• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.209-214
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• 2012

Indigo crop, Persicaria tinctoria H. Gross is an annual plant containing natural colorant, the blue dye indigo, and local cultivars had been cultivated to produce natural indigo for textile dyeing in Korea since ancient times. Naju No. 2 is a new mass-selected line from the mother population, Naju Local cultivar. In this study, two breeding lines of Naju Local and Naju No. 2, have been cultivated in four different locations, the South regions of Korea, to compare plant growth and yield characteristics between two lines. Naju No. 2 was higher in plant height, and Naju Local has more 1st branches. Naju No. 2 has larger leaf area and higher width/length ratio of leaf, showing the round leaf type as morphological stable character without regional differences. Though there was considerable regional variation in fresh and dry top weight of harvested plant, the significant difference of plant weight between two lines were not shown. The ratio of leaf to total shoot of dry weight of Naju No. 2 was higher than one of Naju Local, indicating that Naju No. 2 has better yielding of colorant which is synthesized mostly in leaf. Naju No. 2 contained more Niram (crude indigo extract) and indigo, and showed much blueness at dyeing of silk using fresh leaves than Naju Local. We concluded that a new line, Naju No. 2 could be a superior cultivar due to having higher leaf yield and better quality of natural colorant than Naju local cultivar.

• Textile Coloration and Finishing
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• v.28 no.1
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• pp.1-13
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• 2016

Natural colorant extracts were obtained by extraction from tumeric root, gardenia seeds, mugwort and green tea using water, methanol, ethanol and acetone as extractants at room temperature for 3 hours under shaking condition(180rpm) with liquor ratio(solid:solvent; 1:100). The main pigment components of tumeric root, gardenia seeds, mugwort and green tea are known to be curcumin, crocin, chlorophyll b and epigallocatechin gallate, respectively. The effects of the kind of extractant and pH on the color characteristics of natural colorant extracts were investigated. The solubility parameters of pigment components were determined to find adequate extractant. The solubility parameters of curcumin, crocin, chlorophyll b and epigallocatechin gallate were found to be 27.85, 29.40, 19.48 and $37.97(J/cm^3)^{1/2}$. As expected, solvents that have a solubility parameter similar to that of pigment component were generally found to be effective to obtain pigment extracts having high visible absorbance(A). The extract(pigment/solvent) with high visible absorbance was generally found to have low $L^*$(lightness) and high Chroma($C^*$, purity).

• Food Science of Animal Resources
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• v.34 no.4
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• pp.472-481
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• 2014

The purpose of this study was to assess red beet as a natural colorant in emulsified pork sausage and to investigate the effect of red beet on quality characteristics of emulsified pork sausage during 20 d of cold storage. Red beet was prepared as a powder and a substitute with sodium nitrite at 0.5% and 1.0% levels in emulsified pork sausage. Red beet significantly increased the moisture content and pH (p<0.0001) and affected color traits. Lightness of emulsified pork sausage decreased by the addition of red beet powder (p<0.01), whereas lightness with red beet treatments slightly increased during 20 d of cold storage at $4^{\circ}C$ (p<0.05). Redness dramatically increased with red beet powder (p<0.0001). Color by sensory evaluation also showed a significant effect from red beet addition (p<0.05), whereas the other sensory properties such as flavor, tenderness, juiciness, and overall acceptability were not affected by the addition of red beet powder (p>0.05). Texture and 2-thiobabituric acid reactive substance were also not affected by red beet addition (p>0.05). Therefore, red beet could be a good natural colorant in emulsified pork sausage but it needs additional processing, such as betalain concentration and extraction as a juice, to be used as an antioxidant in meat products.

• Journal of Environmental Science International
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• v.20 no.7
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• pp.899-905
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• 2011

In order to develop bacterial cellulose (BC) with antimicrobial activity against pathogenic microorganisms, silver and chitosan were incorporated into BC, respectively. Experiment results showed that antimicrobial activity against pathogenic microorganisms was improved with increasing silver concentration. Chitosan also showed a direct proportion between its concentration and antimicrobial activity. These results suggest that antimicrobial effects of BC using silver and chitosan are well proven to be effective. We also tested the stainability of BC with natural colorant for the application of food industry. Stainability of BC was enhanced with increasing natural colorant concentration. Decolorization of BC stained was observed by dipping it into distilled water with one hour-intervals. As a result, there was no significant difference. Combination of natural colorant-stainability and antibiosis of BC is expected to be useful in making colored antibiotic BC in various industrial application areas, considering its antimicrobial activity, high stainability and low decolorization tendency.

• Fashion & Textile Research Journal
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• v.8 no.4
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• pp.465-470
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• 2006

Walnut hull is a by-product from the Walnut tree, used as natural dyestuff from ancient times. This study was done to examine the effects of extractive conditions on the properties of walnut hull extracts for making efficient use of the walnut hull as a natural colorant. Aqueous extracts of walnut hull were prepared at various extractive concentration, temperature and time. Then they were characterized using UV-Vis. Spectrophotometer, FT-IR Spectrometer, Prep Liquid Chromatography, and Energy dispersive X-ray spectrometer. The aqueous extracts have two absorbency peaks of UV-Vis. Spectrum, shoulder type peak in the range of 270-280 nm and broad type band around 420 nm. Intensity of absorbency is increased with increase of extraction concentration and time. However, Boiling temperature extraction method showed the most efficiency of all. Intensity of absorbency is also affected by extraction pH. The Prep LC examined two kinds of isolated colorant with different molecular weight. FT-IR spectra of hull extracts showed an absorption band around $3400cm^{-1}$, the peaks at $1700-1600cm^{-1}$, which are characteristic of aromatic compounds with unsaturated ketone and benzene ring. It showed that the extraction contained some mineral ions, such as K, Ca, Si, Mg.

• Textile Coloration and Finishing
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• v.27 no.2
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• pp.142-148
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• 2015

The aim of this study was to investigate the possibility utilizing Metasequoia(Metasequoia glyptostroboides) cone as a new natural dye resource. Dyeing onto cotton fiber was carried out to study the effect of dyeing conditions and mordanting effect on dye uptake, color change, and colorfastness. FT-IR analysis supported that hydrolyzable tannins were contained in the extracted colorant. Metasequoia cone colorant showed low affinity to cotton fiber and maximum dye uptake was obtained at pH 3.5 showing YR Munsell color. Mordanting improved dye uptake regardless of mordant type, especially Fe($C_5H_{10}FeO_6$) mordant was effective as much as 2 times higher dye uptake comparing with un-mordanted sample. The color of dyed fabric with mordanting showed YR Munsell color except of the Fe($FeSO_4{\cdot}7H_2O$) mordanted sample showing Y Munsell color. Colorfastness to rubbing and washing was relatively good, whereas lightfastness of the dyed fabrics was above grade 3/4 except that the dyed samples with Fe mordanting showed grade 2. It is necessary to apply Metasequoia cone colorant onto other fibers, especially protein fibers, for evaluating its efficacy as a new natural dye resource.

• Textile Coloration and Finishing
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• v.11 no.2
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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.

• Textile Coloration and Finishing
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• v.22 no.4
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• pp.314-324
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• 2010

The purpose of this study is to obtain the dyed-fabrics of the elaborate patterns using the natural dye powders extracted from Galla Rhois, Sophorae Flos Immaturus, Clove, Sappan Wood, Madder, Log Wood and Japanese Green Alder. Specific informations on the separation and powder-making of each colorant were disclosed. Appropriate printing paste preparation and printing conditions including the viscosity and mordant concentration in the printing paste were investigated. The dyeability and colorfastness of the screen-printed silk fabrics with the colorant powders were discussed in terms of practical applicability. The deodorization and antimicrobial activities of the silk fabrics screen-printed with natural dyes were also assessed.

• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.9-15
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• 2010

Extraction Efficiency of colorants from sorghum and its storage stability were examined according to the various extracting and storage conditions in this study. The obtained results were as follows ; The absorbance values of extracted colorants were increased with increasing extract time and temperature. The extraction at pH 4 extract was most efficient among the various pH conditions. In the juice extractor system, the amount of extracted colorant was more in distilled water pre-treatment than pH 5, but it was more in pH 5 in the long time pre-treatment above 20 hour. The color of extract solutions changed through variation of the pH. Its color changed from light yellow to heavy yellow finally red ton by pH increasing. The Methionine addition gave an effect on the storage stability of colorant solution and then had better storage stability. And so it delayed the color change up to storge period 18th day and the stabilizing effect was revealed in order of Methionine 10mmol-addition>20mmol-addtion>non-addtion.

• Fashion & Textile Research Journal
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• v.5 no.4
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• pp.399-407
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• 2003

The natural dyeing of silk fabric with Purple-Fleshed Sweet Potato (PSP) was investigated. The colorant was extracted with distilled water, and the color difference (${\Delta}E^*$) was increased with increasing the amount of PSP in extraction. The proper temperature and time for the extracting of colorant with PSP were $60^{\circ}C$ and 60 minutes. The optimum temperature, time and pH for the dyeing of silk with extracted PSP were $60^{\circ}C$, 60 minutes and pH 4 respectively. In various mordanted methods, the color difference values of post-mordanted silk fabric were higher than those of pre- and simultaneous-mordanted method. And the wide range of colors( GY, Y, YR, R, RP) were obtained according to various mordants, mordanting methods and mordant concentrations. Light colorfastness of the mordanted silk fabric was improved. Laundering colorfastness, dry cleaning colorfastness and perspiration colorfastness were shown to be good.