• Textile Coloration and Finishing
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• v.31 no.1
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• pp.1-13
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• 2019

In this study, eco-friendly functional leather was developed by recycling wastes such as eel skin, marigold(Tagetas erecta l.), hinoki cypress(Chamaecyparis obtusa). The hot water extracts of marigold and hinoki cypress leaves were freeze-dried at $-80^{\circ}C$ to prepare colorant powder. The dyeing of eel leather with marigold was carried out to investigate the effects of dyeing conditions, mordanting on dye uptake, color, morphological change, and color fastness. Considering shrinkage of eel leather caused by dyeing, the optimum dyeing conditions were $60^{\circ}C$ of dyeing temperature and 60 min of dyeing time at 1:100 of bath ratio, and color of the dyed eel leather was Y to YR Munsell series. In order to prevent the degradation of leather from microbe, we conducted combination dyeing with marigold and hinoki cypress leave colorants. In this case, the combination dyed eel leathers showed excellent antimicrobial activity with above 99% bacterial reduction rate against S. aurieus and K. pneumoniae. It was confirmed that all of the dyed eel leathers were sufficient to meet the Korean Standard for color fastness of leather products. It can be applied practically for the development of eco-friendly functional leather by utilizing some useful active components extracted from plant resources and by recycling food wastes.

• Analytical Science and Technology
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• v.34 no.4
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• pp.160-171
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• 2021

Synthetic azo dyes are used extensively in herbal medicines to render the medicines more visually attractive to consumers. This study developed and validated a rapid high-performance liquid chromatography (HPLC) method to determine whether synthetic colorants such as Tartrazine, Auramine O, Metanil yellow, Sunset yellow, and Orange II are used extensively in Typha orientalis. To increase the recovery of the synthetic dyes, this method employed containing 50 mM ammonium acetate in 70 % methanol at first extraction and 100 mM HCl in 70 % methanol at second extraction. Five synthetic pigments in Typha orientalis were separated by gradient elution with a mobile phase consisting of acetonitrile and 50 mM ammonium acetate in distilled water at ultra-violet (UV) detection 428 nm or 500 nm. Additionally, this study established the liquid chromatography tandem mass spectrometry (LC-MS/MS) method to confirm positive samples suspected by HPLC results. The HPLC-UV method had good linearity, indicating r²> 0.999. The recoveries of the samples spiked with three different concentration ranged from 73.8~91.5 %, and relative standard deviation values indicated 0.2~5.2 %. The established LC-MS/MS could successfully identify the synthetic pigments in herbal medicine samples. The study demonstrates that Typha orientalis adulterated by yellowish synthetic dyes can be successfully distinguished when using the HPLC-UV method.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.4
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• pp.156-161
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• 2020

Recently, as there has been growing demand for aesthetic quality in structural materials, the development of excellent color cement concrete having good coloration properties has become a requirement. This study is designed to analyze the basic physical properties of mortar and the properties of keeping the coloration under an ultraviolet ray accelerated weathering test environment according to changes in the mixing ratio between carbon black and iron oxide used as colorants. The test results show that the use of carbon black and iron oxide reduces the initial flow by 6.3~17.2 % and the air content by 3.5~31.5 % but increases the unit volume weight by 3.4~5.5 %, compared to ordinary Portland cement (OPC). In addition, the study shows that the addition of iron oxide increases the self drying shrinkage. So, caution needs to be taken on the workability of the concrete. The brightness value L^⁎ represented by black showed the most excellent black colour when carbon black 3 % and iron oxide 5 % are added. According to UV accelerated weatherproof test, the brightness value L^⁎ was found to increase in all experiment specimens by 4.28~11.97 %, and the color change by UV was found to be higher for the case where carbon black colorant was not used. Therefore, in terms of color revelation characteristics, the case using carbon black 3 % and iron oxide 5 % was found to show the best black color.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.5 s.164
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• pp.659-669
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• 2007

The purpose of this study was to investigate the degradation of silk fabrics dyed with gardenia and sappanwood by Ultraviolet Light(UV). To asses the effect of uv on dyed silk fabrics, physical and chemical properties of samples were explored. K/S value rapidly decreased with increasing exposure time. Mordanting improved ultraviolet-cut ability and the sappanwood dyed samples were superior to those of gardenia dyed in ultraviolet-cut ability. Color progressively faded away as uv exposure time increased, accordingly, $L^*,\;a^*,\;b^*$, H/VC, ${\Delta}E$ were changed. Morphological change observed with SEM represented degradation of silk fabrics from the outer fibril to the inner fibril. Tensile Strength abruptly decreased as uv exposure time increased and the mordanted samples showed higher tensile strength than the unmordanted. FT-IR analysis confirmed that main peaks at 3297 and $1704cm^{-1}$ band for silk fabric were due to N-H and C=O stretching, gardenia peaks at 1654 and $668cm^{-1}$ band representing C=O(ester), C=C(alken) and O-C=O(carboxylic acids) of crocin and sappanwood peaks at $1715cm^{-1}$ band representing C=O(cyclic keton) of brazilin appeared on the samples exposed for 14 days, but these peaks indicating colorants after 28 days of uv exposure faded away due to prolonged exposure of uv.

• Applied Biological Chemistry
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• v.30 no.3
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• pp.201-209
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• 1987

Solutions of food colorants were tested with insoluble drugs (kaolin, active carbon, talc, natural aluminum silicate) for their adsorption phenomena in purified water, gastric and intestinal fluid test solutions, respectively. The adsorption isotherms of kaolin with Red 2 in purified water, and active carbon with Red 2, 3, 40 in the three media, with Yellow 4 in purified water, gastric fluid, with Yellow 5 in intestinal fluid and natural aluminum silicate with Red 3 in purified water, intestinal fluid, with Yellow 4, 5 in purified water followed the Freundlich equation, and those of talc with Red 2, 3, Yellow 5 in the three media, with Red 40 in purified water, gastric fluid, with Yellow 4 in intestinal fluid fitted the Langmuir equation. With decrease of the alcohol content of aqueous solutions, the adsorption of coloring food additives is increased, but it decreased in high temperature. Also the activation energy of adsorption of coloring food additives by active carbon was determined.

• Current Research on Agriculture and Life Sciences
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• v.33 no.1
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• pp.1-5
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• 2015

This study investigated the chelation of a sorghum bran extract using iron (Fe) as a new natural colorant. The composition of the sorghum bran extract and chelation conditions were both examined. The thermal properties of the chelated colorants were analyzed using differential scanning calorimetry (DSC) and a thermal analyzer system(TGA). The sorghum bran extract solution showed a maximum absorbance at 281 nm based on UV/Vis spectrophotometry. According to the chelation pH conditions, pH 7.5 was the most effective. The chelation of the sorghum bran extract increased rapidly when increasing the iron concentration up to 2 mg/L, with no further chelation at a higher concentration. The particle size distribution curve for the chelated tannin revealed four groups: $4.5{\sim}17{\mu}m$, $20{\sim}42{\mu}m$, $45{\sim}80{\mu}m$, and $83{\sim}160{\mu}m$. In a DSC analysis, endothermic peaks attributed to the pyrolysis of the extract and chelated tannin were found at $318^{\circ}C$ and $415^{\circ}C$, respectively. In a TGA analysis, the chelation was shown to increase the final degradation temperature from $253^{\circ}C$ to $382^{\circ}C$, confirming that the chelation improved the thermal stability.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.226-235
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• 2017

Carotenoids such as phytoene, lycopene, and ${\beta}-carotene$ are used as food colorants, animal feed supplements, and for human nutrition and cosmetic purposes. Previously, we reported the isolation of a novel marine bacterium, Kocuria gwangalliensis, which produces a pink-orange pigment. Phytoene desaturase (CrtI), encoded by the gene crtI, catalyzes lycopene formation from phytoene and is an essential enzyme in the early steps of carotenoid biosynthesis. CrtI is one of the key enzymes regulating carotenoid biosynthesis and has been implicated as a rate-limiting enzyme of the pathway in various carotenoid synthesizing organisms. Here, we report the cloning of the crtI gene responsible for lycopene biosynthesis from K. gwangalliensis. The gene consisted of 1,584 bases encoding 527 amino acid residues. The nucleotide sequence of the crtI gene was compared with that of other species, including Kocuria rhizophila and Myxococcus xanthus, and was found to be well conserved during evolution. An expression plasmid containing the crtI gene was constructed (pCcrt1), and Escherichia coli cells were transformed with this plasmid to produce a recombinant protein of approximately 57 kDa, corresponding to the molecular weight of phytoene desaturase. Lycopene biosynthesis was confirmed when the plasmid pCcrtI was co-transformed into E. coli containing the plasmid pRScrtEB carrying the crtE and crtB genes required for lycopene biosynthesis. The results from this study will provide valuable information on the primary structure of K. gwangalliensis CrtI at the molecular level.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1996.04a
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• pp.25-25
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• 1996

;Jindo Hongju is an unique red-colored traditional distilled wine of Korea. The unique attractive color of Jindo Hongju is due to the pigments of gromwell (Lithospermum erythrorhizon) root, derivatives of naphtoquinone such as shikonin and acetylshikonin. Which are extracted during the distillation process. The attractive color of the gromwell pigments is easily changed to dark red or to brown causing deterioration of the Quality of Jindo Hongju. Due to the discoloration of the pigments and to the limited supply of gromwell roots, some brewers manufacture spurious Jindo Hongju using artificial colorants. This study was performed to devise a simple method of detecting spurious Jindo Hongju products. The color of the gromwell pigments was greatly affected by pH change and the change could be demonstrated by the change of the absorption spectrum. At pH 4.0 the normal pH of Jindo Hongju, the absorption spectra of gromwell pigments and genuine Hongju products showed an absorption maximum of 520 nm. The absorption maximum was shifted to 570 nm and to 616 nm as the pH was raised to 7.0 and 11.0 respectively. This transition due to the pH change was also demonstrated on em chromaticity diagram. The characteristic transition due to pH change of gromwell pigment solution was not observed with an artificial colorant (red No.2) which was suspected to be used in the manufacture of imitation products. The absorption spectra of most of the Jindo Hongju collected from the market were similar to that of the gromwell pigments and showed the characteristic transition due to pH change with the addition of NaOH. However, with a few of the products, the absorption spectra was similar to that of the artificial colorant and the characteristic transition due to pH change was not observed, indicating these products might have been forged. The result of study suggests that the transition of the absorption spectrum and the change of the color due to pH change be used for the detection of imitation products. Farther more, since, at pH above 9.0, the color of the gromwell pigments and genuine Jindo Hongju could be visually differentiated from that of the artificial colorant and forged products, it might be possible that the forged products be easily detected by raising the pH to above 9.0 and visually comparing the color with that of the gromwell pigment at the same pH.me pH.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.91-98
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• 2006

The purpose of this study is to investigate the opacity and printing strength of MG paper overlaid plywood. The printing strength of ink on MG paper can be evaluated effectively by a formula $E^{*2}=[(L^{*})^{2}+(a^{*})^{2}+(b^{*})^{2}]^{1/2}$ that we proposed. Higher E value indicates good printing strength of ink-on-paper. We also assess the real color of translucent printed MG paper with a formula CIE ${\bigtriangleup}E^{*}$ (color difference between a pile of same paper to be opaque and fancy paper laminated board). In addition, the color difference on paper surface caused by the color of wood-based board (bottom) can be evaluated by a formula of Pc. No. Generally, an acceptable appearance quality of fancy boards is ${\bigtriangleup}E^{*}$ <2.0 and small Pc.No. value. The experimental results showed that Japan-made MG papers -J1, J2 and J3 have better printing strength and gloss than that of Taiwan-made paper (T1). The reason for this was that Taiwan-made paper has poor printing strength and low gloss, which might be correlated to the fiber compositions in paper. Higher printing strength can be seen for short fiber containing handsheets when comparing to that of handsheets. Nonetheless, low-freeness sheets gives better printing strength than that of high-freeness sheets. High-opacity MG paper gives good opacifying effect to the fancy paper laminated wood-based boards. Comparing the surface color of 2 kinds of fancy paper laminated boards, paperboard T1 laminated with high-opacity fancy paper showed slight color difference. The same results can be seen for $??g/m^{2}$ handsheets. Higher-opacity Acacia and Eucalyptus bleached sulfate pulps (short fiber) gives higher opacifying effect on the plywood when comparing to Northan pine and Radiata pine sulfate pulps(long fiber). The former ones also showed small color differences when comparing the color differences between the color of fancy paper and laminated paper board. Additionally, the color of bottom plywood can't be shown through for the high-opacify surface paper adhered to. Besides, the PC No of the base paper laminated board is small as well. Apparently, we can add colorants to the binders for the manufscture of various handsheets ($30g/m^{2}$) with various pulp mix ratios to increase the opacity of paperboards to certain extents. When we using yellow and brown binders in paper laminated board, the color difference between Acacia and Eucalyptus handsheets overlaid boards decreasing to 2.0 (acceptable ${\bigtriangleup}E^{*}$ <2.0, hard to discern), but not much improvement for Northern and Radiata pines. Definitely, show-through defects can be discernible for lower opacity papers. In general, admirable printing strength of fancy paper by which glued to plywood can be made with high-opacity paper and colored binders techniques.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.5
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• pp.572-582
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• 2004

Statement of problem: The clinical criteria of soft lining materials are resilience over an extended period, capability of forming a strong bond with denture base materials, dimensional stability, adequate tear strength, and color stability. Many researches and reports dealt with food colorants or denture cleanser, but not with fermented foods. Purpose : This study was designed to assess what fermented foods, such as soy sauce and red pepper paste that many Koreans have eaten, influence on the color stability of soft denture liners. Material and methods: The color differences (${\Delta}E^*$) were measured by spectrophotometer with different immersion time. For the procedure, thirty disk-shape specimens per 4 soft denture linears(Molloplast-$B^{(R)}$, Ufi Gel $SC^{(R)}$, Dura $Base^{(R)}$, Sofreliner $MS^{(R)}$) were fabricated with a thickness of 2mm and 16mm in diameter. Each 10 specimen were immersed into the beakers of fermented foods distilled water, and $L^*$, $a^*$, $b^*$ values were measured for the color difference(${\Delta}E^*$), on the 1st, 7th, and 28th day with spectrophotometer. Result and conclusion : 1. There were significant differences between samples(soy sauces, red pepper pastes, and distilled water) in Sofreliner $MS^{(R)}$ of 1st day after immersion(p<0.05). There were significant differences between samples in Sofieliner $MS^{(R)}$ and Ufi Gel $SC^{(R)}$ of 7th days after immersion(p<0.05). There were significant differences between samples in Molloplast-$B^{(R)}$ of 28th day after immers ion(p<0.05). 2. In red pepper pastes, ${\Delta}E^*$ values of Molloplast-$B^{(R)}$, Ufi Gel $SC^{(R)}$, Sofrelinev $MS^{(R)}$ weve higher than 3.3. Those values were not clinically acceptable. In soy sauces, ${\Delta}E^*$ values of all denture liners were lower than 3.3. ${\Delta}E^*$values of Ufi Gel $SC^{(R)}$ were higher than those of other denture liners 3. Based on the above results , red pepper paste causes more discoloration than soy sauce.