by approximately 10%, weight contents of elements such as Ca, Si, and Al were low. In the chemical composition of the colored layer, the non-cement based elements of Mn, Cr, and Cu increased. Also, Fe and alkali elements of K and Na increased.

• Applied Biological Chemistry
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• v.39 no.3
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• pp.245-248
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• 1996

Thermal stability of the major color component, cyanidin 3-glucoside, isolated from Korean pigmented rice (Oryza sativa var. Suwon 415) were investigated to explore possible application of value-added natural colors as food additives. The anthocyanin showed red and blue color with maximum absorption peaks at 511 nm and 572 nm in acidic (pH 2.0) and alkaline (pH 9.0) buffer solutions, respectively, and the thermal degradation reactions were carried out with different temperature ranges at $50{\sim}95^{\circ}C$. Degree of degradation was determined with UV/Vis spectra which indicate characteristic absorption patterns with sharp isosbestic points at 350 nm (pH 2.0), and 275, 310, and 405 nm (pH 9.0). Thus the reaction follows simple first-order kinetics. The anthocyanin was very stable against heat at acidic pH and relatively stable at alkaline pH with half-life values of 50.3 hr and 0.6 hr at $70^{\circ}C$, respectively. The activation energies and Arrhenius frequency factors of the pigment were 26.9 kcal $mol^{-1}\;and\;6.0{\times}10^{11}\;s^{-1}$, at pH 2.0, and 15.2 kcal $mol^{-1}\;and\;1.4{\times}10^{6}\;s^{-1}$, pH 9.0, and respectively.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.81-96
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• 2018

In this study, physicochemical properties of the natural jadeite powder were investigated and also the wash-off pack and liquid foundation containing the jadeite powder were prepared. In addition, each of these formulations was evaluated by various functional effects, sensory evaluation, stability and skin safety. In the wash-off pack, the far-infrared ray emissivity and radiation energy values increased as a function of the jadeite powder content. At a 3% jadeite powder content, the skin temperature increased by about $0.5^{\circ}C$ when the jadeite powder-containing formulation was applied to the skin. Besides, the chroma of the liquid foundation containing the jadeite powder more clearly expressed the original color of the skin. Moisture content measurements of the wash-off pack and liquid foundation containing the jadeite powder showed the highest moisture uptake of 5.0% and 63.0%, respectively. In sensorial test, the wash-off pack formulations containing the jadeite powder demonstrated improved affinities toward a skin, adherency, and moistness and combatted itching. The liquid foundation containing jadeite powder showed also improved affinities except for the coverage when compared to control formulations. Furthermore, the stability evaluation for 8 weeks revealed neither discoloration nor separation phenomenon for the formulations containing the jadeite powder. Moreover, the pH was found to be stable up to 8 weeks and the viscosity up to 4 weeks. Skin safety assessments showed that all formulations containing the jadeite powder were non-irritating. These results suggest that the jadeite powder as an inorganic pigment may serve as a new multi-functional cosmetic ingredient with stability and safety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.791-800
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• 2006

This study examined the effects of gromwell (Lithospermum erythrorhizon) extracts on the storage characteristics of Kangjung. At an increase of $0{\sim}0.25%$, there was no significant difference in the moisture content of wild and cultivated gromwell extract added to Kangjung, whereas there was a significant difference when increased to 0.5%. When compared, the occurrence of lipid oxidation among the controlled gromwell extract group stored at $60^{\circ}C$, resulted in peroxide values exceeding 40 meq/kg which is a maximum value for Hankwa within 12 hours of storage. However, at an increase of 0.25%, the cultivated gromwell extract added group reached limits within 16 hours. Furthermore, at a 0.5% increase in cultivated gromwell and 0.25% in wild gromwell, extract added groups exceeded this limit within 20 hours of storage. Gromwell added Kangjung, a fried food, showed efficiency in suppressing oxidation of fat, more so in the wild gromwell than the cultivated gromwell. In addition, efficiency in suppressing oxidation of fat increased at the 0.5% level than the 0.25% level. In conclusion, it is believed that an unused pigment resource called Lithospermum erythrorhizon, normally reserved for medicinal use, can be distributed as a safe food additive. In addition, as Lithospermum erythrorhizon is a natural antioxidant in fried foods, we believe this satisfies the demand for natural food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.2
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• pp.181-188
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• 1989

The present study has been carried out to investigate the effect of Bactokil(made from didecyldimethyl ammonium chloride isopropanol and water) and Taipet-F (made from natural vitamin E, L-ascorbic acid, glyceride and gallic acid) on retarding lipid oxidation in boiled-dried anchovy. To process boiled-dried anchovy, boiled anchovy dried in cabinet drier $(dry-bulb\;temperature\;40^{\circ}C)$ for 1 hour were fronted with the Bactokil, the Taipet-F and mixture of Bactokil and Taipet-F, respectively. Anchovy fronted with chemicals were redried for 8 hours, packed in polyethylene film bag, and then stored at room temperature $(24{\pm}3^{\circ}C)$. These products were compared with control(untreated with chemicals) during storage. The changes in volatile basic nitrogen of each product was negligible during storage. The thiobarbituric acid and peroxide values of each product increased up to 10 days of storage, and then decreased. In color value of each product, L value increased, while n, b and ${\bigtriangleup}E$ values decreased during storage. The changes in brown pigment formation of each product increased up to final stage of storage. From the results of chemical analysis and sensory evaluation, the product treated with Taipet-F(0.5%, v/v) was the most effective on retarding lipid oxidation of the boiled -dried anchovy, followed by the product treated withthe mixture of Bactokil (0.04%, v/v) and Taipet-F (0.5%, v/v), the product treated with Bactokil(0.04%, v/v) and control, in the order named.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.2
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• pp.221-226
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• 2012

For the investigation of a possibility as a useful functional material, 6 cultivars (Takinosawa Gold, Kawanakawase Hakuto, Madoka, Yumefuji, Nagasawa Hakuho, Hong Bak) of Prunus persica L. Batsch were studied at unripe stage to determine the physicochemical properties and chemical compositions. The cultivars were picked in late May, and all samples were analyzed for external properties, physicochemical properties, pH, Brix value, Hunter's color value, hardness, vitamin C, and reducing sugar. The size of the fruit from all six cultivars was compared, and it was determined that cultivars, fruit from Madoka was the largest, while that from Yumefuji was the smallest. Comparing fresh weight, the fruit from Yumefuji was lowest in moisture contents (89.13~89.96%), and that from Nagasawa Hakuho had significantly higher crude protein (1.02~1.62%). The contents of crude lipids (0.18~0.23%) and carbohydrates (8.00~9.35%) were not significantly different between cultivars and Madoka included higher crude ash contents (0.32~0.69%) than other cultivars. The pH of 6 cultivars from unripe peaches were significantly higher from Kawanakawase Hakuto, and the Brix value was also highest from Kawanakawase Hakuto, followed by Yumefuji, Madoka, Nagasawa Hakuho, Takinosawa Gold, and Hong Bak. In chromaticity, the L value, the indicator of brightness, was significantly higher in fruit from Nagasawa Hakuho. The a value, the indicator of redness, was the highest with Hong Bak and overall lower than -5. The b value, the indicator of yellowness, was the highest in fruit from Madoka and ranged from 16.51 to 18.33. In physical characteristics, the hardness of the unripe peaches was the highest in fruit from Hong Bak, and overall, white peaches have a higher hardness value than yellow peaches. The vitamin C content of the fruit didn't show any significant differences between cultivars, and the reducing sugar showed a higher percent than 6.34% in fruit from all cultivars. These results suggest that unripe peaches were commensurate with the development of natural pigment and as a functional foods.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.3
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• pp.131-140
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• 2015

To set up unicellular cyanobacterial strains with photo-biological $H_2$ production potential, live samples were repeatedly collected from 68 stations in the coastal zone of Korea for the four years since 2005. Among 77 cyanobacterial strains established six (KNU strains, CB-MAL002, 026, 031, 054, 055 and 058) were finally chosen as the excellent strains for $H_2$ production with $H_2$ accumulation over 0.15 mL $H_2\;mL^{-1}$ under general basic $H_2$ production conditions as well as positive $H_2$ production for more than 60 hr. To explore optimum procedures for higher $H_2$ production efficiency of the six cyanobacterial strains, the inter-strain differences in the growth rate under the gradients of water temperature and salinity were investigated. The maximum daily growth rates of the six strains ranged from 1.78 to 2.08, and all of them exhibited $N_2-fixation$ ability. Based on the similarity of the 16S rRNA sequences, all the test strains were quite close to Cyanothece sp. ATCC51142 (99%). The six strains, however, were grouped into separate clades from strain ATCC51142 in the molecular phylogeny diagram. Chlorophyll- a content was 3.4~7.8% of the total dried weight, and the phycoerythrin and phycocyanin contents were half of those in the Atlantic strain, Synechococcus sp. Miami BG03511. The growth of the six strains was significantly suppressed at temperatures above the optimal range, $30{\sim}35^{\circ}C$, to be nearly stopped at $40^{\circ}C$. The growth was not inhibited by high salinities of 30 psu salinity in all the strains while strain CB055 maintained its high growth rate at low salinities down to 15 psu. The euryhaline strains like CB055 might support massive biotechnological cultivation systems using natural basal seawater in temperate latitudes. base seawater. The biological and ecophysiological characteristics of the test strains may contribute to designing the optimal procedures for photo-biological $H_2$ production by unicellular cyanobacteria.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.6
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• pp.586-593
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• 1985

The rose bitterling, Rhodeus ocellatus (KNER) is commonly distributed in the fresh waters of Korea and Japan. On January 15, February 15, and March 18 in 1984, mature adults of rose bitterling were caught in the watercourse of Maeri, Kimhae, South Korea. The authors fertilized the eggs employing dry method in the laboratory on May 7, 16 and 25 in 1984. Hatched larvae were reared in small aquariums at $17{\sim}25.5^{\circ}C$ (average around $21.2^{\circ}C$). Mollusks, Anodonta woodiana in the gill chamber of which, rose bitterling lay eggs were caught in order to study natural spawning of the rose bitterling in the same watercourse. The eggs of this species are not adhesive and demersal. The size of the eggs varies from 2.54 to 2.75mm in long diameter and 1.45 to 1.65mm in short diameter. The eggs are cylindrical in form when they are extruded from ovipositor, immediately after entering water, but they acquire their distinctive form of a greatly elongated pear. Hatching took place in ca. 39 hours after fertilization. The newly hatched larvae were $2.65{\sim}2.70mm$ in total length possessing yolk sac and 13-14 myotomes. Thirteen days after hatching, the prelarvae attained 6.5 mm in total length, and the first melanophores appeared on the head, and the anterior part and sides of the yolk sac. One month after hatching, the postlarvae attained 8.5mm. in total length and emerged from the gills of the mollusks. Then the yolk sac was completely resorbed. Two months after hatching, the rose bitterling attained 14.4mm in total length, and entered the fingerling period of life. All the rays already present were the D. III, 11-12, A. III, 11-12, P. 10, V. 7. and a distinguishing, feature is the presence of a black pigment spot in the lobe of the dorsal fin.

• Conservation Science in Museum
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• v.29
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• pp.133-152
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• 2023

This study references preceding studies to examine the history of paint application techniques using various paints in the past, with the aim to contribute to the long-term preservation of large military cultural heritage assets situated outdoors. To this end, the study compared the findings of preceding research with the findings of an analysis conducted on a H-13 helicopter housed at the War Memorial of Korea. Upon collecting and analyzing samples from three grounded WWII aircraft from above-ground by preceding studies, it was confirmed from each sample that the various chemical properties of chrome ensured the effectiveness of the protective coating. The compound was first tested as a corrosion-inhibiting pigment in the early 1940s and proved its excellent moisture-resistant properties over the course of 80 years, despite the deterioration of the paint layer and long-term exposure to the natural environment. For this reason, it has been widely used as a corrosion inhibitor for aluminum alloys in the aviation industry. In other word, the most widely-used material for preventing corrosion was an organic primer containing chromate. In this study, based on the paint analysis of a H-13 helicopter operated in the Korean War, it was shown that the second layer, consisting of the primer, contains chromium oxide (Cr₂O₃). In addition, it was estimated that red lead tetraoxide (Pb₃O₄) was used for the vehicle. Analysis results and data from previous studies can help to confirm the continued effectiveness of corrosion prevention function provided by chromate. Meanwhile, the result of infrared spectroscopy analysis confirmed the use of alkyd resin. In the future, comparisons with a more diverse range of artifacts will allow the identification of changes in the manufacturing technology of paints used to protect alloys from corrosion.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.1
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• pp.41-51
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• 1987

This study was carried out to prepare powdered smoked-dried mackerel which can be used as a soup base, and to examine storage stability and the taste compounds of Products. Raw mackerel are filleted, toiled for 10 minutes and pressed to remove lipids, and then soaked in extract solution of skipjack meat. This soaked mackerel are smoked 3 times to $10-12\%$ moisture content at $80^{\circ}C$ for 8 hours. And the smoked-dried mackerel were pulverized to 50 mesh. Finally, the powdered smoked-dried mackerel were packed in a laminated film $bag(PET/Al\;foil/CPP:\;5{\mu}m/15{\mu}m/70{\mu}m,\;15\times17cm)$ with air(product C), nitrogen(product N) and oxygen absorber(product O), and then stored at room temperature for 100 days. The moisture and crude lipid content of powdered smoked-dried mackerel was $11.3-12.3\%,\;12\%$, respectively, and water activity is 0.52-0.56. And these values showed little changes during storage. The pH, VBN and amino nitrogen content increased slowly during storage. Hydrophilic and lipophilic brown pigment formation showed a tendency of increase in product(C) and showed little change in product(N) and (O). The TBA value, peroxide value and carbonyl value of product(N) and (O) were lower than those of product (C). The major fatty acids of products were 16:0, 18:1, 22:6, 18:0 and 20:5, and polyenoic acids decreased, while saturated and monoenoic acids increased during processing and storage of products. The IMP content in products were 420.2-454.2 mg/100 g and decreased slightly with storage period. And major non-volatile organic acids in products were lactic acid, succinic acid and $\alpha-ketoglutaric$ acid. In free amino acids and related compounds, major ones are histidine, alanine, hydroxyproline, lysine, glutamic acid and anserine, which occupied $80.8\%$ of total free amino acids. The taste compounds of powdered smoked-dried mackerel were free amino acids and related compounds (1,279.4 mg/100 g), non-volatile organic acids(948.1 mg/100 g), nucleotides and their related compounds (672.8 mg/100 g), total creatinine(430.4 ntg/100 g), tetaine(86.6 mg/100 g) and small amount of TMAO. The extraction condition of powdered smoked-dried mackerel in preparing soup stock is appropriate at $100^{\circ}C$ for 1 minute. Judging from the results of taste and sensory evaluation, it is concluded that the powdered smoked-dried mackerel can be used as natural flavoring substance in preparing soups and broth.