• The Research Journal of the Costume Culture
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• v.20 no.4
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• pp.463-474
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• 2012

The purpose of this research was to find the suitable dyeing method for dyeing cotton fabric into indigo blue color using the raw indigo powder dyes sold in the Korean market. The research focused primarily on the comparison of the non-reduced dyeing method and the reduced dyeing method. The dyeing effects using different dyeing temperatures ($2{\sim}80^{\circ}C$) and different concentrations of reducing agent and alkali were also investigated. It was found that the reduced dyeing method must be used for dyeing cotton into indigo blue color using the commercial raw indigo powder dyes. The best result was obtained by $20^{\circ}C$ dyeing with the $40^{\circ}C$ dyeing giving a comparable result. The intensity of the blue color could be enhanced by increasing the alkali concentration. The non-reduced dyeing could not dye cotton fabric into indigo blue color at any given dyeing temperatures ($2{\sim}80^{\circ}C$). The reduce-dyed cotton fabrics showed a gradual color change upon repeated washing and extended sunlight exposure, the most color change occurring after the first two washing cycles and the first 5 hours of sunlight exposure. The standard tests of colorfastness showed that the reduce-dyed cotton fabrics had good to excellent colorfastness whereas the colorfastness of the non-reduce-dyed cotton fabrics were mostly poor.

• Food Science and Industry
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• v.55 no.1
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• pp.23-32
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• 2022

Processed foods using food additives designated as the other countries but not yet in Korea can be mixed and distributed among imported foods in Korea. Accordingly, it is necessary to develop an analysis method of undesignated food additives in order to continuously monitor. This paper introduced a study on the development and validation of analytical methods conducted in academia. The development of analytical methods was conducted using the analytical methods presented in previous studies. We first exhibited that simultaneous analysis of 12 food dyes was easy to reproduce, but the second introduced analytical method of emulsifiers cannot be utilized analysis using expensive equipment not provided in general laboratories, and it is difficult to reproduce due to the old publications. Therefore related national institutions, research and industry-academia circles need to constantly conduct research on the development of analytical methods for undesignated food additives.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.6
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• pp.929-941
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• 2014

Dyeability of Indian natural dyestuffs to fabrics was investigated. Indian dyestuffs are more inexpensive than domestic dyestuffs purchased at oriental medicine stores. We studied the dyeability of madder, marigold, and pomegranate imported from India on cotton, silk, and wool fabrics. Dyebaths of a combination ratio of 80:20, 60:40, 50:50, 40:60 and 20:80 of madder and marigold, fabrics with orange colors were dyed. To evaluate the dyeability of dyed fabrics, K/S values, Munsell color values and CIE L, a, b, ${\Delta}E$ were measured. The dyeability of fabrics dyed in dyebaths of pH 4 and pH 7 were higher than pH 10. The dyeability in pH 4 was better than pH 7. Silk fabrics dyed with madder and marigold showed good dyeability and wool fabrics showed good affinity in madder dyebath and fair affinity in marigold dyebath. Cotton fabrics showed fair affinity in a marigold dyebath of pH 4 and pH 7. Cotton fabrics dyed with a 60:40 ratio of madder and marigold showed 4.76YR of Munsell color value. Silk Fabrics dyed with a 40:60 ratio showed 4.76YR and wool fabrics dyed with 20:80 ratio showed 5.57RY. The ratios produced the closest colors to 5.0YR of orange. This result indicated that marigold had a more powerful effect on cotton fabrics while madder was stronger on wool fabrics. Fading grades of washing colorfastness of wool and silk fabrics dyed in mixed dyebaths were higher than 3.5-4.0 and higher than homogeneous dyebaths. Staining grades of washing colorfastness of all dyed fabrics were between grades 3.5-5.0. Colorfastness to dry-cleaning was high as grades 4.0-5.0 in all of dyed fabrics. Colorfastness to light of dyed fabrics showed a fair grade of 3.5-5.0; in addition, wool fabrics showed lower grades than silk and cotton fabrics.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.977-983
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• 2002

This study was performed to establish the precise and rapid method to distinguish croakers through the pigment analysis of colored imported white croakers for adultration. We surveyed the coloring behaviors, extraction test by water and organic solvent and using pigments such as targeting, curcumine, and azo dye products. The pigment of yellow croaker is not stained on wet cloth or tissue which is rubbed on epidermis of yellow croaker and was not eluted in water extraction test, while adulterated pigments were easily extracted by water and acetone, but edible diluted yellow, Yellow No. 4 and Yellow No. 5 were not extracted. Reactive pigment was detected easily by extraction with water and dispersed pigment was also detected by extraction test. As a result of discoloring characteristics of carotene having similar structure to yellow croaker and azo dye by oxidation and reduction, azo dyes were not discolored by oxidation with sodium percarbonate or peracetic acid but that were discolored by oxidation with Fenton reagent after 1hr and by hypochlorite promptly. On the other hand, carotenes were not discolored by sodium precarbonate and Fenton reagent but discolored by sodium hypochlorite after 2 hr and by peracetic acid promptly. Azo dyes were discolored by reduction with sodium hydrosulfite and sodium carbonate but carotenes were not discolored by these reagents. This discoloring test was applicable to detect adulterated pigments and other marine product.