• 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.

• Korean Journal of Human Ecology
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• v.11 no.4
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• pp.391-400
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• 2002

This study was intended to research the dyeing with natural walnut hull extracts over cotton, flax, rayon, wool, nylon and silk. We studied the dyeing conditions and mordant effect, and observed dyeability. The result are as follows: 1. In the dyeability with natural walnut hull extracts, protein and polyamide fiber has more dye uptake rather than cellulose fiber. 2. The optimum condition in the dyeing with natural walnut hull extracts was at $90^{\circ}C$, 12%(o.w.b) concentration in 90 mins. 3. In the case of the dyeability by repeated dyeing number, the dyeability of good dyeability fiber is improved in the first or second dyeing, but that of bad dyebality fiber is improved when it is dyed more repeatedly. 4. In the dyeablity treated with mordants, Al, Sn, and Mg don't have any differences, but Cu and Fe have some difference. The color of Fe mordant is green and the color of Cu mordant is blue. 5. In the case of the color fastness with mordant treatment, nylon is better than silk and wool in color fastness to washing but silk is better than nylon and wool in color fastness to light.

• Korean Journal of Pharmacognosy
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• v.29 no.1
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• pp.28-34
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• 1998

It has been known that diseases related with aging or cancer result, at least in part, from free radicals, and antioxidants may reduce or prevent the abnormalities associated with free radical formation via its scavenging action. Thus, this study was carried out to investigate the antioxidative and antimicrobial activities of nut species for the purpose of developing antioxidant from natural products. Antioxidant activities of four kinds of nuts such as chestnut, groundnut, walnut and acorn were examined by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The extracts from chestnut hull and acorn barnyard millet showed strong antioxidative activities among 10 samples tested. Because of their highest antioxidative activity among 10 samples, radical scavenging effects of 4 different extract compartments (Hexane, EtOAc, BuOH and $H_2O$ extracts) from chestnut hull and acorn barnyard millet, were further examined by DPPH method. EtOAc and BuOH extracts exhibited antioxidative activities similar to those of natural, tocopherol or synthetic antioxidants, BHA. These findings demonstrates that major fraction of the antioxidative activity of chestnut hull or acorn barnyard millet was the EtOAc and BuOH extract compartments. However, antimicrobial activities against food-related bacteria and yeasts was relatively weak.