• Journal of dental hygiene science
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• v.21 no.1
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• pp.38-44
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• 2021

Background: Dental caries and periodontal disease are bacterial infectious disease, mainly caused by plaque, a bacterial colony deposited on the tooth surface and gum tissue. Dental plaque disclosants easily stain the dental plaque, making them effective for scaling and tooth brushing education. As the erythrosine typically contained in dental plaque disclosants is highly cytotoxic, a low toxicity additive is needed. In this study, we aimed to examine the natural pigments with negligible cytotoxicity but can effectively stain the dental plaques for use in dental plaque disclosants. Methods: The pigmentation of eight types of natural pigments was tested on bovine tongue and teeth, as well as on head and neck tissue sections of experimental ICR mice. The cytotoxicity of gingival epithelial cells was measured via MTT assay. Pigmentation was performed on the bovine tongue and tooth surface. Pigmentation in the oral environment was observed in four mandibular incisors. A 2 Tone was used as a control. Results: Of the eight types of natural pigments, purple and blue pigments were effective in coloring dental plaques on the enamel surface as well as in the head and neck tissue sections. Additionally, purple and blue pigments were visible on the surface of the bovine tongue. Red, pink, orange, green, purple, and yellow pigments showed strong cytotoxicity, whereas brown and blue pigments had relatively low cytotoxicity. Blue pigment was effective in staining the dental plaque of four mandibular incisors. Conclusion: We suggest that the blue pigment derived from Gardenia jasminoides Ellis (Rubiaceae), which is effective for coloring dental plaques and has low cytotoxicity, is useful as a naturally derived dental disclosant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.127-131
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• 2012

In this study we examined the changes in expression of pigments in black rice during kernel development, which were sampled at 2~3-day intervals to the 40th day after flowering. The first expression of pigment on kernels was observed on the seed coat about 5 days after flowering. At that times, the ratio of pigment expression was 0.08% of total area. The order in expression of pigments in black rice during kernel development was top first, followed by bottom, dorsal side, then ventral side. Maximum percentage of the total colored area in kernel was about 25 days after flowering. After that, the color has changed to dark purple from pale purple during kernel development after flowering. After harvesting, the non-uniform color kernels were observed. As a result, the ventral side in a kernel was a position of the non-uniform color such as a mixture of pale purple and dark purple. Also, we could be concluded that patten of pigment expression was similar in kernel development.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.345-351
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• 1996

Studies on extraction and color characteristics of purple sweet potato (PSP) pigment were performed to provide the basic information for the utilization of PSP as a new source of natural food colorant. PSP pigment was extracted well with the polar solvents such as distilled water, ethanol, and methanol. but hardly extracted with the non-polar solvents. Among the tested solvents, 20% ethanol solution containing 0.1% citric acid was found to be the most efficient for extraction of the pigment from PSP. PSP contained high amount of pigment not only in the epidermis but also in the flesh of the potato. The PSP pigment was heat stable even under pretreatments such as autoclaving and blanching of the potato before extraction. The optimum temperature of the extraction for the PSP Pigment was decided to be $30^{\circ}C$ by considering the stability and the rate of extraction. The pigment was markedly influenced by the change of pH. The color of the pigment solution was red at the pH range of $1.0{\sim}3.0$, became blue at $7.0{\sim}8.0$, then turned green at $9.0{\sim}10.0$. A characteristic batho-chromic shift of the pigment solution was observed as the pH of the solution increased.

• Journal of the Korean Society of Costume
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• v.14
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• pp.133-144
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• 1990

The purpose of this study is to investigate the absorbance of the Shikonin, one of the major purple pigments, and the stability against the effect of light, $O_2$, and temperature. The effect of mordant and mordanting condition to color and color-fastness is compared and analysed through the color-fastness-test, color-difference value-test, and IR-test. The results were as follows; 1. The absorbance of Shikonin was examinated through 6 kinds of solutions and distilled water. Shikonin was absorbed by solutions rather easily than distilled water. 2. The light effect to Shikonin indicated that the solution with the light was more stable than that without it. 3. The effect of $O_2$ to Shikonin showed that the solution with the $O_2$ was more stable that without it $O_2$. 4. Shikonin -methyl alcohol solution was stable in $25^{\circ}C$. It was unstable in $60^{\circ}C$ and $100^{\circ}C$ with lowered absorbance and changed colors. 5. Color-fastness test to silk and cotton indicated washing color-fastness and perspiration color-fastness was more than 3 grade. But the light color-fastness and crocking color-fastness was low. 6. The comparison between non -colored sample and colored-sample showed the latter was better in fastness. 7. Mordant as $Alk(SO_4)_2{\cdot}24H_2O$ and $AlCl_3{\cdot}6H_2O$ was better than anything else in fastness. 8. Color-difference value-test indicated that the mordant which had the jade green color, the original purple pigment color, was the best in use. 9. The best way to extract the original purple pigment color was in $25^{\circ}C$, because extracted dyeing solution by Soxhlet had the bluish color.

• Korean Journal of Human Ecology
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• v.21 no.4
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• pp.791-803
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• 2012

This study intends to identify applicability of natural dye extracted from Aplysia kurodai, aiming to standardization of Aplysia kurodai natural dyeing through scientific validation by analyzing characteristics of pigment elements to review dyeability, colorfastness and antibacterial activity. Such material as silk fabrics that is animal fiber were used for this purpose, and derived following summarized results. UV/VIS spectrum analysis on the pigment of Aplysia kurodai that was extracted from purple gland showed that maximum absorbtion was near 540 nm. The silk fabric optimal dyeing can be achieved at a temperature of $55^{\circ}C$ with a colorant concentration of 5%. Dyed at $55^{\circ}C$ with interval of 10~90 minutes for identifying dye uptake over time to observed slow increase of dye uptake over time, and equilibrium occurred at 50 minutes. For dye uptake according to pH, while dye uptake was superior in acidity, it decreased rapidly in a base after pH 7. For color changes according to pH variation, it was reddish purple in acidity and was purplish red in a base. For color changes according to mordanting method, more clear color change had been obtained when process with aluminium pre-mordanting than non-mordanting and post-mordanting. The colorfastness to light, perspiration and washing was 1, 4~5, and 3~4 ratings respectively. The silk fabric dyed with Aplysia kurodai demonstrated excellent antimicrobial activity to Staphylococcus aureus and Klebsiella pneumoniae. The Aplysia kurodai can be used as a new colorant for the natural dyeing of silk.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.113-118
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• 2013

This study was carried out to evaluate the dyeing possibility of purple corn stem and leaf. The UV absorbance of the purple corn stem extract and leaf extract at different pH does not change. It is considered to use to efficiently measure the purple corn pigment content when using UV absorbance at 520~560 nm. By adjusting higher pH values in the extraction dyed fabrics, silk and cotton fabric used by the purple corn leaf extraction decreased lightness and redness. Extent for dyeing the fabric depending on the concentration, lightness and redness showed a tendency to increase color values when silk and cotton concentration increases. Also when the longer the dyeing time, silk and cotton increased lightness but redness decreased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.173-178
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• 2006

Anthocyanin in blackish purple rice is composed of cyanidin, peonidin, malvidin, pelargonidin and delphinidin flavylium ion and their glucosides, which shows antioxidant activity similar to a-tocoperol. It has been demonstrated that cyanidin-3-glucoside(C3G) of anthocyanin has a high-potency antioxidant activity, and is a prominent in anticancer and antithrombotic activity. In analysis of content of anthocyanin from the genetic source of blackish purple rice, the level of C3G was approximately 80% of total contents of anthocyanins, and showed the highest content in Heugjinjubyeo, of which contains an amount of 500 mg by weight of 100g brown rice in comparison that most of varieties has less than 50mg by weight of 100g brown rice. We found that C3G pigment in blackish purple rice was considerably affected by cultural season, cultivation area, ripening temperature, and weather condition, etc. as well as genetic properties. In cross combination between Heugjinjubyeo and Suwon425, intermediate parent $F_9$ generation which was three times higher or more in C3G content than that of Heugjinjubyeo was bred, of which it contained an amount of 1678 mg by weight of 100g brown rice, and we called it 'C3GHi' Rice. And, we found that the C3GHi rice was more excellent than that of the existing Heugjinjubyeo in anticancer and antithrombotic activity. Methanol extract from Heugjinjubyeo was fractionated by organic solvents in order of n-hexane, $CH_{2}Cl_2$ and n-BuOH, and then oryzafuran, quercetin, vanillic acid and protocatechuic acid and their structures from the n-BuOH fraction were ascertained. Oryzafuran of these compounds was a natural compound found firstly in nature. Quercetin and protocatechuic acid besides new compound oryzafuran showed excellent antioxidant ability to vitamin C. These results suggest that blackish purple rice has very high value as a source of various functional food as well as staple food.

• Korean Journal of Materials Research
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• v.23 no.5
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• pp.271-275
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• 2013

Cobalt (Co) compounds have been used for centuries to impart rich blue color to glass, glazes and ceramics. Cobalt monoxide (CoO), an oxide of Co, is an inorganic compound that has long been used as a coloring agent in the ceramic industry. Unlike other coloring agents, CoO can be used to develop colors other than blue, and several factors such as its concentration in the glaze and firing condition have been suggested as possible mechanisms. For example, CoO produces a typical blue color called "cobalt blue" at very low concentrations such as 1 wt% in both oxidation and reduction firing conditions; a higher concentration of CoO (5 wt%) develops a darker blue color under the same firing conditions. Interestingly, CoO also develops a purple color at high concentrations above 10 wt%. In this study, we examined the applicability and mechanism of a novel purple glaze containing cobalt(II, III) oxide, one of the well characterized cobalt oxides. Experimental results show that an Augite crystal isoform (Augite-Fe/Co) in which Fe was replaced with Co is the main component contributing to the formation of the purple color. Based on these results, we developed a glaze using chemically synthesized Augite-Fe/Co crystal as a color pigment. Purple color glaze was successfully developed by the addition of 6~15 wt% of $Co_3O_4$ to magnesia lime.

• Journal of the Korean Ceramic Society
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• v.36 no.4
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• pp.333-342
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• 1999

This research was performed to investigate how the basic glaze change affected colour development at high temperature with a stable colorant (spinel structure CoAl2O4 pigment) The compounded pigment which is widely used for porcelain was also tested for the basic glazes adaptability. The data from the test were recorded in a computer data-base program. Therefore could be easily used in the study related with a pottery field. CoO : Al2O3 system spinel pigment of barium glaze lime glaze zinc glaze lead glaze and talc glaze were chosen for this study. The colors of Cobalt blue bright blue, blue purple were seen at the wave lengths of 455-480nm at the firing temperature of 1250$^{\circ}C$. Stable color were obtained from lime glaze bar-ium glaze zinc glaze. All the information in the database were used to examine all the possible result of the test in the study of porcelain. When the test results database were examined in all temperature ranges the lack of adhesion with the pigment occurred at the temperature of 1150$^{\circ}C$. The lack of adhesion is seen due to vaporization of the lead glaze.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.200-209
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• 2012

The effect of water temperature, salinity and water column nutrient contents on pigment composition and concentration of purple lavers were studied at the main purple lavers production areas in Southwestern coast of Korea, during January to March, 2011. Water temperature was between 3.0 and $11.3^{\circ}C$. Salinity range was between 32.7 and 34.7, those were lower St. 1 and St. 6, which were at close to the seashore. Water column dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and silicate concentrations were $1.73{\sim}12.84{\mu}M$, $0.07{\sim}0.67{\mu}M$ and $4.93{\sim}18.29{\mu}M$, respectively. Chl a concentration was between 0.41 and $9.14{\mu}g\;L^{-1}$, and it was the highest at St. 1 during January. Photosynthetic pigment of fucoxanthin was dominant at all sites, which showed its highest concentration ($0.06{\sim}3.41{\mu}g\;L^{-1}$) at St. 1 on January. Water column DIN concentration was higher at January during low salinity period at all sites, but it was low at St. 1. Photosynthetic pigment of Chl a, PE and PC concentration of porphyra blades was between $1,173{\sim}8,124{\mu}g\;DW\;g^{-1}$, $3,281{\sim}10,076{\mu}g\;DW\;g^{-1}$, $388{\sim}1,346{\mu}g\;DW\;g^{-1}$, respectively. The concentration was relatively high at the St. 2 and St. 3. The pigment concentration of porphyra blades was higher at only Porphyra yezoensis was cultured than at Porphyra yezoensis and Porphyra seriata were cultured. The pigment concentration of porphyra blades was higher at St. 2 and St. 3 in only Porphyra yezoensis was cultured. This study shows that pigment concentration of porphyra blades may depend on habitat environment and culture methods.