• Textile Coloration and Finishing
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• v.24 no.3
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• pp.165-172
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• 2012

The stability of yellow and red dyes prepared from safflower (Carthamus tinctorius L.) in aqueous solution and in solid state was investigated. External factors such as light irradiation and temperature on the stability were examined during storage. Changes in absorbance of dye solutions and the color changes of fabrics dyed after long time storage were measured. Also, color reproducibility during storage was investigated by dyeing test on various fabrics. Red colorant in aqueous solution was very unstable to light, resulting that about 40% of absorbance were lost in 12hrs. The absorbance of yellow dye solutions was not decreased within 84hrs. In aqueous medium, yellow dye was much more stable than carthamin. Both dyes are relatively stable for long storage when they are stored in solid state compared to when in aqueous solution. Color changes are marginal in both dyes.

• 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.

• Science of Emotion and Sensibility
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• v.13 no.4
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• pp.693-702
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• 2010

This study was carried out in order to investigate the colorimetric values, the color sensation and sensibility for naturally dyed fabrics with microbial prodiginine colorant and to find out the relationship among color sensation, color sensibility factors and colorimetric properties of them. Color sensation and sensibility of four different fabric stimuli coloring red purple by a microbial prodiginine colorant produced from Zooshikella sp. were subjectively evaluated by university students. The color sensibility for the naturally dyed fabrics was classified into four factors: 'pleasantness', 'gracefulness', 'characteristic' and 'relax'. Color sensibility factor 'pleasantness' was the dominant factor for the naturally dyed fabrics with microbial prodiginine colorant. All color sensibility factors showed a significant correlations with the color sensation and colorimetric properties of the dyed fabrics with prodiginine. There were showed significant relationships between the color sensibility factors and lightness $L^{\ast}$, color saturation $C^{\ast}$, $a^{\ast}$ and $b^{\ast}$. Also, color preference of the dyed fabrics with prodiginine was found to be influenced mainly by color sensibility factors.

• Textile Coloration and Finishing
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• v.23 no.3
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• pp.179-186
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• 2011

For the application of Jeju scoria scattered around the island as a natural dye, cotton fabrics were dyed with the dye and their properties were measured including dyeability, colorfastness, antibacterial activity, deodorization efficiency, ultraviolet protection, and far-infrared emission. The dyed cotton fabrics were in yellowish red and optimal dyeing conditions were obtained with a colorant concentration of 25%(o.w.b) at a temperature of $80^{\circ}C$ for the dyeing time of 120 minutes. The ratings of colorfastness to light, rubbing, perspiration, and washing were 8, 5, 5, and 4~5 respectively. After 15 wash cycles, colorfastness remained as much as 4~5 rating. The cotton fabric dyed with Jeju scoria demonstrated excellent antimicrobial activity and deodorization efficiency of 99.9% and 93.9% respectively. Ultraviolet protection factor was 50+. Far-infrared emission rate and far-infrared emission intensity were 90% and 362(W/$m^2{\cdot}{\mu}m$) respectively. The Jeju scoria can be introduced as a new colorant for the natural dyeing of cotton.

• Textile Coloration and Finishing
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• v.32 no.2
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• pp.89-95
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• 2020

In this study, the efficacy of Amaranth(Amaranthus spp. L.) as a natural dye resource was investigated for wool fabrics. It is known that a large amount of flavonoid and anthocyanin colorant are contained in leaves and stems, as well as red flowers. The optimum condition of dyeing was 1.3% of dye concentration(o.w.b.) at 100℃ for 60 minutes, resulting the K/S value, 23.43 and R Munsell color on the wool fabrics. Al, Fe, Zinc and Titanium were used as a mordant. The mordant improved the dye uptake, regardless of the mordant type and mordant method. The pre-mordanting method was more effective than the post-mordanting method. Al pre-mordanted fabric showed the highest K/S, 30.02. Light fastness and washing fastness were high in grades 4-5 and 5, and rubbing fastness was good in grades 4 and 4-5 in dry condition, but low in grades 2-3 and 3 in wet condition. The dry cleaning fastness was excellent in all 5 grades. However, the alkaline perspiration fastness ratings were low in grades 2-3 and 3. The results show Amaranthus spp. L. colorant can be used as a functional natural dye for wool fabrics.

• Food Science and Preservation
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• v.7 no.3
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• pp.285-290
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• 2000

Color values of anthocyanins from seven natural food colorants, such as purple-fleshed sweet potato (PSP), red flower cabbage (RFC), red cabbage (RC), grape skin (GS), black rice (BR), egg plant (EP), and fig fruit (FF) were evaluated, resulting in the selection of four color sources with higher color values including PSP, RFC, RC and GS. The stabilities of anthocyanins from the selected colorant sources against metal ions, ascorbic acid, ultra-violet light, and heating were investigated. Anthocyanins from PSP and GS were degraded significantly by $Mn^{2+}$, while those from RFC and RC were degraded by $Cu^{2+}$. Asthocyanins from PSP were the most stable against the color-degrading factors, followed by RFC, RC, and GS in descending order.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.716-721
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• 1999

It has been known that continuous cultivation of hairy root is difficult to maintain for a long period of time compared to the microbial and callus cultures. Chemostat cultivation was successfully carried out in order to economically produce a plant-based colorant, betacyanin, from red beet hairy root for more than 85 days in a 14-1 fermentor. The result from the chemostat cultivation was compared to those of the batch and fed-batch cultivations of red beet hairy roots. It was shown that hairy root reached its steady state within 50 days of the cultivation, and then maintained for about 25-30 days in a wide range of dilution rates. Total betacyanin production from the continuous process was also calculated to be 2.65g at 0.28(l/d) of dilution rate, compared to 0.196g from fed-batch cultivation. It was found that betacyanin production was a partially growth related process, yielding 0.376 mg/g-fresh wt. cell and $1.89{\times}10^{-5}$ mg/g-fresh wt. cell/d, with 0.92 of correlation factor in a partial growth-product model. It was also shown that the cell growth required was relatively large for maintenance amount of energy at a low dilution rate. The growth of hairy root was inhibited by high light intensity in following a photo-inhibition model. The growth parameters were estimated to be 0.3(l/d), $10.56kcal/\textrm{m}^2/h$,{\;}and{\;}35.81kcal/\textrm{m}^2/h$ for the maximum specific growth rate, half saturation light intensity, and inhibition light intensity, respectively.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.149-152
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• 2001

Extraction characteristics of anthocyanin pigment from red flower cabbage(Brassica oleracea L. var. acephala) as a new source of natural food colorant were investigated. The pigment extracted from red flower cabbage showed the characteristic bathochromic shift of the maximum wavelength of light absorption(${\lambda}_{max}$) as pH of the solution changed from pH 1 to 12. As the concentration of citric acid in the extraction solvent increased, extraction rate and total optical density(TOD) of the extract increased. Maximum TOD was obtained by using the extracting solvent including $0.8{\sim}1.0%$ citric acid and stable pigment solution was obtained by using the extracting solvent including $10{\sim}20%$ ethanol in distilled water. As a result, 10% ethanolic solution with 0.8% citric acid was decided as the optimum extraction solvent for the anthocyanin pigment from red flower cabbage. Within the experimental ranges, the extraction rate increased and therefore extraction time decreased as the extraction temperature increased. The times to reach a certain value of TOD i.e., 2.1 were 24, 8, 4 and 2 hours at extraction temperature of 5, 20, 40 and $60^{\circ}C$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.4
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• pp.453-457
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• 2007

The physicochemical properties of red beets and the stability of betalain pigments irradiated at 2.5, 5, 10 and 30 kGy were evaluated. Betalain extraction yield of irradiated red beets was not significantly different from non-irradiated red beet. The red beet irradiated at 5kGy showed high optical density value in betacyanin and betaxanthin. In Hunter's color value lightness (L), redness (a) and yellowness (b) decreased with increment of irradiation dose. All red beets showed no difference in pH. The red beets irradiated above 10 kGy had poor textural property quality but antioxidant activity of betalain was not significantly changed by gamma irradiation. Considering natural colorant and textural quality, the gamma irradiation above 10kGy was an undesirable technique for red beets.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1309-1314
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• 2004

The red carotenoid, astaxanthin was studied to improve the meat quality of broiler chickens. Astaxanthin pigmented chickens and delayed oxidation of lipid in them. Two sources of astaxanthin were used to pigment broiler chickens in a five-wk feeding trial: biological astaxanthin (BA) from the red yeast, Xanthophyllomyces dendrorhous, and chemical astaxanthin (CA) from chemical synthesis. The concentrations of CA (45 mg/kg feed) and BA (22.5 mg/kg feed) were set to give similar levels of pigmentation. The colorimetric values (a and b) of breast muscles were significantly changed by astaxanthin (p${\leq}$0.01). Absorption and accumulation of BA were higher than those of CA, probably due to the high contents of lipids in the yeast (17%). Lipid peroxide formation in skin was significantly decreased by astaxanthin (p${\leq}$0.05). This result indicated that the production of lipid peroxides in the carcasses of broiler chickens during storage could be delayed by astaxanthin. Therefore, astaxanthin could be used as an antioxidant as well as a colorant for broiler chickens.