| In recent decades, an increasing tendency has been developed towards the use ofnatural pigments instead of the synthetic ones, and more and more potential sideeffects to human health have been reported for the use on synthetic pigments. Incomparison to synthesis pigments, natural pigments have drawn much attention totheir benefits for human health and no harm to environment. Walnut green huskpigment is a kind of natural plant pigment, which had been used to dye hair for a longtime. In this papers, the analysis of main active ingredient both qualitative andquantitative on walnut green husk were studied. The extraction and separationtechnologies for walnut green husk pigment were optimized. As more, the stability ofpigment and its application in wool dyeing and its dyeing properties and functionswere also investigated. The main works are as follows:Firstly, soxhlet method was used to extract crude fat from walnut green husk andthe content of crude fat is1.41%±0.13%, and its composition and relation contentswere analyzed by GC-MS combining with the standard spectrum library.48compounds were identified and their relative concentrations were accounted for94.85%of the total components. Alkanes, Alcohols, Ketones, Esters, Carboxylic acidswere the main compositions and9-hexacosene (2.63%), hentriacontane(8.61%),Pentatriacontane (8.42%), Phytol (5.07%), isosclerone (19.3%), n-hexadecanoic acid(6.86%) and (Z,Z)-9,12-Octadecadienoic acid (6.17%) were higher than others. Theresults on a systematic pre-experiment both aqueous extract and50%ethanol extractfrom walnut green husk showed that tannins, quinones, flavonoids and its glycosideswere main components, but no alkaloids, proteins, cardiac glycosides were detected.The mineral elements was analyzed by using ICP-MS, and the results indicated that walnut green husk has rich nutritional elements of K, Na, Mg, Fe,etc with content upto199.45±16.24mg/kg,24.46±0.63mg/kg,0.63±3.59mg/kg, and107.38±10.92mg/kg, respectively. High iron content in hair dyes can improve the generation of dandruff.Secondly, the extraction technologies were investigated by using extractiveefficiency of anthraquinones pigments in walnut green husk. The results demonstratedthat colorimetric method has high recoveries (90.44%~103.52%), with good stabilityand reproducibility. The linearity with correlation coefficient (R2=0.9997) was foundwithin the range from0.00416mg/mL to0.0250mg/mL. The highest pigmentextraction rate can be obtained when solid-liquid ratio is1:30(g/mL), ultrasonic time30min, extraction temperature60℃and ethanol concentration50%. In this condition,the extraction yield of anthraquinones pigments can reach as high as2.67±0.02(mg/g).Furthermore, the results also displayed that the metallic ions of K+, Na+, Mg2+, Ca2+and Zn2+have no apparent effect on pigment stability, and Fe3+has hyperchromiceffect significantly. The pigment has good stability below80degrees. In conclusion,the walnut green husk pigment was a kind of pigment with good light resistance, goodresistance to oxidation and reduction ability, have certain ability of withstand hightemperatures.Finally, it was investigated that dyeing technology and dyeing behaviour ofwalnut green husk extract on wool dyeing based on the value of k/s (on behalf ofdyeing depth) and L*(on behalf of dyeing brightness). The results showed that dyeingpost-mordant method should be adopted, and the optimized conditions were obtainedby combining single factor test and orthogonal design methods, namely60℃, dyeingtime2.5h, dye bath pH=4, the best dosage of mordant is5.0g/100mL. In thiscondition, the maximum k/s value and the minimum L*value were observed and thedyeing color rate was the highest. In addition, dyed wool using above the methodexhibited a best stability on light, and also a good stability for water washing, soapingwashing and picking. |
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