• 한국염색가공학회지
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• 제34권2호
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• pp.77-92
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• 2022

Natural colorants are regarded as substitutes for synthetic colorants in the fields of fiber dyeing, hair dyeing, cosmetic, and food industries. The use of natural colorants has been increased in view of global environment and sustainability. However, scientific approach to the production is required because the supply of natural colorants depends on the climate, soil, and cultivation methods. This brief review contains the advances in science and technology related to natural colorants including characterization, analysis, CIEL^*a^*b^* and Munsell color systems, and future prospects. For the characterization and the analysis of natural colorants, chromatography, some spectroscopic techniques (UV-Vis, FT-IR, NMR), mass spectrometry, and X-ray diffraction are generally used.

• 한국염색가공학회지
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• 제11권2호
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• pp.38-45
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• 1999

Natural red colorants were extracted from Phytolacca americana Linne by using 50% ethanol solution at room temperature for 12 hours. The colorant components were partially purified as yellow and deep red colorants by thin layer chromatography. Natural red colorants were consisted of major water-soluble red colorant, having maximum absorbance at 538nm and alcohol-soluble yellow colorant, having maximum absorbance at 664nm. Concentration of red colorants were calibrated by the equation of dye(mg/ml) $A_{538nm}\times{1.284}$. Red colorants were changed to yellow at extreme alkali pH and repaired 55% color intensity by neutralization of pH and stabled below $55^\circ{C}$. Dyeability of red colorants against wool fabrics was mainly operated by red pigment having 538nm absorbance without big color differences. Below $55^\circ{C}$, color differences $(\Delta{E}^*_{ab})$ were not changed in spite of big difference of chroma$(c^*)$, having higher scores at higher temperature. The effect of mordants were not drastically changed parameters of color difference without copper ion. Citric acid was big changes of color difference$(\Delta{E}^*_{ab})$ in spite of similar chroma$(c^*)$ values. From these experimental results, red colorants from Phytolacca americana Linne is available for wool fabric dyeing.

• Journal of Microbiology and Biotechnology
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• 제23권6호
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• pp.802-810
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• 2013

This work aims at investigating the production of yellow, orange, and red natural colorants in a submerged culture of Penicillium purpurogenum DPUA 1275. For this purpose, different experimental conditions evaluating the effect of incubation time, type and size of inoculum, and different carbon and nitrogen sources were performed. Furthermore, the growth kinetics were obtained in the conditions of $10^8$ spores/ml and 5 mycelia agar discs during 360 h. These experiments showed that 5 mycelia agar discs and 336 h promoted the highest yellow (3.08 $UA_{400nm}$), orange (1.44 $UA_{470nm}$), and red (2.27 $UA_{490nm}$) colorants production. Moreover, sucrose and yeast extract were the most suitable carbon and nitrogen sources for natural colorants production. Thus, the present study shows a new source of natural colorants, which can be used as an alternative to others available in the market after toxicological studies.

• 한국의류산업학회지
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• 제15권1호
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• pp.138-146
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• 2013

Chemical compositions and biological functions of brown colorants extracted from pine bark(Pinus densiflora) have been studied. Dyeing test using multifiber fabrics with extracted colorants were preliminary carried out. Dyeing conditions and fastness tests of selected fabrics have been also studied. The brown colorants were produced 1.5% concentrations by solvent extraction from milled pine bark using methanol. The colorants were extracted with 80% methanol as best choice by a criteria of solid quantity and dyeability on fabrics. The chemical compositions were identified as mixtures of taxifolin epicatechin and procyanidin by LC/MS analysis. The brown colorants could be dyed not only natural fibers such as cotton, silk and wool but also synthetic fiber as nylon and semi-synthetic fiber as viscose rayon. Maximum K/S values was shown at 400 nm according to different fiber with color appearance of redish brown. Optimum pH and temperature of dyeing conditions was 4 and above $80^{\circ}C$, respectively. The brown colorants had a strong antioxidant activity compared to Butylated hydroxyanisole as standard and weak antimicrobial activity against E. coli. compared to kanamycin. Washing, rubbing, perspiration, dry cleaning and light fastness for cotton, nylon and silk dyed with the brown colorants were carried out by KS K method. Most of color fastness such as washing, rubbing, perspiration, and dry cleaning were represented as 4-5 grade. However, light fastness was reported as 2-3 grade. From this studies, brown colorants produced pine bark have a high potentials for natural dyeing on fabrics with antioxidant activity.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2012년도 제46차 학술발표회
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• pp.122-122
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• 2012

The aims of this study were to examine the efficacy of phytochemical compounds of colorants as anti-oxidant agent. The bioactive properties of natural colorants were studied by total phenolic contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and anti-bacterial activity in Escherichial coli. The concentration ($IC_{50}$) of various extracts from colorants required to exert 50% reducing effect on DPPH radical were found to be 0.007-4 mg/ml. Especially, the gallnut (Schlectendalia Chinensis) displayed remarkable effect of DPPH as compared to positive control ascorbic acid. The total phenolic contents (TPC) and restraint of E coli. also analyzed. It was found that gallnut extracts effectively inhibited DPPH radical at a concentration below 0.01 mg/ml. Natural colorant extracts could be of good resources as anti-oxidant and anti-bacterial agents. The results suggest that our study may contribute to the development of natural and functional materials with potential application to reduce oxidative damage.

• 한국염색가공학회지
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• 제23권3호
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• pp.169-178
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• 2011

The purpose of this study is to develop eco-printing method using natural dyes combined with chitosan treatment to impart various pattern effect on cotton fabric. It was examined whether tone-on-tone pattern effects could be produced by screen printing with chitosan paste and subsequently dip-dyed in natural dye bath. For polychromic colorants, fabrics were pre-mordanted and then screen printed with chitosan, while only chitosan printing treatment was applied for monochromic colorants. Color, dye uptake, washing, light and rubbing fastnesses of printed fabrics were measured in relation to the presence of chitosan printing. Pre-mordanting and chitosan printing treatment were applied to such polychromic colorants as madder, sappanwood, onion and cochineal. Also, printing pattern formation on fabrics was evaluated by differences in dye uptake and color. The results suggested that madder, onion and cochineal were effective on pattern formation. Regarding sappanwood, since dye uptake was increased only by pre-mordanting without chitosan printing treatment, there was little color difference and thus patterns were not clearly distinguished. Chitosan printing treatment tended to increase washing, light and rubbing fastnesses of dyed fabrics with polychromic colorants. Chitosan printing treatment was applied to monochromic colorants such as chlorophyll, gardenia and indigo and the effect of printing formation was examined according to the difference in dye uptake. Among monochromic dyes tried, chlorophyll was effective and chitosan printing improved washing and light fastnesses.

• 한국의류산업학회지
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• 제6권2호
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• pp.239-244
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• 2004

On the whole the various medium colors were developed by repeat dyeing with different colorants after dyeing with one colorant in case of natural dyeing. In this study, in order to obtain various colors on wool fabrics with Gardenia and Sappan wood colorants, pre-mordanting and combination dyeing were carried out. Gardenia and Sappan wood used as natural colorants for combination dyeing showed good miscibility in dye bath, Metal compounds containing alum, copper and iron were used for pre-mordants. The various medium colors such as yellow-red were obtained according to various metal compounds for pre-mordants and various mixing portion of these natural colorants. The surface reflactance spectra and color characteristics of wool fabrics by mordanting and combination dyeing were investigated.

• 한국염색가공학회지
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• 제24권4호
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• pp.247-252
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• 2012

The objective of this study was to find an appropriate method and process for protecting the green color in bamboo leaves and subsequent extraction of the green colorants, chlorophyll. Various inorganic salts including cupric sulfate, ferric sulfate, and zinc chloride were employed as green color protectors. Accordingly, the effects of metal salts and treatment conditions on color protection were investigated to find appropriate protector and conditions. And also, the efficacy of bamboo colorants as a natural green dye was evaluated through dyeing and colorfastness tests. Antimicrobial activity of dyed fabrics was measured by shake flask method in terms of bacterial reduction rate using Staphylococcus aureus(ATCC 6538). On the basis of experimental results for stabilizing bamboo leaves colorants, it was confirmed that Cu was the most appropriate metal type considering dye uptake, photostability and light fastness, and its optimum concentration was 0.025%. After the stabilization, the colorants were extracted efficiently at NaOH aqueous solution of 1.00%. It was concluded that bamboo leave has a high potentiality as new resources to produce a natural green dye with antimicrobial functionality.

• 한국염색가공학회지
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• 제24권1호
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• pp.18-26
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• 2012

In this work, colorants extraction process from gromwell was studied for making powder form of colorants by solving the high viscosity problem of gromwell extracts. In order to do that, sugar extracted together with colorants must be pre-extracted. For sugar decomposition, gromwell roots were pretreated with various enzyme solutions. The total sugar content of pre-extract with enzyme solution was measured. Accordingly, the effects of enzyme type and pretreatment condition on sugar decomposition were investigated to find appropriate enzyme(amylase, hemicellulase, pectinase) and enzyme activity (100~1000unit), pre-extracted time(3~24hr). Color characteristics and dye uptake of dyed fabrics were evaluated. Gromwell colorants were assessed for their potential antimicrobial activities, which possibly expand their end use as functional pigments. The efficiency of removing sugar was increased in the order of hemicellulase, pectinase, amylase, $H_2O$. Gromwell colorants powder yield was in the range of 4.4% to 9.8% depending on pretreatment enzyme. Gromwell colorants produced RP color on the silk and wool fabrics with good dye uptake. Antimicrobial activity of gromwell colorants will greatly increase its potentiality for applying as functional natural colorants in the future.

• 한국염색가공학회지
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• 제19권6호
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• pp.12-20
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• 2007

Four kinds of natural dying solutions (natural colorant extracts)were obtained by extraction from sappan wood, black tea, peony, and clove using water as extracting solvent at $90^{\circ}C$ for 90 min with liquor ratio (solid natural colorant material/solvent water, weight ratio) of 1/10. The dyeing, colour fastness and deodorizing properties of fabrics (cotton, silk, and wool fabrics) dyed with natural colorant extracts were compared. It was found that these properties were significantly dependent on the concentration of extracts, the structure of colorant, and the kind of fabrics. The K/S value of dyed cotton fabric increased in the order of peony < sappan wood < clove < black tea, however, the values of dyed silk and wool fabrics were in the order of peony < sappan wood < black tea < clove. Colour fastness (light, water, and perspiration fastness) was in the range of 3 - 5 grade except for sappan wood. The deodorizing performance of fabrics dyed with various natural colorants extracts was in the range of 56 - 99%. The deodorizing performance increased in the order of peony < black tea < sappan wood < clove. Especially, the deodorizing performance of all fabrics dyed with clove was found to be the highest at 98-99%.