Identification Of Pigment From Naturally Brown Cotton And Performance Study Of Brown Cotton Fiber

Natural colored cotton is a kind of textile fiber with environmental friendly feature， whoseproducts are well received by consumers because of their wearing comfortable and safety.However, there are also some factors restrict their further development, such as color limitation,their color not bright enough and stable. Research on composition of colored cotton pigment, canprovide guidance for the processing and daily care of their products. In this paper natural browncotton was studied, analyzed the effect of alkali solution on the extraction efficiency andcomposition of natural brown cotton pigment, and determined the target product according to thepigment extraction ability with different ethanol content, then effectively isolated the targetproduct by C18reverse phase chromatography column and analyzed by ESI-MS, IR, UV-VIS.Finally, the inhibitions of free radicals of brown and white cotton fiber were tested.In this paper, the effect of alkali solution on the extraction efficiency and composition ofnatural brown cotton pigment is firstly studied. According to the alkali-soluble ability ofpolyphenols, with ultrasound-assisted extraction technology, we use different pH alkalinesolution for natural brown pigment extraction, analyzed extraction capacity and changes insubstances. Trough UV-VIS spectral scanning and analysis of the pigment component extractedby deionized water, the result shows the main ingredient of brown cotton fibers pigments is notflavonoid. Alkali solution has conditions favor of natural brown cotton pigment extraction, withhigher pH value, the extraction will be more complete and efficiency. HPLC chromatogramsshows pigment component of natural brown cotton are complicated, not a single component.Pigment composition varies with different pH value alkali extraction solution. With alkalineconditions some of the substances structures changed, but has no obvious effect on mainingredient of pigment.Different ethanol content extraction solution on the brown pigment extraction and cotton fibers extracted material differences are significant.100%ethanol has the worst extract ability,and not extracted the substances witch retention time is1.42min on HPLC chromatograms.Separate the pigment with DM101macroporous resins, polyamide column chromatography, C18reverse phase column chromatography and high performance liquid chromatography, the resultshows DM101macroporous resins has bad separate ability; polyamide column chromatographycan enrichment brown cotton pigment, but some substances are very difficult to elution, with thisway will waste a lot of pigment; C18reverse phase column chromatography has good separateability, the pigment consists of two part with larger differences in polarity for their differentcolors and HPLC chromatograms of elution segments. With preparative C18reverse phasecolumn chromatography separate many times, one colored pigment was got, this pigment is notflavonoids, condensed tannins and other categories according to the analysis of UV-VIS and IR.Through the ABTS+·and DPPH·scavenging activity test of brown and white cotton fiber,result shows natural brown cotton has radical scavenging capacity, this ability absolutely higherthan that with white cotton. And we also find the scavenging capacity can improved with somekinds of treatment, such as petroleum treatment, enzyme treatment. Within the limited number ofwashing, radical scavenging capacity of fiber also will be improved.